JP3368644B2 - Wiring pattern inspection apparatus and method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring pattern inspection apparatus and method for inspecting a wiring pattern on a printed circuit board, a photomask or the like.

[0002]

2. Description of the Related Art Conventionally, visual inspection by humans has been used to inspect defective printed circuit boards. However, as products become smaller and lighter, the wiring patterns of printed circuit boards are becoming finer and more complex. Under such circumstances, it is becoming difficult for a person to keep a very fine wiring pattern for a long time while maintaining high inspection accuracy, and automation of inspection is strongly desired.

As a conventional example of a printed circuit board appearance inspection apparatus, Yasuo Nakagawa and Takanori Ninomiya: "Appearance inspection technology for electronic circuit boards", O plus E, No. 3 132, pp 138-15
2. Various inspection devices were introduced in November 1990. Pattern inspection methods are roughly classified into a feature extraction method (or design rule method: DRC method) and a comparison inspection method. The design rule method inspects whether or not the design rule is violated from the characteristics of the line width and the wiring pattern (connection points, end points, etc.). For example, Japanese Patent Laid-Open No. 61-15343 and Japanese Patent Laid-Open No. 62-263404. There is a bulletin, etc.

On the other hand, the comparison inspection method is a method for comparing the pattern to be inspected with the non-defective pattern or design pattern on a pixel- by- pixel basis, and is disclosed in, for example, JP-A-60-061604 or JP-A-6-160604.
2-140009 and the like.

[0005]

However, in the above-mentioned conventional configuration, there are advantages and disadvantages, and there are several methods to supplement the respective methods. Yasuo Nakagawa, Takanori Ninomiya: "Appearance inspection technology for electronic circuit boards" , O plus E, N
o. 132, pp. 138-152, November 1990, a method of combining the comparative inspection method and the feature extraction method and adopting their respective advantages and compensating for their defects is introduced. Further, as a promising method, a method of setting a region to which a required inspection method is applied from a plurality of inspection methods prepared in advance for the pattern region of JP-A-1-180404 is set for each inspection method. Specifically, the inspection is performed for each area by the comparison inspection method and the feature extraction method.

However, according to this method, it is difficult to manually set several tens to several hundreds of regions for a wiring pattern which is becoming finer and more complicated in recent years, and the set region and the substrate to be inspected There was also a problem that the problem of the positional deviation of was large.

The present invention solves the above-mentioned problems of the prior art. Since the micro inspection and the macro inspection adapted to various patterns on the substrate are inspected in parallel, a wide variety of substrates existing on the substrate can be obtained without dividing the processing area. It is an object of the present invention to provide a simple and highly reliable wiring pattern inspection device that does not overlook or falsely report various defects.

[0008]

In order to achieve this object, the present invention firstly requires measuring the line width and line spacing of a binary image obtained from a printed circuit board and the criteria set in the design rule. using violation position and the design rule checking means for detecting the type as feature information, previously non-defective substrate design
Feature information storing feature information from in-rule inspection means
It is detected by the storage means and the design rule inspection means.
Feature information and feature information from the feature information storage means
Comparing with and detecting only true defects
A micro-inspection device comprising: and a binary image, a direction code representing an edge direction is given to a contour position of the image,
Specific shape detection means for detecting a point where the direction code changes as a characteristic point and detecting a characteristic code consisting of the coordinates of the characteristic point and a code indicating the change of the direction code, and a non-defective substrate in advance.
To store the feature code from the specific shape detector
It is detected by the feature code storage means and the specific shape detection means.
A macro inspection device comprising a second comparison and determination means for comparing the issued feature code with the feature code from the feature code storage means to detect only true defects is provided.

Secondly, in the specific shape detecting means, the direction code assigning means for giving a direction code indicating the direction of the edge to the contour position of the image and the point where the direction code changes are detected as the characteristic points, and the characteristic points are detected. A feature code representing changes in coordinates and direction code is generated.

Thirdly, in the second comparison / determination means, a feature code consisting of a code indicating the change in the coordinates and the direction code of the feature point from the specific shape detection means is set to an arbitrary allowable range (r
In (s), a characteristic code string is sequentially generated by connecting with the corresponding characteristic code, and the characteristic code string from the characteristic code storage means generated in advance on the non-defective substrate is compared and judged in code string units. .

Fourth, in the second comparison / determination means, a feature code consisting of a code indicating a change in the coordinates of the feature point and the direction code from the specific shape detection means is set to an arbitrary allowable range (r).
The characteristic code string (B) is generated by sequentially connecting the corresponding characteristic codes in s), and the characteristic code string (A) from the characteristic code storage means generated in advance on the non-defective substrate is compared and judged in code string units. At this time, the feature codes of the two code strings (A) and (B) are sequentially compared in similarity, and the missing feature code is interpolated, and the missing feature code is a pair code string (two feature codes are mirror images of a code string. For example, 12-21, 34-4
If it is 3), the verification is performed, and otherwise, it is determined as a defect.

Fifth, in the second comparison / determination means, a feature code consisting of a code indicating the change in the coordinate and the direction code of the feature point from the specific shape detection means is set to an arbitrary allowable range (r).
The characteristic code string (B) is sequentially connected to the corresponding characteristic code in s), and the characteristic code string (A) from the characteristic code storage means generated in advance on the non-defective substrate is compared and judged in code string units. , Short to the mismatched feature code string,
This is to inspect whether or not a specific element of the basic code string indicating a disconnection, a chip, a protrusion, etc., is included to determine the type of defect.

Sixthly, in the second comparison / determination means, a feature code consisting of a code indicating the change in the coordinate and the direction code of the feature point from the specific shape detection means is set to an arbitrary allowable range (r
The characteristic code string (B) is sequentially connected to the corresponding characteristic code in s), and the characteristic code string (A) from the characteristic code storage means generated in advance on the non-defective substrate is compared and judged in code string units. , Short to the mismatched feature code string,
After inspecting whether the element of a specific basic code string indicating disconnection, chipping, protrusion, etc. is included, and determining the type of defect, the defect area is calculated from the characteristic code string (for chipping and protrusion) in advance. Only the defects of the set size are detected.

Seventh, in the second comparison / determination means, a feature code consisting of a code indicating the change in the coordinates of the feature point and the direction code from the specific shape detection means is set to an arbitrary allowable range (r).
In (s), a characteristic code string is sequentially connected to the corresponding characteristic code to generate a characteristic code string, and when the characteristic code string from the characteristic code storage unit generated in advance on the non-defective board is compared and judged in the code string unit, there is a mismatch. If the feature code sequence includes a pair code sequence generated due to a quantization error or the like, the feature code sequence is not defective.

Eighth, in the specific shape detecting means, the direction code assigning means for giving a direction code indicating the direction of the edge to the contour position of the image and the direction code of the two contour pixels connected to the target pixel are the same. When the code is the code and the direction code of the pixel of interest is different from the direction codes of the two contour pixels, the direction code conversion means for changing the direction code of the pixel of interest and the change of the direction code are feature points. the feature code representing the change of direction codes of coordinates and the feature points of the feature point is obtained by a so that the out extraction.

[0016]

According to the present invention, according to the above construction, first, after the image in which the through hole portion is filled by the through hole detecting means is generated, the design rule checking means displays the characteristic information based on the design rule such as the line width of the signal line. By performing detection, the specific shape detection means detects a predetermined graphic shape such as a corner of a rectangular pattern, thereby performing a micro inspection and a macro inspection that are suitable for various patterns on the substrate in parallel, so that the processing area is divided. It is possible to detect defects with high accuracy without overlooking various defects existing on the substrate.

Secondly, in the specific shape detecting means, a direction code representing the direction of the edge is given to the contour position of the image, a point at which the direction code changes is detected as a feature point, and the coordinates of this feature point and the direction code are detected. Macro defects such as large shorts can be detected by comparing the change points with the characteristic codes from the non-defective substrate.

Thirdly, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted and sequentially connected with a corresponding characteristic code within an arbitrary range. A characteristic code string is generated and compared with the characteristic code string from the characteristic code storage unit generated in advance on a non-defective substrate in comparison with the characteristic code string, so that it is possible to make a strong judgment against a minute edge shape change.

Fourthly, in the second comparison / determination means, a change position of the direction code from the specific shape detection means and a characteristic code consisting of the code are inputted and sequentially connected with corresponding characteristic codes within an arbitrary range. When a characteristic code string is generated and compared with the characteristic code string from the characteristic code storage unit generated in advance on a non-defective board in the characteristic code string unit and judged, the judgment is made by the similarity and the edge is missing due to a minute shape change. Misjudgment due to the feature code can be prevented and stable judgment can be performed.

Fifthly, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted and sequentially connected with a corresponding characteristic code within an arbitrary range. A feature code string is generated and compared with the feature code string from the feature code storage means generated in advance on a non-defective board in feature code string units, and the mismatched feature code string is checked for shorts, disconnections, chips, protrusions, etc. By inspecting whether the element of the specific basic code string shown is included and determining the type of the defect, the process control can be facilitated and the operator can easily understand.

Sixth, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted, and sequentially connected with a corresponding characteristic code within an arbitrary range. A feature code string is generated and compared with the feature code string from the feature code storage means generated in advance on a non-defective board in feature code string units, and the mismatched feature code string is checked for shorts, disconnections, chips, protrusions, etc. Prevents erroneous determination by inspecting whether the element of the specific basic code string shown is included and determining the type of defect, then calculating the area of the defect from the feature code string and detecting only the defect of a preset size To do.

Seventh, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted and sequentially connected with a corresponding characteristic code within an arbitrary range. A characteristic code string is generated, and the characteristic code string from the characteristic code storage means generated in advance on a non-defective board is compared and judged on a feature code string unit basis. if it contains a pair code string Ri by the fact that do not defect
Reduce the imaginary report and stable inspection can be.

[0023]

【Example】

(First Embodiment) A first embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a wiring pattern inspection apparatus according to the first embodiment of the present invention.

