WO2001075800A1

WO2001075800A1 - Pattern inspecting device

Info

Publication number: WO2001075800A1
Application number: PCT/JP2000/002039
Authority: WO
Inventors: Akifusa Takahashi
Original assignee: Kokusai Gijutsu Kaihatsu Kabushiki Kaisha
Priority date: 2000-03-30
Filing date: 2000-03-30
Publication date: 2001-10-11

Abstract

The pattern widths and gaps are inspected. On the basis of image data acquired by imaging a substrate having a pattern formed by CCD, the areas where the pattern widths are not the prescribed values are erased from the image data, and the areas where the gaps are not the prescribed values are added to the same. The resultant image data is compared with the normal image data to judge whether the pattern is acceptable or not.

Description

TECHNICAL FIELD The present invention relates to an apparatus for determining a pattern, and more particularly, to an apparatus for determining a pattern. More specifically, the present invention relates to an apparatus for inspecting a substrate on which a conductor pattern is formed as a wiring, as an object to be inspected, and from an image obtained by the imaging. The present invention relates to an apparatus for judging whether a pattern has a defect or not. BACKGROUND ART Conventionally, an apparatus has been proposed in which a substrate on which a plurality of patterns are formed is photographed, and the quality of the image is determined from an image obtained by the photographing. The pattern is formed by an etching process, cutting, or the like, and becomes a printed board or a CSP board. This pattern can be partially thinned, thickened, or, in extreme cases, broken or shorted during various manufacturing processes. The width of the pattern and the distance between adjacent patterns (hereinafter referred to as the gap) have an allowable range. For this inspection, the pass / fail of the pattern is measured by measuring the width and gap of the pattern visually, using a microscope, or from the captured image.

However, in the determination of the pattern width and gap measurement based on the image, the pattern width and gap cannot be measured correctly due to irregularities at the pattern edge, and non-defective products may be regarded as defective products. So-called masking processing, etc., which is excluded from the target, is required.

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above facts, and an object of the present invention is to provide an apparatus for judging the width and gap of a pattern with high accuracy and good quality at high speed. According to a first aspect of the present invention, there is provided a photographing means for photographing a pattern on a substrate, and a width of the pattern based on image data obtained by photographing the pattern on the substrate by the photographing means. Determining means for determining whether or not the width is smaller than a predetermined threshold value; and if the determining means determines that the width is smaller than the threshold value, erasing means for treating the image data at this location as a non-pattern; There is provided a judging means for performing labeling from the image data obtained in this way and comparing the result with the labeling result of image data of a regular pattern prepared in advance.

In such a configuration, if the pattern is completely broken, it is treated as a different pattern by labeling, and is judged to be defective by the comparison and judgment means with the result of labeling with a regular pattern. If there is a part where the pattern width is smaller than the specified value, the part is deleted by the above-mentioned erasing means and separated into a different pattern, which is equivalent to the case where the wire is broken by subsequent labeling, and is determined to be defective. Is done.

According to a second aspect of the present invention, there is provided a photographing means for photographing a plurality of patterns on a substrate, and a decision on the pattern of the pattern based on image data obtained by photographing the pattern on the substrate by the photographing means. Determining means for determining whether or not the gap is smaller than the threshold value. If the determining means determines that the gap is smaller than the threshold value, the image data at this location is added to the image data as a pattern. There is provided a determination means for performing labeling and comparing the labeling result of image data of a regular pattern prepared in advance.

In such a configuration, when the adjacent pattern is completely short-circuited, it is treated as the same pattern by labeling, and is judged to be defective by the comparison judgment means with the result of labeling with a regular pattern. Also, if there is a part where the gap is smaller than the specified value, the part is connected to the above-mentioned additional means and has the same pattern, so it is equivalent to the case where the label is short-circuited by the subsequent labeling, and it is judged as defective Is done.

