JP2942343B2 - Inspection equipment for printed wiring boards - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for detecting a defect of a wiring pattern on a printed wiring board, and more particularly to an inspection apparatus for preventing a false report from around a through hole. .

(Prior art)

In the manufacturing process of a wiring pattern on a printed wiring board, a defect shape such as disconnection, chipping (line thinning), short circuit, defective line-to-line connection, or dust adhesion may occur. Therefore, various inspection devices for detecting such a defect shape have been proposed.

On the other hand, as shown in FIG. 8, the printed wiring board 10 has a through hole 90 and a wiring pattern 9. The wiring pattern 9 includes a land 91 formed in an annular shape at the periphery of the opening of the through hole 90 and a line pattern 92 connecting between circuit terminals (not shown). The wiring pattern 9 is formed by a metal plating layer.

And, in general, the width of the land 91 (for example, about 50 μm)
Are formed narrower than the width of the line pattern 92 (for example, about 150 μm). Therefore, as shown in FIG. 9, when the land 91 is formed slightly off the axial center of the through hole 90, a narrow portion 911 and a wide portion 912 are formed. Further, the narrow portion 911 also occurs due to a small seat width due to poor etching.

Then, when the above-mentioned land portion is inspected by the inspection device, the inspection data 94 is detected as shown in FIG.
In the inspection data 94, the narrow portion 911 of the land 91 is considerably narrower than the width of the line pattern 92, and the line pattern 92 is recognized as having a defect shape. Therefore, the narrow portion 911 is detected as being in the missing (line thinning) state 941.

However, the narrow portion 911 is not in a disconnected state as shown in FIG. 9, and the land 91 has no practical problem. As described above, false information is likely to occur in the inspection data obtained by the conventional inspection device. Such false information is particularly large for the land 91 formed around the through hole.

In order to solve the above problem, there is an inspection apparatus which performs a mask process on a through-hole portion, does not perform an inspection around the through-hole when inspecting a line pattern, and eliminates erroneous determination around the through-hole. .

As shown in FIG. 11, the inspection device includes an imaging device 11 such as a CCD camera that reads a wiring pattern 91 on a printed wiring board 10, and an A / D that converts an analog signal of the imaging device 11 into a digital image signal. It comprises a converter 12, a mask section 81, and a defect data section 82.

The mask unit 81 includes a through-hole mask creating unit 811 that forms a through-hole mask based on a binary image signal from the A / D conversion unit 12 based on a standard wiring pattern of a printed wiring board. A mask memory unit 812 for storing the through-hole mask and reading the through-hole mask at the time of inspection is provided.

The defect data section 82, an inspection processing section 821 for detecting defect candidate data from the image signal of the CCD camera 11, and the defect candidate data are compared with the through-hole mask of the mask memory section 812 to obtain a true data. It comprises a collating unit 822 for detecting defect data, a data compiling unit 823 for compiling the collation results, and a terminal 824 as operation and display means.

Next, the creation of the through-hole mask in the through-hole mask creation unit 811 is performed by performing imaging around the through-hole using the master substrate. The master board is a standard board corresponding to the printed wiring board to be inspected. As such a master substrate, a drill board having a hole for a through-hole before forming a wiring pattern, or a sufficient seat residue on a land of the through-hole, and a break in a binary image when an image is taken. Use no printed wiring board.

In this way, a mask having a sufficient size is created so that the position of the through hole is recognized and a false report is not generated at the time of actual inspection. Then, these are stored in the mask memory unit.

Next, the inspection processing unit 821 of the defect data unit 82
The image signal from the D converter 12 is processed by a spatial filter, and a defect shape related to disconnection, short-circuit, etc. is recognized (detected) by a feature extraction method.

Each of the spatial filters is designed to pass only an image signal corresponding to a defect shape such as a disconnection or a short-circuit.

If the binary image signal from the A / D converter 12 is data (defect candidate data) that is temporarily determined to be a defect shape, the inspection processing unit passes the defect candidate data through a through-hole mask. The data is transmitted to the matching unit 822.

Next, in the through-hole / mask matching unit 822, the defect candidate data and the mask memory unit 812 are stored.
Against the through-hole mask from.

When it is determined that the defect candidate data has a true defect shape as a result of the collation in the through-hole mask collation unit 822, a signal to that effect is sent to the data aggregation unit 823 and the terminal 824. That is, if the defect candidate data is not inside the through-hole mask, it is recognized as a true defect shape.