In FIG. 1, 21 is a printed circuit board, 11
Is an image input means provided with a reflective illumination 22 for irradiating with diffused light, a transmissive illumination 23 for irradiating the printed board 21 from below, and an image pickup device such as a CCD camera 24. Reference numeral 12 is a grayscale image.
Binarization means for converting into a value image, 13 is a through hole detecting means for separating the wiring pattern and the through holes to generate an image in which the through holes are filled, and for detecting a position where the residual width of the pad is insufficient, and 14 is a pattern Design rule inspecting means for measuring the width and interval of the pattern and detecting a position violating the design rule or a position such as a disconnection or a branch as feature information, and 15 is a feature code for detecting a position having a predetermined shape such as a corner of a pattern as a feature code. Shape detection means,
Reference numeral 17 is a characteristic information storage unit for storing characteristic information of a non-defective substrate, 19 is a characteristic code storage unit for storing a characteristic code of a non-defective substrate, 16 is characteristic information detected by the through-hole detection unit 13 and the design rule inspection unit 14. ,
First comparison determination means for comparing the feature information from the feature information storage means 17 and determining a feature point that does not match as a defect, 1
Reference numeral 8 is second comparison / determination means for comparing the feature code detected by the specific shape detection means 15 with the feature code from the feature code storage means 19 and determining a feature point that does not match as a defect, 25 is a through hole detection. It is a changeover switch for selecting whether to pass the means 13.

The operation of the wiring pattern inspecting apparatus having the above structure will be described. First, the printed circuit board 21 to be inspected is illuminated by the reflection illumination 22 from above and the transmission illumination 23 from below, and is picked up by the image input means 11 using a CCD camera or the like to obtain a grayscale image. In the present embodiment, an example in which a CCD line sensor camera is used as the image input unit 11 and the processing of the through hole detection unit 13 is performed will be described. The reflection illumination 22 is not particularly limited, but it is well known that the reflection illumination 22 can be easily binarized by using a wavelength near 600 nm in which the difference in reflection luminance between the base material (glass epoxy or the like) and the copper pattern is large. Recently, ultra-high brightness LEDs (eg GaAlAs 660 nm or InG
aAl 620 nm) has been commercialized, and it can be said that arranging them in an array and irradiating from multiple directions is also an effective illumination method. At the same time, the printed board 21 is illuminated from below by the transmitted illumination 23. In this embodiment, a diffused beam type high brightness LED is arranged in a line. This is because, as described in Japanese Patent Application Laid-Open No. 04-120448 and Japanese Patent Application No. 03-225898 of the same applicant, the transmission illumination is controlled by the HSYNC signal (not shown) of the CCD camera 24. This is because when the pulse lighting is performed in synchronization with the synchronization signal), the response is accelerated and a high-speed pulse operation is possible. In this embodiment, it is assumed that the transmission illumination 23 is turned on and off every line cycle in synchronization with the HSYNC signal from the CCD line sensor camera 24. C
The grayscale image signal obtained from the CD line sensor camera 24 is binarized by the binarizing means 12 at a threshold level previously obtained from a density histogram or the like, and the pattern side is "1" and the substrate side is "0". To the binary image 101. The binary image 101 obtained by the above procedure is an image in which a stripe pattern for each line is formed by pulse lighting of transmitted light in the through hole portion as shown in FIG. The through hole detecting means 13 extracts the striped area, generates an image 102 in which the through holes are filled, and detects a position where the pad remaining width is insufficient. FIG. 3 is a block diagram of the through hole detecting means 13. The operation of the through hole detecting means 13 will be described below with reference to FIG. In FIG. 3A, 30 is a through-hole area extraction unit, 31 is an expansion processing unit, 32 and 34 are delay circuits, and 36 is coordinate detection that detects and outputs the position coordinate of the value “1” from the output of the gate circuit 35. 37, a terminal for setting the expansion size of the expansion processing unit 31, 101 a binary image from the binarizing means 12, 111 a binary image with a hole portion having a value “1” and a background value “0”, 11
Reference numeral 2 is a binary image showing the insufficient position of the seat of the pad. The operation of the through-hole detecting means 13 configured as described above will be described below. 2 from the binarizing means 12
In the value image 101, the conductor portion is “1”, the base material portion is “0”, and the through hole portion is formed in a striped pattern in which “1” and “0” are alternated for each line. The area of the striped pattern is detected by the extraction unit 30, and the binary image 111 in which only the through hole portion is "1" and the background is "0".
To generate. Also, the binary image 1 from the binarizing means 12
01 is delayed by the delay circuit 32, and the OR gate 33 takes the logical OR with the through hole image 39 to generate an image in which the through holes are filled. Expansion processing unit 31
Is to thicken the input image by the number of pixels set by the terminal 37, and the AND gate 35 calculates the logical product of the image obtained by inverting the logic of the image signal delayed by the delay circuit 34 and the expanded hole image. As a result, the image 112 in which only the non-coincidence region 53 shown in FIG. 3B has a value of "1" is generated. The non-coincidence region 53 means a shortage of the remaining seat width of the pad. For example, when a remaining seat width of k pixels or less is detected as a defect, k is set as the number of pixels to be expanded by the expansion processing unit 31. Is. The through-hole region extracting section 30 will be described in more detail below with reference to FIG. FIG. 4A shows a block diagram of the through-hole area extraction unit 30, and FIG. 4B shows a pixel arrangement of 3 × 3 scanning windows. In FIG. 4A, 40, 41, 42 and 4
Reference numeral 3 is the first, second, third and fourth filling circuits for filling the stripe pattern area of the through hole portion with the value “1”, 44, 45,
Reference numerals 46 and 47 are contraction circuits for contracting the output images of the filling circuits 40, 41, 42 and 43 by 1 pixel, and 49 is an expansion circuit for expanding the input image by 1 pixel. The first filling circuit 40 is composed of a 3 × 3 window scanning circuit and a logical operation circuit of pixels in the window, and fills the stripe pattern by the operation of (Equation 1). The specific configuration of the image signal processing using the scanning window is a general technique and will not be described. With the same operation, the logical operation of (Equation 2) is performed in the second filling circuit 41, the logical operation of (Equation 3) is performed in the third filling circuit 42, and the logical operation of (Equation 4) is performed in the fourth filling circuit 43. Each is performed independently and in parallel.

[0027]

[Equation 1]

[0028]

[Equation 2]

[0029]

[Equation 3]

[0030]

[Equation 4]

However, + is a logical sum, · is a logical product, and − is a logical inversion. Since the contour lines of the pattern also remain in the output images of the first to fourth filling circuits, the contraction circuits 44, 45, 46 and 47 perform the operation of (Equation 5) to erase the contour lines.

[0032]

[Equation 5]

Further, the contraction circuits 44, 45, 46 and 4
The output of 7 is ANDed by the AND gate 48 to detect a matching area, and the expansion circuit 49 performs the operation of (Equation 6) to restore the through hole to the original size.
Output as 1.

[0034]

[Equation 6]

Next, the specific processing of the expansion processing section 31 will be described with reference to FIG. FIG. 5 shows an expansion or contraction (erosio) of an arbitrary number of pixels.
FIG. 6 shows the pixel arrangement of the scanning window for performing the process n).
In FIG. 5, (a) shows a mask that expands and contracts at equal distances in all directions, and (b) shows a mask that expands and contracts at equal distances in the horizontal and vertical directions. In FIG. 5, “0” indicates the target pixel, the number given to each pixel indicates the distance from the target pixel, (a) is the approximate Euclidean distance, and (b) is 8
Proximity distance (chess-board distance)
Is. In addition, 4 neighborhood distances (city-block
There are diamond-shaped masks having a distance), but the mask shape is selected according to the purpose of processing.
These image processing techniques are relatively well known techniques and are described in A. Rosenfeld & A. C. By Kak,
Shino Nagao "Digital Image Processing", Modern Science Company (1992)
It is omitted here because it has been explained in detail in (Year).

The expansion processing section 31 in this embodiment is intended to detect the shortage of the remaining width of the pad,
Since it is necessary to expand all the directions equidistantly, the same figure (a)
Circular mask is used. When the input image is to be thickened by k pixels, the image is raster-scanned one pixel at a time in the scanning window, and all the pixels of number k or less including the pixel of interest 0 are selected at each scanning position and the logical sum is calculated to obtain the operation result. A dilated image can be obtained by outputting. When the input image is contracted by k pixels, a contracted image can be obtained by calculating a logical product instead of the logical sum.

Since it is not necessary to fill the through-holes in the printed circuit board before the through-holes are processed, the through-hole detecting means 13 is made to pass by the changeover switch 25.

Next, the design rule inspection means 14 and the specific shape detection means 15 will be described in detail.

In the design rule inspection, for example, as described in Japanese Patent Application Laid-Open No. 03-252545 and Japanese Patent Application No. 02-340409 filed by the same applicant, the distance conversion image is extracted at the same time as the core line of the pattern is extracted. Generate,
By measuring the pattern width along the core wire and recognizing the shape of the core wire such as branch points and end points, a pattern which is not allowed by design such as insufficient line width, short circuit, or wire breakage is detected. FIG. 6A shows a block diagram of the design rule inspection means 14, and 70 is a thinning processing unit for thinning the pattern pixel by pixel while maintaining connectivity from the background.
Is a distance conversion processing unit that gives a distance value to an internal point of the pattern simultaneously with the thinning process, 72 is a feature extraction unit that detects a defect feature from the thinned image 116 and the distance conversion image 117, 73
Is a length measuring circuit for measuring the width of the pattern, 74 is a shape detecting circuit for recognizing the shape of the core wire of the pattern, 75 is a terminal for setting a reference line width such as a minimum line width to the length measuring circuit 73,
Reference numeral 76 is a coordinate detection unit that detects the position coordinates and the feature type of the feature points detected by the feature extraction unit. Thinning processing unit 7
The thinning at 0 is a well-known image processing method, in which the process of erasing the pattern one pixel at a time from the background side is repeatedly performed to extract the core line of the pattern, which is a well-known image processing method. For example, Tamura: "Considerations on thinning method", IEICE technical report, PRL 75-66 (197).
5), one layer of thinning processing is divided into four sub-iterations, pixels are erased from the top, bottom, left, and right in each sub-iteration, and finally a core line connected with one pixel width is obtained. The distance conversion processing unit 71 is a process of giving a distance value from the background to the pattern portion, and is a binary image 1
01, the distance value "1" is given to the entire pattern area as an initial value and "0" is given to the background, and the distance value of the pixels in the pattern not erased is incremented each time the thinning is repeated. A distance value from the background is given to all pixels including the core line. At this time, Japanese Patent Application No. 02-3340
As described in No. 09, if the contour pixels to be erased in the thinning are selectively controlled by 4 connected edges or 8 connected edges for each thinning, a distance conversion image extremely close to the Euclidean distance can be obtained. it is obtained Rukoto. Figure 6
(B) shows an example of the output image of the distance conversion processing unit 71. The two-digit number given to the pattern shows the distance value from the background, and the pixels enclosed by □ are the thinned lines. The core line position extracted by the processing unit 70 is shown. Feature extraction unit 72 scans the distance conversion <br/> image 117 from the thinned image 11 6 及 beauty distance conversion processing unit 71 from the thinning processing unit 70 with 3 × 3 window, breach position of the line The first comparison / determination means 16 detects the positions of the branch points and the end points of the core line of the pattern and the pattern and uses the coordinates and the type of the characteristic as the characteristic information.
To notify. The operation of the feature extraction unit 72 will be described below with reference to FIG. The feature extraction unit 72 has a length measurement circuit 73.
The shape measuring circuit 73 has a 3 × 3 window for scanning the distance conversion image 117, and the shape detecting circuit 74 has a 3 × 3 window for scanning the thinned image 116. ing. When the central pixel of the 3 × 3 window is on the core line of the thinned image, the length measuring circuit 73 determines the distance value D0 of the central pixel of the 3 × 3 window and the distance values Di of its 8 neighborhoods (i = 1 to 8). Is used to calculate the pattern width Tn.

