JPH0239420A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To increase the throughput by selectively exposing the periphery of a wafer to rays with an exposure part having two or more tangents to a circle of a radius equal to the length obtained by subtracting the depth of the part to be selectively exposed from the radius of the wafer. CONSTITUTION:For example, an exposure part is shaped into the form of a square of 5mm sides a side on the side of the center of a wafer is shaped into the form of the combined two tangents to a circle of 47mm radius by selectively exposing the wafer to rays to 3mm depth from the peripheral surface. Exposing the wafer to with the exposure part of the abovementioned shape remarkably reduces the difference between the quantity of effective UV rays applied to the center of the exposure part and that applied to the periphery on the side of the center of the wafer of the exposure part, which is unavoidable when a circular exposure part of the prior art is used, and makes the inclination of the cross section of the photoresist steep to shorten the inclined part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method and apparatus for manufacturing a semiconductor device. In particular, it relates to selectively exposing the periphery of a wafer on which a photoresist is applied over the entire surface of the wafer on which a pattern is to be formed.

[Prior art] A conventional method for manufacturing a semiconductor device is disclosed in Japanese Patent Publication No. 61-7922.
As shown in No. 7, the peripheral portions 2 to 3 wn of a wafer whose entire surface was coated with photoresist were selectively exposed to irradiation with UV light in a circular shape having a diameter of 2 to 5 M.

[Problems to be Solved by the Invention] However, the above-mentioned prior art has a drawback in that the cross-sectional shape of the photoresist has a gentle slope as shown in the cross-sectional view of the photoresist shown in FIG. This is because the exposure of the photoresist is a circular exposure area as shown in Figure 3, so the more effective the UV light is at the periphery of the exposure area on the center side of the wafer compared to the center of the exposure area. This is because the irradiation decreases rapidly. The fact that the cross-sectional shape of the photoresist has a gentle slope in this way means that the film thickness of the photoresist is gradually becoming thinner.
Depending on some kind of mechanical shock during the heating process and the way the wafer is handled, the wafer easily cracks and becomes chipped, resulting in dust, which has an unacceptable adverse effect on the production of semiconductor devices. In particular, when a missing photoresist piece adheres to a wafer, it becomes an obstacle during etching and causes pattern defects, causing areas that are not etched, and during ion implantation, it also prevents normal ion implantation. Therefore, the manufacturing yield of the semiconductor device is lowered because the semiconductor device no longer functions as a semiconductor device.

Furthermore, this structure cannot be said to be good in terms of throughput. As the UV light irradiation at the location that affects the shape of the photoresist is circular as mentioned above, it is extremely inefficient, and while the center of the exposed area is sufficiently exposed to the photoresist, the UV light irradiation is performed at the center of the wafer. It takes a considerable amount of time to expose the photoresist. In order to solve this problem, it may be possible to increase the size of the UV light source, but this would increase the price of the device.

The present invention solves the problems of the prior art, such as a decrease in yield and an increase in equipment cost, and its purpose is to provide a
The objective is to provide technology that enables inexpensive equipment with high throughput.

[Means for Solving the Problems] The semiconductor device manufacturing method of the present invention selectively exposes the periphery of a wafer to a circle whose radius is the radius of the wafer minus the length of the selective exposure. The above-mentioned problem is solved by performing exposure using an exposure section having at least two or more tangents to the surface.

[Example] FIG. 1 is a diagram showing the relationship between a 4-inch (10 mm) wafer and an exposure section in an example of the present invention. Figure 2 shows photoresist (
Cross-sectional view of positive type photoresist). The shape of the exposure area is based on a square with a side of 5 mm, and the shape of one side of the wafer center side is selectively exposed from the wafer periphery, resulting in a shape that combines two tangents to a circle with a radius of 47 fl. And so.

By exposing using an exposure part with this shape,
The effective UV radiation generated in the center of the exposed area and the periphery of the exposed area on the wafer center side, which was generated in the circular exposure area of the conventional technology.
The difference in the amount of light irradiation was significantly reduced, and the result was the cross-sectional shape of the photoresist shown in Figure 2. The slope became steeper, and the length of the slope was reduced to about 30 μm or less. .

In addition, the throughput was also improved, as the UV light irradiation time was shortened by about 50% due to the stronger UV light irradiation in the exposure area, particularly in the peripheral area on the center side of the wafer.

[Effects of the Invention] As described above, according to the present invention, the shape of the exposure part that selectively exposes the periphery of the wafer is determined by subtracting the tangent of the radius from the wafer radius by the length from the outer periphery of the wafer to be selectively exposed. By combining the two, the cross-sectional shape of the photoresist can be made to have a steep slope with less risk of damage to the photoresist.This prevents the pattern from being etched by broken pieces of the photoresist that are likely to occur during the process. This can prevent a decrease in yield due to the occurrence of defects or impediments during ion implantation, resulting in poor characteristics of the semiconductor device.

Furthermore, by changing the shape of the exposed area, the photoresist can be exposed more evenly and uniformly over the entire exposed area, making it possible to shorten the exposure time. As a result, throughput improved and productivity increased. Furthermore, if the shape of the exposed area is not changed, a UV light source that outputs a stronger irradiation amount is required, which inevitably leads to higher prices and running costs. This problem was also solved by the shape of the .

Note that the effects of the present invention are not limited to the embodiments, but are similar to those of wafers other than 4-inch wafers, and the same effects can be obtained even if the length of exposure is selectively changed.

[Brief explanation of the drawing]

Figure 1 shows a 4-inch (100+m++) embodiment of the present invention.
An explanatory diagram of the relationship between a wafer and an exposure section. FIG. 2 is a sectional view of a photoresist according to an embodiment of the present invention. FIG. 31 is an explanatory diagram of the relationship between a 4-inch (100m+n) wafer and an exposure section in the prior art. FIG. 4 is a cross-sectional view of a conventional photoresist. 1...Exposure section 2...- and wafer 5...Photoresist 4...Exposure section 2

Claims (2)

[Claims] (1) In the step of selectively exposing the periphery of the wafer on which a photoresist is applied to the entire surface of the wafer on which a pattern is to be formed, the exposure is carried out over a length calculated by subtracting the selectively exposed length from the radius of the wafer. 1. A method of manufacturing a semiconductor device, comprising performing exposure using an exposure section having at least two or more tangents to a circle whose radius is . (2) In the step of selectively exposing the periphery of the wafer on which a photoresist is applied to the entire surface of the wafer on which a pattern is to be formed, the light shielding is made by subtracting the length of the selective exposure from the radius of the wafer. 1. An apparatus for manufacturing a semiconductor device, comprising an exposure section having at least two or more tangents to a circle whose radius is .