JPH08191185A - Manufacture and inspection method of electronic circuit board, and through hole inspecting method and through hole inspecting equipment - Google Patents

Abstract

PURPOSE: To reduce the position deviation of a through hole, by optically detecting the surface condition of a through hole in a printed wiring board after each process, detecting position deviation amount, calculating position deviation correction amount so as to minimize position deviation error in each process, and performing position alignment. CONSTITUTION: After a through hole working process P2, a filling process P5 for filling a through hole 2 with filler, and a process P10 for forming a circuit pattern by using a mask after the through hole 2 is filled with the filler, electronic circuit boards 1, 6, 10 are irradiated with light, and image signals are detected by using optical inspection equipments 3, 7, 11. From the image signals, the position deviation amount in each process is detected, and the position deviation correction amount is calculated. On the basis of the calculated position deviation correction amount, position alignment of electronic circuit boards 1, 6, 10 are performed. Thus the position deviation of the through hole 2 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic circuit board manufacturing method and inspection method, a through hole inspection method and a through hole inspection apparatus, and more particularly to a multilayer ceramic printed wiring board (formed of ceramic or the like of an electronic circuit board). (Including a wiring board) and a method for manufacturing and inspecting an electronic circuit board, and a defect is optically detected when a conductor paste is filled in a through hole formed on the board or in a through hole which is still penetrated. The present invention relates to a method for detecting a through hole that is detected automatically and a through hole inspection apparatus for inspecting the method.

[0002]

2. Description of the Related Art As a conventional method for manufacturing a multilayer ceramic printed wiring board, for example, circuit technology, V
ol 4, No. 3, PP 151-155 (1989), the technique is discussed. Further, as a device for detecting the position of a through hole of a green sheet for a multilayer ceramic substrate, there is a method disclosed in Japanese Patent Laid-Open No. 3-120447, which is a filling state of a conductor portion generated after filling a through hole with a conductor paste. There is a method disclosed in Japanese Patent Laid-Open No. 4-111336 as an apparatus for inspecting.

[0003]

Conventionally, an electronic circuit board represented by a multilayer printed wiring board made of ceramic or the like has an electrical connection between front and back printed wirings formed on the board or between printed wirings of respective layers. In order to
It is created by the following steps.

First, a through hole is formed in a substrate of a non-sintered sheet called a green sheet, and a material having good electric conductivity (generally, tungsten, molybdenum, metal such as copper, silver or the like) is formed in the formed through hole. Fine particles), and the substance having good electric conductivity is screen-printed on the surface of the green sheet to form a circuit pattern. Then, a large number of the above green sheets are laminated and sintered to form a multilayer ceramic substrate.

The structure of the multilayer wiring board after the lamination and sintering will be described below with reference to FIG. FIG. 21 is a cross-sectional view of the multilayer wiring board after laminated sintering.

In this multilayer wiring board, the inside 6
01 through-hole filling portion 602, circuit pattern portion 60
3, a circuit is formed, and I / O pin connection patterns 604 and LSI connection patterns 605 are formed on the front and back surfaces of the substrate. I / O pins (I
/ O pin) 606 is brazed with a solder 607, and LSI
608 is connected with solder 609. This multilayer wiring board is connected to a printed board or the like via I / O pins 606 and serves as an electronic circuit board, which serves as a high-speed arithmetic circuit such as a large-scale computer or a VLSI module.

By the way, in this electronic circuit board, a wiring short circuit 611 due to a position shift through hole 610, a wiring short circuit due to a position shift of a conductor portion which occurs after the through hole is filled with a conductor paste, a conductor paste not filled or a printed circuit. Even if a disconnection occurs in the wiring portion due to the unconnection of the patterns, these shape defects cannot be inspected after sintering. For this reason, in order to ensure the reliability and yield of the multilayer wiring board, the through hole has a defective shape or misalignment at the stage of the green sheet, the filling state of the conductor portion that occurs after filling the through hole with the conductor paste, and the filling portion. It is necessary to inspect the misalignment of 1 to eliminate defective products and repair defective parts. Therefore, the device for detecting the position of the through hole of the green sheet described in Japanese Unexamined Patent Publication No. 3-120447 mentioned above as the prior art, and Japanese Unexamined Patent Publication No. 4-111133.
The reliability and yield of the multilayer wiring board have been ensured by the device for inspecting the filling state of the conductor portion that occurs after filling the through holes with the conductor paste described in Japanese Patent Laid-Open No. In the conventional electronic circuit board, the through hole diameter is 100
μm-300μm, through hole pitch is 500μm-
About 1000 μm and minimum conductor spacing is 100 μm
Since it is about m, even if the through hole is displaced in the range of about several tens of μm, there is no problem in performance.

However, in order to realize a higher speed arithmetic circuit, the electronic circuit boards of recent years have further improved the circuit mounting density, the through hole diameter is within 100 μm, the through hole pitch is within 500 μm, and the minimum conductor interval is 10 as well.
It is within 0 μm. There is an increasing demand for minimizing the positional deviation of through holes as shown in FIG. 21. If the conventional positional deviation of several tens of μm is allowed, there is a fear that short circuits and disconnection defects will occur frequently. .

For example, in the through hole inspection apparatus according to the above-mentioned Japanese Patent Laid-Open No. 3-120447, it is difficult to detect the positional deviation of the through holes with high accuracy within a few μm and eliminate defective products.

This will be described below with reference to FIG. FIG. 22 is a diagram showing a cross-sectional view of a wiring board having a through hole, and an image signal obtained by illuminating the wiring board and a detected image for comparison.

That is, in JP-A-3-120447, the transmitted illumination light from the through hole of the green sheet is detected to obtain the position data of the through hole. Therefore, as shown in FIG. 22, when the through hole 620 is formed perpendicularly to the green sheet surface 621 (S surface and R surface) (in the case of the through hole G shown in FIG. 22), an optical image is obtained. Can be detected as a shape substantially equal to the shape of the through hole, but when the through hole 622 is not processed perpendicularly to the green sheet surface 621 (in the case of the through hole H shown in FIG. 22),
Since the optical image is deformed with respect to the shape of the through hole, there is a problem that the center position of the through hole cannot be accurately detected. Further, there is also a problem that it is not possible to identify whether the through hole position detected in the detected image is the position of the hole viewed from the S surface side of FIG. 22 or the position of the hole viewed from the R surface side.

On the other hand, Japanese Patent Application No. 4-111336 discloses
Although a means for detecting a filling state defect (insufficiency, bleeding, scattering, inclusion of foreign matter, etc.) of the conductor paste filled in the through hole is disclosed, depending on the inspection device described in this publication, the conductor portion of the conductor paste is disclosed. There is a problem in that it is not possible to determine the amount of positional deviation and it is not possible to exclude defective products causing positional deviation, and it is not possible to prevent short-circuit defects caused by positional deviation.

Further, Japanese Patent Laid-Open No. 22850/1992 discloses a method of inspecting a substrate by sucking air and holding the green sheet flat, but when there is a through hole therethrough. However, there is a problem in that the adsorption power is lowered and this method cannot be very effective.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and the first object thereof is to have a through hole (through hole) or a through hole filled with a filling material. It is an object of the present invention to provide a highly reliable method for manufacturing an electronic circuit board in which the positional deviation of through holes connecting front and back wirings of the existing printed wiring board is small.

A second object of the present invention is to provide a printed wiring board having a through hole that is misaligned, or a through hole that is misaligned after the through hole is filled with a filling material. , A method for manufacturing a highly reliable electronic circuit board, in which a through hole of a non-defective printed wiring board is filled with a filling material, a wiring pattern is formed, and only the non-defective printed wiring board is laminated and sintered. Is to provide.

A third object of the present invention is to enable high-speed and high-accuracy measurement of displacement of a through hole formed in a printed wiring board or a through hole filled with a filling material. An object of the present invention is to provide a through hole inspection method and inspection device.

Further, a fourth object of the present invention is to provide through holes formed in the printed wiring board,
Alternatively, a through-hole inspection method and inspection device capable of accurately measuring the misalignment of the non-defective through hole by inspecting the through hole filled with the filling material by distinguishing between the non-defective through hole and the defective through hole. Is to provide.

A fifth object of the present invention is to provide a method for inspecting an electronic circuit board, which can hold the substrate flat and inspect it when inspecting a printed wiring board having a through hole. is there.

[0019]

In order to achieve the first object, the structure of the invention relating to the method for manufacturing an electronic circuit board of the present invention is such that the wiring on the front and back of the board is electrically connected by utilizing the through holes. In a method of manufacturing an electronic circuit board formed by connecting, when the electronic circuit board is formed in a multilayer,
A means for irradiating the electronic circuit board with light, a means for detecting an image signal measured by irradiating the light, a means for calculating a positional deviation correction amount, and an electronic circuit board based on the positional deviation correction amount And a means for irradiating the electronic circuit board with light, and a means for irradiating the electronic circuit board with light and detecting an image signal measured by irradiating the light, By detecting the image signal measured by irradiating the light and calculating the positional deviation correction amount, the positional deviation correction amount of the through hole between the electronic circuit boards is calculated from the image signal, The circuit board position adjusting means performs the position adjustment between the electronic circuit boards based on the calculated positional deviation correction amount.