[0040]

[Equation 7]

Here, [*] indicates rounding of *. The length measurement circuit 73 notifies the pattern width Tn to the shape detection circuit 74, and compares the pattern width Tn with the minimum line width Wmin set in advance from the terminal 75. If Tn is less than Wmin, detection of insufficient line width is detected by coordinate detection. Notify the department 76. The shape detection circuit 74 detects branch points and end points from a 9-bit bit pattern using a 3 × 3 window, but the pattern width data Tn from the length measurement circuit 73 is equal to or smaller than a preset minimum pad size Tpad. In this case, the coordinate detection unit 76 is notified. The branch point and the end point are detected by using a look-up table of 9-bit address (hereinafter abbreviated as LUT). In the LUT, it is assumed that end points are assigned to patterns satisfying the condition of (Equation 8) and branch points are assigned to patterns satisfying the condition of (Equation 9).

[0042]

[Equation 8]

[0043]

[Equation 9]

Here, di (i = 1 to 8) follows the definition of FIG. 4 (b). In FIG. 6B, the scanning window 77
At the position of, the pattern width Tn = 2 pixels, and if the minimum signal line width Wmin = 4 pixels is set, Tn is less than Wmin, and the coordinate detection unit 76 is notified that the line width is insufficient. When the minimum pad size Tpad = 15 pixels, the condition of (Equation 9) is satisfied at the position of the scanning window 78, and the branch is detected at the position of the scanning window 79 because the condition of (Equation 8) is satisfied. Detector 76
Will be notified to. Although not shown, the binary image 101
Reverse the logic of "1" for the substrate side and "1" for the pattern side
The same design rule inspection is performed as 0 ″, but in this case only the line spacing inspection using the length measurement circuit 73 is performed. The coordinate detection unit 76 detects the coordinates of the notified feature point and The characteristic information 103 is notified to the first comparison / determination means 16.

Next, the operation of the specific shape detecting means 15 will be described with reference to FIGS. 7 and 8. FIG. 7 is a circuit configuration diagram of the specific shape detecting means 15. In the figure, 90 is 9 × 9.
A window scanning circuit, 91 is a 3 × 3 window scanning circuit for detecting the edge of the pattern, 92 is an edge detection circuit for detecting the edge of the pattern from the data of the 3 × 3 window 91, and 93 is the 9 × 9 window scanning. Shape detection L for detecting a predetermined pattern shape from 16-pixel data hatched in the circuit
UT, 94 is a gate circuit that gates the output of the shape detection LUT 93 by the output signal of the edge detection circuit 92, and 95 is a coordinate detection unit that detects the position coordinates and shape type of the specific shape detected by the shape detection LUT 93. Is. Hereinafter, with reference to FIG. 7, the specific shape detecting means 15
The specific operation of will be described. Binary image 101 9 ×
9 Scan window 90, shape detection LUT from the data in the window
A predetermined shape is detected using 93. In this embodiment, the corner of the pattern is detected as the specific shape, and the operation of corner detection will be described below. First, in the 9 × 9 window scanning circuit 90, the data 121 of the four neighboring pixels is taken out from the internal 3 × 3 window scanning circuit 91, the edge of the pattern is detected by the edge detection circuit 92, and the position where the specific shape is detected is determined as the contour of the pattern. Decide on the area. The edge detection circuit 92 performs the logical operation of (Equation 10) and inputs the operation result 122 to the gate circuit 92.

[0046]

[Equation 10]

Here, d1, d3, d5 and d7 are shown in FIG.
According to the definition of (b). In the 9 × 9 window scanning circuit 90, simultaneously with the above processing, the 3 × 3 window scanning circuit 9
Data 123 of the outer 16 pixels hatched with 1 is extracted and input to the shape detection LUT 93. In the shape detection LUT 93, from the 16-bit pattern configuration,
It identifies angles such as right angles, acute angles, and obtuse angles, and determines the direction of corners, and outputs an identification code. FIG. 8 shows a specific pattern configuration for corner identification. In FIG. 8, white pixels have a value “0” and black pixels have a value “1”.
Pixels are arranged adjacent to each other and are expressed as a 5 × 5 rectangular pattern. The figure (a) shows that there is a right-angled corner in the upper right, and the figure (b) shows that the logic has a corner of 270 ° in the lower left. Similarly, (c) and (e) are 135 °,
(D) and (f) are 225 °, (g) and (i) are 45 °,
(H) and (j) show that there is a 315 ° corner. Although not shown in the figure, a code is also given to each 90 ° rotation target pattern to classify a total of 40 corners. Corresponding to this, a 6-bit identification code is registered in the shape detection LUT 93. Also above 4
Identification codes of patterns other than 0 are given as "0". Since the output data 124 of the shape detection LUT 93 is gated by the edge detection signal 122, 45 °, 90 °, 135 °, and 225 of the contour of the pattern.
The corner positions of 270 °, 270 °, and 315 ° are notified to the coordinate detection unit 95 with a code other than “0”. Coordinate detection unit 95
Detects the coordinates of the notified feature point and notifies the feature code to the second comparison / determination means 18. Therefore, only the corners that form the large-area pattern such as the shield pattern are subject to the comparison and determination processing in the second comparison and determination means 18.

Next, the first comparison / determination means 16 will be described. The first comparison determination unit 16, the feature information notified from the through-hole detection means 13 and the design rule checking means 14, compared with the feature information stored in the feature information storage unit 17 learns a previously non-defective substrate Feature information that does not match is detected as a defect. The operation of the first comparison / determination means 16 will be described below with reference to FIG. The first comparison / determination means 16 is composed of a CPU system as shown in FIG. 9A, and is connected to the characteristic information storage means 17 via a CPU bus. After the inspection is started, the characteristic information 103, 105
Are buffered in the FIFO memories 133 and 134, respectively, and the CPU 130 reads out the respective characteristic information via the I / F circuit 135. Characteristic information storage means 17, pre
The type of coordinates and characteristics previously remembers as feature information of the good product substrate had was the order of scanning the fit printed circuit board. In the present embodiment, it is assumed that the characteristic information 103 and 105 are stored in individual storage areas in the characteristic information storage means 17. The CPU 130 is a FIFO memory 133,
Each characteristic information is read out from the 134, and the characteristic information 105 from the through-hole detecting means 13 is the defect information as it is.
Is stored in the distribution storage unit 131, reads the characteristic information of non-defective from the characteristic information storage means 17 with respect to the feature information 103 collates the type of coordinates and characteristics, and stores the feature information that does not match the defect information storage unit 131. Collation between the coordinate and the type of feature will be described with reference to FIG. FIG. 9B is an example in which the position of the characteristic information is represented in a two-dimensional space. The symbol ◯ is characteristic information of a non-defective board (abbreviated as non-defective data), and the symbol ◎ is characteristic information of the board to be inspected (inspection data). (Abbreviated). The first comparison / determination means 16 in the present embodiment allows the misalignment between the non-defective product data and the inspection data to make a coincidence determination.
Allowable areas 150, 151, 152, 153 of p × p pixels are defined around 0, 141, 142, 143, and it is determined whether the corresponding inspection data is included in the allowed area. That is, the inspection data 145, 147, 148
Are included in the permissible areas 150, 152, and 153, respectively, and are considered to match the non-defective item data 140, 142, and 143, respectively. If the inspection data has the same feature type and is included in two or more permissible areas, the inspection data is made to match the non-defective product data having the shorter distance. In FIG. 8B, the distances from the inspection data 147 to the non-defective product data 142 and 143 are calculated and matched with the short-range non-defective product data 142. The inspection data 146 and the non-defective product data 141 are characteristic information that does not match, and it is assumed that some defect exists in the non-defective substrate, and the coordinates and the characteristic information are stored in the defect information storage means 131. Finally, the defect information storage means 13
The characteristic information stored in 1 is reported to the worker as the inspection result.

Next, the second comparison / determination means 18 will be described. The second comparison / determination means 18 compares the feature code notified from the specific shape detection means 15 with the feature code previously learned from the non-defective substrate and stored in the feature code storage means 19, and the feature code that does not match is defective. To detect as.
The operation of the second comparison / determination unit 18 will be described with reference to FIG. The second comparison / determination means 18 is composed of a CPU system as shown in FIG. 9A, and is connected to the characteristic code storage means 19 via a CPU bus. The second comparison / determination means buffers the feature code 104 detected by the specific shape detection means 15 in the FIFO memory 161, fetches it into the CPU 160 via the I / F circuit 162, and stores it from the feature code storage means 19 stored in advance. Compare with feature code. In the first embodiment, the collation of the characteristic code is the same as the first determination process, and thus the description thereof is omitted. Further, in the present embodiment, the first comparison determination means and the second comparison determination means are configured by respective CPU systems, but one CP
It is also possible to easily realize the processing by configuring it with a U system and switching each processing by multitasking.

As described above, according to the present embodiment, the image of the print pattern is inspected by the inspection method in which the design rule inspection means which is a micro inspection and the specific shape detection means which is a macro inspection are used together. Applying design rule detection means that strictly inspects with high precision to thin signal lines,
By applying a specific shape detecting means for roughly inspecting a large area pattern such as an SMD pad or a shield pattern, highly accurate defect detection can be performed without overlooking various defects existing on the substrate. In addition, the design rule detection means does not separate the application area, and if the number of processing steps of the thinning / distance conversion processing unit is limited, the design rule detection means has only one pixel width for thin signal lines, pinholes, residual copper, etc. It is not detected because it does not have a width of one pixel, and in the specific shape detection means, the point where the mask size to be detected is set large and the shape detection LUT makes it thick without detecting thin signal lines, pinholes, residual copper, etc. Only pattern defects are detected. Similarly, the specific shape detecting means 1
Since 5 is for detecting a short circuit having a large width, it goes without saying that the binary image 101 in FIG. 7 may be reduced and the shape detection circuit may be downsized.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 10 is a block diagram of the specific shape detecting means 15 in the wiring pattern inspecting device according to the second embodiment of the present invention. In FIG. 10, 201 is a direction code assigning unit that assigns eight direction codes to the binary image 101 from the binarizing unit 12, and 202 is a feature point in which the direction code changes, and indicates a change in the direction code. The feature extraction means for extracting the coordinates of the code and the feature point as a feature code is shown. In the present embodiment, as a method of detecting a specific shape, a direction code is given to the contour pixel of the wiring pattern and a change point of the direction code is detected, so that a corner is detected as the specific shape of the wiring pattern. The direction code is assigned by a Freeman chain code (H. Freeman: “On the encodi”).
ng off-farbitary geometric
configurations ”, IRE Tran
s. Electron. Comput. EC-10, 1
961, pp260-268) is well known.

First, the direction code assigning means 201 will be described with reference to FIG. FIG. 11A is a circuit configuration diagram of the direction code assigning means 201. FIG. 11 (a)
In the figure, 211 is a line memory, 212 is a 3 × 3 scanning window, and 213 is a LUT (look-up table) that outputs a 4-bit direction code image 214 according to the bit pattern of the scanning window 212. Direction code is shown in Figure 1.
As shown in FIG. 1 (b), the eight directions from the pixel of interest 204 to the adjacent contour pixels are used as direction codes, respectively.
It is represented by a value of 1 "to" 8 ". The direction code assigning means 201 uses the 3x3 scanning window 212 for the binary image 101.
Scan with the LUT 21 with the bit pattern from within the scan window.
3 is used to output a 4-bit direction code. LUT2
Data 13 is created in advance by calculation. For a pattern that satisfies the condition (Equation 11), (Equation 1
The direction code i is calculated by 2), and the direction code is given in the clockwise direction. However, for example, a value “a” is assigned to a special pattern having a pixel width that satisfies the condition (Equation 13), a value “f” is assigned to the inside of the pattern, and a value “0” is assigned to the base material portion. I shall.

[0054]

[Equation 11]

[0055]

[Equation 12]

[0056]

[Equation 13]

Here, it is assumed that the pixels d1 to d8 in the scanning window comply with the definition of FIG. 4 (b). Note that Nc (8) is 8
The number of connections, Nc (4), is called a four-connection number and is well known as a parameter indicating the connectivity of patterns. An example of the direction code image obtained by the above processing is shown in FIG.

Next, the feature extracting means 202 will be described with reference to FIG.
Will be explained. FIG. 13 is a circuit configuration diagram of the feature extraction means. In FIG. 13, 221 is a line memory, 2
22 is a multi-valued 3 × 3 scanning window, 223 is an MPX (multiplexer) that selects the output of a signal 225 of D1 to D8 according to the D0 signal 226 from the scanning window 222, and 224 is M.
By referring to the output 234 from the PX 223 and the D0 signal 226, L that outputs a feature code for indicating the shape of the feature
Indicates UT. In the present embodiment, points at which the direction code changes are extracted and the feature code representing the shape is notified. The operation of the feature extracting means 202 will be described below. First, the direction code image 214 from the direction code assigning means 201 is input to the scanning window 222 and scanned pixel by pixel.

The feature extracting means 202 MPX the direction code signals 225 of D1 to D8 from the scanning window 222, respectively.
223, and the direction code 226 of the target pixel position D0
The peripheral pixel positions D1 to D8 indicated by are selected. From the direction code 226 of the target pixel D0 and the direction code 234 of the selected peripheral pixels, the feature code Cf is calculated by the LUT 224.
And the synchronization signal 227 and the XY coordinates generated by the XY coordinate generator 228 are output to the first comparison / determination means 16 as the characteristic information 104. However, when the value of the direction code 227 of the peripheral pixels is "a", the value "a" is notified as the characteristic code Cf. The characteristic code Cf is for registering the result calculated in advance (Equation 14) in the LUT 224.

[0060]

[Equation 14]

However, Di is the direction code of the pixel adjacent in the direction indicated by the direction code D0. In Figure 14,
An example of the feature code extracted from FIG. 12 is shown. Numerical values in "" shown in FIG. 14 indicate feature code values. In this embodiment, the direction code is given in the clockwise direction, but it may be given in the counterclockwise direction. In this embodiment, the characteristic code is 135 ° or 2 such as 1-2 or 1-8.
To believe the basic 25 ° corner, such as 1-
For 3 (90 °) or 1-6 (45 °), a binary filter for rounding an acute corner after binarization is inserted, or the second comparison / determination processing means 18 has a feature prior to processing. It should be pointed out that it is necessary to perform processing such as replacing the code. For example, feature code "1
-3 "is" 1-2 "and" 2-3 ", and feature code" 1- "
6 "is read as" 1-8 "," 8-7 "and" 7-6 ", and the coordinates are the same.

As described above, the specific shape detecting means 1
Reference numeral 5 is a macro inspection, which represents a pattern by approximating it with direction codes in eight directions, detects a change point of the direction code as a corner point, and makes a comparison judgment with a corner point of a non-defective product by the second comparison and judgment means 18. It is a thing. In addition, since this method assigns a direction code on a pixel-by-pixel basis, it can detect residual copper and pinholes with high accuracy, not to mention thick patterns. It is what is reported.

(Embodiment 3) The third embodiment of the present invention will be described below. The third embodiment of the present invention is the comparison / determination processing of the feature code from the specific shape detection means 15 in the second comparison / determination means 18 in the wiring pattern inspection apparatus, and the specific shape detection means 15 is the same as the second embodiment. The block diagram of the second comparison / determination unit 18 is similar to that of FIG. 9A described in the first embodiment, and the difference is that the processing content of the comparison / determination processing is different, and the different points will be mainly described.

In the comparison / determination processing of the present invention, the feature code detected by the specific shape detecting means 15 is associated with the feature code within the arbitrary permissible range (rs) around the feature point of interest in the second comparison / determination means 18. a code string of processing for generating a sequentially linked feature code string data as a point, is code string comparison processing or we configured to compare a feature code string by the code string units from the feature code storage means 19 created in advance good substrate It In FIG. 9A, the characteristic code 104 from the specific shape detection means 15 is subjected to comparison / determination processing by software processing of the CPU 160 via the FIFO 161 and the I / F circuit 162. First, the concept of the code string conversion process will be described with reference to FIG. FIG. 15 (a)
Shows an example of a feature code string of a certain pattern, it is a feature code string that is concatenated with eight feature codes from a start point 241 "feature code 12" to an end point 242 "feature code 65" as one feature code string. is there. FIG. 15B is a diagram for explaining the procedure of connection, in which an allowable range 249 is set around the feature point 244 of interest, and a partner to which the feature point 244 of interest can be connected is searched for. At this time, the first connecting direction is the right direction, and the feature code “12” or “corresponding to the feature code“ 21 ”of the feature point 244 of interest.
18 "to explore. Characteristic code" 21 ", wherein the code that can be linked to the right of the direction" 1 "direction from" 2 "or direction" 8 "as a feature code corresponding to only points that change does not exist in the" 12 "or" 18 ".
In the example of 5 (b), the feature code “1” existing in the right direction
8 "can be connected. Next, the feature point of interest is the feature code" 1.
8 "and similarly search for the corresponding feature code, and repeatedly process until there are no feature points in the allowable range.
When there is no feature point corresponding to the allowable range, the target feature point becomes the end point 242. This time, the same processing is performed for the left direction, and the feature point 24 of interest is within the allowable range.
Feature code "12" corresponding to feature code "21" of 4
Or search for "32". In this case, the feature code ”
32 "is the corresponding feature point. Similarly, the corresponding feature code is searched and repeatedly processed until there are no feature points in the allowable range. the start point 241. also, when searching for feature points, it is possible to determine the range to be searched by the feature code, for example, when searching for a direction "1" in the feature code "21" in the search shown in FIG. 15 (b) Range 24
It can be seen that it is sufficient to search only 5 and there is no need to search in the left lateral direction. Also, when connecting as a feature code string,
A code string can be easily generated by preparing a register or a buffer as shown in FIG. 15C, putting the first corresponding point 240 at the center position of the register, and connecting it at the center. Next, the procedure of the code string conversion process will be described with reference to the flowchart of FIG. Step 1: First, the first feature point is held in the center of the code string register as the target point from the feature code storage means 132. Step 2: An allowable area is set around the target point. Step 3: If the candidate points in the allowable region is present, considered a candidate point with the same number as the low-order feature code of the target point to the upper digit of the feature code and the object point and the same Ichigu loop.
If there are multiple candidate points, the point with the shortest distance is selected.
For example, if the feature code of the target point is "21", the lower digit is "1", and the feature code of the target candidate point is "1".
8 ”and“ 12. ”Step 4: The candidate points that are the targets are connected to the code string register, and the candidate points are used as the target points, and the process is repeated from step 2 until there is no next candidate point. If no candidate point exists, the target point is connected as an end point to the code string register, and the process proceeds to step 6. Step 6: Return to the position of the first target point Step 7: A permissible area is centered on the target point setting step 8:. If the candidate point is present in the allowable region, now considered a candidate point with the same number as significant digit of the feature codes in the lower digit of feature code and the object point and the same Ichigu loop. Step 9: Concatenate the target candidate points to the code string register, and repeat from step 7 until there is no next candidate point with that candidate point as the target point Step 10: There is a target candidate point. If not,
The target point is connected to the code string register as a starting point, the average coordinates of the connected feature points are calculated, registered in the feature code string file (reference or inspection), and the process proceeds to step 11. Step 11: Not stored in the feature code storage means. If there is a feature code for processing, the process returns to step 1, otherwise ends.

