JPH02143248A - Photomask - Google Patents

Abstract

PURPOSE:To allow the easy collation of the relative positions between patterns by forming mask patterns for reference to be used for collating the relative positions of mask patterns for exposing on the same mask substrate. CONSTITUTION:The same mask patterns as the mask patterns for exposing to be used for formation of other layers or the mask patterns before the revision of the mask patterns 4 for exposing are formed as the mask patterns 5 for reference to be used for collating the relative positions of the mask patterns 4 for exposing together with the mask patterns 4 for exposing to be used for forming arbitrary layers on the same mask substrate 3. The mask patterns 5 for reference to be used for collating the relative positions of the mask patterns 4 for exposing are previously formed together with the mask patterns 4 for exposing on the same mask substrate 3 in such a manner, by which the collation of the relative positions by comparison of the mask patterns on the same mask substrate 3 is enabled and the easy collation of the relative positions between the patterns is possible.

Description

[Detailed Description of the Invention] [1 Summary] Regarding the improvement of photomasks for manufacturing semiconductor devices, particularly means for verifying the relative positions between patterns, the present invention provides a photomask that allows easy verification of the relative positions between patterns. In addition to the exposure mask pattern used for forming any layer, the same mask pattern as the exposure mask pattern used for forming other layers, or the mask pattern before revision of the exposure mask pattern, is used for exposure. The reference mask pattern is formed on the same mask substrate as a reference mask pattern used for comparing the relative position of the reference mask pattern.

[Industrial application field]

The present invention relates to a photomask used in the manufacture of semiconductor devices, and more particularly to an improvement in means for verifying relative positions between patterns.

When forming a photomask, which is essential for forming a semiconductor device, if a pattern deviates from a predetermined position, it will engage with a pattern in another layer, making it impossible to manufacture a semiconductor device with desired characteristics. In recent years, as the density of semiconductor devices has increased, the margins between patterns have been decreasing, and matching of the relative positions between patterns has become increasingly important.

However, at present, there is no appropriate means for such verification, and it costs a lot of money and takes a long time. Therefore, there is a need for the development of a means that can easily match the relative positions between patterns.

[Conventional technology]

FIG. 6 is a schematic diagram showing a conventional photomask, and FIG. 7 is a diagram showing an example of a conventional related position matching means.

When manufacturing a semiconductor device, for example, when a plurality of patterns A, B, and C are sequentially formed on a wafer 1 as shown in FIG. 6(a), a photomask for printing each pattern is prepared. . That is, Fig. 6 (b
) Mask pattern A shown in FIG.

A first photomask 2A with a mask pattern B° shown in FIG. 6(C), a second photomask 2B with a mask pattern B° shown in FIG.
A third photomask 2C having a mask pattern C° shown in FIG. 6(d) is used.

In the conventional photomask, FIGS. 6(b) to 611iI
As shown in D(d), a plurality of mask patterns A′, mask patterns B′, and mask patterns C° are formed on the glass substrate 3, respectively. Each of these photomasks has alignment marks (not shown), and by placing the alignment marks on the wafer 1 so that the alignment marks overlap, patterns A, B, and C can be placed at predetermined positions on the wafer 1. are formed sequentially.

However, if there is an error during mask pattern formation or photomask formation, it is impossible to form a normal pattern even if the alignment marks are placed so that they overlap. Such mask pattern defects can be detected by comparing the relative positions between the patterns.

However, since each mask pattern is formed on a different glass substrate 3, even if mask patterns on the same glass substrate 3 are compared, the defects described in "2" cannot be detected. Therefore, in the conventional photomask, the related positions are verified by the following method.

That is, as shown in FIG. 7(a), mask patterns formed on two photomasks, for example, mask pattern A' of photomask 2A and mask pattern B' of photomask 2B, are optically synthesized. By doing so, the relative positions of each are verified. Alternatively, as shown in FIG. 7(b), use a photomask forming reticle to form patterns A, B1, and C on the wafer l, and estimate the consistency of the mask patterns from the actual characteristics of the completed device. do.

[Problem to be solved by the invention]

However, the number of photomasks necessary for manufacturing semiconductor devices is extremely large, and each photomask is stored at the factory where it is used. Therefore, the method of matching using two photomasks may require a lot of time to procure the matching photomasks, and if they are used frequently, there is a problem that the work will stop during the matching. be.

Furthermore, the method of forming a device using a reticle for forming a photomask requires a lot of cost and time to form the device and evaluate its consistency, which is not practical.

An object of the present invention is to provide a photomask that allows easy verification of relative positions between patterns.

[Means to solve the problem]

FIG. 1 is a schematic diagram showing a photomask according to the present invention. The same objects are represented by the same symbols throughout the plan.

The above problem is caused by the exposure mask pattern 4 used for forming any layer, the same mask pattern as the exposure mask pattern used for forming other layers, or the mask pattern before revision of the exposure mask pattern 4. This is achieved by the photomask of the present invention, which is formed on the same mask substrate 3 as the reference mask pattern 5 used for comparing the relative positions of the exposure mask pattern 4.

