JPS58206124A - Applying method for resist - Google Patents

Abstract

PURPOSE:To maintain film thickness uniformly extending over the whole surface of a substrate by flowing out the vapor of a solvent dissolving a resist applied to the surface of the substrate from an upper section of a base body in a device applying the resist through a spinner method. CONSTITUTION:The substrate 11 is fixed to a head 12 by a vacuum chuck. A residual liquid of the resist collects in an effluent reservoir 13. The solvent stored in a vessel 21 is vaporized by a heating vessel 22, and the vaporized gas is forwarded to a duct 25 by a blower 23 and injected onto the rotatory substrate under application from the vertical direction. A heater 24 for heating the vapor of the solvent is set up between the blower 23 and the duct 25 as required. The duct 25 is positioned at the upper section of the substrate, and forwards a solvent vapor flow 26 to a resist thin-film 14' on the substrate. The vapor flow 26 reduces the generation of the vapor of the solvent in a spinner tank and the generation of ununiform volatilization and a turbulence with the discharge of the vapor, and a uniform resist film is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resist coating method, and particularly to a resist coating method suitable for coating a blank mask with a resist when producing a mask for manufacturing a semiconductor integrated circuit.

When manufacturing semiconductor integrated circuits, a mask is used to turn a wafer, which is a substrate, using photolithography technology. In order to manufacture this mask, a photosensitive layer is usually formed by applying a resist to a glass substrate having a thin film of chromium or the like on its surface. A pattern based on the circuit design is exposed to light using an electron beam or a light exposure device to create an exposed area and an unexposed area, and a resist layer for etching is created by removing 10,000 layers using a developing means. A mask pattern is created by removing 10,000 oxides by etching. The present invention relates to a method of coating the resist. The dipping method, the spray method, the spinner method, and the like are practically used as resist coating methods, and the present invention is particularly applicable to the spinner method. In this spinner method, a glass substrate is placed on a rotating substrate holder using a vacuum chuck, and the holder is rotated at a high speed of 500 to 7000 r, p, m to uniformly distribute the resist dropped onto the substrate. It is spread and applied. The resulting resist film has a thickness of 1 μm or less, and is effective for etching fine patterns. As described above, the spinner method has the advantage of being able to coat the entire surface of the substrate while keeping the resist film thin.However, due to various factors, it is difficult to maintain a uniform resist film thickness over the entire surface of the substrate, and there are problems with non-uniform film thickness. The result is observed as interference fringes, and uniform light absorption is not performed during pattern exposure, resulting in non-uniformity of the resist pattern.
The accuracy of the pattern will decrease. This effect becomes more significant as the pattern becomes finer. This is especially a big problem in processes that affect subsequent processes, such as mask creation.

Therefore, an object of the present invention is to provide a resist coating method that can solve the above-mentioned drawbacks, that is, can maintain a uniform film thickness over the entire surface of the substrate.

The present invention relates to a coating method in which a resist thin film is formed on a substrate (by dropping a resist solution and rotating the substrate at high speed), in which the vapor of a solvent that dissolves the applied resist flows out from above the substrate onto the substrate surface. This is a resist coating method characterized by the following.

The present invention focuses on the fact that the above-mentioned non-uniform film thickness is caused by solvent vapor volatilized from a resist solution on a rotating substrate, non-uniform volatilization and turbulence accompanying the exhaust of the solvent vapor, and solves this problem. In order to reduce the effects of uneven volatilization and turbulence caused by the generation and exhaust of solvent vapor in a spinner tank, the resist to be applied to the substrate is dissolved from above and the solvent vapor flows out.
This made it possible to eliminate uneven volatilization.

The invention will be explained below according to the drawings.

First, FIG. 1 shows a side view of an example of a conventional apparatus for carrying out a general resist coating method using a spinner method.

11 is a substrate, and this substrate 11 is fixed to the head 12 by a vacuum chuck (not shown).

The head and substrate are rotated by a motor.

A suitable amount of resist 14 is dropped approximately at the center of the substrate, and when the substrate 11 is rotated at high speed, it is affected by surface tension and centrifugal force and spreads as a thin film on the substrate 11, and the remaining liquid is removed. It collects in the drainage reservoir 13. Coating +1-1'll• used in the present invention to prevent film thickness unevenness that tends to occur with such spinner coating equipment.

An example of the device is shown in FIG. In this figure, 11.
Reference numerals 12 and 16 are the substrate, head and liquid reservoir already mentioned. Container 2 storing a solvent 20 for dissolving resist
The solvent in 1 is vaporized in a heating container 22 by appropriate means such as heating, and is sent to a duct 25 by an air blower 23 and sprayed in a substantially vertical direction ρ.onto a rotating substrate on which resist is being applied. A heater 24 is provided between 26 and 25 to heat the solvent vapor depending on the substrate.A duct 25 is located above the substrate and provides a flow of solvent vapor 26 to the resist thin film 14VC on the substrate. This vapor flow 26 effectively reduces uneven volatilization and turbulence caused by the generation of solvent vapor in the spinner tank and its exhaust, and forms a uniform resist film.

The temperature of the solvent vapor to be discharged is appropriately set, but a range of ambient temperature or 20° C. higher than the ambient temperature is generally suitable.

Example 1 Using the coating device shown in FIG. OgBR-100, Tokyo O, Kasei) 5-
After dropping (viscosity 51]cp), a glass plate ft40
While rotating at a speed of 00 r, p, co, 0.5 J/1 nin of 65°C vapor of ethyl cell solve acetate was flowed out from the duct 25 (10 cm diameter) toward the surface of the glass plate (within a spinner tank). (The temperature before steam blowing is 26℃). Rotate for about 2 minutes and apply 400 liters of photoresist
It is possible to form a thin film with a thickness of 0x.As a result of examining the uniformity of this thin film, the film thickness was 400mm except for the four corners of a square substrate.
It was within the range of 0 A±100X. Visually, no interference fringes were observed.For comparison, in this example, the thin film formed without solvent vapor flowing out from the duct had poor uniformity, with 4000±500 holes, and no interference fringes were visually observed. It leaked.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional spinner coating device. FIG. 2 is an explanatory diagram of the apparatus used in the coating method of the present invention. 11...Substrate, 12...Head, 14'...Resist thin film, 20...Solvent, 21...Container, 22...
・Heating container, 23...Blower, 24...Heater,
25...Duct, 26...Solvent vapor flow. Applicant: Canon Co., Ltd. Agent: Gi Marushima −゛!

Claims (1)

[Claims] A coating method in which a resist solution is poured onto a substrate and the substrate is rotated at high speed to form a thin resist film. There is also a resist application method that is characterized by flowing out onto the surface.