TWI446984B - Processing method for a workpiece, dividing method for a workpiece, and laser processing apparatus - Google Patents

Description

Processing method of workpiece, method of dividing workpiece, and laser processing apparatus

The present invention relates to a laser processing method for irradiating laser light to process a workpiece.

As a technique for processing a workpiece by irradiation of pulsed laser light (hereinafter also referred to simply as a laser processing or a laser processing technique), various techniques are known (for example, refer to Patent Document 1 to Patent Document 4).

The method disclosed in Patent Document 1 is a method of forming a groove (fracture groove) having a V-shaped cross section along a line to be divided by laser ablation when dividing a mold as a workpiece, and using the groove as a groove The starting point divides the mold. On the other hand, the method disclosed in Patent Document 2 is a method of irradiating laser light in a defocused state along a predetermined line of division of a workpiece (divided body), thereby generating a crystal state in the irradiated region. The cross section that is more collapsed around is a substantially V-shaped melt-modified region (metamorphic region), and the workpiece is divided by the lowest point of the melt-modified region.

When the division starting point is formed by the techniques disclosed in Patent Document 1 and Patent Document 2, in order to perform the subsequent division well, a V-shaped cross section having a uniform shape is formed along the direction of the dividing line in which the scanning direction of the laser light is written. Profiles or metamorphic zone profiles are important. In response to this, for example, the irradiation of the laser light is controlled such that the irradiated region (beam spot) of the laser light for each pulse is repeated before and after.

For example, when the repetition frequency (in kHz), which is the most basic parameter of laser processing, is set to R, and the scanning speed (unit: mm/sec) is set to V, the ratio V/R becomes the beam point. In the technique disclosed in Patent Document 1 and Patent Document 2, in order to overlap the beam spots, the laser beam is irradiated and scanned under conditions of V/R of 1 μm or less.

Further, Patent Document 3 discloses a method in which a laser beam is irradiated to the inside of a substrate having a laminated portion on the surface thereof to illuminate the laser beam, thereby forming a modified region in the substrate, and the modified region is The starting point of the cut.

Further, Patent Document 4 discloses a method in which a plurality of laser beams are repeatedly scanned for one separation line, and a groove portion and a reforming portion which are continuous in the direction of the separation line in the depth direction are formed. A sub-continuous internal reforming unit in the off-line direction.

On the other hand, Patent Document 5 discloses a state in which a laser beam processing technique using an ultrashort pulse having a pulse width of psec is used to adjust the position of a focused spot of the pulsed laser light to form a spot. From the surface layer portion of the workpiece (plate body) to the surface, a minute melting trace of minute cracks is formed, and a linear separation facilitating region in which the melting traces are connected is formed.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2004-9139

[Patent Document 2] International Publication No. 2006/062017

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2007-83309

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-98465

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2005-271563

The method of forming the starting point of the division by the laser light and then dividing it by the crusher is superior to the diamond scribing method as the mechanical cutting method performed in the prior art in terms of autonomy, high speed, stability, and high precision. advantageous.

However, when the formation of the division starting point using the laser light is performed by the prior method, so-called processing marks (laser processing marks) are inevitably formed in the portion irradiated with the laser light. The term "processing mark" refers to a metamorphic region in which the material or structure is changed before irradiation, as a result of irradiation with laser light. The formation of the processing marks usually adversely affects the characteristics and the like of the divided workpieces (segmented segments), and therefore it is preferable to suppress the formation of the processing marks as much as possible.

For example, an LED (Light Emitting Diode) is formed on a substrate including a hard brittle and optically transparent material such as sapphire by using the prior laser processing as disclosed in Patent Document 2. The workpiece to be processed such as a structure of a light-emitting element is divided into an edge portion of a light-emitting element obtained by a wafer unit (a portion irradiated with laser light at the time of division), and a width of about several μm and a depth of several μm to several tens of μm are continuously formed. Processing marks. This processing mark has a problem of absorbing light generated inside the light-emitting element and reducing the efficiency of light extraction from the element. In particular, this problem is remarkable when a light-emitting element structure of a sapphire substrate having a high refractive index is used.

As a result of repeated efforts by the inventors of the present invention, it has been found that when the workpiece is irradiated with laser light to form a starting point of the division, the cracking or cleavage of the workpiece is utilized, thereby preferably suppressing the processing. The formation of marks. In addition to this, a more appropriate insight into the use of ultrashort pulsed laser light in this process is obtained.

In Patent Document 1 to Patent Document 5, no disclosure or suggestion is made regarding the formation of the starting point of the division using the cracking or cleavage of the workpiece.

On the other hand, when the process of dividing the workpiece into the wafer unit after forming the division start point using the laser light is performed, it is preferable that the end portion before the division start point reaches the deepest portion of the workpiece. It is: the accuracy of segmentation is improved. This is also the case when using ultrashort pulsed laser light.

The present invention has been made in view of the above problems, and an object of the invention is to provide a method for processing a divided body which can suppress formation of a processing mark and can more accurately realize a division starting point of a workpiece, and realize the processing method Laser processing equipment.

In order to solve the above problems, the invention of claim 1 is a processing method for forming a starting point of a segment on a workpiece, comprising: a placing step of placing a workpiece on a platform; and a transparent substance disposing step, a transparent material transparent to the pulsed laser light used in the processing of the workpiece, disposed adjacent to the surface to be processed of the workpiece placed on the stage, and an irradiation step to cause the above The pulsed laser light is transmitted through the transparent material, and the irradiated region of each unit pulsed light is discretely formed on the surface to be processed, and the pulsed laser light is irradiated onto the workpiece, and the irradiated regions are sequentially arranged The cracking or cleavage of the workpiece is generated to form a starting point for division on the workpiece.

The invention of claim 2, wherein the pulsed laser light has a pulse width of ultrashort pulse light of a psec order.

The invention of claim 1 or 2, wherein the transparent substance disposing step is disposed adjacent to the transparent member which is substantially transparent solid with respect to the pulsed laser light used in the processing of the workpiece. a step of disposing a transparent member on a surface to be processed of the workpiece on the platform, wherein the pulsed laser light is transmitted through the transparent member and discretely on the surface to be processed in the irradiating step The pulsed laser light is irradiated onto the workpiece to form an irradiated region of the unit pulsed light, and the crack or cleavage of the workpiece is sequentially generated between the irradiated regions, thereby A starting point for segmentation is formed on the workpiece.

The invention of claim 3, wherein in the transparent member disposing step, the transparent member is placed in contact with the surface to be processed.

The invention of claim 3, wherein in the transparent member disposing step, the transparent member and the machined surface are disposed apart from each other by a distance of 100 μm or less.

The invention of claim 3, wherein in the transparent member disposing step, the transparent member is adjacent to a portion of the irradiated position including the pulsed laser light among the processed surface The configuration is such that the configuration position is migrated corresponding to the migration of the illuminated position.

The invention of claim 1 or 2, wherein the transparent substance disposing step is performed on a processed surface of the workpiece to be placed on the platform, by processing with respect to the workpiece a liquid layer forming step of forming a liquid layer by using a pulsed laser light used as a transparent liquid, wherein the pulsed laser light is transmitted through the liquid layer and discretely formed on the processed surface in the irradiating step Irradiating the pulsed laser light to the workpiece to be irradiated to the workpiece, and sequentially generating cracking or cleavage of the workpiece between the irradiated regions, thereby processing the above-mentioned workpiece A starting point for segmentation is formed on the object.

The invention of claim 7 is characterized in that in the liquid layer forming step, the workpiece is immersed in the inside of the storage tank formed on the platform at least during the irradiation step. In the liquid, the liquid layer is formed on the surface to be processed.

According to a seventh aspect of the invention, in the liquid layer forming step, the liquid is continuously or intermittently flowed during at least the irradiation step, whereby the processed surface is processed. A fluid layer is formed on the upper layer.

The invention of claim 10, wherein the processing method according to claim 1 or 2, wherein at least two of the unit pulse lights are formed in a manner that is adjacent to the workpiece in an easy splitting or splitting direction Irradiation area.

The invention of claim 1 or 2, wherein the source of the pulsed laser light is moved relative to the workpiece, and the outgoing direction of the pulsed laser light is perpendicular to the relative movement direction. The inner portion is periodically changed to form a plurality of the irradiated regions satisfying the zigzag arrangement relationship on the workpiece.

The invention of claim 1 or 2, wherein the plurality of output sources of the pulsed laser light are moved relative to the workpiece, and the unit pulse light from each of the plurality of output sources is The irradiation timing is periodically changed, thereby forming a plurality of the irradiated regions satisfying the zigzag arrangement relationship on the workpiece.

The invention of claim 13 is a method for dividing a workpiece, comprising: a placing step of placing a workpiece on a platform; and a transparent substance disposing step for use in processing the workpiece The pulsed laser light is a transparent transparent material disposed adjacent to the processed surface of the workpiece placed on the platform; and the irradiating step is such that the pulsed laser light passes through the transparent material and is processed as described above Irradiating the irradiated region of each unit pulsed light on the surface, the pulsed laser light is irradiated onto the workpiece, and the crack or cleavage of the workpiece is sequentially generated between the irradiated regions. A starting point for dividing is formed on the workpiece, and a dividing step is performed to divide the workpiece having the dividing starting point by the irradiation step along the dividing starting point.

The invention of claim 14 is a laser processing apparatus characterized by comprising: a light source that emits pulsed laser light; and a stage that mounts the workpiece; and further includes a workpiece to be used in processing relative to the workpiece The pulsed laser light is substantially a transparent transparent material disposed adjacent to the transparent material disposing mechanism on the processed surface of the workpiece placed on the platform, and the workpiece is placed on the platform. And moving the platform so that the transparent region is disposed adjacent to the surface to be processed, and the irradiated region of each unit pulse light of the pulsed laser light is discretely formed on the surface to be processed. The pulsed laser light is irradiated onto the workpiece, and cracking or cleavage of the workpiece is sequentially generated between the irradiated regions, whereby a starting point for division is formed on the workpiece.

The invention of claim 15 is the laser processing apparatus according to claim 14, wherein the pulsed laser light has an ultrashort pulse light having a pulse width of psec.

A laser processing apparatus according to claim 14 or 15, wherein said transparent substance disposing mechanism is a transparent member body which is substantially transparent solid with respect to pulsed laser light used in processing of said workpiece. a transparent member arranging mechanism disposed on the surface to be processed of the workpiece placed on the platform, wherein the workpiece is placed on the platform, and the transparent member is disposed adjacent to the processed portion In the state of the surface, the stage is moved such that the irradiated area of each unit pulse light of the pulsed laser light is discretely formed on the surface to be processed, and the pulsed laser light is irradiated onto the workpiece. Further, cracking or cleavage of the workpiece is sequentially generated between the irradiated regions, whereby a starting point for division is formed on the workpiece.

A laser processing apparatus according to claim 14 or 15, wherein said transparent substance disposing mechanism is disposed on a surface to be processed of said workpiece on said platform, by said object to be processed a liquid layer forming mechanism for forming a liquid layer by using a pulsed laser light for processing is a transparent liquid, and the workpiece is placed on the stage, and the liquid layer is formed on the surface to be processed. And moving the stage so that the irradiated area of each unit pulse light of the pulsed laser light is discretely formed on the surface to be processed, and irradiating the workpiece with the pulsed laser light. The object to be processed is sequentially cleaved or cleaved between the irradiated regions, whereby a starting point for division is formed on the workpiece.

The invention of claim 18, wherein the liquid layer forming mechanism comprises a cylindrical member, wherein the cylindrical member constitutes a storage tank disposed on the platform to store the liquid, and the storage tank is Inside, the workpiece is placed on the stage and immersed in the liquid to form the liquid layer on the surface to be processed.

The invention of claim 17 is the laser processing apparatus of claim 17, wherein the liquid layer forming mechanism has a storage tank having the platform as a bottom, and the workpiece is placed on the platform inside the storage tank. The liquid layer is formed on the surface to be processed by immersing in the liquid.

The invention of claim 18, wherein the liquid layer forming mechanism comprises a discharge mechanism, wherein the workpiece is placed on the platform in a state where the workpiece is placed on the platform The liquid is ejected, and the pulsed laser light is irradiated in a state in which the fluid layer is formed by the liquid ejected from the ejecting mechanism, whereby a starting point for the division is formed on the workpiece.

