JPS60221758A - Exposing method by reducing projection - Google Patents

Abstract

PURPOSE:To shorten as a whole the work time by a reducing projection aligner, by executing an exposure by using a reticle having plural patterns. CONSTITUTION:Patterns A-C of each different kind are provided in an effective area in a reticle 4. The reticle 4 is fixed in a supporting frame 6 in a reducing projection aligner, a shielding plate 7 is opened and closed, and a selective projection of each different pattern A-C is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an exposure method, particularly to a reduction projection exposure method.

In the manufacture of semiconductor devices, mask aligners are used for optical processing of organic photosensitizers applied to the surface of a semiconductor substrate for selective diffusion, oxidation, and etching of the surface of the substrate.

Conventional mask aligners can be broadly categorized by projection method: (
1) A method in which the mask pattern is projected onto the wafer surface at a ratio of 1=1, and (2) a method in which the mask pattern is projected at a ratio of 1/10, for example.
There is a method of reducing the size and moving and projecting it onto the wafer surface. Of these, (1) uses a pattern for, say, 200 chips arranged on one master mask (or reticle), and the light projection time is short, about 10 seconds, but the pattern is fine and has the same size as the object to be processed. Therefore, there is a limit to resolution, making it difficult to manufacture masks with precise patterns. On the other hand, (2) uses a mask 1 in which a pattern 2 having a size approximately 10 times that of one chip is arranged as shown in FIG. 1, so extremely high precision can be obtained. Although the amount of light for projection can be small, the processing time is long because, as shown in FIG. 2, projection of, for example, 200 chips is sequentially performed while moving the mask relative to one wafer 3 in the X and Y directions.

For example, it takes 20 minutes. Such a reduction projection exposure method is particularly problematic in cases where production is required more quickly than in large quantities, such as for small-volume production items or express prototype items.

For example, a method of reducing projection exposure of one pattern on a reticle onto a wafer is described in Electronic Materials 1983.
It is described in the March issue of 2007, pages 72-78.

The present invention has been made to solve the problems of the prior art described above, and an object of the present invention is to provide an exposure method that can reduce the overall working time using a reduction projection aligner.

In order to achieve the above object, one embodiment of the present invention processes two or more types at the same time in the same process by arranging different patterns of multiple types in the effective area within one reticle, thereby shortening the overall process. The main point is what to do.

FIG. 3 shows an example of the structure of a mask for a reduction projection aligner used in an embodiment of the present invention. In the figure, reference numeral 4 indicates a reticle, and the area within the dashed dotted line 5 indicates the effective area within the reticle, that is, the effective diameter of the reduction lens.

Different patterns A and B of multiple products within this effective area
, C are provided. These A, B, and C belong to the same layer on the surface of the semiconductor wafer to be processed, and are processed in the same process.

By using such a reticle, the image shown in FIG.
As shown in Figure 1, three types of patterns can be printed on the wafer at the same time; conventionally, one reticle has only one pattern, so printing three types of patterns requires three times as much effort and time. However, in one embodiment of the present invention, only one step is required, and the number of steps can be significantly reduced. The same figure (b
l, (cl is a case where two or only one pattern of different types is extracted from one reticle and selectively printed, and a selection mask (shielding plate) is used.

FIG. 4 shows a mask support frame 6 in a reduction projection aligner used in one embodiment of the present invention. A mask (reticle) 4 is fixed in the support frame, and by opening and closing the shielding plate 7, different patterns of the mask can be adjusted. This enables selective projection of images.

According to the exposure method of the embodiment of the present invention, it has the high precision that is an advantage of the reduction projection exposure method, and also has the advantage of printing different types of patterns at the same time, thereby simplifying the process for small-lot, multi-product production. It became possible to shorten the number. In addition, according to an embodiment of the present invention, the punch uses a reduction projection exposure method such as a reticle with multiple different patterns and performs selective projection for each different pattern. In this case, mask setting time can be saved, which is particularly effective when processing small quantities of prototypes on an urgent basis.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the form of a conventional reduction projection aligner mask, Fig. 2 is a schematic diagram showing the principle structure of a reduction projection aligner, and Fig. 3 is a reduction projection aligner used in an embodiment of the present invention. FIG. 4 is a schematic sectional view showing the mask support portion of a reduction projection aligner used in an embodiment of the present invention, and FIGS. FIG. 3 is a plan view illustrating a part of a method for selectively extracting different types of patterns from a reduction projection mask according to an embodiment of the present invention. 1...Mask, 2...Pattern, 3...Ueno)
, 4... Reticle, 5... Effective area, 6... Mask support frame, 7... Shielding plate to open and close, A, B, C...
Different patterns for each variety.

Claims (1)

Claims: 1. A reduction projection exposure method in which a pattern on a reticle is reduced and exposed onto a wafer, the reduction projection exposure method being characterized in that exposure is performed using a reticle having a plurality of patterns. 2. The reduction projection exposure method according to claim 1, wherein in the reduction projection exposure method, a plurality of patterns on the reticle are exposed at once. 3. The reduction projection exposure method according to claim 1, wherein in the reduction projection exposure method, at least one pattern from a plurality of patterns on the reticle is selectively exposed.