More specifically, in the electronic circuit board, at least these steps of a through hole processing step, a step of filling a through hole with a filling material, and a step of filling a through hole with a filling material and then forming a circuit pattern by the mask are performed. After one of the steps, the means for irradiating the electronic circuit board with light, the means for irradiating the electronic circuit board with light, and the means for irradiating the light to detect an image signal measured Detecting an image signal measured by irradiating with, detecting the positional deviation amount of the through hole in each step from the image signal, and calculating the positional deviation correction amount from the detected positional deviation amount. , The positional deviation correction amount is calculated so that the positional deviation error between the electronic circuit boards formed in multiple layers is minimized, and the positional adjustment of the electronic circuit boards is performed. The means for performing, in which to perform the alignment between the electronic circuit board on the basis of the positional deviation correction amount the calculated.

In order to achieve the first object, another structure of the invention relating to the method for manufacturing an electronic circuit board of the present invention is to electrically connect the wirings on the front and back of the board by using through holes. A method of manufacturing an electronic circuit board formed by: a means for irradiating the electronic circuit board with light; a means for detecting an image signal measured by irradiating the light; and a means for calculating a positional deviation correction amount. A through-hole processing step, a step of filling a through-hole with a filling material, and a through-hole. After filling a filling material, at least one of these steps of forming a circuit pattern by the mask has been completed, and then the electronic circuit board is irradiated with light by means of irradiating the electronic circuit. The plate is irradiated with light, and the image signal measured by irradiating the light is detected by means for detecting the image signal measured by irradiating the light, and the through hole in each step is detected from the image signal. Position deviation amount and the position deviation correction amount is calculated by the means for calculating the position deviation correction amount, and the position deviation error from the design reference through hole position or the through hole position of the mask forming the through hole or pattern is detected. By calculating a positional deviation correction amount so as to minimize the positional deviation correction amount based on the calculated positional deviation correction amount by means for aligning the electronic circuit board and the mask. The position is adjusted.

In order to achieve the above first object, still another aspect of the invention relating to the method of manufacturing an electronic circuit board according to the present invention is the method of manufacturing an electronic circuit board having wiring. Means for irradiating the electronic circuit board with light when electrically connecting to the wiring of the electronic circuit board and mounting an electronic circuit component, and means for irradiating the light and detecting an image signal measured. A means for calculating a positional deviation correction amount, and means for aligning the electronic circuit board and the electronic circuit component on the basis of the positional deviation correction amount, the means for radiating light to the electronic circuit board, By irradiating the electronic circuit board on which electronic components are mounted with light, by means of irradiating the light and detecting an image signal measured,
Detecting the image signal measured by irradiating the light, from the image signal, the amount of positional deviation of the electronic circuit component is detected, by the means for calculating the amount of positional deviation correction, from the amount of positional deviation detected, The calculated position is calculated by a means for calculating the position deviation correction amount so that the position deviation error between each electronic component and the predetermined mounting position is minimized, and aligning the electronic circuit board with the electronic circuit component. The electronic circuit board and the electronic circuit components mounted on the electronic circuit board are aligned based on the deviation correction amount.

Next, in order to achieve the above second object, the structure of the invention relating to the method for manufacturing an electronic circuit board of the present invention is such that the wiring on the front and back of the board is electrically connected using the through holes. A method of manufacturing an electronic circuit board to be formed, comprising means for irradiating the electronic circuit board with light and means for detecting an image signal measured by irradiating the light. Filling the filling with
There is a step of forming a circuit pattern by the mask after filling the through hole with a filling material, and the through hole position shift amount allowable in each of the above steps is set, and at least one of these steps is performed. After passing, the electronic circuit board is irradiated with light by means of irradiating the electronic circuit board with light, and the means of irradiating with the light and detecting an image signal measured is irradiated with the light and measured. Image signal is detected, the through hole position deviation amount in each step is detected from the image signal, and the detected through hole position deviation amount is larger than the through hole position deviation amount allowable in each step. Eliminate the enlarged electronic circuit board and use only the electronic circuit board whose through hole position deviation is within the allowable range for the subsequent process. One in which the.

Next, in order to achieve the above-mentioned third and fourth objects, the structure of the invention relating to the through-hole inspection method of the present invention uses the through-holes to electrically connect the wiring on the front and back sides of the substrate. In a through hole inspection method for an electronic circuit board formed by connection, when the through hole is a through hole, a means for irradiating the electronic circuit board with light and a method for irradiating the light are measured. A means for detecting an image signal, the means for irradiating light to the electronic circuit board irradiates the electronic circuit board with light from above or obliquely above, and the means for detecting the image signal irradiates light. The image signal measured by the above is detected from above or obliquely above the point where the light is irradiated, and the threshold value V _H11 of the image signal in the normal through hole and the reference position are set in advance. The threshold value V _{H11 of the} image signal.
When the area of the detected through hole is S _H11 and the peripheral length is ₁₁ on the basis of the reference position, these areas S
_H11, perimeter l _11, based on the reference position, without through-hole defects, debris jam defect, large defects, small defects, detected in a state in which the identified defect type of the defect through hole in a state that the hole deformation defect Alternatively, the positional deviation from a normal through hole is detected.

More specifically, in the above through-hole inspection method, in the method of irradiating the electronic circuit board with light from above or obliquely above by means of irradiating the electronic circuit board with light, linearly polarized light from above or obliquely above In the state of being illuminated by the illumination light, the polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and is measured by illuminating the light by the means for detecting the image signal. The method of detecting the image signal from above or diagonally above the point where the light is irradiated is to detect from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. is there.

In order to achieve the above-mentioned third and fourth objects, another structure of the invention according to the through-hole inspection method of the present invention is to use the through-holes to electrically connect the wiring on the front and back sides of the substrate. In a method of inspecting a through hole of an electronic circuit board formed by connecting to, a means for irradiating the electronic circuit board with light and a method for irradiating the light when the through hole is filled with an electrically conductive substance. And means for irradiating the electronic circuit board with light, and means for irradiating the electronic circuit board with light from above or obliquely above to detect the image signal. , an image signal that is measured by irradiating the light detected from above or obliquely above the point at which light is irradiated, the threshold V _H1 of the image signal in advance a normal through-hole, the reference position Have been determined, the threshold V _H1 of the image signal, based on the reference position, the area of the detected through holes S _H1, when the circumferential length l, these areas S _H1, perimeter l ₁ , Based on the reference position, the bleeding defect, the defect without through hole, the foreign substance mixing defect, the scattering defect, and the defect defect in the state are detected in the identified state, or the position shift from the normal through hole is detected. Is to be detected.

More specifically, in the above through-hole inspection method, in the method of irradiating the electronic circuit board with light from above or obliquely above by means of irradiating the electronic circuit board with light, linearly polarized light from above or obliquely above In the state of being illuminated by the illumination light, the polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and is measured by illuminating the light by the means for detecting the image signal. The method of detecting the image signal from above or diagonally above the point where the light is irradiated is to detect from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. is there.

In order to achieve the above-mentioned third and fourth objects, still another structure of the invention according to the through-hole inspection method of the present invention is to use the through-holes to electrically connect the wiring on the front and back sides of the substrate. In a method for inspecting a through-hole of an electronic circuit board formed by electrically connecting the electronic circuit board with a conductive material filled in the through-hole, a means for irradiating the electronic circuit board with light and a method for irradiating the light And means for detecting the image signal measured by, by means for irradiating the electronic circuit board with light, by irradiating the electronic circuit board with light from obliquely above, by means for detecting the image signal, an image signal is measured by irradiating light detected from obliquely above the point at which light is irradiated, the threshold V _H1 of the image signal in advance a normal through-hole, the reference position is not determined Based on the threshold V _H2 of the image signal, the area of the detected through hole when the S _H2, on the basis of the area S _H2, irregular defect of the electronic circuit board, filled in the through hole The deficiency defect of the electrically conductive substance is detected.

More specifically, in the above-mentioned through-hole inspection method, in the method of irradiating the electronic circuit board with light from obliquely above by means for irradiating the electronic circuit board with light, irradiation is performed with linearly polarized illumination light from above obliquely. In this state, the polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and by the means for detecting the image signal, the image signal measured by irradiating light is displayed. The method of detecting obliquely from above the point where the light is irradiated is to detect obliquely from above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light.

Next, in order to achieve the above-mentioned third and fourth objects, the structure of the invention relating to the through-hole inspection apparatus of the present invention uses the through-holes to electrically connect the wiring on the front and back sides of the substrate. In a through-hole inspection device for an electronic circuit board formed by connection, when the through-hole is penetrated, a means for irradiating the electronic circuit board with light and a method for irradiating the light are measured. A means for detecting an image signal, the means for irradiating light to the electronic circuit board irradiates the electronic circuit board with light from above or obliquely above, and the means for detecting the image signal irradiates light. The image signal measured by the above is detected from above or obliquely above the point where the light is irradiated, and the threshold value V _H11 of the image signal in the normal through hole and the reference position are set in advance. The threshold value V _{H11 of the} image signal.
When the area of the detected through hole is S _H11 and the peripheral length is ₁₁ on the basis of the reference position, these areas S
_H11, perimeter l _11, based on the reference position, without through-hole defects, debris jam defect, large defects, small defects, detected in a state in which the identified defect type of the defect through hole in a state that the hole deformation defect Alternatively, the positional deviation from the normal through hole is detected.