In addition, the above-described defect inspection is performed while the imaging device 11 scans above the printed wiring board 10 as shown in FIG. The printed wiring board 10 is a sheet having 12 pieces A to L provided with the same wiring pattern. These pieces A to L are cut from the sheet into pieces after the defect inspection, and used as individual printed wiring boards.

In addition, as shown in FIG. 12, the scanning at the time of the above inspection is basically performed in a zigzag manner with the width of each piece being a scanning width such as A → D, E → H, I → L. The scanning width may be equal to or larger than the piece width (see FIG. 2 described later).

[Problem to be solved]

However, as shown in FIG. 8, the width of the land 91 around the through hole 90 is smaller than the width of the line pattern 92. Further, the position of the drill hole in the printed wiring board 10, that is, the hole position of the through hole 90 is not constant due to a variation in the hole position at the time of drilling (for example, ± 100 μm).

For this reason, the position of the remaining portion of the land 91, that is, the position of the plating layer portion left as a land when a pattern is formed by etching, is slightly different for each printed wiring board 10. It should be noted that the variation in the perforation position in a relatively limited area (area of an individual piece) in one printed wiring board 10 is substantially constant. FIG. 13 shows this, and shows a case where the hole position of the through hole 90 is eccentric to the left of the land 91. FIG.

On the other hand, in the above-described conventional inspection method, as described above, the position of the through-hole is used as a reference, and the hole is compared with the through-hole mask having the predetermined size. That is, the through hole
The mask is a mask having a size centered on the through-hole by taking an image of a printed wiring board having no break in the drill board or land and recognizing a hole position on the printed wiring board from the image.

Therefore, if the above-described variation occurs at the hole position of the through hole 90 of the printed wiring board 10, as shown by a dotted line in FIG. Is determined to be “line thinning” and is output as defective.

Therefore, as shown in FIG. 15, when a through-hole mask 96 larger than the above is used, a chipped portion 921 generated at the base of the line pattern 92 and the land 91 or a defective protrusion of the adjacent line pattern 92 is formed. 925 cannot be detected, and it is erroneously determined that there is no defect.

As described above, in the above-described conventional inspection method, since a through-hole mask is created, stored, and collated based on the position of the through-hole, false information is generated from around the through-hole as described above.

The present invention has been made in view of the above-mentioned conventional problems, and provides an inspection apparatus for a printed wiring board capable of comparing an optimum through-hole mask with defect candidate data and preventing a false report from around the through-hole. What you want to do.

[Solutions to solve the problem]

An inspection apparatus for a printed wiring board according to the present invention includes: an imaging apparatus for imaging a wiring pattern on the printed wiring board;
It comprises a mask section for creating and storing a through-hole mask, a defect data section for detecting a defect in a wiring pattern, and a memory control section for controlling position correction of the through-hole mask.

A mask creating unit for creating a through-hole mask based on the position of the through-hole;
The through-hole mask is temporarily stored, and the through-hole mask for collation is accessed by the memory control unit.
A mask memory section for storing a mask, wherein the defect data section includes an inspection processing section for detecting defect candidate data from an image signal of the imaging device; and a through hole for collation between the defect candidate data and the mask memory section. A collating unit for collating with a mask to detect true defect data, and a data tallying unit; Further, the memory control unit stores the through-hole mask stored in the mask memory unit.
At the time of inspection, the memory control CPU unit for correcting the position from the hole position reference to the land position reference of the through hole and storing the matching through hole mask in the mask memory unit, and the correction amount of the position correction And a scale memory unit for deriving.

According to the present invention, a certain tendency (for example, toward the left or toward the upper right) is observed in a part of the area of the printed wiring board, that is, in the direction of variation in the hole position of the through hole within the area of about an individual piece. It focuses on the point that can be done.

Prior to mask matching, the position of the through-hole mask is corrected in accordance with the position of the land, that is, the land position, and the corrected through-hole mask is repeatedly used over the entire printed wiring board, so that false information is obtained. A highly accurate inspection that does not occur is performed.

One cause of the variation in the positional relationship between the center of the hole position and the center of the land position is that the drill blade is bent when several printed wiring boards are stacked and drilled.

In the present invention, the printed wiring board to be inspected is usually a sheet in which individual printed wiring boards are repeatedly arranged and formed in a matrix of a plurality of pieces (see FIG. 2). That is, the one piece constitutes one piece printed wiring board. After the inspection, the sheet is cut into pieces to obtain individual printed wiring boards.

