JPS59100524A - Application of resist - Google Patents

Abstract

PURPOSE:To reduce sharply an applying resist liquid by a method wherein a flat board is pressed against the resist liquid dropped on a sample to diffuse the resist liquid to the circumferential part on the sample, and then the sample is rotated. CONSTITUTION:A jig 11 constructed by equipping an arm 13 to a flat board 12 is prepared, and the jig 11 is pressed against the face of a resist liquid dropped on a wafer 14 to diffuse the resist liquid. Then the wafer 14 is rotated. Then, by removing the flat board 12, and performing the final application process according to spin coating, a resist film is adhered on the wafer 14 at the desired film thickness. Accordingly, the resist liquid can be reduced sharply.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a resist coating method for coating a resist solution using a spin code method in photolithography and the like.

(b) Background of the technology This is a photo-etching technique in which unnecessary parts are optically and chemically removed in order to obtain a desired integrated circuit pattern on a sample such as a semiconductor. , etching is performed, but a protective film against this etching is required, and a resist coating is used as this protective film.

In particular, it is necessary to form a resist film of uniform thickness on a wafer, which is becoming increasingly popular, and any variation in film thickness will degrade performance.

(c) Conventional technology and problems The film thickness obtained with the spin code method depends on the viscosity of the resist solution.
It is determined by a function of the rotational speed of the spinner, the solvent of the resist solution, and the initial rotational force 4 of the spinner. On the other hand, with the development of microfabrication technology, the diameter of the evaporator has become large due to the trend towards higher density and higher integration, making it difficult to coat the film to a uniform thickness.

FIG. 1 is a block diagram showing a conventional resist coating apparatus.

In the figure, 1 is a resist coating device that coats a resist solution onto a wafer 3 using a spin code method in a free/booth 2, and sends a certain amount of resist solution from a resist tank 6 to a bellows pump 5 via a cylinder 4. Then, the bellows pump 5 is pressed to drop a certain amount of resist liquid onto the wafer 3. As the wafer holder supporting the wafer 3 rotates, the resist liquid dropped onto the wafer 3 is spread from the center to the periphery. In the piping system, tick pulps Vl and V2'ffl are connected to the cylinder 4, and the resist liquid flows in the direction of the arrow.

To fill the bellows pump 5 with resist liquid, open v1.
Vzt close. When dropping the resist solution, V1 is closed and V2 is open, and a two-dollar valve 8 is provided to adjust the flow rate of the solution so that excess resist solution does not leak onto the rotating wafer 3 when the resist solution is diffused. It is also configured to include a leaker 9 for removing dust present in the resist solution. The resist liquid to be filled into the bellows pump 5 is specified so as to obtain a desired film thickness, but it is not easy to obtain a uniform film thickness with large diameter wafers, and the film tends to be thick at the center and thin at the periphery.

Furthermore, air currents generated on the wafer rotating at high speed may cause radial film thickness unevenness, so-called venation. Moreover, the thickness of the film formed on the wafer by the dripping resist solution is several microns, and the amount deposited is only a few percent of the entire resist solution, resulting in a large amount of loss (d) Purpose of the Invention The present invention solves the above drawbacks. In view of this, it is an object of the present invention to provide a coating method that is effective in saving the resist liquid by pressing a flat plate against the surface of the resist liquid dropped on a wafer, diffusing the resist liquid, and further spin-coding the resist liquid.

(e) Structure of the Invention According to the present invention, the above object can be achieved by pressing a flat plate against a resist solution dropped onto a sample to diffuse the resist solution to the periphery of the sample, and then rotating the sample. It will be done.

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

FIG. 2 is a side view showing a coating method according to an embodiment of the present invention.

In the figure, a jig 1 consisting of an arm 13 attached to a flat plate 12
In the 1t-setting, the jig 11 is pressed against the surface of the resist liquid dropped onto the wafer 14 to spread the resist liquid. The gap between the resist coated surface of the wafer 14 and the flat plate 12 is approximately 0.1 to 0.2
easily kept. Surface 12a of flat plate 12 in contact with resist liquid
The flat plate 12 is coated with a resin that is not adhesive or corrosive to liquids, such as Teflon resin, or the flat plate 12 is made of a tear 0 material. It is desirable that both be flat with no distortion or bending, and the jig 1
Step 1 is to move and press the jig 11 onto the wafer 14. Return the jig 11 to a predetermined position in the clean booth, step 1, and drop the resist solution onto the wafer 14. Next, the jig 11 is moved onto the wafer 14 and lowered to press the resist liquid level and spread the resist liquid from the center of the wafer to the peripheral portion.

Since the gap between the flat plate 12 and the wafer 14 is adjusted to form a constant gap as described above, the thickness of the resist film to be diffused is ylO,1 to 0,2. That will happen. Thereafter, the flat plate 12 is returned to its original position and a final coating process is performed using a spin cord, thereby making it possible to deposit a resist film with a desired thickness on the wafer 14. With this configuration, the amount of resist liquid can be significantly reduced compared to the conventional method. In this example, whereas conventionally 5 cc of resist solution is dropped onto a wafer with a diameter of 4 inches, the desired film thickness can be obtained with 1 cc of resist solution. is obtained, and the effect of saving resist liquid is particularly large.

(B) Effects of the Invention As explained in detail above, by using the coating means using the flat plate jig of the present invention in combination with the spin cord means, the amount of resist liquid can be greatly reduced, and the economical effect thereof is remarkable.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional resist coating apparatus, and FIG. 2 is a side view showing a coating method according to an embodiment of the present invention. In the figure, 11... jig, 12... flat plate, 13... arm, 14... wafer.

Claims (1)

[Claims] 1. A resist coating method comprising: pressing a flat plate against a resist solution dropped onto a sample to diffuse the resist solution around the sample; and then rotating the sample.