More specifically, in the above-mentioned through-hole inspection apparatus, when the electronic circuit board is irradiated with light from above or obliquely above by means of irradiating the electronic circuit board with light, linear polarization from above or obliquely above is performed. In the state of being illuminated by the illumination light, the polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and is measured by illuminating the light by the means for detecting the image signal. When detecting an image signal from above or diagonally above the point where the light is irradiated, it is detected from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. is there.

Further, in order to achieve the above-mentioned third and fourth objects, another structure of the invention relating to the through-hole inspection apparatus of the present invention is such that the wiring on the front and back of the substrate is electrically connected by utilizing the through-hole. In a through-hole inspection device for an electronic circuit board formed by connecting to, a means for irradiating the electronic circuit board with light and a method for irradiating the light when the through-hole is filled with an electrically conductive substance. And means for irradiating the electronic circuit board with light, and means for irradiating the electronic circuit board with light from above or obliquely above to detect the image signal. , an image signal that is measured by irradiating the light detected from above or obliquely above the point at which light is irradiated, the threshold V _H1 of the image signal in advance a normal through-hole, the reference position Have been determined, the threshold V _H1 of the image signal, based on the reference position, the area of the detected through holes S _H1, when the circumferential length l, these areas S _H1, perimeter l ₁ , Based on the reference position, the bleeding defect, the defect without through hole, the foreign substance mixing defect, the scattering defect, and the defect defect in the state are detected in the identified state, or the position shift from the normal through hole is detected. Is detected.

More specifically, in the above-mentioned through-hole inspection apparatus, when the electronic circuit board is irradiated with light from above or obliquely above by means of irradiating the electronic circuit board with light, linear polarization from above or obliquely above is performed. In the state of being illuminated by the illumination light, the polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and is measured by illuminating the light by the means for detecting the image signal. When detecting an image signal from above or diagonally above the point where the light is irradiated, it is detected from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. is there.

Further, in order to achieve the above-mentioned third and fourth objects, still another structure of the invention according to the through-hole inspection apparatus of the present invention is to use the through-holes to electrically connect the wiring on the front and back sides of the substrate. In a through-hole inspection device for electronic circuit boards that are connected to each other, when the through holes are filled with an electrically conductive substance, a means for irradiating the electronic circuit board with light and a method for irradiating the light And means for detecting the image signal measured by, by means for irradiating the electronic circuit board with light, by irradiating the electronic circuit board with light from obliquely above, by means for detecting the image signal, an image signal is measured by irradiating light detected from obliquely above the point at which light is irradiated, the threshold V _H1 of the image signal in advance a normal through-hole, the reference position is not determined Based on the threshold V _H2 of the image signal, the area of the detected through hole when the S _H2, on the basis of the area S _H2, irregular defect of the electronic circuit board, filled in the through hole The deficiency defect of the electrically conductive substance is detected.

More specifically, in the above-mentioned through-hole inspection device, when the electronic circuit board is irradiated with light obliquely from above by means of irradiating the electronic circuit board with light, it is irradiated from above obliquely with linearly polarized illumination light. With the
The polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and the image signal detected by the means for detecting the image signal is irradiated with light. When the light is detected obliquely from above, the light having a polarization component orthogonal to the polarization direction of the linearly polarized illumination light is detected from obliquely above.

Next, in order to achieve the fifth object, the structure of the invention relating to the electronic circuit board inspection method of the present invention is the electronic circuit board inspection method for inspecting an electronic circuit board of a through hole. The electronic circuit board has means for sucking air from one surface of the electronic circuit board, the electronic circuit board is mounted on a suction holder that holds the electronic circuit board, and the sheet is placed on the surface of the electronic circuit board opposite to the suction holder. The electronic circuit board is inspected after air is sucked from one surface of the electronic circuit board.

More specifically, the sheet is a member that transmits light.

[0038]

According to the method of manufacturing an electronic circuit board according to the present invention, a through hole processing step for a printed wiring board in which a large number of through holes (through holes) or through holes filled with filler are formed, or through holes are formed. Optically detect the surface state of the through hole of the printed wiring board after either or each of the step of filling the hole with the filling material and the step of filling the through hole with the filling material and forming the circuit pattern. Then, the amount of positional deviation in each process is detected.

Then, based on the amount of the positional deviation, the positional deviation error occurs in each step of the filling and printing of the conductor paste into the through hole, the circuit pattern printing after the filling printing, and the lamination of the printed wiring board after the circuit pattern printing. The positional deviation correction amount is calculated by arithmetic processing so as to minimize the amount. Based on the calculated misregistration correction amount, the positions of the printed wiring board and the circuit pattern forming mask are aligned, or the printed wiring boards that are in close contact with each other when the printed wiring boards are stacked are aligned, and the front and back wiring is It is possible to reduce the displacement when electrically connecting.

Further, the defective printed wiring board having the positional deviation based on the calculation processing of the detected positional deviation amount and the allowable positional deviation amount of each process is eliminated, and a non-defective printed wiring board having no positional deviation defect is obtained. Since it is possible to select, it is possible to eliminate printed wiring boards that have a large defect and select only good quality printed wiring boards with no misalignment. It is possible to obtain a highly reliable electronic circuit board with a small displacement and without a pattern short circuit.

Further, according to the through hole inspection apparatus of the present invention, a straight line is formed from above or obliquely above a printed wiring board having a large number of through holes or through holes filled with a filling material. While illuminating polarized illumination light, detect the optical image of the polarization component in the direction orthogonal to the polarization direction of the linearly polarized illumination light from above or obliquely above, and respond to the normal brightness part in the through hole from that optical image. First threshold value V _H1 for image part extraction of
Based on the above, the through hole and the image portion corresponding to the vicinity of the through hole are extracted.

In this case, the position shift of the through hole can be detected by detecting the center position of the through hole by the area S _H1 in the image portion. In addition, the area S _H1 in the image portion and the perimeter l are detected in a state in which it is identified whether the defect type is a foreign matter adhesion / mixing defect, a scattering defect, a bleeding defect, or a defect without through hole. You can

Further, in the state where the linearly polarized illumination light is illuminated from above the obliquely above, the optical image of the polarization component in the direction orthogonal to the polarization direction of the linearly polarized illumination light is detected from above the obliquely upward side of the illumination light, and the Based on the second threshold value V _H2 for extracting an image portion corresponding to the wall surface portion of the through hole illuminated by the illumination light from the optical image, the through hole and the image portion corresponding to the vicinity of the through hole are extracted. Then, the lacking defect is identified by determining the presence or absence of the area S _H2 in the image portion or the magnitude relationship with the reference value of the area S _H2 ,
The defect can be detected. Then, it becomes possible to distinguish the filling state defect and the non-defective through hole without such a defect.

As described above, according to the method of manufacturing an electronic circuit board according to the present invention, in the manufacturing process of the electronic circuit board, after the through hole processing step and the through hole filling step, the circuit is formed. After the printing process of the pattern, the positional deviation of each through hole is optically inspected, and the positional adjustment of the through hole that electrically connects the front and back wiring is performed to minimize the positional deviation. Since the board is manufactured, short circuit defects of the circuit pattern due to the displacement of the through holes can be surely reduced, and the reliability and productivity of the electronic circuit board are significantly improved.

Further, according to the through hole inspection method and apparatus according to the present invention, the through hole not filled with the electrically conductive substance has no through hole defect, scrap clogging defect, large diameter defect, small diameter defect, and positional deviation. Defects and hole deformation defects can be identified and detected as non-defective through holes, and the misalignment of non-defective through holes can be detected. In addition, bleeding defects, defects without through holes, foreign substance mixing defects, scattering defects, lacking defects, and substrate irregularity defects in the filled state of through holes filled with an electrically conductive substance are detected by identifying them as non-defective through holes. The displacement of the through hole can be detected.

Further, according to the method of inspecting an electronic circuit board according to the present invention, when the atmosphere is sucked, the sheet is placed on the top of the board to hold the board flat without lowering the suction force. You can Moreover, if a transparent sheet is used, it is possible to perform an inspection using an optical method while the sheet is still placed. Of course, the inspection may be performed after removing this sheet.

[0047]

Embodiments of the present invention will be described below with reference to FIGS. 1 to 20.

[Manufacturing Process of Electronic Circuit Board] First, the manufacturing process of the electronic circuit board manufactured by the manufacturing method of the electronic circuit according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a flow chart schematically showing an example of a manufacturing process from the printed wiring board of the present invention to an electronic circuit board. FIG. 2 is a flow chart for explaining the manufacturing process shown in FIG.

