JPH0139043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pattern inspection method for photomasks for printed boards, etc.

In general, a printed board is completed by exposing a copper-clad board coated with a photoresist with a photomask having a printed board pattern in close contact with the board, and then performing an etching process or the like.

Therefore, a large number of printed boards may be created based on one photomask, and it is important to inspect whether the completed photomask has a predetermined pattern shape and pattern width.

Conventionally, such photomasks have been inspected manually using a microscope or the like, but this method has a problem in that pattern inspection efficiency is extremely low. Recently, an automatic inspection method has been developed that scans the pattern surface of the material to be inspected with light, converts the pattern shape into a binary signal, stores it in memory, reads out the stored contents, and measures the pattern width. ing.

However, when automatically measuring the lead width of a printed board pattern, for example, it is necessary to always measure the lead width in a direction perpendicular to the direction in which the leads run.

Automatic length measurement is relatively easy if the lead running direction is parallel to the Y-axis or You need to measure the width. Recently, printed board patterns have become more diverse, and many complex patterns are being adopted.

Automatically inspecting such a complex pattern as described above requires a complex and expensive inspection circuit, and in some cases, automatic length measurement may not be possible.

An object of the present invention is to provide a pattern inspection method that solves the above problems, and allows even complex patterns to be inspected easily.

The purpose of the present invention is to detect whether or not a pattern exists at a plurality of predetermined inspection points on a pattern of a material to be inspected, and to synthesize pattern picture elements registered in advance in accordance with the detected information. death,
This is achieved by comparing this composite pattern and the pattern of the material to be inspected to inspect the pattern.

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

FIG. 1 is a block diagram of a pattern inspection apparatus according to an embodiment of the present invention, FIG. 2 is an example of a pattern picture element recognition point setting diagram, and FIG. 3 is an explanatory diagram of a pattern inspection method according to an embodiment of the present invention.

In the figure, 1 is the inspection material pattern, 2 is the image memory, 3 is the pattern pixel recognition circuit, 4 is the pixel memory extraction circuit, 5 is the pixel memory group, 6 is the pixel memory synthesis circuit, and 7 is the pattern comparison circuit. , 8 is a defective memory circuit, 9 is a display circuit, and 10 is a television camera.

An outline of the operation of the pattern inspection apparatus will be explained with reference to FIG.

A certain range (grit square) of the inspected material pattern 1 is photographed with a television camera, and this pattern information is binarized and stored in the image memory 2. A pattern pixel recognition circuit 3 checks whether a pattern exists at a predetermined recognition point of the pattern on the image memory 2. The picture element memory extraction circuit 4 is
Based on this recognition information, a plurality of picture element memories are extracted from the picture element memory group 5 registered in advance,
A picture element memory synthesis circuit 6 synthesizes the patterns. This composite pattern and the contents of the image memory 2 are compared in a pattern comparison circuit 7, and the portions that do not match are stored as defective portions in the defective portion memory circuit 8.
It is displayed on the display circuit 9.

Next, the pattern inspection method of the present invention will be explained in more detail with reference to FIGS. 2 and 3.

FIG. 2 shows an example of a diagram for setting pattern picture element recognition points within one grit, and 1' to 16' indicate pattern recognition points, and it is checked whether there is a black pattern at these points. B1 to B16 indicate black pattern picture element numbers, and W17 to W25 indicate white pattern picture element numbers.

For example, one grid range A surrounded by dotted lines of the pattern 1 to be inspected as shown in FIG. 3 is photographed with a television camera, and this image is extracted and stored in the image memory 2.

In order to simplify the explanation, the image memory 2 will be explained with respect to the recording pattern portion of a portion a within the range A.

The pattern pixel recognition circuit 3 checks whether a black or white pattern exists at these points corresponding to the recognition points in the pattern a portion. As a result, it is recognized that there is a black pattern at recognition point 9' and that there is no black pattern at recognition points 1', 5', 17', and 19'. Based on this cognitive information, the picture element memory extraction circuit 4 extracts the memory of the picture element 9 from the picture element memory group 5 and synthesizes it in the picture element memory synthesis circuit 6. A pattern comparison circuit 7 compares the contents of the memory synthesized by the synthesis circuit 6 and the contents of the image memory 2, and stores the result in a defective location memory 8.

As explained above in the specific examples, according to the pattern inspection method of the present invention, a normal pattern of the recognition target is created from the recognition target and compared with the test pattern, thereby eliminating the need for a comparison test target.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a pattern inspection apparatus according to an embodiment of the present invention, FIG. 2 is an example of a pattern picture element recognition point setting diagram, and FIG. 3 is an explanatory diagram of a pattern inspection method according to an embodiment of the present invention. In the figure, 1 is the inspection material pattern, 2 is the image memory, 3 is the pattern pixel recognition circuit, 4 is the pixel memory extraction circuit, 5 is the pixel memory group, 6 is the pixel memory synthesis circuit, and 7 is the pattern comparison circuit. , 8 is a defective memory circuit, 9 is a display circuit, and 10 is a television camera.

Claims (1)

[Claims] 1. Means for binarizing pattern information of a grid having a predetermined range of the inspection material pattern and storing it in the memory 2, and means for recognizing the existence of a black pattern or a white pattern at a predetermined recognition point of the grid. and means for extracting a predetermined picture element memory from the picture element memory group based on the cognitive information;
A pattern inspection method comprising: means for synthesizing the extracted picture element memories; and means for comparing the synthesized picture element memories with the contents of the memory 2.