Further, in the mask making section, the position of each hole in the printed wiring board when the standard master substrate is used is detected from the image signal of the imaging device, and the land of each through hole is masked. Create a through-hole mask of the required size.

Then, in the mask memory section, the hole position and the through-hole mask are temporarily stored. This through-hole mask is a temporary through-hole mask based on the hole position of the through-hole. As will be described later, the access from the memory control unit changes the through-hole mask for verification based on the land position. Will be corrected.

The memory control unit includes a memory control CPU unit, a scale memory unit, a CRT interface,
It has an RT and a scanning terminal. The memory control CPU unit comprises:
A temporary through-hole based on the hole position stored in the mask memory unit with respect to the mask memory unit.
The operation of correcting the mask to a position based on the land position on the inspected printed wiring board is performed by accessing the mask memory. And the amount of this position correction is
It is calculated using the scale memory unit.

The scale memory section is a video RAM for the CRTI screen, and a cursor image to be displayed on the CRT to derive the correction amount during the above-described position correction work is arbitrarily accessed by the memory control CPU section. Stored in position.

In the CRT, the cursor image from the scale memory unit, the pattern image from the image pickup device for the printed wiring board to be inspected, and the temporary through-hole mask image in the mask memory unit are displayed in different colors. Display them in layers. These are performed using the CRT interface.

With respect to the above three types of image signals displayed on the CRT, a correction amount for position correction is derived using an operation terminal.

The operation terminal moves the cursor image on the CRT, requests registration of an arbitrary position of the cursor to the memory control CPU unit, and displays the image signal (excluding the cursor image) input to the CRT interface. And select C
Notify the RT interface.

That is, the operation terminal informs the memory control CPU unit of the image center position of the temporary through-hole mask based on the hole position of the master substrate by using the cross scale. The cross cursor is moved to the center position (land position) of the pattern image, that is, the land image, to inform the memory control CPU unit of the land position. The memory control CPU calculates the deviation (correction amount) of the coordinate position of the cross cursor at the two center positions (the hole position reference and the land position reference).

Then, in order to correct the position of the temporary through-hole mask stored in the mask memory unit by the correction amount, the data in the mask memory unit is rewritten. As a result, in the mask memory unit, an appropriate through-hole mask for verification on the printed wiring board to be inspected is corrected and stored.

Next, in the defect data section, the collation section compares the defect candidate data obtained from the inspected printed wiring board with the appropriate through-hole mask for comparison. Therefore, in the collation unit, the defect candidate data relating to the land of the through hole among the defect candidate data is masked by the collation through hole mask.

Therefore, only a defect in a circuit portion other than the land is determined as a defect and sent to the data totaling unit. Note that the defect detection for the land is separately performed as necessary.

[Action and effect]

In the present invention, a memory control unit for accessing the mask memory unit is provided in the conventional technology.
The memory control unit corrects the temporary through-hole mask position based on the hole position on the master substrate based on the land position on the inspected printed wiring board, and stores the corrected through-hole mask for correction. . Then, the matching through-hole mask is compared with defect candidate data detected by the inspected printed wiring board.

Therefore, even when the hole position of the through-hole in the inspected printed wiring board is eccentric from the center of the land, the through-hole mask masks the entire land at the time of matching of the through-hole mask.

Therefore, among the defect candidate data detected by the inspection processing unit of the defect data part, the defect candidate data relating to the land of the through hole is cut by the matching unit, and only the defect of the circuit portion other than the land is detected. Therefore, no false information is generated based on the deviation of the hole position in the through hole.

As described above, according to the present invention, it is possible to provide a printed wiring board inspection apparatus capable of collating the optimum through-hole mask with the defect candidate data and preventing a false report from around the through-hole. it can.

〔Example〕

An inspection apparatus for a printed wiring board according to an embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the inspection apparatus of this embodiment includes an imaging device 11 such as a CCD camera for imaging a wiring pattern 9 on a printed wiring board 10, an A / D converter 12, a through-hole
A mask unit 3 for creating and storing a mask, a defect data unit 82 for detecting a defect in a wiring pattern, and a memory control unit 2 for controlling position correction of a through-hole mask.