Here, labeling refers to treating consecutive pixels in image data as a block, and as a result of the labeling, having the characteristics (position, height, width, total number of pixels, etc.) of the block as parameters. In this case, labeling a plurality of captured patterns results in one labeling result for each pattern corresponding to each pattern. As described above, it is possible to provide an apparatus for judging the pass / fail of a pattern with high accuracy and at high speed. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a pattern pass / fail determination device according to the present embodiment. FIG. 2 is a block diagram of the pass / fail determination device.

FIG. 3 is a flowchart showing a control routine of the pattern width determination processing. FIG. 4 is a flowchart showing the subroutine of step 44 of the control routine of FIG.

FIG. 5 is a flowchart showing a subroutine of step 48 of the subroutine of FIG.

6A and 6B are diagrams for explaining the erasure correction processing.

FIG. 7 is a flowchart illustrating a control routine of the pattern gap determination process.

FIG. 8 is a flowchart showing a subroutine of step 66 of the control routine of FIG.

FIG. 9 is a flowchart showing a subroutine of step 70 of the subroutine of FIG.

FIGS. 10A and 10B are diagrams illustrating the additional correction process. BEST MODE FOR CARRYING OUT THE INVENTION

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

As shown in FIG. 1, the defect determination apparatus according to the present embodiment includes a light source 10 for illuminating the inspection target 200, a camera (for example, a two-dimensional CCD sensor or the like) for photographing the illuminated inspection target 200. And a judging device 14 for judging pass / fail from the image signal of the test object 200 photographed by the camera 12.

Here, in the present embodiment, the re-belt 13 is moved by the motor 11 driven in accordance with the control of the determination device 14, and the test object 200 arranged on the belt 13 is conveyed. I'm trying.

The object to be inspected, for which a judgment result has been obtained, is sent to a device for marking a defective portion or sorting defective and non-defective products by a marking device (not shown).

FIG. 2 shows a block diagram of a control system for image processing of the determination device 14. As shown in FIG. 2, the judging device 14 includes an AMP 16 that amplifies an analog signal of the inspection object 200 photographed by the camera 12 and an AZD converter 18 that converts the analog signal amplified by the AMP 16 into a digital signal. And a shading processing circuit 20 for performing shading processing based on the digital image signal converted by the A / D converter 18. A look-up table 22, a data compression circuit 24, and a data processing circuit 26 are connected to the shading processing circuit 20. Here, when the same data continues, the data compression circuit 24 outputs a so-called run-length code indicating the length. Here, the following operation is described for the case where a data compression circuit that can obtain XRL and YRL run-length codes in the orthogonal X and Y directions, respectively, is used.

FIG. 3 shows a pattern width determination processing routine executed by the determination device according to the present embodiment. That is, if there is a place where the pattern width is smaller than a certain threshold, this place is treated as a non-pattern. A labeling process is performed on the image data corrected for erasure in step 44. In step 46, the labeling result is compared with the labeling result of the normal pattern to judge pass / fail.

As shown in FIG. 4, the erasure correction processing in step 42 is to perform the erasure correction on the X-direction scanning line of the pattern in step 48, and the erasure correction on the Y-direction scanning line in the pattern in step 50. I do.

In the erasure correction processing on the scanning line in the X direction of the pattern in step 48, as shown in FIG. In step 54, it is determined whether the pattern is a pattern or a non-pattern from the level portion of the run-length code. If the pattern is a non-pattern code, the next X-direction run-length code XRL is fetched from the image data. If it is a pattern in step 54, go to step 56. In step 56, the length data Wx of the run-length code is Determine whether it is small.

If Wx is smaller than the threshold value Wth, in step 58, the level portion of the run-length code is rewritten from a pattern to a non-pattern, and the process proceeds to step 60. As a result, a pattern having no specified width is disconnected. If Wx is equal to or greater than the threshold value Wth, the process proceeds from step 56 to step 60. In step 60, it is determined whether or not one line of XRL code has been processed in the X direction. If one line has not been processed, the process returns to step 52 for reading the next XRL code. If one line has been completed, go to step 62. If one frame has not been completed, go to step 52 to read the XRL code of the next line.