In the following, the process of manufacturing a multilayer ceramic substrate from a green sheet will be taken as an example. A large number of through holes 2 of a predetermined size are formed on the green sheet 1 in a grid pattern or a zigzag pattern at intervals based on design information (p1, p2).

Next, the optical inspection device 3 detects the defect and the through hole position of the through hole machined in step p2 (p3), identifies the defect, and determines the amount of displacement of the through hole ( p4). Then, the defects that can be repaired are repaired, and the defects having too many defects or the defects that cannot be repaired are discarded. In addition, even if the amount of positional deviation is greatly deviated by an allowable value or more, it is discarded because it cannot be corrected. Of course, the corrected green sheet may be inspected again by the optical inspection device 3 to confirm that it is a non-defective product.

If it can be corrected, a correction amount that minimizes the positional displacement with the screen mask 5b is calculated from the positional displacement amount of the non-defective green sheet 4 detected by the optical inspection device 3 (p5).

The next step is to fill the through-hole 2 with the conductor paste 5a in the non-defective green sheet 4 having the through-holes formed therein (p5). That is, in this step p5, the non-defective green sheet 4 is shifted in the XY directions with respect to the screen mask 5b based on the correction amount calculated in the step p4, the conductor paste 5a is placed on the screen mask 5b, and the squeegee 5c is formed. The conductor paste 5b is moved by moving in the direction of the arrow 5A. (Note that the green sheet 4 is replaced by the screen mask 5b
As for shifting in the XY directions with respect to FIG.
Will be explained. In the green sheet 6 filled with the conductor paste, the defect and the through hole filling position of the through hole filling portion are detected by the optical inspection device 7 (p7), the defect is identified, and the displacement amount of the through hole is determined. (P8). Here again, as in the case of the above step p4, the defects that can be corrected are corrected, and the defects having too many defects or the defects that cannot be corrected are discarded. In addition, even if the amount of misalignment deviates by more than the permissible misalignment value, it is discarded as uncorrectable. The corrected green sheet may be inspected again by the optical inspection device 7 to confirm the non-defective product, as in the case described above.

If it can be corrected, a correction amount that minimizes the positional deviation from the screen mask 9b is calculated from the positional deviation amount of the non-defective green sheet 8 detected by the optical inspection device 7 (p9).

Next, the non-defective green sheet 8 in which the through holes are filled with the conductive paste 5a is printed with the circuit pattern printing machine 9 on the non-defective green sheet 8 (p10). .
That is, based on the correction amount calculated in the step p9, the non-defective green sheet 8 is set to the screen mask 9b.
After shifting in the XY directions, the circuit pattern conductor paste 9a is placed on the screen mask 9b, and the squeegee 9c is moved in the direction of arrow 9A to print the circuit pattern conductor paste 9a. (Again, the good green sheet 8
(See FIG. 4 for shifting the screen mask 9b in the XY directions) Next, in the step p10, the circuit pattern conductor paste 9 is formed.
With respect to the green sheet 10 on which a is printed, the defect and the through hole filling position of the through hole filling portion of the surface on which the circuit pattern is not printed are detected by the optical inspection device 11 (p11) to identify the defect and the through hole. The amount of positional deviation is determined (p12). Similar to the above, defects that can be repaired are repaired, and defects with too many defects or those that cannot be repaired are discarded. In addition, those in which the amount of positional deviation is largely deviated by the positional deviation allowable value or more are discarded because they cannot be corrected. Then, the corrected green sheet is inspected again by the optical inspection device 11 to confirm the non-defective product.

Next, the amount of positional deviation when the non-defective green sheet 12 whose positional deviation is within the allowable range and the non-defective green sheet 14 already laminated in front of this non-defective green sheet 12 are closely contacted with each other is determined by the optical inspection device 11. Detect with.
Then, the correction amount that minimizes the positional deviation is calculated.

Next is a step of laminating the non-defective green sheet 12 having the circuit pattern printed thereon in the next laminating step p14. That is, based on the correction amount calculated in the step p13, the non-defective green sheet 12 is shifted in the X ₁ and Y ₁ directions with respect to the laminated non-defective green sheet 14 to be laminated.

Although the above description has been made for one green sheet for ease of explanation, the same steps p1 to p15 are applied to all the green sheets which are sequentially laminated, from the formation of holes to the lamination of the green sheets. Will be carried out.

The green sheets thus laminated are sintered in the sintering furnace 15 to form the multilayer ceramics 16 (p15).

Next, in order to mount the electronic component, the optical inspection device 17 detects the position of the soldering part of the mounting part of the electronic component 18 and the connection pad, and shifts the position from the reference position when mounting the electronic component 18. From the amount, the correction amount that minimizes the positional deviation is calculated (p17).

Next, after plating or thin film is applied to the surface of the multi-layer ceramics 16, the electronic component 1 such as LSI or resistor is formed.
8 is the step of mounting (p18). That is, based on the correction amount calculated in the step p17, the electronic component 18
And the ceramic substrate 16 are relatively shifted to shift the electronic component 1
8 is mounted (p18), and I / O pins 19 are connected (p19) to complete the electronic circuit board 20 (p2).
0).

[Cause of Position Misalignment] Next, with reference to FIG. 3, details of factors causing misalignment in each step in the method of manufacturing the electronic circuit board will be described. FIG.
FIG. 3 is a plan view of the green sheet 1 having a through hole 2 formed therein. That is, in the example shown in FIG. 3, the through holes 2 are drilled at the grid-like grid points 21 of the grid.

The through-holes 2 formed in the green sheet 1 of FIG. 3 are continuously drilled by a punch or an EB processing machine based on the design information of the circuit board. At present, the diameter is several 10 μm to several 100 μm. □ Tens of thousands per 100 mm
Several hundreds of thousands of holes have been commercialized. These through holes 2 are misaligned due to mechanical errors such as feed accuracy of the hole drilling machine and shape deformation due to wear of the punch and punch. Further, it is conceivable that the green sheet 1 may be displaced due to deformation of the green sheet 1 during drilling due to a partial change in mechanical strength of the printed circuit board represented by the green sheet 1.

When the through-holes 2 are filled with conductors, the through-holes 5d of the screen mask 5b manufactured based on the design information of the circuit board will be shown later in FIG.
1 and the through hole 4a of the green sheet 4 are aligned so as to face each other, and as shown in FIG. 1, the conductive paste 5a is filled with the squeegee 5c while rubbing it on the screen mask 5b. At the time of this filling, the green sheet 4 is deformed by being stretched by the pressure of the squeegee 5b, and the expansion and contraction due to the change of mechanical stress inside the green sheet due to the filling of the conductors in the through holes. It is conceivable that the filled portion of the hole 4a may be displaced from the reference position.

In addition to this, even after the conductor is filled in the through hole, the green sheet 8 is pressed by the pressure of the squeegee 9c when the circuit pattern is printed, as in the case of filling the through hole.
May be deformed, and because the circuit pattern is printed on one side of the green sheet 8, the pattern density may be different between the front and back sides, and it is considered that the filled portion of the through hole is further displaced.

After stacking the green sheets, the solvent in the green sheets is vaporized during sintering, or the temperature is controlled at a high temperature of several hundreds of degrees or more to secure adhesion strength, and heating or cooling is performed. . Therefore, since the multilayer ceramic substrate 16 after sintering is thermally deformed by heating or cooling,
It is difficult for the dimensions to be as designed. In particular, in the case of the multilayer ceramic substrate 16, since the composition material is a substrate material such as alumina, mullite, cordierite, or magnesia, a conductor material such as tungsten, molybdenum, copper, or silver is mixed, and a solvent or the like is mixed. The coefficient of thermal expansion is not uniquely determined, and the amount of deformation differs for each ceramic to be sintered,
It is considered that the positions of the soldering portions and the connection pads for mounting and connecting the electronic component 18 also differ from the design position.

[Alignment in the Method for Manufacturing the Electronic Circuit Board] Next, regarding the method for manufacturing the electronic circuit board according to the present invention, focusing on the position adjustment by correcting the positional deviation described above, This will be described with reference to FIGS. (I) Position Correction in Conductor Paste Filling Step First, the position correcting step p5 in the conductor paste filling step shown in FIGS. 1 and 2 will be described. FIG.
It is a perspective view which shows typically the mode that the screen mask 5b and the green sheet 4 are aligned.

What will be described here is the alignment in the case where the conductor filling printing machine 5 fills the through-hole 2 with the conductor paste 5a after detecting the positional deviation by the optical inspection device 3.

Positioning reference marks 5e _{1 to} 5e ₄ are provided on the screen mask 5b. In addition, similarly to the green sheet 4, a positioning reference mark (for example,
Through-hole) 4e ₁ ~4e ₄ is provided. When aligning the screen mask 5b with the green sheet 4, these positioning reference marks 4e _{1 to} 4e ₄ , 5 are used.
with e ₁ ~5e _4, for example, by a method as disclosed in JP-A 2-42513, JP-aligning the reference position comrades screen mask 5b and the green sheet 4. After this alignment, the reference position of the green sheet 4 (reference marks 4e _1-
The relative shift amount between the screen mask 5b and the green sheet 4 is obtained based on the positional shift amount of the through hole 4a from (detecting 4e ₄ ).

