JPH02123362A - Resist coating method and resist coating device - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding a resist coating method and coating device used in photoprocessing, the purpose of the resist coating method is to coat a resist to a uniform film thickness, and the resist coating method is applied to a substrate that holds a substrate to be coated. The cup containing the holder is sealed, the nuclear force/knob is rotated at the same time as the substrate to be coated and the substrate holder, which is an initial rotation, and then rotation is continued to drip and apply the resist solution. do.

The resist coating apparatus also includes a substrate holder that holds a substrate to be coated, a cup that accommodates the substrate holder, a lid for sealing the inside of the cup, and a lid that protrudes from the center of the lid to hold the substrate to be coated. and a resist liquid dropping nozzle located above, and the cup is integrated with the substrate holder and configured to rotate at the same speed as the substrate to be coated and the substrate holder.

[Industrial application field]

The present invention relates to improvements in a resist coating method and coating device used in photoprocessing.

Photoprocessing is an essential step in the manufacturing method of semiconductor devices, and new improvements are being made every day to form fine patterns. In such a photo process, it is extremely important to apply a resist to a uniform thickness in order to improve yield and quality.

[Conventional technology]

Generally, in order to apply resist to a substrate to be coated, such as a semiconductor substrate or a mask substrate, a resist coating device (generally called a spinner) is used to apply a so-called resist solution in which a photosensitive material is dissolved in an organic solvent. A method is adopted in which the coating material is dropped onto the substrate to be coated, and the substrate is rotated for coating.

FIG. 3 shows a sectional view of a main part of a conventional resist coating apparatus, and 10 is a mask substrate (substrate to be coated).

31 is a cup, 32 is a substrate holder, and 33 is a resist liquid dropping nozzle. The hollow portion of the substrate holder 32 at the center of the holder axis is evacuated by a vacuum device (not shown), so that the mask substrate 10 placed on the substrate holder 32 is chucked by the substrate holder.

Next, while rotating this substrate holder 32, the upper register l-? The resist liquid is dropped from the f1 dropping nozzle 33. Then, the resist solution is diffused onto the mask substrate IO and coated on the entire surface of the substrate.

Usually, a resist is applied to a substrate to be coated using a resist coating device in this way, and then, after prebaking (preliminary heat treatment), exposure and development are performed to form a resist pattern.

[Problem to be solved by the invention]

However, when applying resist using such a resist coating device, it is difficult to apply the resist uniformly over the entire surface of the substrate to be coated, and especially when the substrate to be coated is a rectangular mask substrate, the four corners are covered with the resist film. There is a problem that the thickness increases. This is because the corners farther from the center of the substrate holder come into contact with more air (or gas) than the center, and as a result, the resist dries faster and becomes more viscous. It is thought that the resist film thickness at the four corner portions becomes thicker.

Figures 4(a) and 4(b) illustrate the problem. Figure 4(a) shows the distribution of resist film thickness on a square (5 inch square) mask substrate surface, and the diagonal lines indicate the resist film thickness distribution. The corner portion where the resist is located is the portion where a thick resist film is applied.

In addition, FIG. 4(b) shows the variation data of the resist film thickness at one corner C, where the horizontal axis is the distance from the corner, the vertical axis is the resist film thickness, and the curve I ( -X-
) is the value of the resist film thickness. It is clear that the resist film thickness at the corner portions is thicker than this.

The present invention proposes a resist coating method and a coating device for the purpose of alleviating such problems and coating a resist with a uniform thickness.

[Means to solve the problem]

The task was to seal a cup containing a substrate holder that holds a substrate to be coated, perform an initial rotation in which the cup rotates at the same time as the substrate to be coated and the substrate holder, and then continue to rotate and drop the resist solution. This problem can be solved by a resist coating method that uses resist coating.

Further, as shown in the principle diagram shown in FIG. 1, the resist coating apparatus includes a substrate holder 12 for holding a substrate to be coated 10, a cup 11 for accommodating the substrate holder, and a lid for sealing the inside of the cup. 14, and a resist liquid dropping nozzle 13 protruding from the center of jtjIf and positioned above the substrate to be coated. Configure to rotate. In addition, Fig. 1 (a
) shows a cross-sectional view of a main part of the resist coating device, and FIG. 1(b) shows a cross-sectional view taken along line AA in FIG. 1(a).

[For production]

That is, the present invention has a coating device that is integrated with a sealing force, a knob, and a substrate holder so that the inside of the cup of the resist coating device is sealed and the internal atmosphere (or gas) is rotated at the same time as the substrate to be coated. do.

