JPS60115224A - Resist coating method - Google Patents

Abstract

PURPOSE:To enable to form uniform, thin and rigid photo resist by rotating a substrate by changing the speed in two stages after the photo resist is dripped onto the substrate. CONSTITUTION:After placing a silicon substrate 3 allowing a gold thin film 2 to be deposited on the entire part on a substrate support 1 of a rotatable coating device, a positive photo resist 4 is dropped onto a silicon substrate 3 from a dispensor. Thereafter, a substrate support 1 is rotated at a speed, for example, as high as 5,000rpm for 0.5sec. Thereafter, the substrate support 1 is rotated at a speed as low as 3,000rpm for 20sec. The substrate thus coated with resist is dried. After the resist film is stabilized by prebaking process, the substrate is sent to the exposure process.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a resist coating method, and particularly to a method for obtaining a uniform photoresist film used in a photolithography process for forming semiconductor integrated circuits (ICs), etc. The present invention relates to a photoresist coating method.

[Prior art]

A photophosphorus process is usually employed to form fine/4' turns in the manufacture of semiconductor integrated circuits and the like. In this photorin process, a photoresist film is formed on a metal thin film formed on the entire surface of the substrate by, for example, a vacuum evaporation method, and then the photoresist film is coated with a photomask having a predetermined pattern shape. By performing an exposure process, a predetermined resist film (turn) is obtained, and etching is performed using this resist turn as a mask to remove the metal thin film exposed on the surface - that is, the part not covered by the resist/mother turn. By doing this, a thin film pattern with the desired shape can be obtained. Therefore, the performance of the obtained thin film pattern depends on how faithfully and precisely the photoresist film can be transferred to all i4 turns of the photomask during the exposure process. This will have a big impact.

That is, it is desirable that the thickness of the photoresist film be uniform and as thin as possible, and that the film quality be dense so that it can maintain sufficient resistance as a mask in the subsequent etching process of the metal thin film.

Conventionally, various efforts have been made to form thin resist films, such as using photoresists with low viscosity, but in this case, the result is an uneven film. was extremely difficult to form.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and its entire purpose is to form a uniform, thin, and dense photoresist film.

[Structure of the invention]

In order to achieve the above object, according to the resist coating method of the present invention, after placing a substrate on a rotational coating device and dropping a photoresist (1) onto the substrate, while rotating the substrate,
The rotational speed of this rotation is switched in two stages.

For example, the substrate may be first rotated at high speed and then switched to low speed rotation, or first rotated at low speed and then switched to high speed rotation.

〔Example〕

Hereinafter, a method for applying a photoresist according to a first embodiment of the present invention will be described with reference to the drawings.

First, as shown in FIG. 1, a silicon substrate 3 having a thin gold film 2 deposited on its entire surface is placed on a substrate support 1 of a spin coating device which is connected to a spin coater. ,
From a dispenser (not shown), a photoresist 4 manufactured by Tokyo Ohka Chemical Co., Ltd., commercially available under the trade name ARPG, is dropped onto the silicon substrate 3. The viscosity of 7 Otoresist 4 at this time was 10 c,p, (centidays).

Next, the substrate support stand 1 is rotated at a rotation speed of 500 as shown in FIG.
Rotate at high speed for 0.5 seconds at Or, p, m, (times/min).

Subsequently, the substrate support stand 1 is rotated at a rotation speed of 300 as shown in FIG.
Rotate at low speed for 20 seconds at Or, p, m.

After drying the substrate coated with resist in this way,
After the resist film is stabilized through pre-painting (pre-heating) treatment, it is moved to the exposure process.

The resist film 5 thus formed has a thickness of 2000
It is uniform and dense with X, and the surface properties are also good.

By the way, the same photoresist can be used in the traditional way, i.e.
When coating is performed at a rotational speed of 300 Or, p, rotation for 30 seconds at the center, the resulting resist film has a thickness of 500.
01, the texture was not uniform.

As is clear from these comparisons, compared to the resist film applied by the conventional method, the resist film applied by the method of the embodiment of the present invention is thinner, more uniform, has a denser surface, and is more difficult to apply during subsequent exposure. In addition to being able to faithfully and accurately transfer the photomask pattern during the process, it also sufficiently protects the underlying gold thin film as a mask during the etching process, making it possible to form 79 turns of gold with good dimensional accuracy. be.

That is, according to this method, the resist is diffused on the substrate in a short period of time with the initial high speed rotation, and after scattering unnecessary resist, the resist film is stabilized with the low speed rotation. 6 Furthermore, a second embodiment of the present invention will be described.

First, as in the first embodiment, photoresist is dropped onto a silicon substrate.

Next, the substrate support was rotated at a rotation speed of 200 (l r, p,
Rotate at low speed for 0.5 seconds at m.

Subsequently, it is rotated at a low speed of 500 Or, > m for 20 seconds.

Even with this method, a fairly uniform resist film can be obtained. This method is particularly effective when using a resist with a particularly high viscosity.

In the examples, 0FPR'tl- manufactured by Tokyo Ohka Co., Ltd. was used as the photoresist, but it is not necessarily limited to this, and similar effects can be obtained with other 7 photoresists such as A21350 manufactured by Schsolt Co., Ltd. I can do it.

Furthermore, this method is highly effective not only in the manufacturing process of semiconductor integrated circuits, but also in all processes that involve a photoresist coating process, such as the manufacturing of printed wiring boards.

〔Effect of the invention〕

As explained above, according to the present invention, when applying photoresist onto a substrate, after dropping the resist, the substrate is rotated in two stages, such as from high-speed rotation to low-speed rotation, or from low-speed rotation to high-speed rotation. Since the rotation is controlled by switching the rotation speed, it is possible to form a thin, uniform, and dense resist film.

[Brief explanation of drawings]

1 to 3 are process explanatory diagrams showing the resist coating process of the first embodiment of the present invention. 1...Substrate support stand, 2...Silicon substrate, 3...-
Gold thin film, 4... photoresist, 5... resist film.

Claims (2)

[Claims] (1) Place the substrate on a spin coating device, and apply 7 coats on the substrate.
1. A resist coating method for forming a uniform resist film by rotating a substrate after dropping an otoresist, the method comprising switching the rotation speed of the substrate into two stages. (2) The substrate is first rotated at high speed and then rotated at low speed.
) The resist coating method described in section 2.