JPH04236314A - Inspecting apparatus of minimum pattern gap - Google Patents

Abstract

PURPOSE:To enable execution of inspection without correcting a tilt of a pattern being an object of inspection and to prevent a place of a narrow pattern gap at an acute-angle corner part from being detected as a fault erroneously, by a method wherein inspection of a pattern width is executed by scanning a circular mask of a diameter set beforehand and inspection of a pattern gap is conducted only between different labeled images. CONSTITUTION:An object pattern is scanned by a photoelectric conversion scanner 1, an input signal (a) thereof is turned into a binary-coded image by a binary-coding circuit 2 and a binary-coded image signal (b) is outputted therefrom. This signal is labeled sequentially in a labeling circuit 3 and a labeled image signal (c) is outputted. In a circular mask scanning circuit 4, subsequently, a circular mask of a diameter set beforehand is made to scan the signal (c) synchronously with a raster scan and an inspection position detection signal (d) is outputted when the center of the mask is located in a pattern gap part. In a pattern gap inspection circuit 5, then, a defect signal (e) is outputted on the basis of the signals (c) and (d) when both of two points facing each other on the mask are located in the pattern gap part and when two points being orthogonal thereto are located on the pattern and do not have the same label number. According to this constitution, inspection not requiring correction of a tilt of the pattern can be executed and false detection can be prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minimum pattern spacing inspection device, and more particularly to a minimum pattern spacing inspection device for inspecting the minimum pattern spacing of a target pattern read out by a photoelectric conversion scanner.

0002

[Prior art] As a conventional technology, for example, "Nakajima,
Inagaki et al. “Printed wiring mask automatic inspection system using laser light” Research meeting of the Japan Society of Precision Engineers, Automatic Assembly Expert Committee
No. 82-11 lecture preprint, pp7-11, 1982
There is a pattern inspection device with limited directions as shown in ``. This device has 0,
Pattern edges in each direction of 45 degrees, 90 degrees, and 135 degrees are detected, and the distance between the pattern edges is determined to detect a pattern width defect. Pattern spacing is also inspected by reversing negative/positive.

0003

[Problems to be Solved by the Invention] The above-mentioned conventional technology can only inspect the pattern spacing in a pre-specified direction, so it is necessary to use a high-precision table to correct the inclination of the pattern to be inspected. Another drawback is that normal pattern spacing at points where patterns connect at acute angles is erroneously detected as defective.

0004

[Means for Solving the Problems] The minimum pattern spacing inspection device of the present invention includes: (A) converting an input image signal read out by scanning a pattern to be measured with a photoelectric conversion scanner into a binary image; a binarization circuit that outputs an image signal; (B) a labeling circuit that sequentially labels the binarized image signal based on the connection relationship of the images and outputs a label image signal; (C) the label image signal. A circular mask with a preset diameter is scanned in synchronization with the raster scan, it is determined whether the center of the scanned circular mask is in the pattern interval, and an inspection position detection signal is output. a scanning circuit, (D) two opposing points on the circular mask are both located in the pattern interval portion at a position detected by the circular mask scanning circuit based on the label image signal and the inspection position detection signal; The apparatus also includes a pattern interval inspection circuit that outputs a defect signal when two points perpendicular to this are on the pattern and do not have the same label number.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The minimum pattern spacing inspection device shown in FIG.
) A binarization circuit 2 that converts the input image signal a read out by scanning the measurement target pattern with the photoelectric conversion scanner 1 into a binarized image and outputs the binarized image signal b, (B) Binarized image A labeling circuit 3 that sequentially labels the signal b based on the connection relationship of the images and outputs the label image signal c, (C) Raster scans a circular mask with a preset diameter for the label image signal c. A circular mask scanning circuit 4 that scans synchronously and outputs an inspection position detection signal d when the center of the scanned circular mask is in the pattern interval part, (D) Label image signal c and inspection position detection signal d. Based on this, at the position detected by the circular mask scanning circuit 4, two points facing each other on the circular mask are both located in the pattern interval, and two points perpendicular thereto are located on the pattern, and If the label numbers are not the same, the pattern spacing inspection circuit 5 outputs a defect signal e as a defective minimum pattern spacing.

FIG. 2 is a schematic diagram illustrating the operation of the pattern spacing inspection circuit shown in FIG. 1. When scanning the circular mask 13 with a preset diameter at the inspection position C15,
Two points facing each other on the circular mask 13 (for example, points n and o) are both in the pattern spacing area, and two points perpendicular to these points (for example, points p and q) are also in the pattern spacing area, so it is determined that the pattern spacing is defective. Not detected. Furthermore, when the circular mask 13 is scanned at the inspection position A12, two points facing each other on the circular mask 13 (for example, points d and e) are both located in the pattern interval, and two points perpendicular thereto (for example, points a and b ) is also on the pattern, but since it is on the same label number K pattern 11, it is not detected as a pattern spacing defect.

However, at the inspection position B14, the circular mask 13
When scanning, two points (for example, points l, m) facing each other on the circular mask 13 are both on the pattern interval, and two points perpendicular to these (for example, points g, h) are also on the pattern,
Since they are on different patterns (label number K pattern 11 and label number J pattern 16), it is detected as a pattern spacing defect.

[0009]

[Effects of the Invention] The minimum pattern spacing inspection device of the present invention has the following features:
Instead of calculating the pattern spacing in a limited direction, pattern width inspection is performed by scanning a circular mask with a preset diameter, so inspection can be performed without correcting the tilt of the pattern to be inspected. Since the pattern spacing is inspected only between label images, there is an effect that areas with narrow pattern spacing at acute corner portions are not erroneously detected as defective.

[Brief explanation of the drawing]

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

FIG. 2 is a schematic diagram illustrating the operation of the pattern interval inspection circuit shown in FIG. 1;

[Explanation of symbols]

1 Photoelectric conversion scanner 2 Binarization circuit 3 Labeling circuit 4 Circular mask scanning circuit 5 Pattern spacing inspection circuit a Input image signal b Binarized image signal c Label image signal d Inspection position detection signal e Defect signal

Claims (1)

[Claims] 1. (A) A binarization circuit that converts an input image signal read out by scanning a pattern to be measured with a photoelectric conversion scanner into a binarized image and outputs the binarized image signal; (B)
a labeling circuit that sequentially labels the binarized image signal based on the connection relationship of the images and outputs a label image signal; (C) rasterizes a circular mask with a preset diameter on the label image signal; a circular mask scanning circuit that scans in synchronization with the scan, determines whether the center of the scanned circular mask is in the pattern interval, and outputs an inspection position detection signal; (D) the label image signal and the inspection; Based on the position detection signal, at the position detected by the circular mask scanning circuit, two points facing each other on the circular mask are both located in the pattern interval part, and two points perpendicular thereto are located on the pattern. and a pattern interval inspection circuit that outputs a defect signal when the label numbers are different from each other and the label numbers are not the same.