According to the invention of claim 1 to claim 20, the formation of the processing marks caused by the deterioration of the workpiece, the scattering of the workpiece, and the like are limited to a part, and on the other hand, the cracking or cleavage of the workpiece is positive. The ground is generated, whereby the starting point of the division of the workpiece can be formed at an extremely high speed compared to the prior art. Further, by arranging a transparent substance which is transparent to the pulsed laser light, the energy of the pulsed laser light can contribute more effectively to the formation of the division start point, so that the end portion before the division start point can be made deeper.

In particular, according to the inventions of claim 3 to claim 6 and claim 16, the formation of the processing marks caused by the deterioration of the workpiece or the scattering of the workpiece or the like is limited to a part, and on the other hand, the workpiece is processed. The cracking or cleavage is actively generated, whereby the starting point of the division of the workpiece can be formed at an extremely high speed compared to the prior art. Further, by arranging a transparent member which is transparent to the pulsed laser light, the energy of the pulsed laser light can contribute more effectively to the formation of the division starting point, so that the end portion before the division starting point can be made deeper.

In particular, according to the inventions of claim 7 to claim 9, and the inventions of claim 17 to claim 20, the formation of the processing marks caused by the deterioration of the workpiece or the scattering of the workpiece or the like is limited to a part, and on the other hand, The cracking or cleavage of the workpiece is actively generated, whereby the starting point of the workpiece can be formed at an extremely high speed compared to the prior art. Further, by arranging the liquid layer containing the liquid transparent to the pulsed laser light, the energy of the pulsed laser light can be more effectively contributed to the formation of the division starting point, so that the end portion before the division starting point can be made deeper.

In particular, according to the inventions of claim 9 and claim 20, even if the turbidity caused by the substance detached from the workpiece during processing causes a decrease in the transparency of the liquid layer, the new surface is quickly supplied to the surface to be processed. The transparent liquid is therefore preferably maintained during the processing.

In particular, according to the inventions of the eleventh aspect and the twelfth aspect, the vicinity of the surface of the workpiece as the divided cross section when the workpiece is divided along the formed division starting point can be formed to form adjacent cracking or cleavage. The manner in which the faces are generated by the unevenness of each other forms a starting point of the segmentation. When the workpiece is formed on a substrate including a light-emitting element structure such as an LED structure on a substrate including a hard-brittle and optically transparent material such as sapphire, the uneven shape can be improved by forming the uneven shape on the divided section of the substrate. The luminous efficiency of the light-emitting element.

<The principle of processing>

First, the principle of processing realized in the embodiment of the present invention shown below will be described. The processing performed in the present invention is a process in which pulsed laser light (hereinafter also referred to as laser light) is irradiated onto the upper surface (processed surface) of the workpiece while scanning, thereby Between the irradiated regions of the pulses, the cracking or cleavage of the workpiece is sequentially generated, and the starting point for the division (the starting point of the division) is formed as the continuous surface of the cracking surface or the cleavage plane formed in each of the irradiated regions. .

Further, in the present embodiment, the cleavage means a phenomenon in which the workpiece is substantially regularly split along the crystal plane other than the cracked surface, and the crystal plane is referred to as a cleavage plane. Further, in addition to the cracking or cleavage which is a phenomenon which is completely along the microscopic surface of the crystal face, there is also a case where the crack which is a macroscopic split occurs along a substantially fixed crystal orientation. Depending on the substance, there is also a case where only cracking, cleavage, or cracking is mainly caused, but the following is called splitting/solution in order to avoid cumbersome explanation, and not to distinguish between cracking, cleavage, and cracking. And so on. Further, the processing as described above may be simply referred to as cracking/cleavage processing or the like.

Hereinafter, a case where the workpiece is a hexagonal single crystal material, and the respective axial directions of the a1 axis, the a2 axis, and the a3 axis are easy to open/cleave directions will be described as an example. For example, a c-plane sapphire substrate or the like meets this requirement. The a1 axis, the a2 axis, and the a3 axis of the hexagonal crystal form an angle of 120° with respect to each other in the c-plane, and are in a position symmetrical with each other. In the processing of the present invention, there are several types depending on the relationship between the direction of the equiaxions and the direction of the planned line (the predetermined direction of processing). Hereinafter, the types will be described. Furthermore, the following laser light to be irradiated under each pulse is referred to as unit pulse light.

<1st processing type>

The first processing type is a split/split processing when any one of the a1 axis direction, the a2 axis direction, and the a3 axis direction is parallel to the planned line. More generally, the first processing type is a processing state in which the direction of the splitting/cracking direction coincides with the direction of the planned line.

Fig. 1 is a view schematically showing a processing aspect using a first processing type. In FIG. 1, the case where the a1 axis direction is parallel to the planned line L is exemplified. Fig. 1(a) is a view showing the azimuthal relationship between the a1 axis direction, the a2 axis direction, and the a3 axis direction and the planned line L in this case. Fig. 1(b) shows a state in which the unit pulse light of the first pulse of the laser light is irradiated onto the irradiated region RE1 at the end of the planned line L.

In general, the irradiation of the unit pulsed light gives a relatively high energy to the extremely small area of the workpiece, so that the irradiation makes the illuminated surface equivalent to or more irradiated with the irradiated area of the unit pulsed light (the laser light). Deterioration, melting, evaporation, etc. of substances occur in a wider area.

However, if the irradiation time of the unit pulse light, that is, the pulse width is set to be extremely short, the substance having a narrower spot size than the laser light is present in the substantially central region of the irradiated area RE1 to obtain kinetic energy from the irradiated laser light. In this way, it is scattered or deteriorated in a direction perpendicular to the surface to be illuminated, and on the other hand, an impact or stress generated by irradiation of the unit pulse light is applied to the irradiated area, such as a reaction force generated by the scattering. In particular, it acts on the a1 axis direction, the a2 axis direction, and the a3 axis direction which are easy to open/crack directions. Thereby, in this direction, slight cracking or cleavage occurs partially while maintaining the contact state, or a state of thermal strain is generated inside even if cracking or cleavage is not achieved. In other words, it can be said that the irradiation of the unit pulse light of the ultrashort pulse functions as a driving force for forming a weak portion which is substantially linear in a plan view in the easy-opening/cracking direction.

In FIG. 1(b), the weak intensity in the +a1 direction which coincides with the extending direction of the processing planned line L among the weak strength portions formed in the respective easy opening/dissecting directions is schematically indicated by a broken line arrow. Part W1.

Then, as shown in FIG. 1(c), when the unit pulse light of the second pulse of the laser light is irradiated onto the planned line L, the irradiated area RE2 is formed at a position only a certain distance from the irradiated area RE1. Then, the same as the first pulse, and the weak intensity portion along the easy opening/cracking direction is also formed under the second pulse. For example, the weak intensity portion W2a is formed in the -a1 direction, and the weak intensity portion W2b is formed in the +a1 direction.

However, at this timing, the weak intensity portion W1 formed by the irradiation of the unit pulse light of the first pulse exists in the extending direction of the weak intensity portion W2a. That is, the extending direction of the weak-strength portion W2a becomes a portion which can be cracked or cleaved by energy smaller than other portions. Therefore, in actuality, if the unit pulse light of the second pulse is irradiated, the impact or stress generated at this time propagates toward the easy-opening/cracking direction and the previously existing weak intensity portion, substantially at the moment of irradiation. The complete weakening or cleavage occurs from the weak strength portion W2a to the weak strength portion W1. Thereby, the crack/cleavage plane C1 shown in Fig. 1(d) is formed. Further, the cracking/cleavage plane C1 can be formed in a vertical direction in the pattern of the workpiece to a depth of several μm to several tens of μm. Further, as will be described later, as a result of receiving a strong impact or stress on the crack/cleavage surface C1, smoothness of the crystal surface occurs, and undulation occurs in the depth direction.

Further, as shown in FIG. 1(e), if the unit pulse light is sequentially irradiated to the irradiated areas RE1, RE2, RE3, RE4, ... by scanning the laser light along the planned line L, the corresponding unit pulse light is irradiated. The split/cleavage planes C2, C3, ... are formed in sequence. By this aspect, the splitting/cleaving process in the first processing type of the split/cleavage surface system is continuously formed.

In other words, in the first processing type, the plurality of irradiated regions discretely existing along the planned line L and the split/cleavage plane formed between the plurality of irradiated regions are integrated as a whole. The starting point of the division when the line L divides the workpiece. After the division start point is formed, division using a specific jig or device is performed, whereby the workpiece can be divided substantially in a state along the planned line L.

Furthermore, in order to realize such splitting/cracking processing, it is necessary to irradiate a short pulse of laser light having a short pulse width. Specifically, it is necessary to use laser light having a pulse width of 100 psec or less. For example, it is suitable to use laser light having a pulse width of about 1 psec to 50 psec.

On the other hand, the irradiation pitch of the unit pulse light (the center interval of the irradiation spot) may be set within a range of 4 μm to 50 μm. If the irradiation pitch is larger than the range, the formation of the weak strength portion in the easy splitting/cleaving direction does not progress to the extent that the cracking/cleavage plane can be formed, and thus the inclusion crack as described above is surely formed. The point of view of the starting point of the cleavage/cleavage plane is not good. Further, in terms of scanning speed, processing efficiency, and product quality, the larger the irradiation pitch, the better, but in order to form the cracking/cleavage surface more reliably, it is preferable to set it in the range of 4 μm to 30 μm. , 4 μm ~ 15 μm or so is more suitable.

At present, when the repetition frequency of the laser light is R (kHz), unit pulse light is emitted from the laser light source every 1/R (msec). When the laser light is relatively moved at a speed V (mm/sec) with respect to the workpiece, the irradiation pitch Δ (μm) is determined by Δ = V / R. Therefore, the scanning speed V of the laser light and the repetition frequency are set such that Δ is about several μm. For example, the scanning speed V is about 50 mm/sec to 3000 mm/sec, and the repetition frequency R is from 1 kHz to 200 kHz, and particularly suitable for about 10 kHz to 200 kHz. The specific value of V or R can be appropriately set in consideration of the material of the workpiece, the absorptivity, the thermal conductivity, the melting point, and the like.

The laser light is preferably irradiated with a beam diameter of about 1 μm to 10 μm. In this case, the peak power density in the irradiation of the laser light is approximately 0.1 TW/cm ² to several 10 TW/cm ² .

Further, the irradiation energy (pulse energy) of the laser light can be appropriately set in the range of 0.1 μJ to 50 μJ.

Fig. 2 is an optical microscope image of the surface of a workpiece having a division start point formed by splitting/cracking processing in the first processing type. Specifically, it is shown that the sapphire c-plane substrate is used as a workpiece, and the a1-axis direction is formed as an extending direction of the planned line L on the c-plane, and is formed by being separated by 7 μm. point. The results shown in Fig. 2 suggest that the actual workpiece is processed by the above mechanism.

3 is a SEM (Scanning Electron Microscope) of a sapphire c-plane substrate having a division starting point formed by the processing of the first processing type, which is divided along the division starting point from the surface (c surface) to the cross section. Microscope) like. Further, in Fig. 3, the boundary portion between the surface and the cross section is indicated by a broken line.

The elongated triangular or needle-shaped region which exists at approximately equal intervals in the range of about 10 μm from the surface as viewed in FIG. 3 and has a longitudinal direction from the surface of the workpiece to the inside is by unit A region in which a phenomenon such as deterioration or scattering is directly generated by irradiation of pulsed light (hereinafter referred to as a direct metamorphic region). Further, it is observed that the rib-shaped portions existing between the directly metamorphic regions and having the longitudinal direction in the left-right direction in the drawing are connected to the upper and lower portions in the sub-micron pitch in the upper and lower directions in the drawing. Crack/cleavage surface. The segmentation surface formed by the division is located below the direct metamorphic region and the split/cleavage plane.