Now, in the positional deviation correction method outlined above with reference to FIG. 5, a method for specifically obtaining the correction amount will be described. FIG. 5 is a graph showing the relationship between the positional deviation amount of the through hole in the X direction and the occurrence frequency (in the conductor paste filling step), wherein the horizontal axis represents the positional deviation amount in the X direction and the vertical axis represents the frequency. .

By obtaining the center of the distribution from the position shift amount of the through hole of the green sheet obtained by the optical inspection device 3 and the frequency distribution according to the frequency shown in FIG. 5, the optimum position shift correction amount is obtained as follows. You can ask.

That is, the center X ₀ c of the distribution shown in FIG.
Is, for example, the positioning reference mark 5e _{1 on the} screen 5b.
A reference position determined from ~5e _4. The positional deviation distributions for three types of green sheets are U ₀ ,
We will refer to them as U ₂ and U ₃ .

[0072] In this, the green sheet of the distribution U ₀ is the center of the distribution U ₀ a substantially same as the X ₀ c, shows a case where the positional deviation is very small. Further, green sheets of distribution U _2, when the positional shift of the center X ₂ c distribution U ₂ is generated X _2, distribution U ₃ of the green sheet is positional deviation of the center X ₃ c distributions U ₃ is X ₃ The case where it has occurred is shown.
In this way, the central value of the distribution is obtained, and the difference between it and the reference position is used as the correction amount. In principle, the Y direction can also be obtained in the same manner.

Then, when the green sheet having the distribution U ₂ is filled with the conductor paste, the correction amounts X ₂ and Y ₂ (the correction amounts similarly obtained in the Y direction) thus obtained are used for the screen. The mask 5b and the green sheet 4 are relatively shifted and filled.

Further, although the present description has explained the method of statistically processing the detected position shift amount of the through hole to calculate the position shift correction amount, other methods may be used as the position shift correction amount calculation method.

For example, another method for calculating the positional deviation correction amount will be described with reference to FIG. 5. When the maximum deviation amount in the + X direction of the green sheet of the distribution U ₂ is XR and the maximum deviation amount in the −X direction is XL. , X-direction correction amount Xm,

[0076]

## EQU1 ## Xm = {XR + (-XL)} / 2 (1) The arithmetic mean of the two is calculated to obtain the correction amount Xm, -X.
The position may be corrected by shifting in the direction.

In the above description, the correction of the shift amount with respect to the reference position X ₀ c has been described, but in another possible method, the through holes which are opposed to each other are
The maximum displacement amount may be obtained from the respective displacement amounts, the correction amount may be determined by the same calculation as described above, and the overall correction amount may be determined based on this to perform the positional displacement correction.

(II) Position Correction in Circuit Pattern Printing Process In the above description, the position correction when the conductor is filled in the through hole is described. However, the position correction when the circuit pattern is printed after the conductor is filled in the through hole. Also in step p9, it is possible to perform positional deviation correction and print by the same method.

(III) Position Correction in Laminating Process Next, the position correcting process p13 in the laminating process will be described with reference to FIGS. 6 and 7. Figure 6 is a view of the middle of laminating a green sheet from the side, the n + 1 th layer green sheet GV ₂ on the green sheet GV ₁ of n th layer, also on the (n + 1) th layer green sheet GV ₂ Shows that the n + 2nd layer green sheet GV ₃ is laminated. FIG. 7 is a graph showing the relationship between the position shift amount of the through hole in the X direction and the occurrence frequency (in the stacking process), where the horizontal axis shows the position shift amount in the X direction and the vertical axis shows the frequency.

By obtaining the center of the distribution from the position shift amount of the through hole of the green sheet obtained by the optical inspection device 3 and the frequency distribution according to the frequency shown in FIG. 5, the optimum position shift correction amount is obtained as follows. You can ask.

By obtaining the center of the distribution from the position shift amount of the green sheets GV ₁ , GV ₂ and GV ₃ obtained by the optical inspection device 11 and the frequency distribution depending on the frequency, the position shift correction amount is obtained as follows. You can

[0082] That is, the green sheet GV ₁ misalignment around the V ₁ c of distribution V _1, green sheets GV ₂ misalignment the center of the distribution V ₂ V ₂ c, green sheets GV ₃
The center of the positional deviation distribution V ₃ of V ₃ is set to V ₃ c. When stacking the green sheet GV ₂ on the green sheet GV ₁ ,
In the same way as described in the explanation of (I) above, V ₁ c and V ₁
Seeking difference Vx ₂ of ₂ c, laminating relatively shifted by a corresponding amount. Further, when stacking the green sheets GV ₃ on the green sheet GV ₂ is, V ₂ c and V ₃ difference c Vx ₃
Then, the layers are relatively shifted by that amount and stacked. Although the above has described the X ₁ direction of the laminating step 13, it is a matter of course that the Y ₁ direction can be laminated by performing the positional deviation correction in the same manner.

Also in this embodiment, the positional deviation correction method based on the statistical processing based on the graph of FIG. 7 has been described, but the maximum deviation amount is calculated from the respective deviation amounts of the through-holes facing each other. Then, the correction amount can be obtained by the same calculation as the above equation (1), and the entire correction amount can be obtained, as in the case of (I).

(IV) Position correction in circuit component mounting process Finally, position correction process in circuit component mounting process p17
Let me explain.

The multilayer ceramic substrate 16 has an electronic component 1
In order to mount No. 8, an LSI connection pattern 605 as shown in FIG. 21 is formed. This LSI connection pattern 605 is detected by the optical inspection device 17, and the above (I)
In the same manner as in the cases of (III) to (III), the positional deviation correction amount from the reference position is obtained, and the electronic component 18 is corrected by the above correction amount and mounted on the multilayer ceramic substrate. The misregistration correction amount at this time is calculated in a range corresponding to each area of each electronic component 18a to 18i, and each electronic component 18 is calculated.
a to 18i may be independently corrected and mounted.

Further, this correction method is also described in (I) above.
In the same manner as in the case of (III) to (III), the positional deviation correction method by the statistical processing or the through holes individually facing each other and the connection positions of the respective electronic components are the same as the above, respectively It is also possible to obtain the maximum displacement amount from the displacement amount of each of the connection position of the electronic component or the through hole and the design position, and obtain the correction amount by the same calculation as the above equation (1) to obtain the overall correction amount. .

In this description, the method for correcting the positional deviation of the green sheet used for the multilayer ceramic substrate has been described, but this positioning method can be applied to the multilayer printed circuit board using copper foil or the like as the base material. it can.

[Inspection Method of Electronic Circuit Board] (I) Theoretical Background First, the theoretical background of the inspection method of the electronic circuit board according to the present invention will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic diagram of an image detection method comparing the case of polarization illumination / polarization detection (including epi-illumination and ring-shaped illumination) from above and the case of oblique polarization illumination / polarization detection, and a schematic diagram of the image detection method. It is the figure which put together the signal diagram and the cross-sectional view of a board | substrate in tabular form.
FIG. 9 compares the case where the through holes are filled and the case where the through holes are not filled, and divides the polarized illumination from above and the oblique polarized illumination from one side into the lines of the image signal. It is the figure which put together the figure and the projection view of the through hole by a binary image in the tabular form in order to explain the gap between the signal and the projection view.

First, the state of defect detection and optical characteristics in the case of polarization illumination / polarization detection (including epi-illumination and ring-shaped illumination) from above (left side in FIG. 8) will be described. The light flux from the point light source 201 is converted into a parallel light flux by a condenser lens (not shown). After that, the light passes through the polarizing plate 202 to become linearly polarized illumination light. Then, the linearly polarized illumination light is transmitted to the half mirror 20.
3 is reflected by the circuit board 20 through the objective lens 204.
5 is illuminated with linearly polarized light.

At this time, since the illumination light is diffusely reflected on the circuit board 205 composed of fine particles, the polarization direction of the reflected light is uniformly disturbed even though it is linearly polarized by the polarizing plate 202. Has become. However, since the reflection of the illumination light from the surface of the metal fine particles filled as the filler 205A in the through hole is specular reflection, the polarization direction of the reflected light is the same as the polarization direction of the polarizing plate 202. .

Therefore, when the polarizing plate 206 is arranged so that its polarization direction is orthogonal to that of the polarizing plate 202 on the illumination system side, and the image is detected by the sensor 207 through the objective lens 204, the surface of the metal fine particles is detected. Since most of the reflected light from is blocked by the polarizing plate 206, the filler 205A is detected as dark in the detected image. on the one hand,
Since the reflected light from the circuit board 205 passes through the polarizing plate 206 almost as it is, the circuit board 205 itself is detected as whitish.

That is, the light and dark represented by the image signal 208A detected by the sensor 207 makes the circuit board 205 bright and the filling 205A dark. This filling 205A
At the boundary points a ₁ and b _{1 of the} circuit board 205 and the circuit board 205, the volume of the circuit board 205 that contributes to diffuse reflection is smaller than that at the points a ₂ and b ₂ , so the amount of irregularly reflected light detected is small, and The lightness represented by the signals 208Aa ₁ and 208Bb ₁ is reduced.

