JPH0391231A - Method and device for baking of resist film - Google Patents

Abstract

PURPOSE:To make an exposure sensitivity uniform by previously heating a jig for taking out a substrate up to about a pre-baking temperature of a resist film when the substrate coated with the resist film is taken out of an oven which has been heated up to said pre- baking temperature. CONSTITUTION:A jig 11 for taking out a substrate 2 from a pre-baking oven 1 is provided with a ring-form projection 5 contacting with the lower plane end part of the substrate 2, an intake vent 6 opening in the center of the ring-form projection 5, a suction tube 7 whose one end is communicating with said intake vent 6, a tube 13 in which a heating medium 12 circulates, and a control device 14 which sets the temperature of the jig 11 at a predetermined value and contains it. The tube 13 in which the heating medium 12 is circulated by driving a circulation pump 15 is connected with an oil tank 16 in the control device 14. In the tank 16, a temperature detector 17 for detecting the temperature of the heating medium 12 and a heater 18 for heating the heating medium 12 are arranged. A detecting circuit 19 to which the detector 17 is connected is connected to a heater control circuit 20, which controls the electric power to be introduced into the heater 18 so that the temperature of the heating medium 12 in the tank can be kept at a predetermined temperature. Then, the control device 14 is set so as to keep the temperature of the jig 11 at a pre-baking temperature of the resist film. As a result, the exposure sensitivity can be made uniform over the whole region and the accuracy of a fine resist pattern can be improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a resist film baking method and its apparatus, the present invention aims to reduce variations in resist pattern width in order to improve the accuracy of fine patterns formed on semiconductor device chips, etc. When a substrate on which a resist film is adhered is taken out from a furnace heated to a pre-baking temperature of the resist film, a jig for taking out the substrate is preheated to approximately the pre-baking temperature. constituting the baking method, and the substrate removal jig is provided with heating means capable of heating the jig to the pre-baking temperature, and the heating means is provided with a temperature detector for the jig or the heating medium. The resist film baking device is connected to a temperature control device.

[Industrial application field]

The present invention relates to a method and apparatus for baking a resist film used in the manufacture of exposure substrates etc. which are essential for the manufacture of semiconductor devices, and more specifically to a method for pre-baking a resist film and a tank bottom of the pre-baking apparatus.

[Conventional technology]

In semiconductor devices, etc., the various patterns formed on chips are becoming increasingly finer as the equipment becomes more sophisticated and smaller. - High layer precision is now required.

Such an exposure substrate is made by, for example, depositing a thin film of metal such as chromium on the top surface of a transparent quartz substrate with a thickness of about 2.3 mm by sputtering, and then depositing a resist film on top of the thin film using a resist coater. let

Next, the resist film is heated together with the substrate at 200°C for 1 hour.
After prebaking the resist film by heating for about 0 minutes, unnecessary portions of the resist film are removed by exposure and development to form a resist pattern.

Next, the metal thin film is selectively removed using a resist pattern hardened by post-baking treatment, and then the resist pattern is removed to complete the process.

FIG. 4 is an explanatory diagram of the operation of a jig for taking out a substrate in a pre-baking apparatus, and FIG. 5 is a schematic diagram showing essential parts of the conventional jig shown in FIG.

In FIG. 4, the substrate 2 that has been subjected to the baking process in the pre-baking furnace 1 is moved by the operation of a jig 3 which is waiting outside the pre-baking furnace 1 and has substrate suction means at its tip.
It is taken out from the pre-baking oven 1 and conveyed to the cooling table 4.

In FIG. 5, a substrate 2 on which a resist film is applied
The jig 3 for vacuum suctioning the lower end of the is comprised of an annular protrusion 5 that the end contacts, and an air intake port 6 that opens at the center of the annular protrusion 5.
and an intake pipe 7 whose one end communicates with the intake port 6, and whose other end communicates with a vacuum pump.

FIG. 6 is an explanatory diagram of a sample for measuring variation in resist pattern width formed on an exposure substrate by a conventional method.

In FIG. 6, a resist pattern width variation measurement sample 8 has a predetermined area set at 75 mm x 75 mm at the center of the upper surface of a quartz substrate 9 formed to measure 126 mm x 126 mm, and the predetermined area includes the boundary thereof. 5×5
Set 10 measurement points at equal intervals on the left and right, and set 10 measurement points at each point.
A resist pattern of the same width is formed on both sides.

The resist pattern formed on such sample 8 is -
As an example, a positive EB exposure resist is applied to a thickness of 5,000 yen and is formed after pre-baking at 200°C for 10 minutes. The lower end portion outside the area is held by vacuum suction.

The predetermined area of 75mm x 75mm is 126m
This corresponds to the general maximum required area for conventional exposure substrates, which is m x 126 mm, and the measured value of the resist width at each measurement point 10 is an average value of 2.29 μm.
m, maximum value = 2.46 μm, minimum value -2.23 μm, standard deviation value = 0.18.

FIG. 7 is a schematic diagram showing the tendency of variation in resist pattern width. Measured values are written at each measurement point 10 using bar lines based on the minimum measurement value, and the tips of each bar line are connected vertically and horizontally to form an uneven surface A. In FIG. 7 shown in FIG. 7, the region where the resist pattern width is large, that is, the convex portion of the uneven surface A corresponds to the portion attracted by the jig 3. In FIG.

[Problem to be solved by the invention]

In semiconductor chips that are oriented towards high performance and miniaturization,
It is desirable that the fine pattern has a width of 0.8 μm or less. Therefore, for example, 5
The pattern width of the reticle enlarged twice is 4 μm or less.

However, reticles created using conventional methods have resist pattern width variations of 0.2 μm or more, and pattern widths formed using such reticles have variations of 5% or more, resulting in chip failure. In addition to reducing the performance and reliability of the chip, even if the required area of the exposure substrate is expanded to, for example, 105 mm x 105 mm in response to the increase in chip size, the pattern accuracy will deteriorate outside the conventional required area of 75 mm x 75 mm. There was a problem in that it could not be expanded because of the further decrease in .

[Means to solve the problem]

In order to solve the above problems and improve the precision of fine patterns, in the conventional technology, when a resist film-coated substrate is taken out of a pre-baking furnace, a part of the resist film is rapidly cooled by a jig for taking out the substrate. According to FIG. 1 showing an embodiment of the present invention, when a substrate 2 coated with a resist film is taken out from a furnace heated to the pre-baking temperature of the resist film, a jig for taking out the substrate is used. 11 to about the pre-baking temperature, and the substrate removal jig 11 is provided with a heating means 13 capable of heating the jig 11 to the pre-baking temperature. The resist film baking apparatus is characterized in that a heating means 13 is connected to a temperature control device 14 having a temperature detector 17 for a heating medium 12.

[Effect]

According to the above means, by heating the substrate removal jig in advance, the resist film coated substrate taken out from the pre-baking furnace is not partially quenched by the substrate removal jig.

Therefore, the exposure sensitivity of the resist film after prebaking becomes uniform over the entire surface, and resist pattern accuracy is improved.

〔Example〕

Below, a resist film baking method and apparatus for the same according to the present invention, which were made in view of the above problems, will be explained.

FIG. 1 is a schematic diagram showing the main parts of a jig for taking out a substrate according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a sample for measuring variation in resist pattern width formed using the jig, and FIG.
The figure is a schematic diagram showing the tendency of variation in resist pattern width in the sample.

In FIG. 1, in which the same reference numerals are used for parts common to the previous figure, it corresponds to a conventional jig 3 and is used to move the substrate 2 from the pre-baking furnace 1.
The jig 11 for taking out oil, etc. has an annular projection 5 that contacts the lower end of the substrate 2, an intake port 6 that opens at the center of the annular projection 5, an intake pipe 7 whose one end communicates with the intake port 6, and an annular projection 5 that contacts the lower end of the substrate 2. A tube (heating means) 13 through which a heating medium 12 circulates, and a jig 11
It is equipped with a control device 14, etc., for setting and maintaining the temperature at a predetermined value.

A pipe 13 through which the heating medium 12 circulates by driving the circulation pump 15 is connected to an oil tank 16 in the device 14, and a temperature detector 17. A heater 18 for heating the heating medium 12 is provided, and a detection circuit 19 to which the detector 17 is connected is connected to a heater control circuit 20. The control circuit 20 controls the electric power flowing to the heater 18, and controls the heating medium in the tank. The temperature of No. 12 is maintained at a predetermined value.