[For production]

In FIG. 1, the reference mask pattern used for comparing the relative positions of the exposure mask patterns is formed on the same mask substrate together with the exposure mask pattern, so that the mask patterns on the same mask substrate can be compared. It becomes possible to compare the relative positions, and it is possible to realize a photomask in which the relative positions between patterns can be easily compared.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings. Furthermore, Fig. 2 is a bronch diagram showing the inspection system, Fig. 3 is a schematic diagram showing the first embodiment of the present invention, Fig. 4 is a schematic diagram showing the second embodiment of the invention, and Fig. 5 is a schematic diagram showing the second embodiment of the present invention. It is a schematic diagram which shows the modification of this invention.

As shown in FIG. 1, the photomask according to the present invention is provided on the same mask substrate 3, together with a plurality of exposure mask patterns 4 used for forming arbitrary layers, and used for matching the relative positions of the exposure mask patterns 4. A reference mask pattern 5 is formed, and by combining the exposure mask pattern 4 and the reference mask pattern 5, the relative positions between the respective patterns can be easily verified.

The above-mentioned mask patterns are synthesized using, for example, an inspection system shown in FIG. That is, the inspection system includes a stage 61 on which the photomask 2 is placed, a light source 62 that irradiates the photomask 2 from the back, a lens 63, and a mirror that converts the exposure mask pattern 4 and the reference mask pattern 5 into image signals. Group 6A includes a photoelectric conversion device 65, an image signal conversion device 66, an image memory 67, and an image processing device 68. The image signal output from the image processing device 68 is compared and verified by a comparator 69, and a mask for exposure is used. pattern 4
The relative positions of the reference mask pattern 5 and the reference mask pattern 5 are compared.

In FIG. 3, the first embodiment of the present invention includes a plurality of exposure mask patterns B' used for forming arbitrary layers on the same mask substrate 3, and a relational position verification of the exposure mask patterns B'. As a reference mask pattern used, an exposure mask pattern A' used for forming other layers is formed.

Therefore, by comparing the exposure mask pattern B' and the reference mask pattern A', the consistency of the exposure mask pattern B' with the reference mask pattern A' is inspected. Although a mask pattern B' is shown as a pattern, it is also possible to form a mask pattern C' used for forming other layers.

Further, in FIG. 4, the second embodiment of the present invention includes a plurality of exposure mask patterns B'' used for forming arbitrary layers on the same mask substrate 3, and a relational position verification of an exposure mask pattern B'. As a reference mask pattern for
Mask pattern B before revision of exposure mask butter 7B''
' is formed. Therefore, by comparing the exposure mask pattern B' and the reference mask pattern B°, the relative position of the mask pattern B after revision with respect to the mask pattern B before revision is verified.

The present invention can be applied to reticle pattern verification in addition to mask pattern relational positions 1.9. That is, in pattern verification when printing a reticle pattern onto a photomask, as shown in FIG. By forming the pattern on the plate 7, the consistency of the pattern 71 with respect to the pattern 72 can be easily inspected.

In this way, by forming the reference mask pattern used for comparing the relative positions of the exposure mask patterns on the same mask substrate together with the exposure mask patterns, the mask patterns on the same mask substrate can be compared and related. It becomes possible to verify the positions, and it is possible to realize a photomask in which the relative positions between patterns can be easily verified.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a photomask in which the relative positions between patterns can be easily verified.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing a photomask according to the present invention, Fig. 2 is a block diagram showing an inspection system, Fig. 3 is a schematic diagram showing a first embodiment of the present invention, and Fig. 4 is a schematic diagram showing a photomask according to the present invention. Second
FIG. 5 is a schematic diagram showing a modified example of the present invention. FIG. 6 is a schematic diagram showing a conventional photomask. The seventh factor is a diagram showing an example of a conventional relative position matching means. , is. In the figure, 2 is a photomask, 3 is a mask substrate, 4 is a mask pattern for exposure, 5 is a reference mask pattern, 7 is a Cr wafer glass plate, 61 is a stage, 62 is a light source, 63 is a lens, 64 is a mirror group, 65 is a photoelectric conversion device, 66 is an image signal conversion device, 67 is an image memory, 68 is an image processing device, 69 is a comparator, 7
1.72 ha turn for verification, 2 pieces l light 0 1st f) Implementation 4
9j and Hosai Tsuma Hisa Figure 30 Figure 4 shows the axis system A 4 pro... Figure 2 Figure 2 shows the present invention/l capital e13 Figure 5 Conventional O relationship system, call and match The real thing! '5 = 1.2 Figure 7 Figure 45 East photomask and Hosuomo 2 Hro No. 6 40

Claims (1)

[Claims] 1) An exposure mask pattern (
4), the same mask pattern as the exposure mask pattern used for forming other layers is used as a reference mask pattern used for matching the relative position of the exposure mask pattern (4) on the same mask substrate (3). ) A photomask characterized by being formed on a photomask. 2) Exposure mask pattern (
4), the mask pattern before revision of the exposure mask pattern (4) is placed on the same mask substrate (3) as a reference mask pattern used for matching the relative position of the exposure mask pattern (4). A photomask characterized by being formed.