Also, through holes in the circuit board (through holes)
As for the image signal 208B of 205B, the image signal corresponding to the circuit board 205 becomes bright and becomes dark because no light is reflected from the through hole 205B. At the boundary points c ₁ and d ₁ between the through hole (through hole) 205B and the circuit board 205, the volume diffusely reflected by the circuit board 205 is smaller than that at the points c ₂ and d ₂ as described above, and therefore it is detected. The amount of irregularly reflected light is reduced, and the image signal 208B
As in the above, the brightness represented by c ₁ and 208Bd ₁ is reduced.

Next, the state of defect detection and the optical characteristics in the case of oblique polarization illumination / polarization detection (right side of FIG. 8) will be described. The light flux from the point light source 211 is converted into a parallel light flux by a condenser lens (not shown). After that, the light passes through the polarizing plate 202 to become linearly polarized illumination light. The linearly polarized illumination light illuminates the circuit board 215 with linearly polarized light. At that time, since the illumination light is diffusely reflected on the circuit board 215 composed of fine particles, the polarization direction of the reflected light is uniformly disturbed even though it is linearly polarized by the polarizing plate 212. There is. However, since the reflection of the illumination light from the surface of the metal fine particles filled as the filler 215A in the through hole is specular reflection, the polarization direction of the reflected light is the same as the polarization direction of the polarizing plate 212.

Therefore, when the polarizing plate 216 is arranged so that its polarization direction is orthogonal to that of the polarizing plate 212 on the illumination system side, and the image is detected by the sensor 217 through the objective lens 214, the surface of the metal fine particles is detected. Since most of the reflected light is blocked by the polarizing plate 216, the filler 215A is detected as dark in the detected image. On the other hand, since the reflected light from the circuit board 215 passes through the polarizing plate 216 almost as it is, the circuit board 215 itself is detected as whitish.

That is, the light and dark indicated by the image signal 218A detected by the sensor 217 makes the circuit board 215 bright and the filling 215A dark.

This is because the filler 215A and the circuit board 2 are
Since the boundary of 15 is illuminated obliquely, e ₁ point, e
Circuit board 215 that contributes to diffuse reflection at ₂ points and a ₁ point
Let V (e ₁ ), V (e ₂ ), V (a ₁ ) be the volume of

[0098]

Since V (e ₂ )> V (e ₁ )> V (a ₁ ) ... (2), the amount of reflected light at the point e ₁ is larger than the amount of reflected light at the point a ₁ , and _As compared with the case where the illumination light from above is detected at _one point, the point e ₁ which detects the illumination light from an oblique direction is brighter.

The volume of the circuit board 215 contributing to the diffuse reflection at the points f ₁ , f ₂ , and b ₁ is V (f ₁ ), V
(F ₂ ) and V (b ₁ )

[0100]

Since V (f ₁ ) <V (b ₁ ) <V (f ₂ ) ... (3), the amount of reflected light at the point f ₁ is smaller than the amount of reflected light at the point b ₁ . As compared with the case where the illumination light from above is detected at the point b _1, it is detected darker at the point f ₁ where the illumination light from the oblique direction is detected.

Therefore, in the polarized illumination / polarization detection from an oblique direction, the detected image has a feature of moving to the illumination side as compared with the polarized illumination / polarization detection (image signal of dotted line) from above.

As described in the explanation of the polarized illumination / deflection detection from above, the through hole 2 of the circuit board is formed.
Brightness and darkness represented by the image signal 218B of 15B is darker than that of the circuit board 215 because light is not reflected from the through hole 215B. Through hole (through hole) 21
Since the boundary portion between 5B and the circuit board 215 is obliquely illuminated, the illumination light is applied to the corner of the through hole at the point g ₁ , and a strong specular reflection light component is detected in addition to the diffuse reflection light. It Therefore, the image signal at point g ₁ is 218B
is as g _1, brightness in g ₁ points, the circuit board 215
It becomes brighter than the point g ₂ .

On the other hand, at the point h _{1, the} point d ₁ is detected darker than when the illumination light from above at the point b _{1 of the} circuit board 205 is detected, and the brightness of h ₁ <the brightness of d ₁ <h ₂ It becomes the brightness of. For this reason, even when the through-hole image is obliquely polarized and illuminated and polarized light is detected, the detected image has a feature of moving to the illumination side as compared with polarized illumination and polarized light detection from above (dotted line image signal).

That is, as shown in FIG. 9, in the case of polarization illumination / polarization detection from an oblique direction, polarization illumination / absorption from above is performed.
Compared to polarization detection, the center of the detected through-hole image is XL ₁ minutes when the through-hole is filled with the conductor paste, and when the through-hole is not filled with the conductor paste (through through-hole). , XL ₂ minutes, move to the lighting side. In the experiment by the inventor, when a through hole having a diameter of 60 μm is detected with a detection pixel size of 4 μm, X
L ₁ was about 4 μm and XL ₂ was about 2 μm. (II) Details of Through Hole Defect Detection Method The through hole defect detection method used in the electronic circuit board inspection method of the present invention will be described below in consideration of the theoretical background of the above optical considerations.

(II-1) Upper Polarized Illumination / Polarization Detection First, a through-hole defect detection method in the case of upward polarized illumination / polarization detection will be described with reference to FIGS. FIG. 10 is a perspective view of a main part of an optical inspection device in the case of upward polarized illumination / polarized light detection and a list of defects detected by the optical inspection device. FIG. 11 shows a filling state, an image signal, a binary image, a judgment example of a through hole filled with a conductor paste in the case of a normal case and each defective case in the case of upward polarized illumination / polarization detection. ,
It is a schematic diagram which enabled comparison in tabular form. 12
Can compare the filling state, the image signal, the binary image, and the judgment example of the state of the through-hole in the case of normal polarization and the case of each defect in the case of upward polarized illumination / polarization detection. FIG.

In the defect detection of the electronic circuit board according to the present invention, as shown in FIG. 10, when the through hole is filled with the conductive paste, scattering and foreign matters are considered to occur as a defect case of the filled state of the through hole. Mixing, bleeding, no through holes, misalignment. Also,
In the case of a through hole that penetrates, defects that occur in the state of the through hole include no through hole, jamming, large diameter, small diameter, hole deformation, and misalignment. The present invention recognizes each of these cases and identifies the defect.

In the following, referring to FIG. 11, first, a method of detecting defects in the case of through holes filled with a conductor paste will be described.
Let me explain each case separately.

When the filling state of the paste is normal, in the binary image obtained by binarizing the detected image signal with the threshold value V _H1 , the area S _H1 of the image portion corresponding to the filling is (That is, the area of the portion corresponding to the image signal smaller than the threshold value V _H1 ) and S _H1 ≈S ₁₀ (S ₁₀ : reference value). Further, if S _H1 / (l) ² is obtained from the area S _H1 and the perimeter l, S _H1 / (l) ² ≈ 1 / 4π (about
0.0796). Further, when the center of the area S _H1 is obtained, when the center position is in the normal position, the distances XL ≈ XL ₀ and YL ≈ YL ₀ from the reference center position are obtained.

When the filling state of the paste is defective, the area of the image portion corresponding to the filling material in the normal case and the center position thereof are different. Hereinafter, this will be described for each defective case.

Regarding the bleeding defect, in the binary image obtained by binarizing the detected image signal with the threshold value V _H1 , the area S _H1 of the image portion corresponding to the filling is S _H1 > S
It becomes _H10 ( _SH10 : reference value).

Regarding the defect having no through hole in which the through hole is not processed in the through hole forming step,
The area S _H1 ≈0 of the image portion corresponding to this filling.

When a foreign substance adheres to or is mixed in the filling material, the circular shape as the outer shape collapses as compared with the normal filling state, and the area S _H1 is smaller than that in the normal case, and
Since the perimeter l increases, S _H1 / (l) ² becomes
S _H1 / (l) ² <1 / 4π.

Even in the scattered state, the circular shape as the outer shape is broken due to the scattered filler, and the area S _H1
And the perimeter l is S _H1 / (l) ² <1 / 4π. Further, regarding the positional deviation, XL> XL ₀ and YL> YL ₀ are obtained at the center of the binary image obtained by binarizing the detected image signal with the threshold value V _H1 .

In the defect detecting method of the electronic circuit board of the present invention, when the upper polarized illumination / polarized light is detected, the through hole filled with the conductor paste is, as described above,
By analyzing the area, perimeter, and center position in the image area corresponding to the filler in each case of bleeding defects, defects without through holes, foreign substance adhesion / mixing defects and scattering defects, and misalignment defects, it is possible to ensure that defects. It is intended to detect a defect in the through hole in a state where the case is identified.

Next, with reference to FIG. 12, a method of detecting a defect in the case of a through hole penetrating through will be described separately for each case.