Next, the code string comparison processing will be described with reference to FIG.
It will be described in accordance with the flowchart of. Step 1: A feature code string is extracted from the reference feature code string file and set as a point of interest. Step 2: An allowable range (rc) is set around the average coordinates of the standard feature code string. Step 3: Search the inspection feature code sequence file for the inspection feature code sequence corresponding to the allowable range. If it does not exist, the inspection is registered as a defect, and if it exists, the process proceeds to step 4. Step 4: Next, the reference feature code string and the inspection feature code string are compared, and if they match, the fact that they have been matched is registered. Step 5: If there is an unprocessed reference feature code string,
Repeat from step 1 until there are no unprocessed reference feature code strings. Step 6: A feature code string that has not been matched is searched for in the reference and inspection feature code string file and registered as a defect in the defect information storage means.

[0066]

[Table 1]

[0067]

[Table 2]

An example of the characteristic code string file is shown in (Table 1) and will be described below. (Table 1) shows an example of the standard feature code sequence file, and (Table 2) shows an example of the inspection feature code sequence file. Is the number assigned in the order of occurrence,
Whether processing is unprocessed or processed is indicated by 1/0, matching is “1”, unmatched is “0”, the corresponding number is the corresponding number on the inspection side, and the standard feature code string is converted to a code string. The characteristic code string and average address generated by the process indicate the average coordinates (X coordinate, Y coordinate) of the characteristic points calculated by the code string conversion process. In (Table 1), the standard feature code string of "0004" is
Since it did not collate with the inspection feature code sequence, it was not collated, and the standard feature code sequence of "0006" and the figure (Table 2)
The inspection feature code string of "0004" is unverified because there is no corresponding feature code string. Also,
It is also an effective and effective process that after performing the code string conversion process and the code string comparison process, the feature code strings that do not match are expanded again by expanding the allowable region of the code string conversion process.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below. The fourth embodiment of the present invention is a comparison / determination process of the feature code from the specific shape detection means 15 in the second comparison / determination means 18 in the wiring pattern inspection device, and the specific shape detection means 15 is the same as the second embodiment. The block diagram of the second comparison / determination means 18 is similar to that of FIG. 9A described in the third embodiment, and the difference is that the processing content of the comparison / determination processing is different, and the different points will be mainly described.
In FIG. 9A, the characteristic code 104 from the specific shape detecting means 15 is the FIFO 161 and the I / F circuit 16
The comparison / determination process is executed by the software process of the CPU 160 via 2.

In the comparison / determination processing of the present invention, the feature code detected by the specific shape detection means 15 corresponds to the feature code corresponding to the feature point of interest in the second comparison / determination means 18 within an arbitrary allowable range (rs). An extra feature code that could not be associated by aligning the code sequence conversion process for sequentially combining points with each other to generate the feature code sequence data and the feature code sequence from the feature code storage means 19 created in advance on a non-defective substrate ( The surplus code string) is a pair code string, and the code string similarity comparison processing is performed to compare the code strings in a similar manner.

The second comparison / determination means of the present invention will be described. The code string conversion process is the same as that in the third embodiment, and therefore will be omitted, and the code string alignment will be described with reference to FIG. Reference numeral 401 in FIG. 19 is a reference feature code string, 4
02 is an inspection feature code string. The process of associating the feature points having the same feature code and existing at the shortest distance in the two feature code strings with each other is called alignment. 401 and 402
When the feature code string of is sorted, it can be seen that the feature points corresponding to the feature points 403 and 404 are not in the reference feature code string 401. Extra feature codes such as 403 and 404 that cannot be associated with each other are called extra code strings. This surplus code string is the reference code string 401 and the check code string 40.
It represents the difference between the two. It is not practical to perform the above processing by brute force for the feature points, because it takes a huge amount of time. Therefore, in this embodiment, DP matching (Dynamic Programming
Matching method is applied to align feature code strings at extremely high speed. The DP matching method is a relatively well-known method in speech recognition and pattern matching. (Yoshinori Uesaka and Kazuhiko Ozeki: Algorithms for pattern recognition and learning, Bunichi General Publishing, 1990, 91-
108) and detailed theory will be omitted.

The process of aligning the characteristic code strings using DP matching will be described below.

The characteristic code strings to be aligned are respectively A = a
1a2 ... aI and B = b1b2 ... bJ. I is the length of the characteristic code string A, and J is the length of the characteristic code string B. next,
The evaluation formula of (Equation 15) is given. The expression (15) is called the similarity between the feature codes a and b. In DP matching, it is necessary to define such that a combination of feature codes having a higher priority order has a smaller evaluation value of Expression (15). In the present embodiment, the ones having the same feature code and having the shortest distance have a higher priority order. Therefore, if the feature codes of a and b are the same, the "distance value between two points " and the feature codes of a and b are different. If it is, "400" is output, and if either a or b is missing, the evaluation value "100" is output (Equation 1).
5) Formula was defined. Then, the characteristic code strings can be arranged by associating the characteristic codes so that the sum of the values of the equation (15) is minimized. Further, (Equation 16) and (Equation 17) are used for efficient alignment. Where g (i,
j) is the similarity of each of the corresponding feature points when the feature code sequence up to a1a2 ... ai in A and the feature code sequence up to b1b2 ... bj in B are aligned (Equation 15).
Indicates the sum of. That is, g (I, J) means the sum of the similarities (Equation 15) when the feature code strings A and B are aligned. The equation of (Equation 17) is a recurrence equation, and with (Equation 16) as an initial value, g (i−1, j) and g (i−) that have already been calculated are calculated.
1, j−1) and g (i, j−1), g
A combination of feature codes that minimizes (i, j) is selected. In this way, by calculating the current value using the past minimum value, the minimum g (i,
j) can be obtained. This calculation is i = 1 to I, j =
If 1 to J are continued, g (I, J) is finally obtained. Further, each time g (i, j) is calculated, if the feature code that cannot be handled is stored, the feature code string A
The surplus code string when the B and B are sorted is known.

[0074]

[Equation 15]

Here, a = {Ca, Xa, Ya} and b = {Cb,
Xb, Yb} represents the feature code, and * represents the loss of the feature code.

[0076]

[Equation 16]

[0077]

[Equation 17]

Here, min {} means an operator for finding the minimum value.

[0079]

[Table 3]

[0080]

[Table 4]

Tables 3 and 4 show examples of code string alignment, which will be described below. (Table 3) shows characteristic code sequences to be aligned, (Table 4) shows an example of code sequence alignment processing, i, j, are values of i, j, and g (i,
j) represents the calculation result of the formula (17) in the form of the evaluation formula (15), the marshalling indicates the combination of the corresponding feature codes, and the surplus code string indicates the surplus code string. The results calculated for all i = 1 to 4 and j = 1 to 2 are shown in (Table 4). Therefore, the surplus code string of the characteristic code string in (Table 3) is "81-18".

Next, the concept of code string similarity comparison processing will be described with reference to FIG. FIG. 19 shows an example of comparison / determination between a certain reference feature code sequence and an inspection feature code sequence. Since the inspection pattern is a quantization error, the reference and inspection feature code strings do not match. Here, when code string alignment is performed, the quantization error portion is obtained as a surplus code string. From this surplus code string, it can be seen how different the standard and the inspection are. In the present embodiment, even excess code string is feature code string if paired code string match
And the. The pair code string is defined as follows and will be described with reference to FIG. 20A shows a quantization error and its characteristic code string, and FIG. 20B shows a large step portion and its characteristic code string. A pair code string is a code string such as "12-21" that has a combination of codes in which the lower digit and the upper digit of the mutual characteristic codes are interchanged, and that are mutually within an allowable range (rp). Define. 20 (a) is the distance tolerance of one another point in feature code string "12-21" (rp)
Since it is inside, the pair code string is used. In addition, FIG.
If there is a large step, the feature code string is "12-21".
However, since the mutual points are not within the allowable range (rp), they do not form a pair code string. Thus, the allowable range (rp)
By appropriately setting, it is possible to distinguish a quantization error of about several pixels and a large step portion. By erasing or ignoring such a pair code string, instability of the pattern shape due to the quantization error is allowed, and highly accurate inspection is possible.

The code string similarity comparison process will be described with reference to the flowchart of FIG. Step 1: A feature code string is extracted from the reference feature code string file and set as a point of interest. Step 2: An allowable range (rc) is set around the average coordinates of the standard feature code string. Step 3: Search the inspection feature code sequence file for the inspection feature code sequence corresponding to the allowable range. If it does not exist, the inspection is registered as a defect, and if it exists, the process proceeds to step 4. Step 4: Next, the reference feature code string and the inspection feature code string are aligned, and an extra code string (surplus code string) that cannot be associated is taken out. Step 5: If there is no surplus code string, register the verified one. Step 6: If the surplus code string is a pair code string, register that it has been verified. Step 7: If there is an unprocessed reference feature code string,
Repeat from step 1 until there are no unprocessed reference feature code strings. Step 8: A feature code string that has not been collated is searched for in the reference and inspection feature code string file and registered in the defect information storage means as a defect.

