JPS62219941A - Photomask - Google Patents

Abstract

PURPOSE:To improve the accuracy of checking, to shorten a time required therefore and to prevent the lowering of a yield, by setting on a photomask a pattern showing a region wherein a defect is to be checked. CONSTITUTION:A defect checking region pattern is provided inside a light intercepting zone 3 of a reticle. The size thereof is 4mm, since it is provided at a place separated from a main mask pattern 4 located in the center of the reticle by a distance corresponding to the precision of a light intercepting function that a reduced projection exposure device has. The width of the defect checking region pattern 2 is set to be 2mum, since it is designed to have a pattern size which is not covered by the resolution of the reduced projection exposure device. By forming the defect checking region pattern as described above, a region wherein a defect is to be checked is made definite. When the defect is checked by an optical microscope, for instance, an unnecessary region is not subjected to checking at all, and therefore it does not occur that a time for checking is elongated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photomask used in an exposure apparatus. In particular, it relates to inspection of defects on photomasks.

[Summary of the Invention] The present invention improves the efficiency of defect inspection by forming a pattern on a photomask that indicates a region to be inspected for defects.

[Conventional technology]

Conventional techniques do not form a special pattern on a photomask that indicates the area to be inspected for defects. For this reason, in conventional defect inspection, for example, when performing defect inspection using an optical microscope (aS), the area to be inspected for defects is not accurately displayed. The outer circumferential position of the mask pattern is roughly determined by visual measurement, and inaccurate areas are inspected for defects.

[Problem that the invention seeks to solve]

In the above-mentioned conventional technology, the area in which defect inspection is performed is inaccurate; 9. To compensate for inaccuracies, create a large area.
It took 91 hours to complete the defect inspection without any problems, and there was a lot of waste. As a result of long-term defect inspection, the ff11K of the defect inspection also decreases, causing problems in quality and a decrease in yield by one point.

The present invention is intended to solve all of these problems, and its purpose is to display areas to be inspected for defects and improve inspection accuracy.

The goal is to shorten the time and prevent a drop in yield.

[Means to solve the problem]

The present invention is to provide a pattern on a photomask that indicates a gap area to be inspected for defects.

[Example 1] Figure 1 shows an example. This embodiment relates to a photomask (reticle) of a reduction projection exposure apparatus used for manufacturing semiconductor devices. In other words, the area to be inspected for defects is provided as a defect inspection area pattern, and this indicates that it is sufficient to inspect within this area.

In the case of this embodiment, the defect inspection area pattern is located within the light-shielding area of the reticle (the main mask pattern in the center of the reticle), and the light-shielding function of the reduced projection lens is separated by a small distance. The ninth point set at the distance is 41. In addition, the width of the defect inspection area pattern is reduced projection l1*#
(The turf size was set to 2 μm for the purpose of resolution.)

By forming the defect inspection area pattern as described above, the area to be inspected for defects becomes clear, for example, when defects are inspected using an optical microscope.

There is no need to inspect any extra areas and the inspection time does not increase. Furthermore, the accuracy of defect inspection can be maintained sufficiently without inspecting the area to be inspected insufficiently. Therefore, it is no longer necessary to manufacture semiconductor devices using reticles with defects, making it possible to prevent a drop in yield by one. Furthermore, since the areas to be inspected for defects were clarified, there were no differences between inspection workers, which was a major effect.

〔Effect of the invention〕

As in the above example, by adding a small new pattern, a very large effect can be obtained (indication of defect inspection area on the photomask, inspection accuracy, time reduction, yield improvement, etc.) It is.

Another major advantage of the method of the present invention is that it is completely unlikely that the defect inspection area pattern will cause damage to the semiconductor device itself, whether directly or indirectly. It can be applied to photomasks for electrical manufacturing other than reticles of reduction projection exposure equipment, and can also be applied to display devices other than semiconductor devices such as liquid crystal displays, and information-related equipment such as optical disks. be.

[Brief explanation of drawings]

FIG. 1 is a sketch of a photomask (reticle) used for reduction projection four-beam correction provided with a defect inspection area pattern according to the present invention. 1...Photomask (reticle) fs plate 2...Uninvented defect inspection area pattern 6...Shading zone 4...Main mask pattern and above

Claims (1)

[Claims] A photomask characterized in that a defect inspection area pattern is formed around a main mask pattern to indicate an area where the main mask pattern and other defects are to be inspected.