The mask unit 3 includes a through-hole mask creating unit 31 that creates a through-hole mask from an image signal of the imaging device 11 based on the position of the through-hole, and temporarily stores the through-hole mask and performs the memory control. And a mask memory unit 32 that enables access from the unit 2.

The defect data unit 82 compares the defect candidate data with the matching through-hole mask in the mask memory unit 32 to check the trueness of the defect data from the image signal of the imaging device. It has a collating unit 822 for detecting defect data, a data totaling unit 823, a terminal 824, and a terminal CRT 825.

The memory control unit 2 corrects the position of the through hole mask stored in the mask memory unit 32 from the hole position reference to the through hole land position reference at the time of inspection, and Control for storing the through-hole mask for verification in the memory
CPU unit 21, scale memory unit 22 for deriving the correction amount of the position correction, CRT interface 23, CRT
24 and an operation terminal 25.

Further, as shown in FIG. 1, the inspection apparatus of this example has an alignment unit 5 for positioning the master substrate and the printed wiring board to be inspected, and actually measuring the pitch amount between the pieces. It will be described later.

Therefore, in the inspection, first, a temporary through-hole mask based on the hole position is created and stored in the mask unit 3 using the master substrate. That is, an image of the master substrate such as the drill board is taken by the image pickup device 11, a temporary through-hole mask is created based on the hole position, and the mask is temporarily stored in the mask memory unit 32. This temporary through-hole mask is an image signal composed of a hole position in the master substrate and a mask having a size necessary to mask the land of the through-hole.

Next, an inspection is performed on the printed wiring board 10 to be inspected. In this case, first, as shown in FIG.
The image signal from 11 passes through the CRT interface 23,
4 is displayed as a pattern image 200. Further, the temporary through-hole mask in the mask memory unit 32 is displayed on the same CRT 24 as the through-hole mask image 36 through the CRT interface 23. Furthermore, the CRT24 has
Through the CRT interface 23, a scale cursor image 211 from the scale memory unit 22 is displayed.

As shown in FIG. 3, as shown in the pattern image 200 of the printed wiring board to be inspected, the through hole of the printed wiring board has its hole position 201 shifted from the center position (land position) of the land. (See FIG. 13 of the prior art). Therefore, as seen in Fig. 3, C
Through-hole mask image based on hole position on RT24
There is a displacement between 36 and the pattern image 200 obtained from the inspected printed wiring board.

Then, as shown in FIGS. 4A to 4C, the position correction between the through-hole mask image 36 and the pattern image 200 is performed using the cursor image 221 and the operation terminal 25 of the memory control unit 2. Then, the temporary through-hole mask in the mask memory unit 32 is corrected to a through-hole mask for comparison via the memory control CPU unit 21 and stored.

That is, as shown in FIG. 4A, first, the cursor image 221 is aligned with the center position of the through-hole mask image 36 based on the hole position, and the coordinates are registered in the memory control CPU unit 21 (registering the mask center address).

Next, as shown in FIG. 4B, the cursor image 221 is
The coordinates are registered in the memory control CPU unit 21 in accordance with the land center position of the pattern image 200 from the test object (registration of the land center address). In both figures, reference numeral 290 denotes a hole portion of a through hole, 291 denotes a land portion, and 292 denotes a line pattern portion. FIG. 4C will be described later.

Thereafter, the memory control CPU unit 21 calculates the difference between the coordinate positions, that is, the position correction amount, and corrects the position of the provisional through-hole mask in the mask memory unit based on the calculated position correction amount, and sets it as the matching through-hole mask. . The matching through-hole mask is sent to the matching unit 822 of the defect data unit 82, where it is compared with defect candidate data and mask processing is performed as in the conventional case.

Next, the alignment unit 5 shown in FIG.
And a device for accurately determining the position of the printed wiring board at the time of inspection.

As shown in FIG. 1, the alignment unit 5 includes a table 54 for mounting a master substrate or a printed circuit board to be inspected, and a table 54 for moving the table 54 in the X-axis and Y-axis directions for positioning. The motors 55 and 56, the two-dimensional camera 511 for imaging through holes, lands, wiring patterns, etc. on the master substrate or the printed wiring board to be inspected, the two-dimensional frame memory unit 52, and movement and movement coordinates of the table are managed. And a table control CPU 53. The CPU section
53 connects to the terminal 824 of the defect data section 82.

The motors 55 and 56 are connected to drivers 551 and 552 and coordinate data D / A converters 552 and 562, respectively. An A / D converter 512 is provided between the two-dimensional camera 511 and the two-dimensional frame memory unit 52. Further, a CRT 514 is connected to the two-dimensional camera 511, and a switch 513 for displaying a binary image and an analog image is provided therebetween.

The two-dimensional camera 51 is placed on the table 54.
1 and a one-dimensional CCD camera as the image pickup device 11 are arranged so as to be able to scan (scan) the wiring pattern when the through-hole mask is formed and when the inspection is performed.

Next, as shown in FIG. 12 of the prior art, the scanning of the printed wiring board by the above-mentioned image pickup device may be performed for each piece of the individual printed wiring board, but in this example, it is shown in FIG. As shown, the printed wiring board sheet including the pieces A to P is scanned in the order of downward, upward, and downward in FIG. The field of view 115 in the camera width direction at this time is
As shown by the one-dot chain line in FIG.

The area in which the hole position is recognized when the through-hole mask is created is the leading piece in the scanning direction. For example, for the first downward scan, the depth of piece A
116 (vertical direction) and the camera view width 115 (one-third of A and H, ie, the shaded area in FIG. 2). In the case of upward scanning, the above-mentioned depth 116 in pieces E and L is used.
And the range of the camera view width 115 (part of E and part of L).

Next, the creation of a through-hole mask for comparison will be described with reference to the flowcharts of FIGS.

First, FIG. 5 shows the order in which a temporary through-hole mask is created from the master substrate. That is, here, first, in step 501, the alignment unit 5
Position and fix the master substrate on the table. Then, in step (hereinafter abbreviated) 502, imaging of the master substrate is started. The processing enclosed by loop ends 504 and 508 is
It shows the processing content of one column of the path to be scanned, and is repeated by the number of paths until scanning of all the paths is completed.
The variable for managing the number of paths is path X, and 503 is processing for setting 1 to path X as its initial value.

Next, in 505, a binary through-hole hole image is obtained by the above-described imaging, and this is input to the mask creating unit 31. Also, a through-hole mask image is generated in synchronization with the imaging speed based on the hole image. At 506, the through-hole mask image is stored (stored) in the mask memory unit 32. At this time, the storage start and end timings are determined based on the inspection start position data and the inter-piece pitch data. Next, at 507, the number of passes X for the next column scan
Is set, and it is determined at the loop end 508 whether or not all the paths have been completed, and the processing in the loop 1 is repeated until all the paths have been completed. With the above procedure, all scans of the master substrate are completed, and all temporary through-hole mask images for the first piece of each scan pass are stored.

Next, FIGS. 6A and 6B show the position correction of the through-hole mask, that is, the order in which the matching through-hole mask is created.

First, in 201, the printed circuit board to be inspected is positioned according to the reference position of the master board in the alignment section 5. Next, in step 202, the value of the number of paths X is initialized, and the repetition processing of loop 1 surrounded by loop ends 203 and 215 is executed for all paths. As the contents of the repetitive processing, first, in pass 204, an arbitrary position is picked up in the leading piece in the scanning direction (see the description of FIG. 2).

Next, the binary pattern image captured in 205
The pattern image 200 is input to the T interface 23 and displayed on the CRT 24 in an arbitrary color (for example, red).
Then, at 206, the data of the through-hole mask image of the portion corresponding to the area currently being imaged is read from the mask memory unit 32. At 207, the through-hole mask image 36 is input to the CRT interface 23, and is different in color (for example, blue) from the
Displayed above.

At 208, the memory control CPU unit 21 writes the data of the center cross cursor image 221 in the scale memory unit 22. Then, at 209, the data in the scale memory unit 22 is read and input to the CRT interface 23.
Then, the cross cursor image 221 is displayed on the CRT 24 in a different color (for example, green) from the two images (see FIG. 3).

Next, at 210, the operator moves the cross cursor image 221 to the center of the through-hole mask 36 using the operation terminal 25 (FIG. 4A), and changes the position to the memory control CPU unit 2.
Register to 1. That is, the center address of the mask is registered.

Next, at 211, the cross cursor image 221 is moved again to the center of the land of the through hole corresponding to the etching pattern side (FIG. 4B), and the position is registered. That is,
Register the center address of the land.

Next, at 212, the memory control CPU unit 21 calculates the difference between the mask center address and the land center address, and obtains a vector for shifting the through-hole mask image to the land center.

Then, in 213, the memory control CPU unit 21 moves (rewrites) all data in the mask memory unit 32 according to the obtained shift vector data.

As a result, a matching through-hole mask for each path (scan area) is created and stored in the mask memory unit 32. Next, the number of paths X is incremented at 214, and the loop end 21 is increased.
In 5, it is determined whether or not the processing of all the paths has been completed. Loop 1 until the through hole mask of all paths is corrected
Is repeated.

Next, FIG. 7 shows the order of the defect inspection of the inspected printed wiring board.

First, at 401, the printed circuit board to be inspected is positioned and fixed to the table 54 of the alignment unit 5. And four
At 02, the alignment pattern is imaged, and the position of the inspected printed wiring board is corrected based on the reference value. At 403, imaging by the imaging device 11 is started. An iterative processing loop 1 surrounded by loop ends 405 and 413 indicates processing contents for one scan row (one pass), and manages the number of passes by a variable path X.
Loop 407, 41 for repeating the processing in loop 1 for all paths
An iterative processing loop 2 surrounded by 1 indicates the processing content of one piece in one pass, manages the number of pieces in the scanning direction by a variable piece Y, and performs repetitive processing for all pieces in one pass.

The processing contents of the loop 2 are as follows. First, at 408, the data of the pass × collation through-hole mask from the mask memory unit 32 reaches one piece in the scan direction in synchronization with the imaging by the imaging device 11. Is read. At this time, the read start position data and the piece-to-piece pitch data
The read start timing is determined.

Then, at 409, the read through-hole mask for comparison is input to the matching unit 822 of the defect data unit 82, and is compared with the defect candidate data from the inspection processing unit 821 to perform mask processing. Therefore, if the above processing of loop 2 is repeated for all pieces in the scanning direction and further repeated for all scanning passes (loop 1), the defect inspection of one printed wiring board is completed.

As described above, according to this example, the optimum through-hole mask can be collated with the defect candidate data.
False alarm from around the through hole can be prevented.

[Brief description of the drawings]

1 to 7 show an embodiment, FIG. 1 is a block diagram of an inspection apparatus, FIG. 2 is an explanatory view of a scan of a multi-piece printed wiring board and an image pickup apparatus, and FIG. 3 is on a CRT. 4A to 4C are explanatory diagrams of position correction using a cross cursor image, and FIG. 5 is a through hole mask image, a pattern image, and a cross cursor image displayed.
FIG. 6A and FIG. 6B are flow charts for creating a mask, and FIG.
8 to 15 show a conventional example and its problems, FIG. 8 is an explanatory diagram of a wiring pattern, FIGS. 9 and 10 are explanatory diagrams of through-hole lands,
FIG. 11 is a block diagram of a conventional inspection apparatus, FIG. 12 is an explanatory diagram of a scan at the time of imaging, FIG. 13 is an explanatory diagram showing a deviation between a land and a hole position in a through hole, and FIGS. FIG. 4 is an explanatory diagram of a positional relationship between a through hole and a through hole mask. 10 ... printed wiring board, 200 ... pattern image, 221 ... cross cursor image, 36 ... through hole mask image, 9 ... wiring pattern, 90 ... through hole, 91 ... land,

Claims (2)

(57) [Claims] An imaging device for imaging a wiring pattern on a printed wiring board and a through-hole mask are created.
A mask section for storing, a defect data section for detecting a defect in the wiring pattern, and a memory control section for controlling position correction of the through-hole mask. A mask creation unit for creating a through-hole mask based on a position; and a mask memory unit for temporarily storing the through-hole mask and storing a through-hole mask for comparison by access from the memory control unit. The defect data section includes an inspection processing section that detects defect candidate data from an image signal of the imaging device, and a true defect data by comparing the defect candidate data with a matching through-hole mask in the mask memory section. And a data counting unit, and the memory control unit is stored in the mask memory unit. A memory control CPU unit for correcting the position of the through-hole mask from the hole position reference to the through-hole land position reference during inspection, and storing a matching through-hole mask in the mask memory unit; A printed wiring board inspection apparatus, comprising: a scale memory unit for deriving a correction amount of correction. 2. A printed wiring board sheet according to claim 1, wherein said printed wiring board is formed by repeatedly arranging individual printed wiring boards in a matrix of a plurality of pieces.
An inspection apparatus for a printed wiring board, characterized in that the through-hole mask to be stored in the mask memory section is created only for the first imaging area in one imaging range of the imaging apparatus.