Since the region in which the crack/cleavage plane is formed is not irradiated with the laser light, in the processing of the first processing type, only the directly deteriorated region formed discretely becomes a processing mark. Moreover, the size of the directly deteriorated region on the surface to be processed is only about several hundred nm to 1 μm. That is, by performing the processing in the first processing type, the formation of the division starting point which is preferably suppressed from the formation of the processing mark is realized.

In addition, in the SEM image, it is observed as a rib-like portion, and fine irregularities having a height difference of about 0.1 μm to 1 μm formed on the crack/cleavage surface are observed. The unevenness is formed by the following method: when the inorganic compound such as sapphire hard and brittle is used for the cleaving/cracking process, a strong impact or stress is applied to the unit pulse light irradiation. The workpiece is processed to produce smoothness on a specific crystal face.

Although such fine concavities and convexities are present, it is judged that the surface and the cross section are substantially orthogonal to each other with the dotted line as a boundary, and it can be said that if the fine concavities and convexities are allowed as machining errors, the division starting point is formed by the first processing type. The workpiece is divided along the starting point of the division, whereby the workpiece can be divided substantially perpendicularly to the surface thereof.

Further, as will be described later, there is a case where it is preferable to form the fine unevenness actively. For example, the effect of improving the light extraction efficiency which is remarkably obtained by the processing of the second processing type described below can be obtained to some extent by the processing using the first processing type.

<2nd processing type>

The second processing type is a split/cleaving process when any one of the a1 axis direction, the a2 axis direction, and the a3 axis direction is perpendicular to the planned line. Further, the conditions of the laser light used in the second processing type are the same as those of the first processing type. More generally, the second processing type is in the direction equivalent to the two different easy-opening/cracking directions (the direction in which the symmetry axes of the two easy-opening/cracking directions) become the direction of the planned line. Processing aspect.

Fig. 4 is a view schematically showing a processing aspect using a second processing type. In FIG. 4, the case where the a1 axis direction is orthogonal to the process planned line L is illustrated. Fig. 4(a) is a view showing the azimuthal relationship between the a1 axis direction, the a2 axis direction, and the a3 axis direction and the planned planned line L in this case. 4(b) shows a state in which the unit pulse light of the first pulse of the laser light is irradiated onto the irradiated region RE11 at the end of the planned line L.

The same as the first processing type, the second processing type also forms a weak intensity portion by irradiating unit pulse light of an ultrashort pulse. In FIG. 4(b), the weak-intensity portions formed in the above-described respective easy-opening/cracking directions are schematically indicated in the -a2 direction and the +a3 direction which are close to the extending direction of the planned line L. Weak strength portions W11a, W12a.

Further, as shown in FIG. 4(c), when the unit pulse light of the second pulse of the laser light is irradiated onto the planned line L, the irradiated area RE12 is formed at a position only a certain distance from the irradiated area RE11. Then, the same as the first pulse, and the weak intensity portion along the easy opening/cracking direction is also formed under the second pulse. For example, the weak intensity portion W11b is formed in the -a3 direction, the weak intensity portion W12b is formed in the +a2 direction, the weak intensity portion W12c is formed in the +a3 direction, and the weak intensity portion W11c is formed in the -a2 direction.

In this case, as in the case of the first processing type, the weak-strength portions W11a and W12a formed by the irradiation of the unit pulse light of the first pulse are respectively present in the extending directions of the weak-strength portions W11b and W12b, so that actually When the unit pulse light of the second pulse is irradiated, the impact or stress generated at this time propagates toward the easy splitting/cracking direction and the previously existing weak intensity portion. That is, as shown in FIG. 4(d), the split/cleavage planes C11a and C11b are formed. Further, in this case, the split/cleavage planes C11a and C11b may be formed to a depth of about several μm to several tens of μm in the vertical direction in the pattern of the workpiece.

Then, as shown in FIG. 4(e), if the unit pulse light is sequentially irradiated to the irradiated areas RE11, RE12, RE13, RE14, etc. by scanning the laser light along the planned line L, it is generated by performing the irradiation. The crack/stress is formed along the planned line L to form the split/cleavage planes C11a and C11b, C12a and C12b, C13a and C13b, C14a and C14b, ... in the drawings.

As a result, a state in which the split/cleavage plane is symmetrically located on the planned line L is realized. In the second processing type, the plurality of irradiated regions that are discretely present along the planned line L and the split/cleavage surface that is present in a zigzag manner as a whole are divided into workpieces along the planned line L. The starting point of the time.

Fig. 5 is an optical microscope image of a surface of a workpiece on which a split starting point is formed by splitting/cracking processing in the second processing type. Specifically, the result of processing is as follows: a sapphire C-plane substrate is used as a workpiece, and a direction orthogonal to the a1 axis direction is a direction in which the a1 axial direction is extended on the c-plane, and is 7 μm. The illuminated points are discretely formed at intervals. According to Fig. 5, similarly to the one shown schematically in Fig. 4(e), a saw-toothed (Z-shaped) split/cleavage surface was observed in the actual workpiece. This result suggests that the actual workpiece is processed by the above mechanism.

Moreover, FIG. 6 is an SEM image from the surface (c surface) to the cross section of the sapphire C-plane substrate having the division starting point formed by the processing of the second processing type along the division starting point. Further, in Fig. 6, the boundary portion between the surface and the cross section is indicated by a broken line.

According to FIG. 6, it can be confirmed that the cross section of the workpiece has a zigzag shape schematically shown in FIG. 4(e) in a range of about 10 μm from the surface of the cross-section of the workpiece. Bump. The cracked/cleaved surface is formed by the unevenness. Furthermore, the distance between the concavities and convexities in Fig. 6 is about 5 μm. As in the case of the processing using the first processing type, the cracking/cleavage surface is not flat, and smoothness is generated on the specific crystal surface due to the irradiation of the unit pulsed light, and concavities and convexities of the submicron pitch are generated.

Further, a portion of the direct metamorphic region is extended from the surface portion in the depth direction in accordance with the position of the convex portion of the uneven portion. Compared with the direct metamorphic region formed by the processing of the first processing type shown in Fig. 3, the shape is uneven. Moreover, the split surface formed by the division is located below the direct metamorphic region and the split/cleavage plane.

The case of the second processing type is the same as the first processing type in that the directly deteriorated region formed only discretely becomes a processing mark. Moreover, the size of the direct metamorphic region on the surface to be processed is only about several hundred nm to 2 μm. That is, when the processing in the second processing type is performed, a formation of a preferable division starting point is also achieved as compared with the prior art.

In the case of processing by the second processing type, the adjacent crack/cleavage planes are formed with irregularities at a distance of about several μm apart from the unevenness of the submicron pitch formed on the cracking/cleavage surface. It is effective to form a cross section having such a concavo-convex shape in which a workpiece having a light-emitting element structure such as an LED structure formed on a substrate including a hard brittle and optically transparent material such as sapphire is divided into wafers. (Segmentation) unit. In the case of a light-emitting element, if the light generated inside the light-emitting element is absorbed at a portion of the processing mark formed on the substrate by laser processing, the light extraction efficiency from the element is lowered, but by utilizing In the processing of the second processing type, when the unevenness as shown in Fig. 6 is intentionally formed on the processed cross section of the substrate, the total reflectance at the position is lowered, and higher light extraction efficiency is realized in the light-emitting element.

<3rd processing type>

The third processing type is used for the use of ultrashort pulsed laser light, and any one of the a1 axis direction, the a2 axis direction, and the a3 axis direction is perpendicular to the planned line (relative to the two different easy opening/split directions, etc.) The direction in which the effect becomes the direction of the planned line is the same as that of the second processing type, but the irradiation pattern of the laser light is different from the second processing type.

Fig. 7 is a view schematically showing a processing aspect using the third processing type. In FIG. 7, the case where the a1 axis direction is orthogonal to the process planned line L is illustrated. Fig. 7(a) is a view showing the azimuthal relationship between the a1 axis direction, the a2 axis direction, and the a3 axis direction and the planned line L in this case.

In the second processing type described above, in the same orientation relationship as the orientation relationship shown in FIG. 7(a), the direction between the a2 axis direction and the a3 axis direction in the extending direction of the processing planned line L is written ( The laser light is linearly scanned with respect to the direction in which the a2 axis direction is equivalent to the a3 axis direction. In the third processing type, as shown in FIG. 7(b), each of the irradiated regions is formed in an alternately easy to open/crack direction along the predetermined line L for the processing. In a zigzag (Z-shaped) manner, unit pulse light forming each of the irradiated regions is irradiated. In the case of Fig. 7, the irradiated areas RE21, RE22, RE23, RE24, RE25, ... are alternately formed along the -a2 direction and the +a3 direction.

The case where the unit pulse light is irradiated by this aspect is also the same as the first and second processing types, and a crack/cleavage plane is formed between the irradiated regions with the irradiation of each unit pulse light. In the case shown in Fig. 7(b), the irradiated regions RE21, RE22, RE23, RE24, RE25, ... are sequentially formed, whereby the crack/cleavage planes C21, C22, C23, C24, ... are sequentially formed.

As a result, in the third processing type, a plurality of irradiated regions which are discretely present in a zigzag arrangement in which the planned line L is an axis, and a split/cleavage plane formed between the respective irradiated regions As a whole, the starting point of the division when the workpiece is divided along the planned line L is formed.

Further, when the division is actually performed along the division starting point, as in the second processing type, the split/cleavage plane is formed in a range of about 10 μm from the surface of the cross-section of the workpiece after the division. Concavities and convexities of a few μm pitch are generated. Further, as in the case of the first and second processing types, smoothness is generated on a specific crystal surface by irradiation of a unit pulsed light on each of the cracking/cleaving surfaces, and accordingly, unevenness of submicron pitch is generated. . Moreover, the formation form of the direct metamorphic region is also the same as the second processing type. That is, in the third processing type, the formation of the processing marks is also suppressed to the same extent as the second processing type.

Therefore, the processing using the third processing type is also the same as the processing using the second type, except that the unevenness of the submicron pitch formed on the cracking/cleavage plane is formed by the crack/cleavage planes. In the case where the third processing type is processed for the light-emitting element, the light-emitting element obtained is improved from the viewpoint of the improvement of the light extraction efficiency as described above. Suitable illuminating elements.

Further, depending on the type of the workpiece, in order to more reliably cause cracking/cleavage, the irradiated region RE21 and the irradiated region RE22 of Fig. 7(b) which are both at the position on the processing planned line L may be used. The intermediate point, the intermediate point between the irradiated area RE22 and the irradiated area RE23, the intermediate point between the irradiated area RE23 and the irradiated area RE24, and the intermediate point between the irradiated area RE24 and the irradiated area RE25 form an irradiated area.

However, the arrangement position of the irradiated area in the third processing type is partially along the easy-opening/cleaving direction. The same applies to the case where the intermediate portion on the processing planned line L also forms the illuminated region as described above. In other words, it can be said that the third processing type is the same as the first processing type in that at least two of the irradiated regions are formed adjacent to each other in the easy opening/dissecting direction of the workpiece. Therefore, if the viewpoint is changed, it can be considered that the third processing type periodically changes the direction in which the laser light is scanned and performs the processing type using the processing of the first processing type.

Further, in the case of the first and second processing types, since the illuminated area is located on a straight line, the source of the laser light is moved along the line to be processed along the line to be processed, and is irradiated each time a specific formation target position is reached. It is only necessary to form the irradiated area by the unit pulse light, and this formation form is most effective. However, in the case of the third processing type, since the irradiated area is formed in a zigzag shape (Z shape) instead of being formed on a straight line, not only can the source of the laser light be actually saw-toothed (Z word) The method of ground movement forms an illuminated area, and the illuminated area can be formed by various methods. Further, in the present embodiment, the movement of the emission source refers to the relative movement of the workpiece and the emission source, and includes not only the workpiece being fixed but the source being moved, but also the source being fixed. The movement of the workpiece (actually, the platform on which the workpiece is placed is moved).

For example, by making the exit source and the stage move parallel to each other on the planned line and move at a constant speed, and the direction in which the laser light is emitted periodically changes in a plane perpendicular to the planned line, it is also possible to satisfy the above. The zigzag arrangement relationship forms an illuminated area.