[0084]

[Table 5]

[0085]

[Table 6]

An example of the characteristic code string file is shown in (Table 5) and (Table 6) and will be described below. (Table 5) shows an example of the reference feature code sequence file, and (Table 6) shows an example of the inspection feature code sequence file. Is a number assigned in the order of occurrence, and 1/0 indicates whether the process is unprocessed or processed,
The collation is “1” for collation, “0” for non-collation, the corresponding number on the inspection side is described, the standard feature code string is the feature code string generated by the code string conversion process, and the average address is the code string conversion process. The average coordinates (X-coordinate, Y-coordinate) of the feature points calculated in step 3 are shown. Reference feature code string of "0004" in (Table 5) (Table 6) of the "0006" check code string and aligned with the result of excess code string is "65 - 5 4-43-
It is unmatched because it is not a pair code string of 32 ". The standard feature code string of" 0006 "is" Table 6 ".
As a result of being aligned with the inspection feature code string of “0004”, the surplus code string is “12-21”, which is the pair code string, and therefore the verification is performed.

(Fifth Embodiment) The fifth embodiment of the present invention will be described below. The fifth embodiment of the present invention is a comparison / determination process of the characteristic code from the specific shape detection means 15 in the second comparison / determination means 18 in the wiring pattern inspection apparatus, and the specific shape detection means 15 is the same as that of the second embodiment. The block diagram of the second comparison / determination means 18 is similar to that of FIG. 9A described in the third embodiment, and the difference is that the processing content of the comparison / determination processing is different, and the different points will be mainly described.
In FIG. 9A, the characteristic code 104 from the specific shape detecting means 15 is the FIFO 161 and the I / F circuit 16
The comparison / determination process is executed by the software process of the CPU 160 via 2.

In the comparison / determination process of the present invention, the feature code detected by the specific shape detection means 15 corresponds to the feature code corresponding to the feature point of interest in the second comparison / determination means 18 within an arbitrary allowable range (rs). A code string conversion process for sequentially combining points with each other to generate characteristic code string data, and a code string comparison process for comparing the characteristic code string from the characteristic code storage means 19 previously created on a non-defective substrate in code string units, and a mismatch. The defect shape determination process for inspecting whether the specific feature code sequence includes a specific basic code sequence indicating the defect shape and determining the type of defect.

The second comparison / determination means of the present invention will be described. Since the code string conversion process and the code string comparison process are the same as those in the third embodiment, the description thereof will be omitted, and the different defect shape judgment process will be described below. explain. However, the code string similarity comparison process described in the fourth embodiment may be used instead of the code string comparison process. 22A to 22F show an example of six main types of defects on the printed circuit board and their characteristic code strings. The actual defect may have a more complicated characteristic code string, but the element of the characteristic code string of FIG. 22 is always included. For example, a certain short characteristic code string "12-23-32-23-34-
45 "and" 56-67-76-67-78-81 "include" 12-23-34-45 "and" 56-6, respectively.
The element of 7-78-81 "is always included. Such a characteristic code string is called a basic code string.

[0090]

[Table 7]

[0091]

[Table 8]

[0092]

[Table 9]

[0093]

[Table 10]

[0094]

[Table 11]

[0095]

[Table 12]

[0096] (Table 7) to (Table 12), Ri table der gave identification code and the corresponding all basic code string corresponding to the six types of defects 22, (Table 7) to (Table 10)
The basic code string of the defect type considers the rotation every 45 °.
Eight types are required for each, but with the copper residue in (Table 11)
Pinholes in (Table 12) do not need to consider rotation
Therefore, only one type of basic code string is required. In order to determine the type of defect, it is sufficient to check that the elements of the basic code string shown in (Table 7) to (Table 12) are included in the characteristic code string of the defect. Further, as can be seen from FIGS. 22 (a) and 22 (c), the short and the disconnection can be judged from the fact that the two U-shaped basic code strings correspond to each other.

FIG. 23 shows the procedure of the defect shape determination processing.
It will be described in accordance with the flowchart of. Step 1: The mismatched characteristic code string is taken out from the defect information storage means and set as the focused code string. Step 2: test if there is any element of any basic code column to the attention code column. Step 3: if it does not interest code string is deleted from the defect information storage unit as verification. Step 4: If the basic code string is included, the identification code of the basic code string is registered in the location of the focused code string in the defect information storage means. Step 5: If there is an unprocessed characteristic code string in the defect information storage means, repeat from step 1 until it disappears. Step 6: The feature code string in which the identification code is registered from the defect information storage means is set as the point of interest. Step 7: Check whether the focused code string is a "U-shaped" basic code string. Step 8: For the basic code string other than the "U type", the defect type is registered as it is. Step 9: For the "U type" basic code string, a corresponding partner is searched. Step 10: If there is a corresponding partner, the defect type is registered from the combination of the basic code strings. Step 11: Repeat from Step 6 until there is no feature code string in which the identification code is registered.

[0098]

[Table 13]

Table 13 is an example of a defect information file of inspection data. Here, No. Corresponds to the serial number of the inspection feature code string, x and y are the average coordinates of the feature code string, and the identification code is in the feature code string (Table 7) to (Table 12).
Of the corresponding basic code string, the corresponding code string indicates the serial number of the corresponding partner in the case of a U-shaped basic code string, the defect type is the determined defect type, and the feature code string is inconsistent. Is a feature code string of. "24
The identification codes of 19 "and 2420" are "A1".
And "A5", which are "short" because they are close to each other
Has been determined. Also, "2793" corresponds to the basic code string of "C7" and is determined to be "missing". "46
Since 64 "and" 5156 "do not have corresponding basic code strings, they are erased from the defect information file . (Sixth Embodiment) The sixth embodiment of the present invention will be described below. The embodiment is the second in the wiring pattern inspection device.
The comparison and determination processing of the feature code from the specific shape detection means 15 in the comparison and determination means 18 is the same as that in the second embodiment, and the block configuration diagram of the second comparison and determination means 18 is the third embodiment. 9A is the same as that described in FIG. 9A, and the difference is the processing content of the comparison determination processing, and the different points will be mainly described. In FIG. 9A, the feature code 104 from the specific shape detection means 15 is a FIFO.
Comparison determination processing is executed by software processing of the CPU 160 via the I / F circuit 162 and the I / F circuit 162.

In the comparison / determination process of the present invention, the feature code detected by the specific shape detecting means 15 is associated with the feature code within the arbitrary permissible range (rs) centering on the feature point of interest in the second comparison / determination means 18. A code string conversion process for sequentially combining points with each other to generate characteristic code string data, and a code string comparison process for comparing the characteristic code string from the characteristic code storage means 19 previously created on a non-defective substrate in code string units, and a mismatch. Defect shape judgment processing that inspects whether the specified characteristic code string contains a specific basic code string that indicates the defect shape, and determines the defect type, and from the judged defect type, only for defects such as chips and protrusions It is composed of area calculation processing for calculating a defect area and detecting only defects exceeding a preset size.

The second comparison / determination means of the present invention will be described. The code string conversion process, the code string comparison process, and the defect shape judgment process are the same as those in the fifth embodiment, so that the description thereof will be omitted. Explain the concept. When the mismatched feature code string is determined to be a defect, defects such as defects and protrusions depend on the area value thereof, and when the area value is smaller than the value set by the user, it is not necessary to notify. Therefore, it becomes necessary to calculate the areas of the chip and the protrusion. Therefore, a process of calculating an area value of a rectangular region including feature points as an approximate area of a defect shape and notifying as a defect when the value exceeds a preset allowable value (sc) is called area calculation processing.

In the procedure of the area calculation processing, taking “missing” as an example,
This will be described with reference to FIG. In FIG. 24, the starting point 600
And the length l of a straight line 602 connecting the end point 601 and the straight line 60
A value obtained by multiplying the distance h from the farthest point 603 from 2 is the area of the rectangular region 604. Here, start point 600 and end point 6
The distance 1 to 01 is given by (Equation 18), and the distance h from the straight line 602 to the point 603 is given by (Equation 19). Therefore, the area S of the rectangular region can be calculated by (Equation 20).

[0103]

[Equation 18]

[0104]

[Formula 19]

[0105]

[Formula 19]

However, the coordinates of the farthest point (xmax, ymax)
Is.

[0107]

[Equation 20]

The area calculation processing will be described with reference to the flowchart of FIG. Step 1: From the defect shape determination process, the characteristic code string notified as a chip and a protrusion is set as the focused code string. Step 2: The area value of the rectangular area is calculated from the coordinates of the farthest point and the start point and end point of the focused code string. Step 3: If the obtained area value exceeds the allowable value (sc), it is registered as a defect. Step 4: If the allowable value (sc) is not exceeded,
Do not register. Step 5: Repeat step 1 until there are no defects on the chip and the protrusion.

By the above area calculation processing, the chip and the protrusion can be compared and judged with high accuracy by comparing with the value preset by the user. Further, regarding pinholes and copper residues, it is also possible to easily perform area calculation processing in the same rectangular area and integrate it with the defect notification from the design rule means to report it to the operator.

(Embodiment 7) A seventh embodiment of the present invention will be described below. The seventh embodiment of the present invention is the comparison judgment processing of the characteristic code from the specific shape detection means 15 in the second comparison judgment means 18 in the wiring pattern inspection device, and the specific shape detection means 15 is the same as the second embodiment. The block diagram of the second comparison / determination means 18 is similar to that of FIG. 9A described in the third embodiment, and the difference is that the processing content of the comparison / determination processing is different, and the different points will be mainly described.
In FIG. 9A, the characteristic code 104 from the specific shape detecting means 15 is the FIFO 161 and the I / F circuit 16
The comparison / determination process is executed by the software process of the CPU 160 via 2.

In the comparison / determination process of the present invention, the feature code detected by the specific shape detection means 15 corresponds to the feature code corresponding to the feature code of interest in the second comparison / determination means 18 within an arbitrary allowable range (rs). A code string forming process for sequentially connecting points to generate characteristic code string data, a pair code string erasing process for erasing a pair code string from the characteristic code string, and a characteristic code from the characteristic code storage means 19 created in advance on a good board. It is composed of a code string comparison process for comparing a string with a code string unit.

The second comparison / determination means of the present invention will be described. Since the code string conversion process and the code string comparison process are the same as those in the third embodiment, the description thereof will be omitted, and the pair code string erasing process will be described with reference to FIG. Will be explained. FIG. 26
Is an example of the data of the characteristic code string. FIG. 26 shows data that has been converted into a characteristic code string by the code string conversion process.
First, the combination of feature codes that make up a pair code string is
There are feature points 701 "18" and 702 "81", but they cannot be deleted because their distances are larger than the allowable range (rp). Next, the feature points 703 "12" and 704 "21" correspond to each other, and the mutual distances are within the permissible range (rp), so that they can be deleted. In this embodiment, the pair code sequence is erased after the code sequence conversion process, but the same result can be obtained even if the characteristic code sequence is generated without concatenating the pair code sequences during the code sequence conversion process.

