JPH0233152A - Photolithography - Google Patents

Abstract

PURPOSE:To securely remove the thick peripheral border part of a photoresist efficiently, if very thick, by exposing the border part of the photoresist formed on a substrate and at the same time developing it and repeating the operation. CONSTITUTION:The photoresist 3 is formed on the substrate 2 by the spin coating process, and patternwise exposed, and then development is started by rotating the substrate 2 and dropping a developing solution 6 from a nozzle 7. At the same time, a light source 4 is turned on, the border part 3a of the photoresist is illuminated through glass fibers 5, the illuminated border part 3a is immediately dissolved in the developing solution 6, and an unexposed part is disclosed, likewise immediately dissolved upon the next illumination, and the border part 3a, if very thick, can be securely removed efficiently by repeating the operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to improvements in photolithography methods.

[Conventional technology]

Photolithography is one of the basic techniques for manufacturing semiconductor devices. This method basically consists of a coating process in which a photoresist is applied onto a substrate, an exposure process in which a predetermined pattern is transferred to the photoresist using an appropriate light source, and a predetermined pattern is created by developing the photoresist. It consists of a developing process to obtain a patterned photoresist.

A spin code method is one of the resist coating methods in this photolithography method. In this method, photoresist is dropped onto a horizontal wafer and the wafer is rotated to form a uniform photoresist film on the wafer.

However, the spin code method tends to coat the photoresist excessively on the peripheral edge of the substrate. Therefore, when this substrate is transported or transferred, there is a high possibility that the photoresist on the peripheral edge of the substrate will peel off and become dust. As a result, there has been a problem in that the yield of manufactured semiconductor devices is reduced.

In order to avoid the above-mentioned problems, conventionally, a peripheral edge exposure process was added as a separate process in addition to the normal exposure process, in which the photoresist on the peripheral edge of the substrate was intensively exposed to light before development.

FIG. 3 is a configuration diagram showing a peripheral edge exposure device used in this process. As shown in the figure, a substrate 2 on which a photoresist 3 is formed is provided on a freely rotatable spin chuck 1. The photoresist 3 is installed so that the peripheral edge 3a of the photoresist 3 is exposed to light from a light source 4 via a glass fiber 5.

Then, by intensively exposing only the photoresist peripheral part 3a to light using this apparatus and developing it, the seventh photoresist peripheral part 3a was removed.

(Problem to be Solved by the Invention) The conventional photolithography method in which a photoresist is coated by a spin code method is performed as described above, in which the peripheral portion 3a of the photoresist is intensively exposed and the photoresist is exposed during development. The resist peripheral portion 3a was removed.

However, in the conventional peripheral edge exposure method, as shown in FIG.
As shown in FIG. 4(b), if the film thickness of the photoresist peripheral portion 3a is thick, the exposure cannot be completed, and as shown in FIG.
There was a problem in that the peripheral edge 3a of the photoresist could not be completely removed and was left in an irregular shape, making the peripheral edge 3a of the photoresist more likely to peel off. In addition, Figure 4 (
In b), 6 is a developer.

Furthermore, since the thick peripheral edge 3a of the photoresist is exposed, a very large amount of exposure energy is required, resulting in a long exposure time and poor throughput. However, there was a problem in that it caused a crosslinking reaction, making development even more difficult.

This invention was made in order to solve the above-mentioned problems, and its purpose is to provide a photolithography method that can reliably remove photoresist at a desired location regardless of the film thickness of the photoresist. do.

[Means to solve the problem]

The photolithography method according to the present invention includes a step of exposing a predetermined portion of a photoresist coated on a substrate and a step of degrading the photoresist.

(Function) In this invention, a predetermined portion of the photoresist coated on the substrate is exposed and the photoresist is developed at the same time, so that the photoresist at the predetermined portion is removed from the upper layer at the same time as it is exposed. .

〔Example〕

FIG. 1 is a sectional view showing a developing device used in a photolithography method, which is an embodiment of the present invention.

This developing device is a conventional developing device, that is, a device that develops a photoresist exposed to light in a predetermined pattern, with a photoresist peripheral edge exposure function added. In the same figure, 1.2 degrees 4 to 6 are the same as the conventional one, so the explanation will be omitted.

7 is a developer discharge nozzle, and 8 is a developer cup.

Note that 3 is a photoresist coated by a spin code method and exposed to light in a predetermined pattern.

With such a configuration, the substrate 2 is rotated by slowly rotating the spin chuck 2. Then, the developer 6 is dripped from the developer dripping nozzle 7, and the photoresist 3 begins to be developed into a predetermined pattern.

At the same time, the light source 4 is turned on, and as shown in FIG.
irradiated to a. The peripheral edge part 3a of the photoresist irradiated with light is immediately dissolved in a developer, and the upper part is removed.
As shown in FIG. 2(b), the portion that was unexposed until the upper portion was removed is exposed. When this exposed peripheral edge 3a of the photoresist is also exposed from above, it is immediately exposed to the developing solution 6.
dissolve in

In this way, by repeatedly exposing and dissolving the photoresist peripheral part 3a from above during development, even if the peripheral part 3a is thick, it can be reliably and efficiently removed as shown in FIG. 2(C).

In this embodiment, by fixing the glass fiber 5 and rotating the substrate 2, the photoresist peripheral portion 3a is removed.
Although the substrate 2 may be fixed and the glass fibers 5 may be moved along the photoresist peripheral edge 3a, the tips of a large number of glass fibers 5 may be exposed so as to irradiate the photoresist peripheral edge 3a. It may be placed in

Furthermore, the light may be irradiated directly from a small light source without using the glass fiber 5.

Further, in this embodiment, a conventionally used developing device is provided with an exposure function for the photoresist peripheral edge 3a, but a developing device capable of developing only the photoresist peripheral edge 3a is provided with an exposure function for the photoresist peripheral edge 3a, and the photoresist peripheral edge 3a is Only the portion 3a may be exposed and developed, and normal development may be performed in a separate process.

Further, in this embodiment, an example was shown in which the photoresist peripheral portion 3a was exposed, but the present invention is not limited to this.

〔Effect of the invention〕

As explained above, according to the present invention, the photoresist coated on the substrate is exposed at the same time as the photoresist is exposed, and the photoresist is developed at the same time.
The photoresist is exposed from above and simultaneously removed.

As a result, a predetermined unexposed portion of the photoresist is exposed and can be exposed, and once the unexposed portion is exposed, it can be immediately removed. By performing exposure and development in parallel in this way, it is possible to reliably remove a predetermined portion of the photoresist 7 regardless of the film thickness.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a developing device used in photolithography, which is an embodiment of the present invention, and FIGS. 2(a) to (C)
) are explanatory diagrams showing the operation of the current aim shown in Figure 1, Figure 3 is a configuration diagram showing the peripheral edge exposure device used in the conventional photolithography method, and Figures 4 (a) and (b) are FIG. 3 is an explanatory diagram showing problems of conventional photolithography methods, respectively. In the figure, 1 is a spin chuck, 2 is a substrate, 3 is a photoresist, 3a is a photoresist periphery, 4 is a light source,
5 is a glass fiber, and 6 is a developer. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masuo Oiwa Figure 1 Figure 3 Figure 4 Figure 2 (a) (b) (C)

Claims (1)

[Claims] (1) A photolithography method comprising a step of exposing a predetermined portion of a photoresist coated on a substrate and developing the photoresist in parallel.