Alternatively, by causing a plurality of emission sources to move in parallel and at a constant speed, and periodically changing the irradiation timing of the unit pulse light from each of the emission sources, it is possible to satisfy the zigzag arrangement relationship as described above. The formed area is formed.

Fig. 8 is a view showing the relationship between the planned planned line and the predetermined position at which the irradiated area is formed in the above two cases. As shown in Fig. 8, any of the cases can be considered as follows: the formation positions P21, P22, P23, P24, P25, ... of the irradiated areas RE21, RE22, RE23, RE24, RE25, ... are alternately set. The formation of the irradiated regions on the predetermined positions P21, P23, P25, ... along the straight line Lα and the formation along the straight line Lβ are performed on the straight lines Lα and Lβ parallel to the planned line L. The formation of the illuminated area on the predetermined positions P22, P24, ....

Further, when the output source is moved in a zigzag manner (Z-shape), the laser light is relatively scanned regardless of whether the source of the laser light is directly moved or the platform on which the workpiece is placed is moved, and the laser beam is relatively scanned. The movement of the source or platform is a simultaneous action of two axes. On the other hand, only the operation in which the source or the platform moves in parallel on the planned line is operated in a single axis. Therefore, it can be said that the latter is more suitable for realizing the high-speed movement of the exit source, that is, the improvement of the processing efficiency.

As shown in each of the above processing types, the splitting/cracking process performed in the present embodiment is a processing aspect in which discrete illumination of unit pulsed light is mainly used as a continuous application for imparting processing to a workpiece. Used in the method of cracking/cleavage impact or stress. The deterioration of the workpiece in the irradiated area (i.e., the formation of the processing mark) or the scattering or the like is always only locally generated as an attachment. The mechanism of the splitting/cracking process of the present embodiment having such a feature is essentially the same as the processing by which the irradiation area of the unit pulsed light is overlapped and the deterioration, melting, and evaporation are continuously or intermittently processed. The processing method is different.

Further, it is only necessary to apply a strong impact or stress to each of the irradiated regions in an instant, so that the laser light can be scanned and irradiated at a high speed. In particular, extremely high speed scanning up to 1000 mm/sec can be achieved, ie high speed machining. In view of the fact that the processing speed in the previous processing method is at most about 200 mm/sec, the difference is remarkable. Of course, it can be said that the processing method realized in the present embodiment excels in productivity in comparison with the prior processing method.

Further, in the case of the above-described respective processing types, the splitting/cracking processing in the present embodiment is particularly specific when the crystal orientation of the workpiece (the orientation in the easy splitting/cracking direction) is in a specific relationship with the planned line. It is effective, but the application object is not limited to this. In principle, it can also be applied to the case where the two are in an arbitrary relationship or the case where the workpiece is polycrystalline. In such cases, since the direction of cracking/cleavage relative to the planned line is not necessarily fixed, irregular irregularities may occur at the starting point of the division, but the interval between the irradiated regions is appropriately set, and pulsed. The irradiation condition of the laser light having the width is the same, and it is possible to perform processing which is practically problem-free in which the above-mentioned unevenness falls within the allowable range of the machining error.

<Overview of laser processing equipment>

Next, a laser processing apparatus that can realize processing using various processing types described above will be described.

Fig. 9 is a schematic view showing the configuration of the laser processing apparatus 50 of the present embodiment. The laser processing apparatus 50 mainly includes: a laser beam irradiation unit 50A; an observation unit 50B; a stage 7 including a transparent member such as quartz, and a workpiece 10 placed thereon; and a controller 1 that controls the laser Various operations of the processing device 50 (observation operation, alignment operation, machining operation, etc.). The laser beam irradiation unit 50A includes a laser light source SL and an optical system 5, and is a portion that irradiates the workpiece 10 placed on the stage 7 with laser light, and corresponds to the above-mentioned source of the laser light. The observation portion 50B directly observes the surface of the workpiece 10 from the side irradiated with the laser light (referred to as the surface), and observes the surface of the workpiece 10 on the side of the platform 7 (referred to as the back surface) via the platform 7 The portion observed on the back side of the workpiece 10.

The stage 7 is movable in the horizontal direction between the laser beam irradiation unit 50A and the observation unit 50B by the moving mechanism 7m. The moving mechanism 7m moves the stage 7 in the specific XY2-axis direction in the horizontal plane by the action of a driving mechanism (not shown). Thereby, the movement of the laser beam irradiation position in the laser beam irradiation unit 50A, the movement of the observation position in the observation unit 50B, or the movement of the stage 7 between the laser beam irradiation unit 50A and the observation unit 50B or the like is realized. Further, the moving mechanism 7m may perform a rotation (θ rotation) operation in a horizontal plane centered on a specific rotation axis independently of the horizontal drive.

Further, in the laser processing apparatus 50, surface observation and back surface observation can be performed in an appropriate and switchable manner. Thereby, the optimum observation corresponding to the material or state of the workpiece 10 can be performed flexibly and quickly.

The platform 7 is formed of a transparent member such as quartz, but a suction pipe (not shown) that serves as an intake passage for adsorbing and fixing the workpiece 10 is provided inside. The suction pipe is provided, for example, by machining a specific position of the platform 7 by machining.

In a state in which the workpiece 10 is placed on the stage 7, the suction pipe is suctioned by a suction mechanism 11 such as a suction pump, and the front end of the suction side is placed on the platform 7 of the suction pipe. The suction hole is provided to apply a negative pressure, whereby the workpiece 10 (and the fixing piece 4) is fixed to the stage 7. In the case where the workpiece 10 to be processed is attached to the fixing piece 4, it is preferable to arrange the fixing piece 4 at the outer edge of the fixing piece 4. The fixed ring shown (see Figure 12).

<Lighting system and observation system>

The observation unit 50B is configured such that the workpiece 10 placed on the stage 7 is superimposed on the projection illumination light L1 from the epi-illumination light source S1 and the oblique illumination from the oblique illumination source S2 from above the stage 7. The surface of the surface observation mechanism 6 from the upper side of the stage 7 and the back surface observation by the back surface observation mechanism 16 from the lower side of the stage 7 can be observed by the irradiation of the illumination light L2.

Specifically, the epi-illumination light L1 emitted from the epi-illumination light source S1 is reflected by the half mirror 9 provided in the lens barrel (not shown) and is irradiated onto the workpiece 10. Further, the observation unit 50B includes a CCD (Charge-coupled Device) camera 6a provided above the half mirror 9 (above the lens barrel) and a surface of the monitor 6b connected to the CCD camera 6a. The observation mechanism 6 can observe the bright field image of the workpiece 10 in real time in a state where the illumination light L1 is irradiated.

Further, the observation unit 50B includes a back surface observation mechanism 16 including a CCD camera 16a disposed below the stage 7, and more preferably disposed below the half mirror 19 (below the lens barrel), which will be described later. And a monitor 16b connected to the CCD camera 16a. Further, the monitor 16b and the monitor 6b provided in the surface observation mechanism 6 may be the same monitor.

Further, the coaxial illumination light L3 emitted from the coaxial illumination light source S3 provided below the stage 7 can be reflected by the half mirror 19 provided in the lens barrel (not shown), and collected by the collecting lens 18 It is irradiated onto the workpiece 10 via the platform 7. More preferably, the oblique illumination source S4 is provided below the platform 7, and the workpiece 10 is irradiated with the oblique illumination light L4 via the stage 7. The coaxial illumination light source S3 or the oblique illumination light source S4 may be, for example, an opaque metal layer or the like on the surface side of the workpiece 10, and the observation from the surface side may be difficult due to reflection from the metal layer. It is preferable to use when the workpiece 10 is observed from the back side.

<Laser light source>

As the laser light source SL, a laser light source having a wavelength of 500 nm to 1600 nm is used. Further, in order to realize the processing in the above-described processing type, the pulse width of the laser light LB must be about 1 psec to 50 psec. Further, the repetition frequency R is about 10 kHz to 200 kHz, and the irradiation energy (pulse energy) of the laser light is preferably about 0.1 μJ to 50 μJ.

Furthermore, the polarization state of the laser light LB emitted from the laser light source SL may be circularly polarized or linearly polarized. However, in the case of linear polarization, it is preferable that the polarization direction and the scanning direction are substantially parallel with respect to the bending of the processed cross section and the energy absorption rate in the crystalline material to be processed, for example, the two are formed. The angle is within ±1°.

<Optical system>

The optical system 5 sets a portion of the optical path when the laser light is irradiated onto the workpiece 10. The laser light is irradiated onto the specific irradiation position (predetermined position at which the irradiated region is formed) of the workpiece according to the optical path set by the optical system 5.

FIG. 10 is a schematic view showing the configuration of the optical system 5. The optical system 5 mainly includes a beam expander 51 and an objective lens system 52. Further, in the optical system 5, in order to change the direction of the optical path of the laser light LB, a suitable number of mirrors 5a may be provided at appropriate positions. In Fig. 10, a case where two mirrors 5a are provided is exemplified.

Further, in the case where the emitted light is linearly polarized, it is preferable that the optical system 5 is provided with the attenuator 5b. The attenuator 5b is disposed at an appropriate position on the optical path of the laser beam LB, and functions to adjust the intensity of the emitted laser light LB.

Further, in the optical system 5 illustrated in FIG. 10, the laser light LB emitted from the laser light source SL is set to be irradiated onto the workpiece 10 in a state where the optical path is fixed during the processing. In addition to this, it is also possible to actually or hypothetically set a plurality of optical paths of the laser light LB when the workpiece 10 is irradiated with the laser light LB emitted from the laser light source SL, and can be provided by the optical path setting mechanism 5c. (Fig. 11), the optical paths when the respective unit pulse lights of the laser light LB are irradiated to the workpiece are sequentially switched in the plurality of set optical paths. In the latter case, a state in which a plurality of parts on the upper surface of the workpiece 10 are simultaneously scanned in parallel or a state assumed in a hypothetical manner is realized. In other words, it can be said that the optical path of the laser light LB is multiplexed.

In addition, in FIG. 9, the case where the three laser beams LB0, LB1, and LB2 are scanned in three places is illustrated, but the multiplex of the optical path of the optical system 5 is not necessarily limited to this. A specific configuration example of the optical system 5 will be described later.

<controller>

The controller 1 further includes a control unit 2 that controls the operation of each of the above-described units to realize processing of the workpiece 10 in various aspects described later, and a storage unit 3 that stores a program for controlling the operation of the laser processing apparatus 50. 3p or various materials referenced during processing.

The control unit 2 is realized by a general-purpose computer such as a personal computer or a microcomputer, and the program 3p stored in the storage unit 3 is read into the computer and executed, whereby various components are used as the function of the control unit 2. Realized by the constituent elements of sex.

Specifically, the control unit 2 mainly includes a drive control unit 21 that controls the operation of various driving portions related to the machining process by the driving of the stage 7 of the moving mechanism 7m or the focusing operation of the collecting lens 18; the imaging control unit 22 The control unit 23 controls the imaging of the CCD cameras 6a and 16a, and the illumination control unit 23 controls the illumination of the laser light LB from the laser light source SL and the setting mode of the optical path in the optical system 5; the adsorption control unit 24 controls the use thereof. The suction and fixation operation of the workpiece 10 of the suction mechanism 11 toward the table 7; and the machining processing unit 25 executes the processing target data based on the supplied machining position data D1 (described later) and the machining mode setting data D2 (described later). Processing of the location.

The storage unit 3 is realized by a storage medium such as a ROM (Read-Only Memory), a RAM (Random Access Memory), or a hard disk. Furthermore, the storage unit 3 may be realized by realizing the components of the computer of the control unit 2, and may be provided independently of the computer when it is a hard disk or the like.

The machining position data D1 describing the position of the planned line to be set by the workpiece 10 is supplied from the outside and stored in the storage unit 3. Further, the storage unit 3 stores in advance a processing mode setting data D2 in which the conditions of the respective parameters of the laser light or the optical path in the optical system 5 are described in each processing mode. The processing mode setting data such as the setting conditions or the driving conditions of the platform 7 (or the range that can be set).

Furthermore, the various input instructions given by the operator to the laser processing apparatus 50 are preferably performed using a GUI (Graphical User Interface) implemented in the controller 1. For example, the menu for processing processing is provided by GU1 by the action of the processing unit 25. The operator selects a processing mode to be described later or inputs a processing condition based on the processing processing menu.

<Alignment action>

In the laser processing apparatus 50, an alignment operation for finely adjusting the arrangement position of the workpiece 10 can be performed in the observation unit 50B before the processing. The alignment operation is performed by matching the XY coordinate axis set in the workpiece 10 with the coordinate axis of the stage 7. When the processing in the above-described processing type is performed, the alignment processing is important in that the crystal orientation of the workpiece and the processing direction of the processing line and the scanning direction of the laser light satisfy the specific relationship required in each processing type.

The alignment action can be performed using well-known techniques, and can be performed in a suitable manner corresponding to the type of processing. For example, if a case where a plurality of element wafers produced by using one mother substrate are cut out is equal to a case where a repeating pattern is formed on the surface of the workpiece 10, an appropriate pair is achieved by using pattern matching or the like. Quasi-action. In this case, in general, the CCD camera 6a or 16a acquires a captured image of a plurality of alignment marks formed on the workpiece 10, and the processing unit 25 determines the relative relationship between the imaging positions of the captured images. With respect to the amount of alignment, the drive control unit 21 moves the stage 7 by the moving mechanism 7m in accordance with the amount of alignment, thereby achieving alignment.

By performing this alignment operation, the machining position in the machining process is accurately determined. Further, after the alignment operation is completed, the stage 7 on which the workpiece 10 is placed is moved toward the laser beam irradiation unit 50A, and then processing by irradiating the laser beam LB is performed. Further, the movement of the stage 7 from the observation portion 50B to the laser light irradiation portion 50A is ensured so that the predetermined machining position and the actual machining position are not deviated during the alignment operation.

<Summary of processing>

Next, the processing in the laser processing apparatus 50 of the present embodiment will be described. In the laser processing apparatus 50, the irradiation of the laser light LB emitted from the laser light source SL and passing through the optical system 5 is combined with the movement of the stage 7 on which the workpiece 10 is placed and fixed, thereby passing through the optical system 5. The laser light is relatively scanned by the workpiece 10, and the workpiece 10 can be processed.

The laser processing apparatus 50 is characterized in that the basic mode and the multi mode are alternatively selected as a mode (processing mode) by which the processing of the laser light LB is (relatively) scanned. These processing modes are set corresponding to the setting pattern of the optical path in the optical system 5 described above.

The basic mode is a mode in which the optical path of the laser light LB emitted from the laser light source SL is fixedly set. In the basic mode, the laser light LB always passes through one optical path, and the stage 7 on which the workpiece 10 is placed is moved at a specific speed, thereby realizing that the laser light scans the workpiece 10 in one direction. Processing. In the case of the optical system 5 illustrated in Fig. 10, only the processing in this basic mode can be performed.

The basic mode is suitable for the case of performing the processing in the first and second processing types described above. In other words, the workpiece 10 is set so as to be parallel to the easy-opening/cracking direction, so that the workpiece 10 is aligned in such a manner that the easy-opening/cracking direction coincides with the moving direction of the stage 7. The processing in the basic mode is performed, whereby the processing of the first processing type can be performed. On the other hand, the workpiece 10 is set to be perpendicular to the easy-opening/cracking direction, so that the workpiece 10 is oriented such that the easy-opening/cracking direction is orthogonal to the moving direction of the stage 7. After the alignment, the processing in the basic mode is performed, whereby the processing of the second processing type can be performed.

Further, in principle, it is also possible to apply the processing in the third processing type by appropriately changing the moving direction of the stage 7.

On the other hand, the multi-mode substantially or hypothetically multiplexes the optical paths of the laser light LB to set a pattern of a plurality of optical paths. It is a mode in which a plurality of laser lights are substantially or hypothesized by, for example, a straight line Lα, Lβ parallel to the planned line L as shown in FIG. 8, or further along the planned line L itself. The ground scan is performed to achieve the same processing as in the case of scanning the laser light with the pattern intersecting the processing line L repeatedly. Further, the fact that the plurality of laser beams are scanned hypothetically means that the optical path of the laser beam is irradiated with one light path in the same manner as the basic mode with time, thereby realizing the irradiation of the laser light with a plurality of optical paths. The same scanning situation.

The multi-mode is suitable for the case of processing in the third processing type. That is, as in the case of the second processing type, the workpiece 10 is set to be perpendicular to the easy opening/cracking direction for the processing planned line L so that the easy opening/dissecting direction is orthogonal to the moving direction of the stage 7. In the manner of aligning the workpiece 10, the processing in the multi-mode is performed, whereby the processing of the third processing type can be performed.

The processing mode is preferably selected by the processing unit 25 in accordance with, for example, a processing menu that is available to the operator in an available manner. The processing unit 25 obtains the machining position data D1, and acquires a condition corresponding to the selected machining type from the machining mode setting data D2, and performs the operation corresponding to the condition by the drive control unit 21 or the illumination control. The part 23 and the like control the operations of the corresponding parts.

For example, the wavelength or output power of the laser light LB emitted from the laser light source SL, the repetition frequency of the pulse, the adjustment of the pulse width, and the like are realized by the illumination control unit 23 of the controller 1. When the processing unit 25 issues a setting signal specific to the processing mode setting data D2 to the irradiation control unit 23, the irradiation control unit 23 sets the irradiation conditions of the laser light LB based on the setting signal.

Further, particularly in the case of processing in a multi-mode, the illumination control unit 23 synchronizes the emission timing of the unit pulse light from the laser light source SL with the switching timing of the optical path by the optical path setting unit 5c. Thereby, the unit pulse light is irradiated to the optical path corresponding to the predetermined position among the plurality of optical paths set by the optical path setting means 5c for the predetermined position of each of the irradiated regions.

Further, in the laser processing apparatus 50, when processing is performed, the laser beam LB may be irradiated in a defocused state in which the focus position is intentionally deviated from the surface of the workpiece 10 as needed. This can be achieved, for example, by adjusting the relative distance between the platform 7 and the optical system 5.

<Configuration example of optical path setting mechanism and its operation>

Next, an example of the specific configuration of the optical path setting means 5c and its operation will be mainly described for the operation in the multi mode.

In the following description, the processing is performed while the stage 7 on which the workpiece 10 is placed is moved in the movement direction D that coincides with the extending direction of the planned line L.

Further, in the operation in the multi-mode, the laser beam LB0 to be irradiated when the irradiation region RE is formed on the processing target L is set to be irradiated when the irradiation region RE is formed on the straight line Lα parallel to the planned line L. The laser light LB1 is irradiated with the laser light LB2 when the irradiated area RE is formed on the straight line Lβ which is parallel to the planned line L and which is parallel to the planned line L.

Further, the processing of the third processing type in the multi-mode is realized by positioning the plurality of irradiated regions sequentially or simultaneously at positions along the easy-opening/cracking direction.

Fig. 11 is a view schematically showing the configuration of the optical path setting means 5c. The optical path setting mechanism 5c is provided as one of the constituent elements of the optical system 5. The optical path setting mechanism 5c includes a plurality of half mirrors 53, a mirror 54, and an optical path selecting means 55.

The half mirror 53 and the mirror 54 form a plurality of optical paths (laser lights LB0, LB1, LB2) in order to branch the optical path of the laser beam LB emitted from the laser light source SL in the in-plane direction perpendicular to the moving direction D of the stage 7. Set on the light path). Furthermore, the number of half mirrors 53 depends on the number of optical paths. In Fig. 11, two half mirrors 53 are provided in order to obtain three optical paths. By providing the half mirrors 53 and the mirrors 54, the laser light LB is emitted and the stage 7 is moved, whereby a plurality of laser light scanning states of the workpiece 10 are realized.

The optical path selecting means 55 is provided to control the emission timing of the laser light toward the workpiece 10 in the plurality of optical paths. More specifically, the optical path selecting means 55 is provided with an optical switch SW in the middle of the optical path of each of the laser beams branched by the half mirror 53 and the mirror 54. The optical switch SW is composed of, for example, an AOM (Acousto-Optic Modulator) or an EOM (Electro-Optical Modulator), and has an ON light that allows the incident laser light to pass through. In the state, it blocks the laser light that is incident or attenuates it (becomes a non-passing state). Thereby, in the optical path selecting means 55, only the laser light that has passed through the optical switch SW in the ON state is irradiated onto the workpiece 10.

The operation in the multi-mode of the laser processing apparatus 50 having the optical path setting means 5c having such a configuration is realized by the irradiation control unit 23 such that the optical switch SW on the optical path of the laser light LB0, LB1, LB2 The ON/OFF operation of each optical switch SW is controlled in such a manner that the emission timing of the unit pulse light of the laser light LB according to the repetition frequency R is sequentially and periodically turned ON. By this control, each of the laser beams LB0, LB1, and LB2 is irradiated onto the workpiece 10 by the optical path selecting means 55 only when the timing of forming the irradiated regions by the respective laser lights LB0, LB1, LB2 is reached.

In other words, a plurality of optical paths for irradiating the workpiece 10 are actually provided, and the irradiation timing of each unit pulse light is different, and the plurality of laser beams are simultaneously scanned in parallel to perform the operation in the multi-mode. .

Further, the operation in the basic mode can be realized by, for example, simply emitting the laser light LB by setting only the optical switch SW on the optical path of any of the laser beams LB0, LB1, and LB2 to the ON state, and moving the stage 7 .

<High efficiency of splitting/cracking processing>

The above-described splitting/cracking processing method uses a shock or stress generated by irradiation of a unit pulsed light to cause cracking/cleavage on the workpiece. Therefore, the larger the impact or stress acting on the workpiece during the irradiation of the pulse light of each unit, the more the cracking/cleavage occurs until the workpiece is deeper, and the end portion of the starting point before reaching the workpiece reaches the workpiece. The deeper part. In order to achieve such processing, it is desirable to make the energy imparted to the workpiece at each time the unit pulse light is irradiated as much as possible, thereby contributing to the formation of the crack/cleavage surface.

For example, by irradiating the pulsed laser light, part of the substance present in the illuminated area acquires kinetic energy and scatters toward the outside at high speed. The cracking/cleavage can be formed more effectively by suppressing the scattering of such a substance and contributing to the formation of the cracking/cleavage surface in the workpiece by the energy that should be consumed during the scattering. surface.

In the present embodiment, the efficiency of the splitting/cracking processing is performed based on the above viewpoint. Specifically, in the state on the surface to be processed of the workpiece, the material (transparent material) which is transparent to the pulsed laser light used in the splitting/cracking process is adjacent to each other, and is processed by each of the above-described processing types. Split 1 split processing. Transparency with respect to pulsed laser light means that the pulsed laser light that is irradiated is not substantially absorbed. As the transparent material, there are a transparent solid member (hereinafter referred to as a transparent member) or a transparent liquid (hereinafter referred to as a transparent liquid). Hereinafter, each case will be described in detail.

<High efficiency of using transparent members>

Fig. 12 is a schematic view showing a method of achieving high efficiency of splitting/cracking processing using a transparent member. At the time of the splitting/cracking processing, after the workpiece 101 is attached to the fixing piece 102, it is placed on the stage (not shown in FIG. 12) together with the fixing piece 102. Then, the peripheral portion of the fixing piece 102 is fixed by the fixing ring 103. So far, it is the same as the general general laser processing.

In the present embodiment, the member is transparent to the pulsed laser light used in the splitting/cracking process so as to be adjacent to the processed surface 101a of the workpiece 101 placed on the stage as described above. Transparent member 104. For example, a transparent plate containing sapphire or quartz or a film containing PET (Polyethylene Terephthalate) or the like can be used as the transparent member 104. The selection of the specific transparent member 104 can be appropriately selected in accordance with necessary conditions such as the wavelength of the pulsed laser light to be used.

The arrangement in which the transparent member 104 is disposed adjacent to the surface to be processed 101a includes a case where the transparent member is placed in contact with the surface to be processed 101a. This is achieved, for example, by placing the transparent member 104 on the workpiece 101 that is horizontally fixed, or by attaching the transparent member 104 to the surface 101a to be processed.

When the transparent member 104 is disposed as described above, when the splitting/cracking processing is performed by each of the above-described processing types, the scattering of the substance from the irradiated region is suppressed by the transparent member 104, and thus the scattering does not occur. The contribution of the energy imparted by the unit pulsed light to the formation of the crack/cleavage plane is higher than in the case where the transparent member 104 is not provided. As a result, the starting point of the division until the front end portion reaches a deeper position than in the case where the transparent member 104 is not provided is formed.

Further, in the case where the transparent member 104 is disposed adjacent to the surface to be processed 101a, the transparent member is disposed separately from the surface to be processed 101a. Specifically, when the distance between the two is in the range of 100 μm or less, even when the two are disposed separately, the same effect as in the case where the two are placed in contact with each other can be obtained.

<Specific aspects of the configuration of transparent members>

Hereinafter, various aspects of realizing the arrangement of the transparent member 104 as described above will be described in order.

(1st configuration aspect)

FIG. 13 is a side cross-sectional view showing a first arrangement of the transparent member 104. In Fig. 13, as in the example shown in Fig. 12, the fixing piece 102 to which the workpiece 101 is attached is placed on the stage 7, and the fixing ring 103 is placed on the outer edge portion of the fixing piece 102. Further, a plate-shaped transparent member 104 is placed on the workpiece 101. In addition, FIG. 13 exemplifies a case where the workpiece 101 includes the sapphire substrate 1011 and the LED structure 1012 formed thereon by a group 111 nitride or the like (the same applies to each of the following figures).

On the outer side of the transparent member 104, a fixing member 111 for fixing the transparent member 104 is disposed. The fixing member 111 is a substantially cylindrical member having an L-shape when viewed from a cross section of the protruding portion 111a toward the inner side at one end portion.

The fixing member 111 is disposed in a state in which the leg portion 111b which is the end opposite to the protruding portion 111a is placed on the blank portion 102a of the fixing piece 102 (the portion to which the workpiece 101 is attached and placed thereon) Between the portions of the fixing ring 103, the protruding portion 111a abuts against the upper surface 104a of the transparent member 104 at the edge portion 104e of the transparent member 104, and the inner surface 111c substantially abuts against the side of the transparent member 104. Face 104b. Further, the protruding portion 111a may be provided so as to be in contact with the transparent member 104 in a range in which the processing target region on the processed surface 101a is not blocked with respect to the laser light LB when the laser processing is performed.

By disposing the fixing member 111 as described above, the movement of the transparent member 104 in the upper, lower, left and right directions is restricted, so that the positional displacement of the transparent member 104 placed on the surface to be processed 101a is prevented from occurring during the laser processing. That is, the transparent member 104 is fixed by the fixing member 111, thereby achieving a good splitting/cracking process which improves the utilization efficiency of the energy of the pulsed laser light.

Further, the material of the fixing member 111 is not particularly limited as long as it is stably placed on the fixing piece 102 and preferably has a function of preventing the positional displacement of the transparent member 104.

Further, the transparent member 104 and the fixing member 111 are respectively prepared as an independent one that can be disposed before the processing and removed after processing, and can be freely disposed with respect to the laser processing apparatus 50, but may be set to be The two are integrated into one body by screwing or the like, and are detachably attached to the laser processing apparatus 50. Further, the fixing member 111 may be configured to be disassembled and assembled.

Further, the above-described substantially cylindrical fixing member 111 is in contact with the entire side peripheral surface 104b of the transparent member 104, but this aspect is not essential. A plurality of fixing members 111 having the same L-shaped cross section are disposed at appropriate intervals along the outer circumference of the transparent member 104, and the respective fixing members 111 are partially abutted against the side peripheral surface 104b, thereby being fixedly transparent. Member 104.

(2nd configuration aspect)

Fig. 14 is a side cross-sectional view showing a second arrangement of the transparent member 104. In the second configuration aspect, as shown in FIG. 14, the transparent member 104 is configured using a fixing member 112 similar to the fixing member 111 shown in FIG.

Like the fixing member 111, the fixing member 112 has a substantially cylindrical shape, but is different from the fixing member 111 in that not only one end portion thereof has the same protruding portion 112a as the protruding portion 111a but also the intermediate portion of the inner surface 112c. The profile of the support portion 112d is F-shaped.

As in the first aspect, the fixing member 112 is disposed in a state in which the workpiece 112 is placed on the stage 7 together with the fixing piece 102, and the leg portion 112b is placed on the fixing piece 102. The blank portion 102a supports the end edge portion 104e of the transparent member 104 from the lower surface 104c side by the support portion 112d, and the inner surface 112c substantially abuts against the side peripheral surface 104b of the transparent member 104. Further, the protruding portion 112a is configured to be close to or adjacent to the upper surface 104a of the transparent member 104. Further, the support portion 112d may be provided in a range that does not interfere with the workpiece 101 when performing laser processing, and the protruding portion 112a is similar to the laser beam LB as long as the laser processing is performed. It suffices to block the processing target area on the processed surface 101a. Further, the material of the fixing member 112 may be the same as that of the fixing member 111.

Further, in Fig. 14, the transparent member 104 is disposed in a state of being separated from the surface to be processed 101a. However, the transparent member 104 may be disposed in such a manner that the contact portion 112d is in contact with each other.

In either case, by arranging the fixing member 112 as described above, the movement of the transparent member 104 in the upper, lower, left and right directions is restricted, thereby preventing the transparent member 104 placed on the processed surface 101a from being subjected to laser processing. A position offset is generated. Therefore, the fixing member 112 is used to separate the transparent member 104 at a distance of 100 μm or less from the surface to be processed 101a or to bring the transparent member 104 into contact with the processed surface 101a, thereby improving the utilization efficiency of the energy of the pulsed laser light. Good splitting/cracking processing.

Further, the transparent member 104 and the fixing member 112 are respectively prepared as an independent one that can be disposed before the processing and removed after processing, and can be freely disposed with respect to the laser processing apparatus 50, but may be set to be The two are integrated into one body by screwing or the like, and are detachably attached to the laser processing apparatus 50. In the case of the former, the transparent member 104 is detachably attached to the support portion 112d of the fixing member 112. Further, the fixing member 112 may be configured to be disassembled and assembled.

Further, the substantially cylindrical fixing member 112 is in contact with the entire side peripheral surface 104b of the transparent member 104, but this aspect is not essential. A plurality of fixing members 112 having the same F-shaped cross section are disposed at appropriate intervals along the outer circumference of the transparent member 104, and the respective fixing members 112 are partially abutted against the side peripheral surface 104b, thereby being transparently fixed. Member 104.

Alternatively, as an alternative to the support member 112d from the lower supporting transparent member 104, the upper surface 104a may be fixed to the protruding portion 112a by screw fixing or the like to the end edge portion 104e of the transparent member 104. The surface of the transparent member 104 may be supported by the frictional force (resistance) between the inner surface 112c and the side peripheral surface 104b by abutting the side peripheral surface 104b of the transparent member 104 against the inner surface 112c.

(3rd configuration aspect)

15 and 16 are side views showing a third arrangement of the transparent member 104. Fig. 15 shows the state before the processing is performed, and Fig. 16 shows the state at the time of the processing. In addition, although illustration is abbreviate|omitted in FIG. 15 and FIG. 16, the aspect with which the workpiece 101 is mounted on the platform 7 is the same as the case of the first and second arrangement aspects.

In the third arrangement, as shown in FIGS. 15 and 16, the end edge portion 104e of the transparent member 104 is fixed to the elevating mechanism 121 provided in the laser processing apparatus 50. Further, in a state in which the workpiece 101 is placed and fixed on the stage 7, the elevating mechanism 121 raises and lowers the transparent member 104 in the vertical direction under the control of the drive control unit 21, thereby realizing the specific direction of the transparent member 104. Location configuration. In other words, the elevating mechanism 121 is an arrangement position adjusting mechanism that disposes the transparent member 104 at an arbitrary position by moving the transparent member 104 forward and backward with respect to the to-be-processed surface 101a.

In the third arrangement, the transparent member 104 is preferably a rigid plate-like body that can maintain a substantially horizontal level during the lifting operation of the elevating mechanism 121. For example, it is more suitable to use sapphire or quartz. Further, the transparent member 104 may be fixed to the elevating mechanism 121 by a screw or a suitable method for stably fixing the transparent member 104.

In FIG. 16, the transparent member 104 is irradiated with the laser beam LB while being in contact with the processed surface 101a of the workpiece 101. However, in the third arrangement, the transparent member 104 and the transparent member 104 may be used. The processed surface 101a is processed in a state where it is disposed at a distance of 100 μm or less. In either case, a good splitting/cracking process that improves the utilization efficiency of the energy of the pulsed laser light is achieved. Further, when the processing is not performed, the elevating mechanism 121 retracts the transparent member 104 upward to the extent that the workpiece 101 can be placed on the stage 7.

Further, in FIGS. 15 and 16, only one end edge portion 104e of the transparent member 104 is fixed to the elevating mechanism 121, but the other end edge portion 104e may be fixed to the elevating mechanism 121 at the same time. The aspect may be such that the end edge portion 104e is integrally fixed to the lifting mechanism 121.

In addition, in FIGS. 15 and 16, the transparent member 104 is disposed as a whole in the left-right direction in the drawing of the surface to be processed 101a, but it is not essential. The transparent member 104 may be disposed only in the vicinity of the irradiated region of the laser light LB in a direction perpendicular to the plane of the paper.

15 and 16, the embodiment in which the elevating mechanism 121 and the optical system 5 are supported by one base portion 122 is exemplified, but the actual arrangement of the two is not limited thereto.

(fourth configuration aspect)

17 to 19 are side views showing a fourth arrangement of the transparent member 104. Fig. 17 shows the state before the processing is performed, and Fig. 18 shows the state at the time of the processing. Figure 19 shows the movement of the transparent member 104 before and after processing. Further, although not shown in FIGS. 17 to 19, the state in which the workpiece 101 is placed on the stage 7 is the same as in the case of the first and second arrangement aspects.

In the fourth arrangement, as shown in FIGS. 17 and 18, the both end portions (the end portion 104p and the end portion 104q) are respectively wound around the first winding mechanism 131 included in the laser processing apparatus 50, and The strip-shaped transparent member 104 formed in the second winding mechanism 132 is horizontally stretched and held between the first winding mechanism 131 and the second winding mechanism 132. Further, in a state in which the workpiece 101 is placed and fixed on the stage 7, the elevating mechanism (not shown) synchronizes the first winding mechanism 131 and the second winding mechanism 132 under the control of the drive control unit 21. The timing is raised and lowered in the vertical direction, thereby achieving the configuration of the transparent member 104 toward a specific position. That is, similarly to the third arrangement aspect, in the fourth arrangement aspect, the transparent member 104 may be placed at an arbitrary position by moving the transparent member 104 forward and backward with respect to the to-be-processed surface 101a.

In the fourth arrangement, the transparent member 104 is preferably formed of a material and a thickness that can be wound by the first winding mechanism 131 and the second winding mechanism 132. For example, a PET film or the like is preferably used.

In FIG. 18, the laser beam LB is irradiated while the transparent member 104 is in contact with the processed surface 101a of the workpiece 101. However, in the fourth arrangement, the transparent member 104 and the transparent member 104 may be used. The processed surface 101a is processed in a state where it is disposed at a distance of 100 μm or less. In either case, a good splitting/cracking process that improves the utilization efficiency of the energy of the pulsed laser light is achieved.

In addition, in FIGS. 17 and 18, the transparent member 104 is integrally formed in the left-right direction in the drawing of the surface 101a to be processed, but it is not essential. The transparent member 104 may be disposed only in the vicinity of the irradiated region of the laser beam LB in a direction perpendicular to the plane of the paper (that is, a direction perpendicular to the direction in which the transparent member 104 is disposed).