When the through hole shape is normal,
In the binary image obtained by binarizing the detected image signal with the threshold value V _H11 , the area S _H11 of the image portion corresponding to the through hole is S _{H11 ≈S 110} (S ₁₁₀ : reference value). It is a thing. Also, the area S _{H 11} and the perimeter L ₁₁ to S
_H11 / by obtaining a (l ₁₁₎ ^2, in the case of generally circular normal filling conditions outer _{shape, S H11 / (l 11)} 2 ≒ 1 / 4π
(About 0.0796). Further, if the center of the area S _H11 is obtained, when the center position is in the normal position, the distance from the reference center position XL ₁₁ ≈XL ₁₁₀ , YL ₁₁ ≈YL ₁₁₀
Becomes

If there is a defect in the through hole shape,
The area of the image portion corresponding to the through hole in the above normal case and the center position thereof are different. Hereinafter, this will be described for each defective case.

Regarding the defect having no through hole in which the through hole is not processed in the through hole forming step,
S _{H11 ≈0} . A large-diameter defect, that is, a defect larger than the diameter of a normal through hole, is obtained by binarizing the detected image signal with a threshold value V _H11.
In the value image, the area S _H11 of the image portion corresponding to the through hole is S _H11 > S _H110 (S _H110 : reference value).
For small-diameter defects, that is, for defects that are smaller than the diameter of a normal through hole, the area S _H11 of the image portion corresponding to the through hole is S _H11 <S _H110 (S _H110 : reference value)
Becomes

When the through-hole is jammed, the area S _H11 of the image portion corresponding to the through-hole becomes S _H11 <S _H110 (S _H110 : reference value) as compared with the normal filling state. Further, the circular shape of the through hole as the outer shape is broken, and the area S of the image portion corresponding to the through hole is reduced.
_H11 is reduced, and, since the circumferential length l ₁₁ is _{increased, S H11 / (l 11)} 2 becomes ^{_{S H11 / (l 11) 2}} <1 / 4π.

Also in the case of hole deformation, the circular shape collapses, and the relationship between the area S _H11 and the peripheral length l ₁₁ is S _H11 / (l
₁₁ ) ² <1 / 4π.

Further, regarding the positional deviation, XL ₁₁ > XL ₁₁₀ , YL ₁₁ > YL at the center of the binary image obtained by binarizing the detected image signal with the threshold value V _H11.
It becomes ₁₁₀ .

According to the defect detection method of the electronic circuit board of the present invention, when the upper polarization illumination / polarization detection is performed, as described above, the through hole penetrated does not have a through hole defect, a scrap jam defect, a large defect. By analyzing the area of the image portion corresponding to the through hole in each case of the diameter defect, the small diameter defect, the hole deformation defect, and the position shift defect, the perimeter and the center position, the defect case is surely identified,
It is intended to detect defects in through holes.

In summary of the above two cases, according to the defect detection method of the electronic circuit board of the present invention, when the upper polarized illumination / polarized light is detected, when the through hole is filled with the conductor paste, It is possible to identify and detect defects such as scattering, contamination with foreign matter, bleeding, no through hole, and misalignment when the filling status of the hole is different. There are no through holes,
It is possible to identify and detect defects such as dust clogging, large diameter, small diameter, hole deformation, and positional deviation.

(II-2) Case of Oblique Polarization Illumination / Polarization Detection Next, a through-hole defect detection method in the case of oblique polarization illumination / polarization detection will be described with reference to FIGS. 13 to 16. FIG. 13 is a perspective view of a main part of an optical inspection device in the case of orthorhombic polarization illumination / polarized light detection and a view listing defects detected by the optical inspection device. FIG. 14 shows a filling state, an image signal, a binary image, and a judgment example of a through-hole filled with a conductor paste in the case of orthorhombic polarization illumination / polarization detection, in which the normal case and the unevenness of the substrate are insufficient. FIG. 9 is a schematic diagram that allows comparison in tabular form at times. Figure 15 shows
When oblique polarization illumination / polarization detection is performed, the filling state, the image signal, the state of the through hole filled with the conductor paste,
FIG. 6 is a schematic diagram that enables comparison of a value image and a determination example in a tabular format between a normal case and each defective case. FIG. 16 is a table format showing the filling state, the image signal, the binary image, and the judgment example of the through-hole state in the case of the normal case and each of the defective cases when the oblique polarization illumination / polarization detection is performed. It is a schematic diagram made possible to compare by.

First, the operation of the optical inspection apparatus in the case of obliquely polarized illumination / polarization detection in this example will be briefly described with reference to FIG. As shown in FIG. 13, on the circuit board 215, the point light source 211a and the polarizing plate 21 are provided.
The image on the circuit board 215, which is illuminated by the linearly polarized illumination light at 2a, is directly detected by the sensor 217b arranged on the illumination light emission side through the objective lens 216b. This image is also detected by the illumination light sensor 217a via the objective lens 216a.

Furthermore, a point light source 211a and a polarizing plate 212a
Also, the point light source 212b and the polarizing plate 212b are similarly illuminated by the linearly polarized illumination light from the opposite directions of the direction illuminated by the linearly polarized illumination light.
The image on the image No. 5 is directly detected via the objective lens 216c by the sensor 217c arranged on the illumination light emission side.

As shown in FIG. 13, the characteristics of the defect detection method by this oblique polarization illumination / polarization detection method are as follows.
In addition to the defects that can be detected by the above-mentioned upward polarized illumination / polarized light detection method, it is possible to detect deficiency defects and substrate unevenness defects.

This will be described below with reference to FIG. FIG. 14 shows polarized oblique illumination from the two opposite directions according to the present invention when the filling state into the through hole is the normal state, the insufficient state, and the substrate uneven state, respectively.
The orthorhombic detection and its determination example are shown together with the detected image signal and the binary image. That is, in FIG. 13, the image is illuminated from the diagonal direction and the image represented by the diagonal direction is detected by the sensor 2
17b and the sensor 217c.

In the case of polarization oblique illumination / oblique detection,
Since the illumination light is specularly reflected on the wall surface of the through hole and the slope of the uneven part of the substrate related to the insufficient defect, the image at that portion is detected brighter than the substrate surface on which the illumination light is diffusely reflected, and a high level It is obtained as a signal. Therefore, a portion where the image signal is higher than the second threshold value V _H2 for extracting the image portion corresponding to the slope of the through hole wall surface portion and the uneven portion of the substrate where the illumination light is irradiated is detected, and the detected signal is detected. _Obtain the area S _H2 of the corresponding area (when the area is divided into two or more areas, the sum of the areas), the presence or absence of such an area, or the magnitude relationship with the reference value (a sufficiently small positive value) S _H20 of the area S _H2. By making the determination, it is possible to detect whether the defect type is a defect defect or a substrate unevenness defect in an identified state.

On the other hand, the optical principle and the detection method for detecting the defect of the substrate from above by the deflection illumination from the oblique direction are as follows. For the through-hole defect filled with the conductor paste, FIG. In the case of the through hole, as shown in FIG. 16, it is basically the same as the upward deflection illumination / deflection detection of (II-1). (FIG. 15 corresponds to FIG. 11 and FIG. 16 corresponds to FIG. 12, and their reference numerals are changed.) Furthermore, in this example of oblique polarization illumination / polarization detection, (I ) As described in the theoretical background, the center position of the through hole of the detected image shifts toward the illumination side from the center position of the through hole of the image detected by the upward polarization illumination / polarization. Therefore, when the positional deviation of the through hole is detected in the present invention, as shown in FIG. 9, for example, the positional deviation is corrected by correcting only the shift amounts XL ₁ (with filling) and YL ₁ (without filling). By determining the amount, the displacement of the through hole can be detected with high accuracy and reliability.

Further, in this embodiment, by obliquely illuminating the polarized light and detecting the obliquely polarized light from the two opposite directions, a partially missing defect as shown in FIG. 14 can be detected with high sensitivity. It is possible to detect dents and protrusion defects on the surface of the green sheet of the substrate with high sensitivity, but it is clear that the detection sensitivity can be improved by further increasing the oblique polarization illumination and the oblique polarization detection direction. . That is,
By additionally adding two directions to the detection direction of FIG. 14 and detecting from four directions, it is possible to detect a defect, which is slightly insufficient in the direction perpendicular to the paper surface of FIG. 14, with high sensitivity. it can. As another embodiment, even if the base material is rotated by an appropriate angle about the optical axis 219 of FIG. 13 and detected, a slightly insufficient defect can be detected with high sensitivity as described above. it can.

(III) Method of Holding Penetrating Through-Hole Substrate Flat and Inspecting Next, an example of a method of holding a penetrating through-hole substrate flat and inspecting it will be described with reference to FIG. To do. FIG. 20 is a cross-sectional view of the green sheet and the suction holder, showing the conditions for flattening the green sheet having the through holes penetrating therethrough.

In order to detect the positional deviation and the defect of the green sheet described above with high accuracy, it is necessary to make the surface of the green sheet flat and inspect it. As a method of holding the green sheet for this purpose, for example, there is a method disclosed in Japanese Patent Laid-Open No. 22850/1992.