Therefore, the control device 14 is set so that the temperature of the jig 11 is maintained at the pre-baking temperature of the resist film, for example, 200°C.

In FIG. 2, the resist pattern width variation measurement sample 21 has a first predetermined area of 105fflIIlx105III at the center of the upper surface of the quartz substrate 9, which is formed to measure 126mm x 126mm.
I11D A second predetermined area is set, measurement points 10 are placed at equal intervals on the left and right at 5×5 locations including the boundary of the first predetermined area, and measurement points 10 are placed at equal intervals on the left and right at the boundary of the second predetermined area including the first predetermined area. Measurement points 22 were set at 24 equally spaced locations along the
and 22 to form resist patterns of the same width.

The resist pattern formed on such sample 21 is
The same conditions as Sample 8 used for the investigation of the prior art were applied, that is, a positive EB exposure resist was applied to a thickness of 5000 mm, and 200 mm thick was applied.
It is formed after pre-baking at 10°C for 10 minutes, and when taken out from the pre-baking furnace 1, the jig 11 vacuums the bottom edge of the second predetermined area outside the first predetermined area. It was retained by adsorption.

The measured values of the resist width in the first predetermined area include an average value of -1,52 μm, a maximum value of -1,53 μm, a minimum value of -1,50 μm, and a standard deviation value of -0,03. The measured values of the resist width in the second predetermined area were an average value of -1.52 μm, a maximum value of −1.53 μm, a minimum value of −1.49 μm, and a standard deviation value of −0.04.

That is, the variation in resist pattern width according to the present invention is
The first predetermined area of 75 mm x 75 mm is about 1/8 of that of measurement sample 8 by the conventional method, and 1
Even in the second predetermined area of 05 mm x 105 mm, the area is about 176 of the conventional measurement sample 8, which is set to 75 mm x 75 mm.

In FIG. 3, the uneven surface B is based on the minimum measured value of the resist pattern width, and the measured values are written in bar lines at each measurement point 10 and 22, and the tips of each bar line are connected vertically and horizontally. The unevenness tendency of the uneven surface B is independent of the position held by the jig 11.

Although the above embodiments relate to exposure substrates, the present invention is not limited to such exposure substrates, and can be applied, for example, to forming resist patterns on chips such as semiconductor devices.
It should be noted that the same effect was obtained.

〔Effect of the invention〕

As explained above, according to the present invention, the resist film deposited on the substrate taken out from the pre-baking furnace is not partially quenched by the substrate removal jig, so that the resist film is coated over the entire area. The exposure sensitivity has been made uniform, and the precision of fine resist patterns in particular has been improved, which has had a remarkable effect in contributing to higher performance and higher density of semiconductor chips and the like.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a jig for taking out a substrate according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a sample for measuring variation in resist pattern width 1 according to the method of the present invention, and FIG. 3 is a resist pattern according to the method of the present invention. A schematic diagram showing the tendency of width variations, Figure 4 is an explanatory diagram of a jig for taking out a substrate in a pre-baking device, Figure 5 is a schematic diagram of a conventional jig for taking out a substrate, and Figure 6 is a resist pattern according to a conventional method. FIG. 7 is an explanatory diagram of a width variation measurement sample. FIG. 7 is a schematic diagram showing a tendency of variation in resist pattern width according to the prior art. In the figure, 1 is a pre-baking furnace, 2.9 is a resist pattern formed substrate, 11 is a jig for taking out the substrate, 12 is a heating medium, 13 is a tube (heating means) through which the heating medium circulates, and 14 is a temperature control device. , 17 is a temperature detector, and 21 is a resist pattern width measurement sample.

Claims (2)

[Claims] (1) When taking out the substrate (2) on which the resist film has been adhered from the furnace (1) heated to the pre-baking temperature of the resist film, the substrate removal jig (11) is heated to approximately the pre-baking temperature. A resist film baking method characterized by preheating the resist film. (2) The jig (11) for taking out the board is
1) heating means (
13) is provided, and the heating means (13) is connected to the jig (11).
) or a heating medium (12) connected to a temperature control device (14) equipped with a temperature detector (17).