Further, during coating, a coating method is performed in which the cup is initially rotated without dropping the resist solution, the atmosphere inside the cup is rotated at a constant speed, and then the resist solution is dropped and rotated.

In this way, the resist can be applied to a uniform thickness.

(Example〕 Hereinafter, embodiments will be described in detail with reference to the drawings.

FIG. 2 shows a cross-sectional view of the main parts of the resist coating apparatus according to the present invention, in which 10 is a mask substrate (substrate to be coated), 21
2 is a cup, 22 is a substrate holder, 23 is a resist liquid dropping nozzle, 24 is a lid, 25 is a rectifying plate, and 26 is a motor shaft for rotation. The cup 21 is covered with 124 to seal the inside thereof, and a sliding ring is interposed between the resist Hff1 dropping nozzle 23 and the lid 24 to shut off the inside atmosphere from the outside atmosphere. Moreover, the cup 21 and the substrate holder 2
2 is integrated with the resist liquid dropping nozzle 23, and thus the other members except the resist liquid dropping nozzle 23 rotate at the same time and at the same speed. In addition, the rectifying plate 25 is provided to quickly converge the influence of the inertia of the atmosphere inside the cup and cause the atmosphere to rotate at a constant speed.Also, as in the past, the substrate holder 22 is placed at the center of the holder axis. The cavity is vacuum-suctioned, and the mask substrate 10 placed on the substrate holder 22 is chucked by the substrate holder.

The sequence of a resist coating method using such a resist coating device will be described below.

■Chucking; attach the mask substrate 10 to the substrate holder 22
Apply vacuum suction.

■ Sealing: Cover the cup 21 with ff124 to seal the inside of the knob.

■Initial rotation: Rotate for the first time without dropping the resist solution. In the coating method according to the present invention, this idle rotation is one of the characteristics, and this initial rotation converges the influence of the inertia of the atmosphere and keeps the atmosphere in the cup rotating at a constant speed.

(2) Dropping of resist liquid; Next, drop the resist liquid and continue rotating to uniformly apply the resist to the surface of the mask substrate.

The results of applying resist to a 5-inch square mask substrate using the above-mentioned resist coating apparatus and the above-mentioned coating method are shown in FIG. 4(a), a square portion including the diagonally shaded corner portions is formed with a uniform resist film thickness. On the other hand, in the conventional method, the circular part has a uniform film thickness, which is considerably improved according to the present invention. In addition, FIG. The horizontal axis is the distance from the corner, the vertical axis is the resist film thickness, and the curve II (-0-) in the figure is the resist film thickness value obtained by the coating method according to the present invention.

It can be seen that, compared to the conventional method, the resist film thickness in the present invention is more uniform at the corner portions.

Although the above example has been explained using a rectangular mask substrate,
Semiconductor substrates are also not perfectly circular, and have an orientation flat/nod on a part of the periphery, and uneven resist film thickness also poses a problem, but the present invention can also be applied to such semiconductor substrates. Of course.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to apply a resist to a more uniform thickness, and a fine pattern can be formed with high precision by photoprocessing, allowing IC,
This is greatly useful for improving the quality and yield of semiconductor devices such as LSI.

[Brief explanation of drawings]

1(a) and 1(b) are principle diagrams, FIG. 2 is a sectional view of main parts of a resist coating apparatus according to the present invention, FIG. 3 is a sectional view of main parts of a conventional resist coating apparatus, and Fig. 4 Fa ), (bl is a diagram showing conventional problems and effects of the present invention. In the diagram, 10 is a substrate to be coated or a mask substrate, 11, 21.31 are cups, 12, 22.32 are substrate holders 13, 23.33 is the resist l night nozzle, 14
, 24 is a lid, 25 is a rectifying plate, and 26 is a motor shaft. Ruri Day Figure 2 Toy and September 1.0.3 Shiji'7 Tomutaro 1 [Mezui (
Ax degree insertion 2nd figure 6 and 5-zrpt sweat IE + 1 section cross section 3rd figure square publication p z ・], LD Hi self -〇〇〇〇〇〈1　　　　　　Figure 4　

Claims (2)

[Claims] (1) The cup containing the substrate holder that holds the substrate to be coated is sealed, the cup is rotated at the same time as the substrate to be coated and the substrate holder, and then the resist solution is dripped and coated while continuing to rotate. A resist coating method characterized by: (2) a substrate holder for holding a substrate to be coated, a cup for accommodating the substrate holder, a lid for sealing the inside of the cup, and a cup protruding from the center of the lid and located above the substrate to be coated. 1. A resist coating apparatus comprising a resist liquid dropping nozzle, wherein the cup is integrated with the substrate holder and rotates at the same speed as the substrate to be coated and the substrate holder.