JPH01111328A - Method for coating thin film - Google Patents

Abstract

PURPOSE:To form a thin film having uniform thickness on the whole face of a wafer by driving to rotate the wafer around a first rotary axis, and then so driving it to automatically revolve around its own axis as to concentrically move in a circular motion at a second rotary axis, thereby coating it with paint. CONSTITUTION:Paint to be coated on a wafer 4 is diffused on the whole face of the wafer 4 by the operation of its centrifugal force F by automatically driving to rotate it as to concentrically move in a circular motion at a second rotary axis 8. Simultaneously, as a result that it is driven to be revolved around a first rotary axis 7, the diffused paint is acted by the centrifugal force F' irrespective of the fine uneven part of the wafer 4 to be uniformized in the thickness of the paint. Thus, a thin film having uniform thickness can be formed on the whole face of the wafer 4.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for coating a wafer with photoresist, etc., and particularly relates to a thin film coating method for forming a uniform film thickness. For the purpose of providing a thin film coating method, the second rotating shaft is connected substantially orthogonally to the first rotating shaft, and the stage is mounted on an end of the second rotating shaft and fixed perpendicularly to the axial direction of the second rotating shaft. The wafer is constructed of a wafer with a paint applied thereto, and at the same time, the wafer is driven to revolve around the first rotation axis and rotated around the second rotation axis so as to perform a concentric movement. The structure is such that the coating is performed using the following methods.

[Industrial application field]

The present invention relates to a method for coating a wafer with photoresist, and more particularly, to a thin film coating method for forming a uniform film thickness.

[Conventional technology]

Light, electron beams, X-rays, etc. are used to create semiconductor element patterns on wafers, and a photosensitive material generally called a photoresist is used to record and form the patterns. .

This photoresist is applied onto a wafer, and a pattern is formed by irradiating it with light or electron beams.

FIG. 2 shows a principle diagram of thin film application using the conventional spin coating method. In the figure, l is a motor, and 2 is a rotating shaft connected to the motor 1, which rotates in the direction of arrow B.

3 is a stage fixed in a plane perpendicular to the rotational axis direction of the rotating shaft 2; 4 is a wafer mounted on the stage 3 so as to perform a concentric movement with the rotation of the rotating shaft 2;

Keeping the surface of the wafer 4 horizontal, the necessary amount of paint to be applied, such as photoresist dissolved in a solvent to an appropriate viscosity, is dropped onto the surface, and the photoresist is coated by rotating it with a motor l. Due to the action of centrifugal force F and the appropriate viscosity of the solvent, the solvent can be uniformly diffused onto the surface of the wafer 4 to form a thin film.

[Problem that the invention seeks to solve]

FIG. 3 shows a diagram for explaining the drawbacks of the conventional example. Third
Figure (a) is a plan view of the wafer, and 5 is a wafer 4.
It shows a convex part that forms a minute step on the surface of the figure. The arrow indicates the direction of action of centrifugal force F.

FIG. 3(b) shows an enlarged cross-sectional view of the convex portion 5, and 6 indicates the photoresist.As shown in the figure, centrifugal force F acts on the convex portion 5, which forms a small step. The film thickness of the paint is thin on the inside of the part 5 in the direction of the centrifugal force, and becomes thick on the outside, which has the disadvantage that the uniformity of the film thickness is hindered.

The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a thin film coating method capable of forming a uniform thin film thickness over the entire surface of a wafer.

[Means for solving problems]

FIG. 1 shows a block diagram of the present invention. A second rotating shaft 8 connected substantially orthogonally to the first rotating shaft 7, and a stage 3 fixed to the end of the second rotating shaft 8 perpendicularly to the axial direction thereof.
The wafer 4 is attached to the first
A thin film coating method characterized in that the coating is carried out by rotating around the rotating shaft 7 and rotating around the second rotating shaft 8 so as to perform concentric circular motion.