The erasure correction processing on the scanning line in the Y direction of the pattern in step 50 is almost the same as the erasure correction processing on the scanning line in the X direction in the step 48, and the erasure correction processing in the X direction is performed in the step 48. On the other hand, step 50 is different only in that the erasure correction processing is performed in the Y direction using YRL, and therefore the description of step 50 is omitted. Figure 6 shows examples of these operations. Assuming that FIG. 6A is a photographed image, the operations of step 48 remove parts A, B, etc., and the result is as shown in FIG. 6B. In addition, the operation of step 50 erases the portion of J, as shown in FIG. 6B.

Here, even if a part such as Wx3 of B is measured as a pattern width, it is determined to be a defective pattern width.In this method, since this width is not directly measured and no pass / fail judgment is made, there is no erroneous detection. .

FIG. 7 shows a gap determination processing routine executed by the determination device according to the present embodiment. In step 66, additional correction is performed. That is, if there is a gap where the gap is smaller than the threshold, this location is treated as a pattern.

A labeling process is performed on the image data that has been additionally corrected in step 44. In step 46, the labeling result is compared with the labeling result of the normal pattern to judge pass / fail.

As shown in Fig. 8, in the additional correction process in step 66, the additional correction on the scanning line in the X direction of the gear is performed in step 70, and the additional correction on the scanning line in the Y direction of the gap is performed in step 72. do.

The additional correction process on the scanning line in the X direction of the gap in step 70 is shown in FIG. In step 74, the first run length code XRL of the image data is fetched. At step 76, it is determined whether the pattern is a re-pattern or non-pattern based on the level value of the code. If the code is a pattern, the run-length code XRL in the next X direction is taken from the image data. If it is non-pattern at step 76, go to step 78. In step 78, it is determined whether or not the data Sx of the length part of the run length code is smaller than a threshold value Sth.

If Sx is smaller than the threshold value Sth, in step 80, the level value of the run-length code is rewritten from a non-pattern to a pattern, and the process proceeds to step 82. As a result, gaps having no specified width are short-circuited. If S x is equal to or larger than the threshold value S th, the process proceeds from step 78 to step 82. In step 82, it is determined whether the XRL code for one line has been processed in the X direction. If the processing for one line has not been completed, the process returns to step 74 for reading the next XRL code. If one line has been completed, go to step 84. If one frame has not been completed, go to step 74 to read the XRL code of the next line.

The addition correction process on the scanning line in the Y direction of the gap in step 72 is almost the same as the addition correction process on the scanning line in the X direction of the gap in step 70, and step 70 performs the addition correction process on the X direction. On the other hand, step 72 is different in that the additional correction process is performed in the Y direction using the YRL, and therefore the description of step 72 is omitted. FIG. 10 shows an example of these operations. If FIG. 10A is a photographed image, M and K portions are added in the operation of step 70, as shown in FIG. 10B. In addition, the portion of N is added in the operation of Step 72, as shown in FIG. 10B.

Here, even if the width of a part such as K, Sx3, or Syl is measured, it is determined that the gap is a bad gap.In this method, the width is not directly measured and the pass / fail judgment is not performed. There is no.

With the above method, the quality of the pattern width and the gap are determined, and a product in which no defect is detected is determined as a good product.

In the embodiment described above, the pattern is erased and added along the X direction and the Y direction. However, when the pattern direction is aligned in one direction, it is assumed that only the X direction is processed. Is also good.

Claims

The scope of the claims

1. A photographing means for dividing and photographing the substrate on which at least one pattern is formed into a plurality of minute regions, and a pattern along a predetermined direction from image data of each minute region of the substrate photographed by the photographing means. A pattern pass / fail judging device, comprising: erasing means for erasing image data of a portion smaller than a width threshold; and judging means for comparing characteristics of the image data with regular image data.

2. A photographing means for photographing a substrate on which a plurality of patterns are formed by dividing the substrate into a plurality of minute regions, and image data of each minute region of the substrate photographed by the photographing means, along a predetermined direction. A pattern quality judgment device comprising: an addition unit that adds image data to a portion where the interval between adjacent patterns is smaller than a threshold value; and a determination unit that compares characteristics between the image data and regular image data. .