JPS593430A - Formation of photoresist film - Google Patents

Abstract

PURPOSE:To form automatically and uniformly photoresist films on two mask substrates by placing the substrates opposite and close to eath other, dropping a photoresist agent, and rotating the substrates in the reverse directions. CONSTITUTION:A glass substrate 3 is put on the chuck 2 of a lower motor 1 from a cassette 4 with a chuck means. A glass substrate 3 is similarly attached to the underside of the chuck 2 of an upper motor 1 from the cassette 4. At this time, a container 7 contg. a photoresist agent is positioned above the substrate 3 on the chuck 2 of the lower motor 1, and the photoresist agent is dropped on the substrate 3 through a filter 8. The upper motor 1 is then moved to the right so as to make the substrate 3 opposite to each other. The substrates 3 are rotated in the reverse directions with the motors 1 to coat uniformly photoresist layers. All of said stages can be automated.

Description

DETAILED DESCRIPTION OF THE INVENTION (1.1 Technical Field of the Invention The present invention relates to a method for forming a photoresist film, and more specifically, to a method for forming a photoresist film in a mask forming step without using a conventional spin code (rotary coating). (2) Background of the technology A mask used for exposing a wafer, etc. is a method of forming a thin film of chromium (Cr) and a low reflection film on a mask substrate, for example, a glass substrate.
These films (hereinafter referred to as chromium thin films) are deposited and patterned. In such buttering, a photoresist agent is applied over the entire surface of the chromium thin film to form a photoresist film (hereinafter referred to as a resist film), and after this resist film is buttered, the chromium thin film is etched.

To form the resist film described above, a step of coating each glass substrate with resist is carried out using a spin type resist coater schematically shown in FIG. In the figure, 1 is a motor, 2 is a vacuum chuck attached to the motor 1, and 3 is a glass substrate. The glass substrate 3 is firmly held by the vacuum chuck 2. The vacuum chuck 2 rotates at high speed due to the rotation of the motor 1, and the glass substrate 3 also rotates at high speed accordingly.

Here, the liquid resist agent is applied to the glass base! When dropped onto the central portion of ii3, the resist agent spreads outward in a ring shape due to the rotation of the glass substrate 3 and is evenly applied onto the glass substrate 3. Such a subin coating method is a technique that is currently widely used because it enables the application of a resist agent using a simple device.

(3) Prior art and problems In the prior art described above, a liquid resist agent is applied onto a glass substrate that is rotating at high speed, but when the resist agent is initially dropped, some amount of it is blown away. There is. The amount of resist agent to be dropped is determined by calculating the area of the glass substrate and the thickness of the resist film, so if some of that amount is splashed off as described above,
This results in variations in the thickness of the resist film formed.

In addition, when the film thickness of the resist film was precisely measured, it was found that the film thickness of the resist film was thinner on the peripheral part of the glass substrate than on the central part of the glass substrate. It was observed that it was not strictly uniform.

With the recent trend toward higher densification of integrated circuits, mask patterns are becoming smaller, but the thickness of the resist film essential for manufacturing the masks used to form them is as described above. , this poses a problem in miniaturization of the mask pattern.

(4) Object of the Invention In view of the above-mentioned conventional drawbacks, the present invention provides a method for forming a resist ++p having a uniform thickness over the entire surface of a mask substrate when applying a resist agent onto the mask substrate.

(5) Structure and object of the invention According to the present invention, two mask substrates are arranged so that the surfaces on which resist films are formed are close to each other and face each other, and a bottom resist is applied to one of the mask substrates. This is achieved by providing a method for forming a photoresist film, which is characterized in that the two mask substrates are rotated in opposite directions.

(6) Examples of the invention Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 2, two mask substrates (glass substrates) are placed close to each other. Note that in the figures below, the same parts as those shown in FIG. 1 are designated by the same reference numerals. 2
In the embodiment of the present invention, the two glass substrates 3 are arranged with a distance of 100 to 500 μm between them, with the surfaces to which the resist agent is applied facing each other, and the resist agent is applied to one side. is dropped onto the glass substrate 3 of.

Next, the glass substrates 3 are each rotated at high speed in opposite directions as indicated by the arrows in the figure. Then, the resist agent not only spreads in a ring shape as in the case of the conventional spin code method, but also in this spreading, the resist agent is thicker than other parts, so that the distance between the two glass substrates 3 is as described above. Since the resist material is narrow on the order of , it is rubbed between the glass substrates and spread, and the resist agent is applied uniformly over the entire surface.

To rotate two glass substrates in opposite directions as shown in FIG. 2, an apparatus shown in FIG. 3 is used.

In the figure, 4 is a cassette that stores the glass substrate 3;
5 is a stand on which the cassette 4 and the lower motor 1 are fixed; 6 is a rail, along which the upper motor 1 and the resist agent container 7 are movable as shown by arrows l and ■ in the figure; 8 indicates a filter for resist agent.

In operation, one glass substrate 3 is placed from the cassette 4 onto the chuck 2 located below (in two directions) using a chuck means (not shown).

Next, the upper motor 1 and resist agent container 7 are moved so that they are located above the center of the glass substrate 3 above the cassette 4 and lower chuck 2, respectively.

Here, the upper chuck 2 holds the glass substrate Mj, 1 by suction, and a predetermined amount of resist agent is dripped from the resist agent container 7 onto the lower glass substrate 3 via the filter 8.

Next, the upper motor 1 and resist container 7 move to the right to the positions shown in the figure, and the upper and lower motors l rotate in opposite directions as described above, rotating the upper and lower glass substrates at high speed in opposite directions as shown in FIG. As it rotates, the resist agent is applied onto the opposing surfaces of the upper and lower glass substrates 3 as described above. As is clear from FIG. 3, all operations of the device can be automated.

(7) Effects of the Invention As explained in detail above, when using the method of the present invention, a resist film is uniformly formed on the mask substrate using an extremely simple device, and the resist film coating process is automated. This is highly effective in contributing not only to the miniaturization of mask patterns but also to improving the manufacturing yield of semiconductor devices.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view of an apparatus used in the conventional spin code method, FIG. 2 is a perspective view showing the arrangement of two glass substrates when carrying out the method of the present invention, and FIG. 1 is a front layout of the apparatus for carrying out the method; FIG. ■-Motor, 2-Vacuum chunk, 3-Glass substrate, 4-Cassette, 5 one unit, 6-Rail, 7-Resist agent container, 8-Filter Fig. 1 Fig. 2

Claims (1)

[Claims] In a method of coating and forming a photoresist film on a substrate,
The method is characterized by arranging two substrates so that the surfaces on which resist films are formed are close to each other and facing each other, dropping a photoresist agent onto one of the substrates, and rotating the two substrates in opposite directions. A method for forming a photoresist film.