[For production]

The paint applied to the wafer 4 is driven to rotate concentrically by the second rotating shaft 8, and is spread over the entire surface of the wafer 4 by the action of the centrifugal force F, as in the conventional example. At the same time, as a result of being driven to revolve around the first rotating shaft 7, a centrifugal force F' acts on the diffused paint regardless of minute irregularities on the surface of the wafer 4, making the film thickness of the paint uniform. It has the effect of working like this.

〔Example〕

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

Note that, in order to make the explanation of the configuration and operation easier to understand, the same parts are given the same reference numerals throughout all the figures, and repeated explanation thereof will be omitted.

FIG. 1 shows a block diagram of the present invention. In the figure, 7 is the first
One end of the rotating shaft is connected to a motor 9 and driven to rotate in the direction of the arrow. The other end is integrally and directly connected to the external casing of the motor 1.

Reference numeral 8 designates a second rotating shaft, one end of which is connected to the motor 1 and driven to rotate in the direction of arrow B, and is the same as the conventional rotating shaft 2 shown in FIG. 2, but it sets the necessary revolution radius. Because of the different lengths. In addition, the first rotating shaft 7 and the second rotating shaft 8
The intersection angle θ of each axis is set to be approximately a right angle.

After dropping a required amount of paint to be applied onto the surface of the wafer 4, such as a photoresist dissolved in a solvent to an appropriate viscosity, the motor 1 rotates and the surface of the wafer 4 is brought into contact with the second rotating shaft 8. By rotating the photoresist in a concentric motion, a centrifugal force F acts on the photoresist coated on the surface of the wafer 4, and by the action of the appropriate viscosity of the solvent, the photoresist is uniformly coated on the surface of the wafer 4 as before. It spreads like that.

At the same time, the motor 9 is driven and the wafer 4 is driven to revolve around the first rotating shaft 7 as shown by the arrow C. As a result, the photoresist on the surface of the wafer 4 is subjected to a combination of centrifugal force F and centrifugal force F'. Centrifugal force acts. That is, a centrifugal force F' is further applied to the photoresist diffused by the centrifugal force F, which acts to make the photoresist film uniform in thickness regardless of minute irregularities on the surface of the wafer 4.

Intersection angle θ of each axis of the first rotating shaft 7 and the second rotating shaft 8
By combining the setting value of and the rotational speed of each rotating shaft, the thickness of the photoresist on the surface of the wafer 4 can be reduced without any distortion even if the shape of the convex part is complex, and a uniform thickness can be obtained. can.

The revolution radius of a 6-inch wafer is 50 cm, the rotation speed of the first rotation axis is 1100 rpm, the rotation speed of the second rotation axis is 1100 Orp, the intersection angle θ of each axis is set to 90 degrees, and the viscosity is 5 cps. When 4 cc of photoresist was applied dropwise, a resist film thickness of IJm could be obtained.

The thin film coating method described above has been explained using the application of photoresist as a paint as an example, but is not limited to this, and can also be applied to the application of resin or the like.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, compared to the conventional resist film with poor coverage, the present invention eliminates the dimensional difference between the stepped portion and the flat portion, and the performance of the device is stabilized. Further, the present invention has an effect of improving dust.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a diagram showing the principle of thin film application using a conventional spin coating method, and FIG. 3 is a diagram for explaining the drawbacks of the conventional example. In FIG. 1, 3 represents a stage, 4 represents a wafer, 7 represents a first rotation axis, and 8 represents a second rotation axis. Sub+411th7cm16&Tt'1itZF-/'5
'Figure 3 Mi

Claims (1)

[Claims] A second rotating shaft (8) connected substantially orthogonally to the first rotating shaft (7), and a second rotating shaft (8) connected to an end of the second rotating shaft (8) orthogonally to the axial direction thereof It consists of a wafer (4) mounted on a fixed stage (3), and the paint is applied to the wafer (4) and the wafer (4) is revolved around the first rotation axis (7). drive,
A thin film coating method characterized in that coating is carried out by driving the second rotating shaft (8) to rotate in a concentric circular motion.