JPH0520890B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection exposure apparatus for manufacturing semiconductor devices.

[Conventional technology]

Conventionally, a projection exposure apparatus used in the photolithography process when manufacturing semiconductor devices projects and exposes a reduced pattern of one mask onto a semiconductor substrate coated with photoresist, and then exposes the semiconductor substrate. The structure is such that exposure is performed repeatedly while moving the image.

By the way, in this type of projection exposure, it is necessary to expose the pattern of the semiconductor device on the same semiconductor substrate and also to expose the pattern for checking various characteristics, or to remove unnecessary photoresist in the peripheral area. In some cases, it may be necessary to expose the peripheral portion of the semiconductor substrate.

As described above, two methods have been conventionally proposed as exposure methods for exposing other patterns in addition to the pattern of a semiconductor device. One method is to create two types of patterns on a mask and expose the two types of patterns separately by covering these patterns alternately with shielding plates. Another method is to expose one part of the substrate with a pattern of one mask, then exchange the mask and expose an unexposed area with the pattern of the new mask.

[Problem that the invention seeks to solve]

Of the two conventional methods described above, the former method forms two types of patterns on a mask and selectively covers them with a shielding plate. Therefore, there is a problem in that the effective area for forming a semiconductor device becomes smaller.

On the other hand, in the method of exchanging the mask, it is necessary to load and unload the semiconductor substrate to and from the exposure apparatus at the same time as exchanging the mask, resulting in a problem of reduced throughput.

The present invention provides two solutions without reducing the effective area of the semiconductor device and without reducing the throughput.
It is an object of the present invention to provide a projection exposure apparatus capable of exposing various types of patterns.

[Problem that the invention seeks to solve]

A projection exposure apparatus of the present invention is a projection exposure apparatus that projects and exposes a first mask illuminated by a light source onto a semiconductor substrate using a projection lens, and a second mask is disposed at a position adjacent to the first mask. In addition to installing mirrors on the top and bottom of the mask,
Mirrors are configured to move forward and backward, respectively, above and below the first mask, and configured so that the optical path of the light source can be switched between the first mask and the second mask by these mirrors, so that the mirrors can be moved forward and backward. The configuration allows switching of projection patterns.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a front configuration diagram of an embodiment of the present invention. In the figure, 1 is a semiconductor substrate coated with photoresist, 2 is a first mask formed with a pattern (here, the pattern is indicated by "A") for forming a semiconductor device on this semiconductor substrate,
Reference numeral 2a denotes a second mask on which a special pattern for characteristic checking (indicated by pattern "B" here) is formed. The first mask 2 is positioned directly above the semiconductor substrate 1, a 1/5 reduction projection lens 3 is placed directly below it, and a light source (not shown) is placed directly above it. Further, the second mask 2a is placed adjacent to the first mask 2.

Furthermore, directly above and below the first mask,
The mirrors 4 and 5, each tilted at 45 degrees, are configured to be able to be advanced and placed by driving means (not shown). Mirrors 6 and 7 are also placed directly above and below the second mask 2a.
It is fixedly placed at a 45° angle.

According to this configuration, when exposing a pattern for forming a semiconductor device, the mirrors 4 and 5 are retracted from directly above and below the first mask 2 as shown in FIG. A pattern "A" is exposed on the semiconductor substrate 1 using the photodiode. By repeating this exposure, the pattern shown in FIG. 2 can be exposed.

Next, when exposing a characteristic check pattern, mirrors 4 and 5 are positioned directly above and directly below the first mask 2, respectively, as shown in FIG. and 6 to illuminate the second mask 2a, and the pattern is reflected by mirrors 7 and 5 and projected onto the semiconductor substrate by the reduction projection lens 3. As a result, as shown in FIG. 4, pattern "B" is exposed in the required area where pattern "A" is not exposed.

Therefore, during this exposure, the semiconductor substrate 1
Since two types of exposure can be performed by simply moving the mirrors 4 and 5 back and forth while keeping them fixed, there is no need to unload and reload the semiconductor substrate 1, and throughput can be improved. Furthermore, since there is no need to provide a margin for positioning the shielding plate in the mask, the effective area for forming the semiconductor device is not reduced.

Here, if the exposure apparatus of the present invention is used, the second
If a pattern is adopted as the pattern of the mask 2a that has no pattern inside and allows light to pass through the peripheral area, the entire peripheral area 1a of the pattern exposed on the semiconductor substrate 1 can be exposed, as shown in FIG. As a result, the peripheral resist can be removed after the photoresist phenomenon occurs, and it is possible to prevent the generation of foreign matter due to peeling of the peripheral resist during transportation of the substrate.

〔Effect of the invention〕

As explained above, the present invention provides mirrors above and below the second mask disposed adjacent to the first mask, and configures the mirrors to move forward and backward above and below the first mask. Since the optical path of the light source is configured to be switchable between the first mask and the second mask, the projection pattern can be switched by simply moving the mirror back and forth, reducing the effective area of the semiconductor device. This has the effect of realizing projection exposure with significantly improved throughput without any problems.

[Brief explanation of the drawing]

FIG. 1 is a schematic front view of one embodiment of the present invention, showing the exposure state using the first mask, FIG. 2 is a pattern diagram of the exposed first mask, and FIG.
A schematic front view showing an exposure state using a mask, FIG. 4 is a pattern diagram of the exposed second mask, and FIG.
The figure is an exposure pattern diagram in another example. 1... Semiconductor substrate, 2... First mask, 2a
...Second mask, 3...Reduction projection lens, 4-
7...Mirror.

Claims (1)

[Claims] 1. In a projection exposure apparatus that projects and exposes a first mask illuminated by a light source onto a semiconductor substrate using a projection lens, a second mask is provided at a position adjacent to the first mask.
A mask is disposed, mirrors are provided above and below the second mask, and the mirrors are configured to move forward and backward above and below the first mask, and these mirrors connect the optical path of the light source to the first mask and the second mask. A projection exposure apparatus characterized in that it is configured to be able to switch between a mask and a mask.