For example, FIG. 19 exemplifies a state in which the transparent member 104 is disposed only on one portion above the processed surface 101a in a direction perpendicular to the extending direction of the transparent member 104. In this case, the processing for the direction in which the transparent member 104 is lowered (the direction perpendicular to the plane of the paper in Fig. 19) is performed in a state where the transparent member 104 is lowered as indicated by an arrow AR1, i.e., processing is performed in the direction along the direction. The line is a scan of the pulsed laser light of the object. When the scanning of the pulsed laser light at the position is completed, the transparent member 104 is shifted only in the direction perpendicular to the direction in which the transparent member 104 is disposed as indicated by the arrow AR2. Distance and rise. That is, the arrangement position of the transparent member 104 is shifted in accordance with the transition of the irradiated position of the pulsed laser light. The laser processing of the workpiece 101 is achieved by repeating the lowering of the transparent member 104, the scanning of the pulsed laser light, and the rise of the transparent member 104. Further, when the processing is not performed, the transparent member 104 can be retracted sideways or upward to the extent that the workpiece 101 can be placed on the stage 7.

(Fifth configuration aspect)

Fig. 20 is a side cross-sectional view showing a fifth arrangement of the transparent member 104. In the fifth arrangement aspect, the transparent member 104 is subsequently fixed to the workpiece 101, whereby the transparent member 104 is brought into contact with the surface 101a to be processed.

Specifically, as shown in FIG. 20, the side surface 101b of the workpiece 101 and the edge portion 104e of the transparent member 104 are joined by the bonding material 141 in a state where the transparent member 104 is placed on the surface 101a to be processed. In consideration of the easiness of the operation, it is preferable to fix the workpiece 101 to the stage 7 after the subsequent steps, but the invention is not limited thereto. Further, since it is necessary to peel the transparent member 104 from the workpiece 101 after the processing, it is preferable to use the sealing material 141 so as to be easily removed by a specific solvent or the like.

By fixing the transparent member 104 as described above, the movement of the transparent member 104 in the upper, lower, left and right directions is restricted. Therefore, at the time of laser processing, the positional displacement of the transparent member 104 placed on the surface 101a can be prevented. Therefore, it is possible to achieve a good splitting/cracking process for improving the utilization efficiency of the energy of the pulsed laser light.

Further, the aspect in which the transparent member 104 is subsequently fixed to the workpiece 101 is not limited to the above-described aspect. For example, the transparent member 104 may be followed by the processed surface 101a by using an adhesive material that is substantially transparent with respect to the pulsed laser light. In this case, the transparent layer formed by curing the transparent member 104 and the adhesive material functions integrally as one transparent member. However, in this case, it is necessary to separate the transparent member 104 from the workpiece 101 after the processing. Therefore, it is preferable to use the material which can be easily removed by a specific solvent or the like.

<High efficiency by liquid layer formation>

Next, the efficiency of the splitting/cracking process using a transparent liquid which is transparent to the pulsed laser light will be described. In the following, in the state shown below, in the state in which the liquid layer formed of the transparent liquid is formed on the surface to be processed of the workpiece by the liquid layer forming mechanism, each of the above processing types is utilized. Perform splitting/cracking processing. Further, in the present embodiment, as the material of the liquid itself, pulsed laser light can be absorbed, but the transparent liquid also contains a case where the thickness of the liquid layer is thin and does not cause substantial absorption. For example, when the pulsed laser light is visible light or ultraviolet (ultraviolet) light, water can be used as the transparent liquid. The selection of the specific type of the transparent liquid can be appropriately selected in accordance with the necessary conditions such as the wavelength of the pulsed laser light to be used.

When the liquid layer containing the transparent liquid is formed as described above, when the splitting/cracking processing is performed by each of the above processing types, the scattering of the substance from the irradiated area is suppressed by the liquid layer without actually generating the scattering. Therefore, the energy imparted by the unit pulsed light contributes more to the formation of the crack/cleavage plane than to the liquid layer. As a result, the starting point of the division until the tip end portion reaches a deeper position than in the case where the liquid layer is not provided is formed.

<Specific aspects of formation of liquid layer>

Hereinafter, various aspects for realizing the formation of the liquid layer as described above will be described in order.

(first formation aspect)

Fig. 21 is a side sectional view showing the first formation of the liquid layer. In FIG. 21, the fixing piece 102 to which the workpiece 101 is attached is placed on the stage 7, and the fixing ring 103 is placed on the outer edge portion of the fixing piece 102. In addition, FIG. 21 exemplifies a case where the workpiece 101 includes the sapphire substrate 1011 and the LED structure 1012 formed thereon by a group III nitride or the like (the same applies to the respective drawings below).

Further, a cylindrical member 71 is disposed on the outer peripheral portion of the stage 7. The cylindrical member 71 has an outer shape corresponding to the contour shape of the stage 7, and is integrated with the stage 7 to constitute a storage tank 72 for storing the transparent liquid 106. With respect to the stage 7, the cylindrical member 71 is fixed by ensuring the sealing property of the transparent liquid by following, screwing, or the like. In other words, the storage tank 72 has the platform 7 as a bottom and the tubular member 71 as a side wall portion. Furthermore, the tubular member 71 can also be detachably attached to the platform 7.

Further, the cylindrical member 71 as the side wall portion of the storage tank 72 is provided with a supply port 73 for supplying the transparent liquid 106 from a specific supply source (not shown), and for the transparent liquid 106 to be self-contained from the storage tank 72. Discharge the discharge port 74. In a state where the workpiece 101 is fixed to the stage 7 by using the fixing piece 102 and the fixing ring 103, the transparent liquid 106 is supplied from the outside to the storage tank 72 as indicated by an arrow AR11, whereby the transparent liquid 106 is stored in In the storage tank 72, the workpiece 101 is immersed in the transparent liquid 106. Thereby, the liquid layer 107 containing the transparent liquid 106 is formed adjacent to the surface to be processed 101a. That is, in the laser processing apparatus 50 of the present embodiment, the liquid layer forming mechanism 70 is constituted by the storage tank 72 including the stage 7, the supply port 73, and the discharge port 74.

When the pulsed laser light LB is irradiated in a state in which the liquid layer 107 is formed by the aspect, and the splitting/cracking processing is performed by each of the above-described processing types, the pulsed laser light LB from the processed surface 101a is The scattering of the substance in the irradiation area is suppressed by the liquid layer 107 adjacent to the processed surface 101a. That is, by forming the liquid layer 107, it is possible to achieve a good splitting/cracking process which improves the utilization efficiency of the energy of the pulsed laser light LB.

It is preferable that the supply of the transparent liquid 106 indicated by the arrow AR11 from the supply port 73 is continuously or intermittently performed during the cleaving/cracking process at least during the irradiation of the pulsed laser light LB, and as indicated by an arrow AR12. The transparent liquid 106 is discharged from the discharge port 74. In this case, a flow of the transparent liquid 106 as indicated by an arrow AR13 is formed on the surface 101a to be processed, that is, a fluidized layer is formed. When the cleavage/cracking process is performed in a state in which the fluid layer is formed, the transparency of the liquid layer 107 is lowered even if turbidity or the like caused by a substance detached from the workpiece 101 during processing is caused. Since the new transparent liquid 106 is supplied to the surface 101a to be processed, the processing accuracy is preferably maintained during the processing.

However, in the liquid layer forming mechanism 70, the supply port 73 and the discharge port 74 are not necessarily essential components, and even if the transparent liquid 10 is supplied or discharged from above the cylindrical member 71 before and after the processing, it is obtained. The effect of the liquid layer 107 is set.

Moreover, it is preferable that the liquid layer forming means 70 is provided with a window portion 75 including a plate-shaped member that is transparent with respect to the pulsed laser light LB on the upper portion of the tubular member 71 which is the upper portion of the storage tank 72. The transparent liquid 106 is stored in the storage tank 72 in a state of being in contact with the window portion 75 at least during the period in which the pulsed laser light LB is irradiated to perform the splitting/cracking process. That is, the transparent liquid 106 is completely filled inside the storage tank 72. Further, the plate-like member constituting the window portion 75 is secured to the tubular member 71 by the O-ring 76 disposed along the tubular member 71. By providing the window portion 75 in this manner, fluctuations in the liquid level of the transparent liquid 106 are prevented, so that the utilization efficiency of the energy of the pulsed laser light to be irradiated is further improved.

(2nd formation aspect)

Fig. 22 is a side sectional view showing a second formation of the liquid layer. Similarly to the first formation shown in Fig. 21, in the second formation shown in Fig. 22, the fixing piece 102 to which the workpiece 101 is attached is placed on the stage 7, and the fixing ring is placed. 103 is placed on the outer edge of the fixing piece 102.

Further, the liquid layer forming mechanism 70 including the tubular member 71 is also the same as the first forming aspect, but the second forming aspect is different from the first forming aspect in that the cylindrical member 71 is disposed. The fixing piece 102 to which the workpiece 101 is attached is attached. That is, in the second formation aspect, the stage 7 is provided with a storage groove 72 having the fixing piece 102 as a bottom portion and the cylindrical member 71 as a side wall portion. The cylindrical member 71 must be fixed in a state in which the sealing property is ensured with respect to the fixing piece 102 before the processing, and is preferably separated from the fixing piece 102 after the completion of the processing. This can be achieved by, for example, screwing the tubular member 71 to the platform 7 in a state where the fixing piece 102 is clamped.

In the liquid layer forming mechanism 70, the following two points are the same as the first forming form: the cylindrical member 71 is provided with a supply port 73 for supplying the transparent liquid 106 from a specific supply source (not shown), as shown by the arrow AR11, and The discharge port 74 for discharging the transparent liquid 106 from the storage tank 72 as indicated by the arrow AR12; and preferably supplying or discharging the transparent liquid 106 continuously or intermittently during the processing, and is processed as the arrow AR13 A fluidized layer is formed on 101a. In addition to this, it is preferable that the liquid layer forming mechanism 70 is provided with the window portion 75 in the same manner as the first forming aspect.

When the pulsed laser light LB is irradiated in a state in which the liquid layer 107 is formed by the second formation state, and the cleaving/cracking process is performed by each of the above-described processing types, the pulsed laser light from the processed surface 101a is irradiated. The scattering of the substance in the irradiated area of LB is also suppressed by the liquid layer 107 adjacent to the processed surface 101a. In other words, when the liquid layer 107 is formed by the second formation state, it is possible to achieve a good splitting/cracking process which improves the utilization efficiency of the energy of the pulsed laser light LB.

(the third formation aspect)

Figure 23 is a side cross-sectional view showing a third formation of the liquid layer. In the third formation aspect, the workpiece 101a to be processed placed on the stage 7 (not shown in FIG. 23) is mounted on a discharge mechanism 80 that is connected to a supply source (not shown) such as an arrow. The transparent liquid 106 is directly discharged as shown in AR 14, whereby the liquid layer 107 is formed on the surface 101a to be processed. More specifically, the discharge mechanism 80 ejects the transparent liquid 106 to form the liquid layer 107 at a portion of the surface to be processed 101a which is at least the irradiated region of the pulsed laser light LB. That is, the discharge mechanism 80 functions as a liquid layer forming mechanism that forms the liquid layer 107. In this case, the liquid layer 107 is formed as a fluidized layer. Further, a discharge portion (not shown) for recovering the discharged transparent liquid 106 is appropriately disposed below the stage 7.

When the pulsed laser light LB is irradiated in a state in which the liquid layer 107 is formed by the third formation state, and the cleaving/cracking process is performed by each of the above-described processing types, the pulsed laser light from the processed surface 101a is irradiated. The scattering of the substance in the irradiated area of LB is also suppressed by the liquid layer 107 adjacent to the processed surface 101a. In other words, when the liquid layer 107 is formed by the third formation state, a good splitting/cracking process which improves the utilization efficiency of the energy of the pulsed laser light LB is also achieved.

