JPH0228919A - Formation of resist film - Google Patents

Abstract

PURPOSE:To form a uniform resist film on a rectangular substrate by providing a semiconductor substrate on a substrate mounting plate having a larger area than that of the substrate, surrounding the periphery of the substrate with resin, securing the plate to a rotating shaft, dropping resist on the substrate, and rotating the shaft. CONSTITUTION:A substrate mounting plate 2 is heated, and resin 5 is melted on the plate 2. Then, a semiconductor substrate 1 is placed on the plate 2, heated for a predetermined period of time, and then cooled. Then, resin 5 solidified on the periphery of the substrate 1 is formed. When the plate 2 mounted with the substrate 1 is secured to a rotating shaft 4, resist 7 is dropped from a dropping nozzle 3, and the shaft 4 is rotated, a resist film 6 is formed. Thus, even if the substrate 1 is rectangular when the periphery of the substrate 1 is surrounded with the resin 5, the shape of the corner is effectively eliminated. Accordingly, a specific resist film thickness distribution generated when the resist film is formed on the rectangular substrate by a spinner method is eliminated, and the uniform film 6 can be formed on the substrate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention' relates to a method for forming a resist film in a photo Ringer fibrosis process in semiconductor device manufacturing.

(Prior Art) Conventionally, in the photolithography process in the manufacture of semiconductor devices, a spin coating method generally called a spinner method is often used as a method for coating a resist onto the surface of a semiconductor substrate. The spinner method will be briefly explained based on FIG. In the figure, 11 is a semiconductor substrate, 12 is a vacuum chuck, and 13 is a dropping nozzle for dropping resist 14. First, the semiconductor substrate 11 is placed on the vacuum chuck 12.
A few drops of resist 14 are dropped onto the surface of the semiconductor substrate 11 from a one-drop nozzle 13, and the shaft of the vacuum chuck 12 is rotated by a motor. Then, the semiconductor substrate 11 rotates, and a very thin resist film is formed by centrifugal force. The thickness of the resist film is determined by the resist viscosity 2
Determined by rotation speed. The thickness and uniformity of the formed resist film greatly affect the resolution of fine pattern formation by photolithography.

(Problems to be Solved by the Invention) In the spinner method described above, a completely uniform film thickness cannot be obtained. In particular, rectangular substrates are often used to fabricate devices made from compound semiconductor materials, and when resist is applied to a rectangular substrate using a spinner method, the thickness of the resist film, which is unique to rectangular substrates and cannot be seen on circular substrates, increases. give rise to a distribution. The situation is shown in Figure 4. As shown in FIG. 4(a), the resist film 14b becomes thicker in the lattice-shaped portions of the rectangular substrate 11. FIG. 4(b) shows the resist film thickness distribution in a cross section taken along the diagonal line AC in FIG. 4(a). Reference numeral 14b indicates a thick portion of the resist film. Since such a film thickness distribution of the resist film forms a fine pattern, if the exposure amount is reduced to near the sensitivity limit of the resist, pattern defects will occur. In other words, in thick parts of the resist film, pattern defects occur because the resist film of the pattern that should be exposed to light and removed by development is not completely removed. This is a major drawback in forming and above.

An object of the present invention is to eliminate the conventional drawbacks and provide a method for forming a uniform resist film on a rectangular substrate.

(Means for Solving the Problems) The method for forming a resist film of the present invention includes the steps of: installing a semiconductor substrate on a substrate installation plate having a larger area than the semiconductor substrate;
This method includes a step of surrounding the semiconductor substrate with resin, and a step of fixing a substrate mounting plate to a rotating shaft, dropping resist onto the semiconductor substrate, and rotating the rotating shaft.

(Function) By applying the present invention to the formation of a resist film on a rectangular substrate, the thick portions of the resist film near the corners that occur on the rectangular substrate by the spin coating method are eliminated, and a uniform resist film can be formed. can. In other words, since the periphery of the substrate is surrounded by resin, effectively eliminating the corner shape of a rectangular substrate, the resist film thickness distribution peculiar to a rectangular shape is eliminated.

A uniform resist film can be formed.

(Example) An example of the present invention will be described based on FIGS. 1 and 2. FIG. 1 shows a substrate installation process according to the present invention. In the figure, 1 is a rectangular compound semiconductor substrate, 2 is a substrate installation plate with a larger area than the semiconductor substrate 1, 3 is a dropping nozzle for dropping resist, 4 is a rotating shaft connected to a motor, and 5 is a rotating shaft. It is a resin that melts with heat (for example, electron wax), and 6 is a resist film.

First, as shown in FIG. 1(a), the substrate installation plate 2 is heated to melt the resin 5 on the substrate installation plate 2. Next, when the semiconductor substrate 1 is placed on the substrate mounting plate 2, heated for a certain period of time, and then cooled, solidified particles are formed around the semiconductor substrate 1, as shown in FIG. The resin 5 is formed.As described above, the substrate setting plate 2 on which the semiconductor substrate 1 is placed is fixed to the rotating shaft 4 as shown in FIG. 4, a resist film 6 is formed. By surrounding the semiconductor substrate 1 with the resin 5 in this way, even if the semiconductor substrate 1 is rectangular, the shape of the corner is effectively eliminated. Therefore, The peculiar resist film thickness distribution that occurs when a resist film is formed on a rectangular substrate by the spinner method is eliminated, and a uniform resist film 6 can be formed on the semiconductor substrate 14 as shown in FIG.

(Effects of the Invention) According to the present invention, a uniform resist film can be formed even on a rectangular substrate using the spinner method, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a board installation process diagram in an embodiment of the present invention.
(a) is a sectional view of the installation board, (b) is a plan view after the semiconductor substrate is installed, (c) is a sectional view taken along the line A-B of (b), and FIG. 2 is a resist film forming process diagram of the present invention. Figure 3 is a schematic diagram showing the conventional spinner method, and Figure 4 is a plan view (a) and a cross-sectional view (a) of resist coating on a rectangular substrate using the spinner method.
b). 1... Semiconductor substrate, 2... Board installation plate, 3...
・Dripping nozzle, 4... Rotating shaft, 5... Resin. 6...Resist film, 7...Resist. Patent applicant: Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] A step of installing the semiconductor substrate on a substrate installation plate having a larger area than the semiconductor substrate, a step of surrounding the periphery of the semiconductor substrate with resin, fixing the substrate installation plate to a rotating shaft, and applying a resist on the semiconductor substrate. 1. A method for forming a resist film, comprising a step of dropping the resist film and rotating a rotating shaft.