JPH06258029A - Method and system for recognizing pattern position - Google Patents

Abstract

PURPOSE:To recognize the pattern position of an object to be inspected accurately by correcting positional shift of the center of gravity between a reference image and an image of the object through coordinate conversion of the position of one center of gravity and then comparing both images. CONSTITUTION:A reference image data 9 is input to a second memory 5 and a processing window is set. The position of the center of gravity of a reference image is then operated 3 based on the data 9 and stored 6. Pattern of an object to be inspected is then imaged 1 and A/D converted 2 to produce an image data 10 of the object and position of the center of gravity thereof as then operated 3 and stored 6. An operating unit 3 compares the data 9, 10 and if the positional difference of the center of gravity is within an allowable range, the data 9, 10 are presented while superposed on a display 8 through a second signal processor 7. When the positional difference exceeds the allowable range, the processing window is subjected to coordinate conversion in order to match the center of gravity for the data 9 and 10 which are then similarly displayed 8. An inspector compares the displayed pattern with a reference pattern to inspect matching thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for inspecting and confirming a pattern position by using a display such as a CRT and a liquid crystal display.

[0002]

2. Description of the Related Art Generally, when confirming the pattern position of a semiconductor element or an electronic circuit in a semiconductor manufacturing apparatus manufacturing line, a reference image in which the pattern is arranged at an accurate position and a target image captured in an image processing memory by an image pickup device are used. It was confirmed by comparing the pattern image of the inspection object with the pattern position of the inspection object.

In the conventional pattern position confirmation method, a captured image of an object to be inspected is displayed in a superimposed manner on a fixed processing window in which a reference image is displayed in advance, and the pattern of the reference image and the pattern of the captured image are compared to determine the position. Was being confirmed.

[0004]

However, in the above-mentioned conventional method, when there is a mechanical error in the stop position of the transport mechanism of the object to be inspected or an attachment error when mounting the object to be inspected on the conveyor. Etc., if there is a mechanical displacement between the object to be inspected and the image pickup device, further displacement of the target image data on the memory due to the synchronization taken in by the image processing memory + the error in the synchronization separation of the image signal, etc. In that case, the positional deviation between the captured image and the reference image directly affects the result of the inspection confirmation, and there is a possibility that a confirmation error may occur.

As a method of correcting the positional deviation, a method of setting a reference mark on the object to be inspected or a method of using the reference mark as a part of the target display is conceivable. Space is required to set
The latter has a problem that the pattern that also serves as the reference mark does not function as the reference mark due to interference unless the pattern is also isolated from the other patterns.

In view of the above-mentioned circumstances, the present invention is capable of accurately confirming the pattern position of the object to be inspected without being affected by the positional deviation of the captured image. .

[0007]

According to the present invention, the barycentric position of a reference image and the barycentric position of an image of an object to be inspected are respectively determined. It is characterized in that at least one of the coordinates is converted to align the positions of both centers of gravity, and the reference image and the image of the inspection object are compared.

[0008]

By eliminating the shift of the image center of gravity position between the reference image and the captured image of the object to be inspected, the influence of the shift between both images can be eliminated, and only the pattern positions to be inspected can be accurately compared.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is an image pickup device for picking up a pattern of an object to be inspected, 2 is a first signal processor for performing signal processing such as A / D conversion of a video signal of the image pickup device into a serial digital signal, 3 is a computing unit, 4 is a first memory for storing captured images,
5 is a second memory for storing a reference image, 6 is the arithmetic unit 3
3 is a third memory for storing the calculation result of, 2 is a second signal processor for converting the signal from the arithmetic unit 3 into a video signal, and 8 is a display.

The operation will be described below with reference to FIG.

First, the reference image data 9 is input to the second memory 5, and the processing window is set. The calculator 3 calculates the barycentric position of the reference image from the reference image data 9 input to the second memory 5, and stores the result in the third memory 6.

Next, the image pickup device 1 picks up an image of the pattern of the object to be inspected, and the first signal processor 2 A / D-converts the signal from the image pickup device 1 and inputs it to the arithmetic unit 3. The arithmetic unit 3
Stores inspected image data 10 from the first signal processor 2 in the first memory 4, and further inspected image data 1
The gravity center position of the image of the object to be inspected is calculated from 0, and the calculation result is stored in the third memory 6.

The arithmetic unit 3 compares the barycentric position of the reference image with the barycentric position of the image data of the object to be inspected. If the difference between the positions is within an allowable value, the reference image data 9 and the image of the object to be inspected. The data 10 and the data 10 are superimposed on the display 8 via the second signal processor 7 and displayed (see FIG. 2).

The inspector compares the pattern to-be-inspected 11 displayed on the display 8 with the reference pattern 12 and inspects whether or not the positions of the two patterns match.

Alternatively, the positions of the corresponding patterns of the reference image data 9 and the image data 10 to be inspected are calculated by the second signal processor 7, and the pattern positions are compared based on the calculated results. It is also possible to display on the display unit 8 which pattern is in the allowable range and which pattern is in the allowable range.

In the arithmetic unit 3, the barycentric position of the reference image is compared with the barycentric position of the image data of the object to be inspected, and if the difference between the two positions exceeds the allowable value, the coordinate conversion of the processing window is performed. , The center of gravity of the reference image is matched with the center of gravity of the image data of the object to be inspected. Then, the reference image data 9 and the inspected image data 10 are superimposed on the display 8 via the second signal processor 7 and displayed, or the reference image data 9 and the inspected image are displayed. The pattern position of the data 10 is calculated and compared by the calculator 3, and the comparison result of the pattern position is displayed on the display 8.

After the confirmation of the pattern of one inspected object is completed, when the coordinate conversion of the processing window is performed,
The state before the coordinate conversion is restored, the image of the inspection object is captured again, and the above-described work is repeated.

As described above, since the data of the barycentric position of the reference image and the captured image and the difference between the positions can be obtained, a mechanical error of the stop position of the transport mechanism of the object to be inspected, Alternatively, it is possible to accurately measure the mounting error when mounting the inspection object on the carrier. Further, in the above embodiment, the coordinate conversion of the reference image was performed in order to align the barycentric positions of the reference image and the captured image. However, the coordinate conversion of the captured image may be performed. Of course, coordinate conversion may be performed for both images.

[0020]

As described above, according to the present invention, even if there is a positional deviation between the captured image and the reference image, the pattern position of the object to be inspected can be accurately confirmed without being affected by the positional deviation. can do.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram showing a comparison state between a captured image and a reference image.

FIG. 3 is a flowchart showing the operation of this embodiment.

[Explanation of symbols]

 1 Imager 2 1st signal processor 3 Arithmetic unit 4 1st memory 5 2nd memory 6 3rd memory 7 2nd signal processor 8 Display 9 Reference image data 10 Inspected image data 11 Inspected pattern 12 Reference pattern

Claims (2)

[Claims] 1. A barycentric position of a reference image and a barycentric position of an image of an object to be inspected are respectively obtained, and when both barycentric positions are displaced beyond an allowable range, coordinate conversion of at least one of the barycentric positions of images is performed. A pattern position confirming method characterized in that the positions of both centers of gravity are aligned and the reference image and the image of the inspection object are compared. 2. An image capturing means for an object to be inspected, a reference image inputting means, a means for calculating the center of gravity of the image to be inspected and the center of gravity of the reference image, and conversion of the position of the center of gravity of at least one of the images. A pattern position confirmation device comprising at least means.