As an example of the suction holder 361 shown in FIG. 20, a porous ceramic 361a is surrounded by a dense ceramic 361b and sintered to form a suction surface 361c.
This is what was polished and finished.

In short, this method is to suck the green sheet 301 by sucking the suction hole 361d provided in the porous ceramic 361a to flatten it.

Here, in the method disclosed in Japanese Patent Laid-Open No. 4-22850, when the through hole of the green sheet 301a is filled with the filling material, it can be made flat, but the through hole penetrates. In that case, since the atmosphere is released from here, there is a concern that the suction force may be reduced and the surface may not be flat as shown in FIG.

In such a case, as shown in FIG. 20B, when the transparent sheet 363 is placed on the surface 301b of the green sheet 301a and adsorbed, the atmosphere flowing from the through hole is cut off, and the green sheet 301 is cut off.
a is held following the suction surface 361c.

Then, even when the transparent sheet 363 is placed and the inspection is carried out by the method shown in FIGS. 10, 13 and 17, a high contrast image can be obtained. That is, in the through-hole inspection method described so far, the transparent sheet 363 is placed on the green sheet 363 for deflection illumination / deflection detection when the step of flattening the green sheet of FIG. 20B is performed. Even as it is, there is an advantage that the reflected light from the surface of the transparent sheet can be reduced and an image from the surface of the green sheet can be detected with high contrast.

After the surface 301b of the green sheet 301a becomes flat as shown in FIG. 20 (b), the transparent sheet 363 may be removed as shown in FIG. 20 (c) for inspection.

In this way, the green sheet 301a
Green sheet portion 30 other than the through through holes 362 of
Since 1b is suction-held on the suction surface 361c, the surface b of the green sheet 301a can be kept flat.

When the inspection is performed after removing the overlaid sheet, it is not particularly necessary to use a transparent sheet which can transmit light, and the member used for the sheet simply passes air for enhancing the suction force by the atmosphere. Any substance that is difficult to use will do.

[Through Hole Inspection Apparatus] (I) Outline of Structure and Operation of Through Hole Inspection Apparatus First, the outline of the structure and operation of the through hole inspection apparatus according to the present invention will be described. A description will be given using 17. Here, for convenience of description, the case of orthorhombic polarization illumination / detection will be described. For upward polarized illumination and detection,
It can be realized in substantially the same manner except that the optical principle is different and the defect identification method is that shown in FIGS. FIG. 17 is a block diagram schematically showing the structure and operation of the through-hole inspection device according to the present invention and their relations, and is an enlarged view of an optical part in particular.

As shown in FIG. 17, the stage base 30
The X stage 303 is mounted on the second stage 2, and the Y stage 304 is mounted on the X stage 303.
The XY stage is configured to be independently movable in the Y direction. A circuit board 301 to be inspected is positioned and mounted on the Y stage 304, and the X stage 303 and the Y stage 304 are respectively an X-axis drive unit 305 and a Y-axis drive unit 306 as external drive devices. By being driven by, it is moved in the X and Y directions, respectively.

The circuit board 1 is moved by this movement in the X and Y directions.
The inspection position above can be moved in the X and Y directions, but in order to actually measure the inspection position, the X stage 3
The amount of movement in each of 03 and Y stage 304 is measured by an X-axis length measuring device 307 and a Y-axis length measuring device 308, respectively.

The inspection position on the circuit board 1 is a linearly polarized light source (point light source 310a and condenser lens 3).
11a) and a polarizing plate 314 generated from 309a.
Illuminated obliquely by the linearly polarized illumination light via a. The image at the inspection position is detected by the line sensor 313a from the vertically upper side through the polarizing plate 315a and the objective lens 312a. At that time, the polarization plate 315a is provided so that the polarization direction is orthogonal to the polarization plate 314a, while the plane formed by the optical axes of the illumination system and the image detection system is set to be perpendicular to the detection target surface. At the same time, the image detection area of the line sensor 313a is also set to be perpendicular to the plane. Further, the image at the inspection position is also detected by the line sensor 313b obliquely above the linearly polarized light source 309a, via the polarizing plate 315a and the objective lens 312b.

On the other hand, the portion parallel to the detection area of the line sensor 313b and separated by the distance D is from the direction opposite to that of the linear polarization parallel light source 309a.
It is illuminated from an oblique direction. And the light source 309
The image is detected by the line sensor 313c via the polarizing plate 315c and the objective lens 312c diagonally above the b side.

Therefore, in the above configuration, if the circuit board 1 is horizontally moved in a direction that is not parallel to the detection longitudinal direction of the line sensors 313a, 313b, 313c, the image signals from the line sensors 313a, 313b, 313c are imaged. A in each of the detection circuits 316, 317, 318
It can be obtained as a multi-valued image signal by the / D conversion process.

Then, a shading correction circuit (for example, a circuit similar to that disclosed in Japanese Patent Laid-Open No. 58-153328) 319, 320, 321 is used for uneven illumination, and line sensors 313a, 313b, 313c respectively. After the sensitivity unevenness is digitally corrected, the binarization circuit 32
2, 323, 324 and the histogram creating circuit 32
5, 326, 327.

In the case of orthorhombic polarization illumination / polarization detection, the threshold value V _H21 shown in FIG. 15 in the histogram creating circuit 325, and the threshold value V H in FIG. 14 in the histogram creating circuits 326 and 327, respectively. The frequency distribution of the actually detected image signal levels is calculated so that _H2 can be obtained optimally. Then, the calculation result is subjected to predetermined arithmetic processing by the microcomputer 328 as the overall control arithmetic processing unit, and finally, the optimum threshold values V _H21 , V _H21 , V
You can get _H2 .

A two-dimensional binarized image signal is obtained by binarizing the multi-valued image signal in the binarization circuits 322, 323 and 324 based on each of these threshold values V _H21 and V _H2. You can Of these, the two-dimensional binarized image signal from the binarization circuit 322 is subjected to predetermined processing as described below by the contour extraction circuit 329, the projection distribution creation circuit 330, and the coordinate addition circuit 336.

First, in the contour extraction circuit 329, two-dimensional 2
Pixels forming the outline of the filling material in the through hole are extracted from the binarized image signal, and the extracted pixels are sequentially aggregated by the perimeter calculation circuit 335, and the final aggregated value is the outline. The total perimeter of is calculated. Also, the projection distribution creation circuit 3
At 30, the two-dimensional binarized image signal is projected in the X direction or the Y direction to create a projection distribution. Based on the projection distribution, the area calculation circuit 332 determines the pixels of the image corresponding to the filling material. The numbers are tabulated and the total area of the image corresponding to the filling is calculated. In the coordinate addition circuit 336, the coordinate values of each of X and Y of the pixels forming the image corresponding to the filling based on the coordinate generation circuit 337 and the coordinate length measurement circuit 338 are totaled, and the total coordinate value is input to the microcomputer. Further, the barycentric coordinate values of X and Y of the image corresponding to the filling material are calculated by dividing by the number of pixels forming the image corresponding to the filling material, which is totalized by the area calculation circuit 332.

On the other hand, the two-dimensional binarized image signal from each of the binarization circuits 323 and 324 is a projection distribution creation circuit 331.
1, 3312, and the area of the image portion corresponding to the through-hole wall surface portion is calculated by the area calculation circuits 333 and 334 based on the projection distribution.

In the coordinate generation circuit 337, the line sensors 313a and 313 currently involved in image detection are connected via any of the image detection circuits 316, 317 and 318.
The scanning position coordinates on the sensor are created based on the scanning clock from either b or 313c. On the other hand, in the coordinate length measuring circuit 338, the X axis length measuring device 30
7. Based on the amount of movement in the X and Y directions from each of the Y-axis length measuring instruments 308, the actual inspection position coordinates on the circuit board 1 are detected by the line sensors 313a, 313b, 313c. From the detected actual inspection position coordinates, the microcomputer 328 recognizes the actual inspection position at that time. On the other hand, in the case of updating the through hole position to be inspected based on the design data from the floppy disk 340,
The X-axis drive unit 305 and the axis drive unit 306 are drive-controlled via the XY drive control unit 339 under the monitoring so that the desired actual inspection position is obtained, and the X-stage 303,
Each Y stage 304 is moved a desired amount. More specifically, in the actual through hole filling state inspection, the through hole filling state inspection is performed while the circuit board 1 is controlled to reciprocate with respect to the parallel light source 309 as indicated by an arrow A. The entire surface is scanned. The floppy disk 340 also stores various design data (position coordinates, through-hole diameter, pitch, etc.) for each through-hole formed on the circuit board 301, and these designs are stored. The data is read by the microcomputer 340 as needed, and the X stage 303 and the Y stage 304 are driven by desired amounts in accordance with the design data. Of those design data,
The position coordinates of each of the holes are transferred from the microcomputer 340 to the through-hole coordinate memory 341 and stored therein, and the contents of the through-hole coordinate memory 341 are stored in the memory.
The output from each of the coordinate generation circuit 337 and the coordinate length measurement circuit 338 is compared in the comparison circuit 342. At the time point when the coincidence comparison result is obtained from the comparison circuit 342, the image of the desired through hole is detected. