JPH042953A - Apparatus for pattern inspection - Google Patents

Abstract

PURPOSE:To stably detect fine defects by providing a binarizing circuit, a terminal part detecting circuit, a terminal width detecting circuit and a terminal part inspecting circuit. CONSTITUTION:An input image (a) read out by scanning a photoelectric conversion scanner 1 is converted into binary images (b) of 0s and 1s in a binarizing circuit 2. A terminal part detecting circuit 3 scans a terminal part detecting mask of a specified size on the binary image (b) while synchronizing with raster- scan to output a terminal part signal (1)c. A terminal width detecting circuit 4 scans a terminal width detecting mask specified on the binary image (b) while synchronizing with raster-scan to output a terminal part signal (2)d. A terminal part inspecting circuit 5 scans a terminal part inspecting mask smaller than the terminal part detecting mask by a specified size by means of the terminal part signal (1)c and the terminal part signal (2)d to output a defect signal (e) when a point not existing on the pattern is included inside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pattern inspection device, and more particularly, to a pattern inspection device that determines whether there is a defect at the end of a pattern to be inspected scanned and read by a photoelectric conversion scanner. .

[Conventional technology]

As a conventional technique, for example, a special mask is used, as shown in ``Automation of Visual Inspection of Printed Circuit Boards'' by Muto and Ando, 9 Mechanical Design, Vol. 29, No. 2, pp. 87-96, 1.985. There is a way.

FIG. 5 is a schematic diagram showing a conventional example.

Four length measurement sensors A to D extending radially from the center P count the number of pixels until the end of the pattern is interrupted, and obtain each length measurement value.Length measurement values of A and C, B and D in opposite directions. Find the center area of the end portion based on the difference between .

When point P is in this area, 1-/of the end width from point P
Determine the value of I-1 for the length measurement sensor E installed at a distance of about 4 meters, take A, C, and B, F, HB, 1-1, and E.
It is checked whether each of the measured length values of and G is within the allowable value, and if even one is outside the allowable value, it is detected as a defect.

[Invention or problem to be solved]

"With conventional pattern inspection equipment that uses two series, it is possible to detect only large defects at the end, and it is impossible to erroneously detect small defects depending on the shape of the end.
:.

[Means to solve the problem]

The pattern inspection apparatus of the present invention scans the pattern to be inspected with a photoelectric conversion scanner and reads out an image at 0°', 1
``The binary image outputted by the binary image outputted by the binary image'' is scanned in synchronization with the raster scan with an end detection mask of preset dimensions and shape. An end detection circuit that detects the position of a pattern end, and a circular mask having a preset dimension on the binary image is scanned in synchronization with the raster scan to detect a pattern width corresponding to the pattern end width. The end width detection circuit 111!8 detects the end width, and the common part of the two detected positions is scanned with the end end inspection mask of the specified size. and a termination inspection circuit for detecting termination defects.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the pattern inspection apparatus shown in FIG. 1, an input image a read out by scanning a photoelectric conversion scanner 1 is converted into a binary image of '0''° and '1' in a binarization circuit 2. . The terminal end detection circuit 3 detects one of the binarized images as follows.
The end portion detection circuit 4 scans the end portion detection mask in synchronization with the raster scan and outputs the end portion signal 1c. The terminal width detection mask is scanned in synchronization with the raster scan, and a terminal end signal 2c is output. The termination part inspection circuit 5 receives the termination part signal 1c and the termination part signal 2c.
Accordingly, a terminal inspection mask of a smaller size than that specified by the terminal detection mask is scanned, and if a point not on the pattern is included therein, a defect signal e is output.

FIG. 2 is a diagram for explaining the operation of the termination detection circuit 3 in FIG. 1.

The input binary image 10 is scanned with a terminal end detection mask 11 having a preset size and shape in synchronization with the raster scan, and the terminal end detection mask is divided into N parts at four opposite locations (for example, at the same time). M3.M7.M
], 1. , M], 5) are simultaneously located on the pattern end point]3, it is detected as the end point detection position 12.

FIG. 3 is a diagram for explaining the operation of the terminal end detection circuit 4 in FIG. 1.

An end width detection mask 20 having a preset size is scanned against the input binary image 10 in synchronization with the raster scan, and the mask center position where the entire inside of the mask is within the pattern end portion 13 is determined as the end width. Detection position 21 is detected.

FIG. 4 is a diagram for explaining the operation of the termination section inspection circuit in FIG. 1.

As mentioned above, = end portion detection position 12 and end width detection position 2
A termination inspection mask 31 of a preset size is scanned around the termination position 30, which is a common part of the pattern 1, and if a point 32 that is not on the pattern is included therein, it is detected as a termination defect 32. .

〔Effect of the invention〕

The pattern inspection device of the present invention detects the termination (17 positions) using a termination detection mask according to the shape of the putter and termination and a termination width detection mask corresponding to the size, and uses a defect detection mask at that point. However, it has the advantage that it is possible to stably detect minute defects.

[Brief explanation of drawings]

FIG. 1 (1) is a block diagram showing an embodiment of the present invention; FIG. 2 is an explanatory diagram of the operation of the termination portion detection circuit shown in FIG. 1; FIG. 3 is an explanatory diagram of the operation of the termination width detection circuit; 5 is an explanatory diagram of the operation of the termination inspection circuit, and FIG. 5 is a schematic diagram showing a conventional example. 1... Photoelectric conversion scanner, 2... Binarization circuit, 3...
... Termination part detection circuit, 4... Termination width detection circuit, 5...
Termination inspection circuit, 10... Input binary image, 11...
Termination part detection mask, 12... Termination part detection position, 13...
・Pattern end portion, 20... Termination width detection mask, 21.
... End width detection position, 30. End position, 31... End end inspection mask.

Claims (1)

[Claims] A binarization circuit converts the image read out by scanning the pattern to be inspected with a photoelectric conversion scanner into a binary image of "0" and "1"; An end detection circuit scans an end detection mask with preset dimensions and shape in synchronization with raster scanning to detect the pattern end position, and a circular mask with preset dimensions on the binary image is scanned in synchronization with raster scanning. A terminal width detection circuit scans synchronously to detect a position having a pattern width corresponding to the pattern terminal width, and a terminal inspection mask having a size specified by the common portion of the two detected positions is scanned. A pattern inspection device comprising: a termination inspection circuit that detects a termination defect when a point that is not on the pattern is included therein.