(Embodiment 8) An eighth embodiment of the present invention will be described below with reference to FIG.

FIG. 31 is a block diagram of the specific shape detecting means 15 in the wiring pattern inspection apparatus according to the eighth embodiment of the present invention. In FIG. 27, 201 is a direction code assigning unit, 801 is a direction code converting unit, 202 is a feature extracting unit, and 800 is a direction code image. Configuration different from the FIG. 10, in order to remove the unstable feature points due to the quantization error of about 1 pixel, when the direction code of the attention pixel is different from the direction code of two contour pixels,
Direction code conversion means 801 for changing the direction code of the pixel of interest is provided.

Except for the direction code conversion means 801, the description is omitted because it is the same as the ninth embodiment, and the specific processing of the direction code conversion means 801 will be explained using FIG. 28 and FIG. 29. FIG. 28 is a circuit configuration diagram of the direction code conversion means 801, where 802 is a first direction code conversion unit that converts only odd direction codes, and 803 is a second direction code conversion that converts only even direction codes. It is a department. First, the specific processing of the first direction code conversion unit 802 will be described with reference to FIG. FIG. 29 is a circuit configuration diagram of the first direction code conversion unit, where 811 is a line memory,
Reference numeral 812 is a multi-valued 3 × 3 scanning window, 813 to 820 are comparators, 821 is an LSB signal at the target pixel position D0, and 823 is an MPX that selects the in-window data D0 to D8 by the output 824 of the LUT 822. 825 is an output of MPX. The first direction code conversion unit 802 scans the direction code image 800 with the scanning window 812, and compares the direction codes of the peripheral pixels D1 to D8 with the comparators 813 to 820 and the MPX823.
Output to. The comparators 813 to 820 have the value "" only when the direction code exists in the pattern shown in FIG. 30 and the direction codes of the pixels adjacent to the pixel of interest have the same value.
1 "is output. The pattern shown in FIG. 30 shows a pattern that requires conversion of the direction code. Black pixels are" 1 to 8 "direction codes, and white pixels are other values. The selection signal 824 of the MPX 823 is the comparator 813.
~ 820 output and LSB signal 821 of the target pixel position D0
(That is, when the direction code of the target pixel position D0 is even, the value is “0”, and when the direction code is odd, the value is “1”)
The LUT 822 described in the table shown in (Table 14) outputs the selection signal 824 of the MPX 823. Also, MP
X823 selects the direction code of D0 to D8 as shown in (Table 14) according to the selection signal 824, and outputs the signal 825.
You output. Also, the second direction code conversion unit which performs the same processing as in the first direction code conversion unit shown in difference in LUT822 table (Table 15).

[0116]

[Table 14]

[0117]

[Table 15]

Next, a processing example of the direction code converting means 801 is shown in FIGS. 31 and 32, and will be described below. Figure 31
Shows an input direction code image, and points 830, 831, and 832 to be particularly noted will be described. FIG. 32 shows the processing results of 830, 831, and 832. The feature point 830 is a point that does not require conversion of the direction code, and based on the table of (Table 14), the pixel of interest is D
A direction code of 0 is selected and the input (FIG. 32 (a)) and output (FIG. 32 (d)) have the same result. The feature point 831 is
The output of the comparator 818 is "1", and MPX is the pixel of interest.
Select the direction code "2" of D7 as the code of
2 (b) is converted into FIG. 32 (e). The same applies to the feature point 832, and FIG. 32 (c) is converted into FIG. 32 (f). Further, the reason why the conversion of the direction code is divided into the first direction code conversion unit and the second direction code conversion unit according to the direction code value (odd number and even number) of the pixel position of interest is that the direction code is "23232323". Becoming like
If there is one type of direction code conversion processing, "22
323233 "only, and therefore replaced next. As described above, the present invention is to convert the direction code by the direction code conversion means, to correct the irregularities caused by the quantization error and the like, stable inspection can be It is a thing.

[0119]

As described above, the effects of the present invention are as follows.
The design rule inspection means as the micro inspection detects the characteristic information based on the design rule such as the line width of the signal line, and the specific shape detection means as the macro inspection detects the predetermined figure shape such as the corner of the rectangular pattern. Since the micro inspection and the macro inspection adapted to various patterns on the board are inspected in parallel, high-precision and high-performance wiring that does not overlook or misreport various defects existing on the board without dividing the processing area A pattern inspection device can be realized.

Secondly, in the specific shape detecting means, a direction code representing the direction of the edge is given to the contour position of the image, a point where the direction code changes is detected as a feature point, and the coordinates of this feature point and the direction code are detected. By comparing the change point with the feature code from the non-defective board, large shorts can be generated locally.
A macro wiring defect such as disconnection or chipping can be detected, and a highly reliable and compact wiring pattern inspection device can be realized.

Thirdly, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted and sequentially connected with a corresponding characteristic code within an arbitrary range. Highly reliable wiring capable of making a strong judgment against a fine shape change of an edge by generating a characteristic code string and comparing the characteristic code string from the characteristic code storage means previously generated on a non-defective board with the characteristic code string in unit of the characteristic code string. A pattern inspection device can be realized.

Fourthly, in the second comparison / determination means, the change position of the direction code from the specific shape detection means and the feature code consisting of the code are inputted and sequentially connected with the corresponding feature codes within an arbitrary range. When a characteristic code string is generated and compared with the characteristic code string from the characteristic code storage unit generated in advance on a non-defective board in the characteristic code string unit and judged, the judgment is made by the similarity and the edge is missing due to a minute shape change. It is possible to realize a wiring pattern inspecting device that can prevent erroneous determination due to a feature code and the like and can perform reliable and stable determination.

Fifth, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted and sequentially connected with the corresponding characteristic code within an arbitrary range. A feature code string is generated and compared with the feature code string from the feature code storage means generated in advance on a non-defective board in feature code string units, and the mismatched feature code string is checked for shorts, disconnections, chips, protrusions, etc. A simple and easy-to-operate wiring pattern inspecting device that facilitates process control by inspecting whether the element of the specific basic code string shown is included and determining the type of defect and making it easier for the operator to understand Can be realized.

Sixth, in the second comparison / determination means, a change position of the direction code from the specific shape detection means and a feature code consisting of the code are input, and sequentially connected with corresponding feature codes within an arbitrary range. A feature code string is generated and compared with the feature code string from the feature code storage means generated in advance on a non-defective board in feature code string units, and the mismatched feature code string is checked for shorts, disconnections, chips, protrusions, etc. Prevents erroneous determination by inspecting whether the element of the specific basic code string shown is included and determining the type of defect, then calculating the area of the defect from the feature code string and detecting only the defect of a preset size It is possible to realize a reliable wiring pattern inspecting device.

Seventh, in the second comparison / determination means, a characteristic code consisting of a change position of the direction code and the code from the specific shape detection means is inputted, and sequentially connected with a corresponding characteristic code within an arbitrary range. A characteristic code string is generated, and the characteristic code string from the characteristic code storage means generated in advance on a non-defective board is compared and judged on a feature code string unit basis. if it contains a pair code string Ri by the fact that do not defect
The reduction was stable inspection can wiring pattern inspecting apparatus imaginary paper can be realized.

Eighth, in the specific shape detecting means, a direction code representing the direction of the edge is given to the contour position of the image, and the direction codes of the two contour pixels connected to the pixel of interest are the same code, and When the direction code of the pixel of interest is different from the direction codes of the two contour pixels, the direction code of the pixel of interest is changed to extract the feature, thereby canceling the unevenness caused by the quantization error or the like. It is possible to realize a highly reliable wiring pattern inspection device by reducing the number of false positives and false reports.

[Brief description of drawings]

FIG. 1 is a block connection diagram of a wiring pattern inspection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a binary image of a striped pattern of a through hole in the wiring pattern inspection apparatus.

FIG. 3 is a block connection diagram of a through-hole detecting means in the wiring pattern inspection apparatus and a conceptual diagram thereof.

FIG. 4 is a block connection diagram of a through hole area extraction unit in the wiring pattern inspection apparatus and a conceptual diagram thereof.

FIG. 5 is a diagram showing a pixel arrangement of a scanning window of an expansion processing unit in the wiring pattern inspection apparatus.

FIG. 6 is a diagram showing a block connection and a processing example of a design rule inspection means in the wiring pattern inspection apparatus.

FIG. 7 is a block connection diagram of specific shape detection means in the wiring pattern inspection apparatus.

FIG. 8 is a view showing an example of a pattern for corner identification of a specific shape detection means in the wiring pattern inspection device.

FIG. 9 is a block diagram of a comparison / determination unit in the wiring pattern inspection apparatus and a conceptual diagram thereof.

FIG. 10 is a block connection diagram of a specific shape detecting means of the wiring pattern inspecting device according to the second embodiment of the present invention.

FIG. 11 is a detailed block connection of a direction code assigning unit in the wiring pattern inspecting apparatus and a conceptual diagram thereof.

FIG. 12 is a diagram showing a processing example of a direction code assigning unit in the wiring pattern inspection apparatus.

FIG. 13 is a detailed block connection diagram of a feature extraction unit in the wiring pattern inspection apparatus.

FIG. 14 is a diagram showing an example of detecting a change point of a direction code of a feature extracting means in the wiring pattern inspection apparatus.

FIG. 15 is a view for explaining the concept of forming a code string of the specific shape detecting means of the wiring pattern inspecting device and the connecting procedure in the third embodiment of the present invention.

FIG. 16 is a diagram showing a processing flow of converting a specific shape detecting means of the wiring pattern inspecting device into a code string.

FIG. 17 is a diagram showing a processing flow of comparing characteristic code strings of a specific shape detecting means of the wiring pattern inspection apparatus.

FIG. 18 is a diagram showing sorting of characteristic code strings in the fourth exemplary embodiment of the present invention.

FIG. 19 is a conceptual diagram of code string similarity comparison processing in the fourth embodiment.

FIG. 20 is a diagram showing a pair code string in the fourth embodiment.

FIG. 21 is a flowchart of similarity comparison processing in the fourth embodiment.

FIG. 22 is a diagram showing a representative defect of the defect determination processing in the fifth embodiment of the present invention.

FIG. 23 is a flow chart of defect determination processing in the fifth embodiment.

FIG. 24 is a conceptual diagram of area calculation processing in the sixth embodiment of the present invention.

FIG. 25 is a flow chart of area calculation processing in the sixth embodiment.

FIG. 26 is a diagram showing processing of pair code string erasing processing in the seventh embodiment of the present invention.

FIG. 27 is a block connection diagram of the specific shape detection means of the wiring pattern inspection apparatus in the eighth embodiment of the present invention.

FIG. 28 is a block connection diagram of direction code conversion means in the eighth embodiment.

FIG. 29 is a detailed block connection diagram of the first direction code conversion unit in the eighth embodiment.

FIG. 30 is a diagram showing an example of a target pattern for direction code conversion in the eighth embodiment.

FIG. 31 is a diagram showing a processing example in the eighth embodiment.

FIG. 32 is a diagram showing a result of processing in the eighth embodiment.

[Explanation of symbols]

11 Image input means 12 Binarization means 13 Through-hole detection means 14 Design rule inspection means 15 Specific shape detection means 16 First comparison determination means 17 Feature Information Storage Means 18 Second comparison / determination means 19 Feature code storage means 24 CCD camera 30 Through-hole area extraction unit 31 Expansion processing unit 36 Coordinate detection unit 40-43 Filling circuit 44-47 contraction circuit 49 Expansion circuit 70 Thinning processing unit 71 Distance conversion processing unit 72 Feature Extraction Unit 73 Length measuring circuit 74 Shape detection circuit 76 Coordinate detection unit 90 5 × 5 window scanning circuit 91 3 × 3 window scanning circuit 92 Edge detection circuit 93 Shape detection LUT 95 Coordinate detection unit 133-134, 161 FIFO memory 136, 162 I / F circuit 131 Defect information storage means 130, 160 CPU 201 Direction code assigning means 202 feature extraction means 211 line memory 212 scanning window 213 LUT 221 line memory 222 scanning window 223 MPX 224 LUT 228 XY coordinate generator 401 Standard feature code string 402 inspection feature code string 403-404 characteristic points 600 Start point of feature code string 601 End point of feature code string 602 A straight line connecting the start point and the end point 603 The furthest point from the straight line 701-704 Features 800 direction code image 801 Direction code conversion means 802 First direction code conversion unit 803 Second direction code conversion unit 811 line memory 812 multi-value scanning window 813-820 Comparator 822 LUT 823 MPX

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI G06F 15/64 D 15/70 455B (72) Inventor Hidehiko Kawakami 3-10-1 Higashisanda, Tama-ku, Kawasaki-shi, Kanagawa Matsushita Giken Incorporated (72) Inventor Hideaki Kawamura 3-10-1 Higashisanda, Tama-ku, Kawasaki City, Kanagawa Matsushita Giken Co., Ltd. (56) Reference JP-A-1-180404 (JP, A) JP-A-3- 252546 (JP, A) JP 4-268444 (JP, A) JP 61-70677 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01B 11/00-11 / 30 102 G01N 21/84-21/958 G06T 1/00 G06T 7/00

Claims (12)

(57) [Claims] 1. A binary image obtained from a printed circuit board,
Design rule inspection means that measures the line width and line spacing and detects the position and its type that violate the criteria set in the design rule as characteristic information, and the design rule using a good board in advance.
Information storage means for storing the characteristic information from the inspection means
And the features detected by the design rule inspection means.
The characteristic information from the characteristic information from the characteristic information storage means.
A micro inspection apparatus comprising a first comparison determination means only detects the compare and true defect, the relative binary image, giving the direction code representative of the edge orientation in the contour position of the image, changes in the direction code A specific shape detection that detects a point as a feature point and detects a feature code that is a code that represents a change in the coordinates of the feature point and the direction code.
From the specific shape detection means using the output means and the good board in advance
Characteristic code storage means for storing the characteristic code of
A macro inspection comprising a second comparison / determination means for comparing only the characteristic defect detected by the fixed shape detection means with the characteristic code from the characteristic code storage means to detect only a true defect.
Wiring pattern inspection apparatus and a査device. 2. A binary image obtained from a printed board is an image input means for illuminating the printed board with reflected illumination from above and transmitted illumination from below, detecting reflected light and transmitted light of the printed board, and performing photoelectric conversion. And a binarization unit for converting the grayscale image from the image input unit into a binary image, and a through hole is separated and extracted from the binary image from the binarization unit to generate an image in which the through hole is filled. The wiring pattern inspection apparatus according to claim 1, wherein 3. The second comparison / determination means, in which the characteristic code, which is a code indicating the change in the coordinate of the characteristic point and the direction code from the specific shape detection means, is sequentially arranged with other characteristic codes existing within an arbitrary allowable range. 2. The wiring pattern inspection apparatus according to claim 1, wherein the characteristic code string is concatenated to generate a characteristic code string, and the characteristic code string from the characteristic code storage unit previously generated on the non-defective board is compared and judged in code string units. 4. The second comparison / determination means includes a characteristic code, which is a code indicating a change in the coordinates of the characteristic point and the direction code from the specific shape detection means, in sequence with other characteristic codes existing within an arbitrary allowable range. When the first feature code string is concatenated to generate the first feature code string and the second feature code string from the feature code storage means previously generated on the non-defective board is compared and judged in code string units, both the first and second The feature codes of the code strings are compared in order of similarity, the missing feature codes are interpolated, and the missing feature codes replace the lower digit and the upper digit of each other.
Have different combinations of codes, and
If it is a pair code string that is a code string existing within the allowable range
The wiring pattern inspection apparatus according to claim 3 , wherein the wiring pattern inspection apparatus performs collation , and otherwise determines the defect. 5. A second comparison / determination means, in which a characteristic code consisting of a code indicating a change in the coordinate of the characteristic point and the direction code from the specific shape detection means is sequentially arranged with another characteristic code existing within an arbitrary allowable range. The first characteristic code string is concatenated to generate the first characteristic code string, and the second characteristic code string from the characteristic code storage means generated in advance on the non-defective board is compared and judged for each code string, and the mismatched characteristic code string is short-circuited. 5. The wiring pattern inspection apparatus according to claim 3 , wherein the type of the defect is determined by inspecting whether an element of a specific basic code string indicating a break, a break, a protrusion, or the like is included. 6. The second comparison / determination means, in which the characteristic code, which is a code indicating the change in the coordinate of the characteristic point and the direction code from the specific shape detection means, is sequentially arranged with other characteristic codes existing within an arbitrary allowable range. The first characteristic code string is concatenated to generate the first characteristic code string, and the second characteristic code string from the characteristic code storage means generated in advance on the non-defective board is compared and judged for each code string, and the mismatched characteristic code string is short-circuited. , It is checked whether the element of a specific basic code string indicating disconnection, chipping, protrusion, etc. is included, and after determining the type of defect, the defect area is calculated from the characteristic code string for chipping and protrusion, and preset 6. The wiring pattern inspection apparatus according to claim 3, wherein only a defect having a specified size is detected. 7. The second comparison / determination means, in which the characteristic code, which is a code indicating the change in the coordinates of the characteristic point and the direction code from the specific shape detection means, is sequentially arranged with other characteristic codes existing within an arbitrary allowable range. When a characteristic code string is concatenated to generate a characteristic code string and the characteristic code string from the characteristic code storage means generated in advance on a non-defective board is compared and judged on a code string unit basis, the mismatched characteristic code string may have a quantization error or the like. 7. The wiring pattern inspection device according to claim 1, wherein when the generated pair code string is included, it is not considered as a defect. 8. In the specific shape detecting means, the direction code assigning means for giving a direction code indicating an edge direction to the contour position of the image and the direction code of two contour pixels connected to the target pixel are the same code. If the direction code of the target pixel is different from the direction codes of the two contour pixels, the direction code conversion means for changing the direction code of the target pixel and the point where the direction code changes are the characteristic points. The wiring pattern inspection apparatus according to claim 1, further comprising a feature extraction unit that extracts a feature code that represents a change in a point coordinate and a direction code of the feature point. 9. A binary image obtained from a printed circuit board,
The line width and line spacing are measured, and the position and its type that violate the criteria set in the design rules are detected as feature information, and compared with the feature information obtained in advance using a non-defective substrate, and only true defects are detected. Design rule inspection, and for the binary image, a direction code indicating the direction of the edge is added to the contour position of the image.
Given the points where the direction code changes, as feature points,
From the code that represents the change in the coordinates and direction code of the feature point
The wiring pattern inspection method is characterized in that: a specific shape inspection that detects only a true defect is performed in combination with the characteristic code that is obtained by using a non-defective substrate in advance. 10. In the specific shape inspection, the detected feature code is sequentially connected with other feature codes existing in an arbitrary allowable range to generate a feature code string, and a feature code string previously generated on a non-defective board is used. 10. The wiring pattern inspecting method according to claim 9 , wherein the judgment is made in units of code strings. 11. A binary image obtained from a printed circuit board.
Then, add the direction code that represents the direction of the edge to the outline position of the image.
Given the points where the direction code changes, as feature points,
From the code that represents the change in the coordinates and direction code of the feature point
Specific shape detecting means for detecting the feature code
The feature code from the specific shape detection means is recorded using the product board.
The characteristic code storage means to be remembered and the specific shape detection means
Feature code detected by the feature code storage means
The ratio that compares only the feature code from
A wiring pattern inspection device having a comparison and determination means . 12. A binary image obtained from a printed circuit board
Then, add the direction code that represents the direction of the edge to the outline position of the image.
Given the points where the direction code changes, as feature points,
From the code that represents the change in the coordinates and direction code of the feature point
The following characteristic codes are detected and obtained in advance using a non-defective board.
Specific shape to detect only true defects by comparing with feature code
Wiring pattern inspection method characterized by having an inspection
Law .