JPS63151021A - Method and apparatus for applying resist - Google Patents

Abstract

PURPOSE:To make it possible to apply resist uniformly, by arranging a plurality of nozzles on a wafer in a scattered pattern, and dropping the resist on the wafer in resist application. CONSTITUTION:Nozzles 2 are provided vertically on the central part and on the four points of the peripheral part of a wafer 1. Photoresist is simultaneously dropped on the wafer, which is sucked with vacuum. The ratio between the thickness L1 of the resist at the central part and the thickness L2 at the peripheral part thereof is L1:L2=1:0.9, which is approximately uniform. Then the wafer is rotated up to 5,000 rpm for 10 seconds. The wafer is rotated intactly for 20 seconds. Thereafter the number of rotation is decreased to zero for five seconds. Then the difference in thicknesses of the resist 5a between the central part and the peripheral part is 10Angstrom or less. The ratio between the resist thickness L1' at the central part and the resist thickness L2' at the peripheral part is L1':L2'=1.0:0.98. Thus the uniform application of the resist can be implemented for especially large-diameter wafers (6 inch or more). As a result, the yield rate of the elements is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a resist coating method and coating apparatus used in semiconductor manufacturing processes and the like.

BACKGROUND OF THE INVENTION As the degree of integration of semiconductor integrated circuits increases, the formation of fine resist patterns becomes increasingly important. or,
At the same time, the diameter of semiconductor manufacturing devices has progressed, and currently 6 inches are the mainstream, with 8 inches and 10 inches expected in the near future.
It is anticipated that even larger diameter wafers, such as inch wafers, will be used.

Under these circumstances, uniform application of resist onto the substrate (wafer) is extremely important and difficult. That is, in pattern formation, non-uniformity in resist film thickness leads to fluctuations in the exposure amount during pattern exposure, which leads to fluctuations in pattern dimensions and, in turn, to a decrease in device yield.

As described above, resist coating is important, but with conventional techniques, uniform coating becomes more difficult as the diameter of the wafer increases. This conventional example will be explained using FIG. 2.

In the resist coating apparatus, about 3 cc of photoresist (MPS-1400-27 manufactured by Sibley) is dropped by one nozzle 3 onto the center of the vacuum-adsorbed wafer having a rotary diameter. At this time, the fluid resist does not have a uniform thickness between the center and the periphery. That is, center part L3: peripheral part L4=
1=0.6. (Equipment used: Tokyo Electron Clean Truck) Figure 2a) Next, the wafer was rotated to 500 rpm for 10 seconds, then rotated at 5000 rpm for 20 seconds, and then the rotation speed was reduced to 0 for the next 5 seconds. . At this time, the resist 5b applied on the substrate had a difference in film thickness, and the difference in film thickness was SOO between the center and the periphery. That is, the center part L3': peripheral part Lj=1:o, 7 (FIG. 2b).

That is, the difference between the central part where the resist is dropped and the peripheral part where it is not is maintained even after rotation. Such a non-uniform resist coating apparatus and method causes a difference in resist film thickness within the wafer diameter as the wafer becomes larger in diameter, which becomes an obstacle to forming a fine resist pattern.

Problems to be Solved by the Invention The present invention solves the non-uniform application of resist as shown in the prior art.

Means for Solving the Problems In order to solve the problems of the conventional art, the present invention makes it possible to apply resist uniformly by using a plurality of nozzles scattered over the wafer to drop the resist onto the wafer. be.

If multiple nozzles are installed and droplets are placed not only at the center but also at the periphery, the resist, which is still in a fluid state, on the substrate before rotation becomes uniform within the surface, and the uniformity due to rotation is improved.

Such methods and devices will be particularly effective in producing large-diameter wafers in the future.

Function: By using the method and apparatus of the present invention, variations in the resist film thickness within the wafer surface are eliminated, resulting in uniform exposure and easy control of resist dimensions.

Example 6 4 points at the center and periphery of inch wafer 1 (9 points from the center)
The photoresist (manufactured by Sibley Ike Co., Ltd. M
A total of approximately 3 cc of Q and 50 C were simultaneously dropped onto a 6-inch wafer vacuum-adsorbed (PS1400-27) (1st
Figure a: Figure 1 C) seen from above. In Figure 1,
The resist 4a was almost uniform within the wafer surface. That is, the ratio of the resist thickness L1 at the center to the resist thickness L2 at the periphery (2 inches from the center) is Ll:L2=1:o, 9, and the resist thickness between the center and the periphery is When Ll is 1, the value was between 0.9 and 1.0. It was found that by dropping the resist at the center and the periphery at the same time in this way, the resist thickness in the fluid state could be made almost uniform.

Next, the wafer is rotated to 600 rpm for 10 seconds, and then rotated at 5000 rpm for 20 seconds,
After that, the rotation speed was set to 0 for 5 seconds.

At this time, the resist (5a) applied on the substrate has a film thickness difference of 10 Å or less between the center and the periphery, that is, the resist thickness L1' at the center and the resist thickness L2' at the periphery.
The ratio was L/1:L2=a 1 , o:0.98 (Fig. 1b).

Note that similar effects were obtained even when the drops were not simultaneously dropped as in this example. In addition, regarding the position and number of nozzles, a large number of nozzles may be provided other than the four points on the periphery as in this embodiment, or the number of nozzles may be two and they may be arranged at a position different from the center. . Of course, even if the fluid is placed at two points, one in the center and one in other localized areas, the thickness of the fluid resist will be more uniform compared to one point in the center, and the subsequent rotation will increase the uniformity of the resist at the center. The difference in film thickness between the film and the peripheral area is 108 or less.

According to the apparatus and method of the present invention, compared to the conventional apparatus and method, it is much more effective in uniformly applying resist even on a flat wafer as in the embodiment, and even on a substrate with steps. The same is true on a flat substrate.

Effects of the Invention The method and apparatus of the present invention are of high industrial value because they can uniformly apply a resist, especially to large diameter wafers (6 inches or more), and as a result, the yield of devices is improved.

[Brief explanation of the drawing]

1A and 1B are cross-sectional views showing a resist application state according to an embodiment of the present invention, FIG. 1C is a plan view of a nozzle in 1Nd, and FIGS. 2A and 1+ are cross-sectional views of a conventional resist application state. − is. 1... Board, 2... Nozzle, 3...
...Conventional nozzle, 4a...Resist before rotation, 5a...Resist after rotation, 6...
・Rotating plate.

Claims (2)

[Claims] (1) A resist coating method that includes a step of dropping the same resist onto a substrate from a plurality of nozzles, and a step of turning the resist into a film by rotating it. (2) A resist coating device having a mechanism for dropping the same resist onto a substrate from a plurality of nozzles.