1. . . Controller

2. . . Control department

3. . . Storage department

3p. . . Program

4, 102. . . Fixed piece

5. . . Optical system

5a. . . mirror

5b. . . Attenuator

5c. . . Optical path setting mechanism

6. . . Surface observation mechanism

6a, 16a. . . CCD camera

6b, 16b. . . Monitor

7. . . platform

7m. . . Mobile agency

9, 19, 53. . . Half mirror

10, 101. . . Processed object

11. . . Suction mechanism

16. . . Back observation mechanism

18. . . Condenser lens

twenty one. . . Drive control unit

twenty two. . . Camera control unit

twenty three. . . Irradiation control unit

twenty four. . . Adsorption control unit

25. . . Processing department

50. . . Laser processing device

50A. . . Laser light irradiation

50B. . . Observation department

51. . . Beam expander

52. . . Objective system

54. . . mirror

55. . . Optical path selection mechanism

70. . . Liquid layer forming mechanism

71. . . Cylindrical member

72. . . Storage tank

73. . . Supply port

74. . . Discharge

75. . . Window

76. . . O-ring

80. . . Ejection mechanism

101a. . . (processed object) processed surface

102. . . Fixed piece

102a. . . Blank part

103. . . M

104. . . Transparent member

104a. . . Upper surface

104b. . . Lateral surface

104e. . . End edge

104p, 104q. . . Ends

106. . . Transparent liquid

107. . . Liquid layer

111, 112. . . Fixed member

111a, 112a. . . Protruding

111b, 112b. . . Foot

111c, 112c. . . inside

112d. . . Support

121. . . Lifting mechanism

122. . . Base

131. . . First winding mechanism

132. . . Second winding mechanism

141. . . Next material

1011. . . Sapphire substrate

1012. . . LED construction

+a1, -a1, +a2, -a2, +a3, -a3. . . direction

AR1, AR2, AR11, AR12, AR13, AR14. . . arrow

C1~C3, C11a, C11b, C12a, C12b, C13a, C13b, C14a, C14b, C21~C24. . . Crack/cleavage plane

D. . . (platform) moving direction

D1. . . Processing location data

D2. . . Processing mode setting data

L. . . Processing line

L1. . . Epi-illumination light

L2. . . Oblique light

L3. . . Coaxial illumination

L4. . . Oblique illumination

LB, LB0, LB1, LB2. . . laser

Lα, Lβ. . . a line parallel to the planned line L

P21, P22, P23, P24, P25. . . Forming a predetermined position

RE, RE1~RE4, RE11~RE15, RE21~RE25. . . Irradiated area

S1. . . Epi-illumination source

S2. . . Oblique illumination source

S3. . . Coaxial illumination source

S4. . . Oblique illumination source

SL. . . Laser source

SW. . . Optical switch

W1, W2, W2a, W2b, W11a, W11b, W11c, W12a, W12b, W12c. . . Weak intensity part

1(a) to (e) are diagrams for explaining processing using the first processing type.

Fig. 2 is an optical microscope image of the surface of a workpiece having a division start point formed by splitting/cracking processing in the first processing type.

Fig. 3 is an SEM image of a sapphire C-plane substrate having a division starting point formed by processing of the first processing type, which is divided from the surface (c surface) to the cross section.

4(a) to 4(e) are diagrams schematically showing a processing aspect using the second processing type.

Fig. 5 is an optical microscope image of a surface of a workpiece on which a split starting point is formed by splitting/cracking processing in the second processing type.

Fig. 6 is an SEM image of the sapphire c-plane substrate having the division starting point formed by the processing of the second processing type, which is divided along the division starting point, from the surface (c surface) to the cross section.

7(a) and 7(b) are diagrams schematically showing a processing aspect using the third processing type.

Fig. 8 is a view showing the relationship between the planned line of the third processing type and the predetermined position at which the irradiated area is formed.

Fig. 9 is a schematic view showing the configuration of a laser processing apparatus 50 according to an embodiment of the present invention.

FIG. 10 is a schematic view showing the configuration of the optical system 5.

Fig. 11 is a view schematically showing the configuration of the optical path setting means 5c.

Fig. 12 is a schematic view showing a method of achieving high efficiency of splitting/cracking processing using a transparent member.

FIG. 13 is a side cross-sectional view showing a first arrangement of the transparent member 104.

Fig. 14 is a side cross-sectional view showing a second arrangement of the transparent member 104.

Fig. 15 is a side view showing a third arrangement of the transparent member 104.

Fig. 16 is a side view showing a third arrangement of the transparent member 104.

Fig. 17 is a side view showing a fourth arrangement of the transparent member 104.

Fig. 18 is a side view showing a fourth arrangement of the transparent member 104.

Fig. 19 is a side view showing a fourth arrangement of the transparent member 104.

Fig. 20 is a side cross-sectional view showing a fifth arrangement of the transparent member 104.

Fig. 21 is a side sectional view showing the first formation of the liquid layer.

Fig. 22 is a side sectional view showing a second formation of the liquid layer.

Figure 23 is a side cross-sectional view showing a third formation of the liquid layer.

+a1, -a1, +a2, -a2, +a3, -a3. . . direction

C1, C2, C3. . . Crack/cleavage plane

L. . . Processing line

RE1, RE2, RE3, RE4. . . Irradiated area

W1, W2, W2a, W2b. . . Weak intensity part

Claims (20)

A processing method for a workpiece, which is a processing method for forming a starting point of a workpiece on a workpiece, comprising: a placing step of placing a workpiece on a platform; and a transparent substance disposing step a transparent transparent material that is transparent to the pulsed laser light used in the processing of the workpiece, is disposed adjacent to the surface to be processed of the workpiece placed on the platform, and an irradiation step is performed on the surface The platform is continuously moved relative to the light source of the pulsed laser light, and the pulsed laser light is transmitted through the transparent substance, and the irradiated area of each unit pulsed light is discretely formed on the surface to be processed. The object irradiates the pulsed laser light, and the crack or cleavage of the workpiece is sequentially generated between the irradiated regions, thereby forming a starting point for division on the workpiece. The processing method of the workpiece according to claim 1, wherein the pulsed laser light has a pulse width of ultra-short pulse light of a psec level. The method for processing a workpiece according to claim 1 or 2, wherein the transparent substance disposing step is disposed adjacent to the transparent member of the solid which is substantially transparent with respect to the pulsed laser light used in the processing of the workpiece. a transparent member disposing step on the surface to be processed of the workpiece to be placed on the platform, wherein the pulsed laser light is transmitted through the transparent member in the irradiating step, and each of the processed surfaces is discretely formed Irradiating the above-mentioned workpiece with the pulsed light in the manner of the irradiated area of the unit pulsed light The light is emitted, and the object to be processed is sequentially subjected to cracking or cleavage between the objects to be irradiated, whereby a starting point for division is formed on the workpiece. A method of processing a workpiece according to claim 3, wherein in the step of disposing the transparent member, the transparent member is placed in contact with the surface to be processed. The method of processing a workpiece according to claim 3, wherein in the transparent member disposing step, the transparent member and the processed surface are disposed apart from each other by a distance of 100 μm or less. The processing method of the workpiece according to claim 3, wherein in the transparent member disposing step, the transparent member is adjacent to a partial region of the irradiated position including the pulsed laser light among the processed surface The configuration is such that the configuration position is migrated corresponding to the migration of the illuminated position described above. The processing method of the workpiece according to claim 1 or 2, wherein the transparent substance disposing step is performed on a processed surface of the workpiece to be placed on the platform, by processing with respect to the workpiece a liquid layer forming step of forming a liquid layer by using a pulsed laser light as a transparent liquid, wherein in the irradiating step, the pulsed laser light is transmitted through the liquid layer, and each of the processed surfaces is discretely formed Irradiating the pulsed light to the workpiece, the pulsed light of the unit is irradiated, and the crack or cleavage of the workpiece is sequentially generated between the irradiated regions, thereby performing the object to be processed. Formed on points The starting point of cutting. The processing method of the workpiece according to claim 7, wherein in the liquid layer forming step, the workpiece is immersed in the inside of the storage tank formed on the platform at least during the irradiation step. In the liquid, the liquid layer is formed on the surface to be processed. The processing method of the workpiece according to claim 7, wherein in the liquid layer forming step, the liquid is continuously or intermittently flowed during at least the irradiation step, thereby being processed on the processed surface A fluid layer is formed. The method for processing a workpiece according to claim 1 or 2, wherein at least two of the irradiated regions formed by the different unit pulse lights are formed adjacent to each other in an easy opening or splitting direction of the workpiece . The processing method of the workpiece according to claim 1 or 2, wherein the source of the pulsed laser light is moved relative to the workpiece, and the outgoing direction of the pulsed laser light is in a plane perpendicular to the relative movement direction. Periodically changing, a plurality of the irradiated regions satisfying the zigzag arrangement relationship are formed on the workpiece. The processing method of the workpiece according to claim 1 or 2, wherein the plurality of emission sources of the pulsed laser light are relatively moved with the workpiece, and the unit pulse light from each of the plurality of emission sources is irradiated The timing is periodically changed, thereby forming a plurality of the irradiated regions satisfying the zigzag arrangement relationship on the workpiece area. A method for dividing a workpiece, which is a method for dividing a workpiece, comprising: a placing step of placing a workpiece on a platform; and a transparent material disposing step, which is relative to the workpiece The pulsed laser light used in the processing is a transparent transparent material disposed adjacent to the processed surface of the workpiece placed on the platform; and an irradiation step of causing the platform and the source of the pulsed laser light The pulsed laser light is irradiated to the workpiece to illuminate the irradiated region of the unit pulse light on the surface to be processed, and the pulsed laser light is irradiated to the workpiece. Splitting or cleavage of the workpiece between the irradiated regions in order to form a starting point for dividing the workpiece, and a dividing step of dividing the segment along the dividing starting point The object to be processed having the division starting point is formed by the irradiation step. A laser processing apparatus comprising: a light source that emits pulsed laser light; and a platform that mounts a workpiece; and further includes pulsed laser light to be used in processing of the workpiece a transparent material disposing mechanism in which a transparent transparent material is disposed adjacent to a surface to be processed of the workpiece placed on the platform, and the workpiece is placed on the platform while the platform is The light source of the pulsed laser light continuously moves relative to each other, and one side will The transparent material is placed adjacent to the surface to be processed, and the platform is moved such that the irradiated region of each unit pulse light of the pulsed laser light is discretely formed on the surface to be processed. The pulsed laser light is irradiated onto the workpiece, and cracking or cleavage of the workpiece is sequentially generated between the irradiated regions, whereby a starting point for division is formed on the workpiece. The laser processing apparatus of claim 14, wherein the pulsed laser light has a pulse width of ultra-short pulse light of a psec order. The laser processing apparatus according to claim 14 or 15, wherein the transparent substance disposing mechanism is disposed adjacent to the transparent member in a transparent solid with respect to the pulsed laser light used in the processing of the workpiece. a transparent member arranging mechanism on the surface to be processed on the workpiece to be placed on the platform, and the transparent member is placed adjacent to the surface to be processed And moving the stage so that the irradiated area of each unit pulse light of the pulsed laser light is discretely formed on the surface to be processed, and irradiating the processed object with the pulsed laser light, The irradiation regions are sequentially subjected to cracking or cleavage of the workpiece, whereby a starting point for division is formed on the workpiece. The laser processing apparatus according to claim 14 or 15, wherein the transparent substance disposing mechanism is used on a processed surface of the workpiece to be placed on the platform, and is used in processing with respect to the workpiece Pulsed laser light is a transparent liquid to form a liquid layer a layer forming mechanism that discretely forms the pulsed laser light on the surface to be processed while the workpiece is placed on the stage and the liquid layer is formed on the surface to be processed The unit is moved by the irradiated area of the unit pulsed light, and the pulsed laser light is irradiated onto the workpiece, and the cracked or cleaved of the workpiece is sequentially generated between the irradiated regions. This forms a starting point for division on the workpiece. The laser processing apparatus according to claim 17, wherein the liquid layer forming means includes a cylindrical member, and the cylindrical member constitutes a storage tank which is disposed on the platform to store the liquid, and the inside of the storage tank The processed object is placed on the above-mentioned stage and immersed in the liquid to form the liquid layer on the surface to be processed. The laser processing apparatus according to claim 17, wherein the liquid layer forming means has a storage tank having the platform as a bottom, and the workpiece is placed on the platform and immersed in the inside of the storage tank. In the liquid, the liquid layer is formed on the surface to be processed. The laser processing apparatus according to claim 17, wherein the liquid layer forming means includes a discharge mechanism that ejects the liquid onto the processed surface in a state where the workpiece is placed on the stage. The pulsed laser light is irradiated in a state in which the liquid-repellent layer is formed by the liquid ejected from the ejecting means, whereby a starting point for the division is formed on the workpiece.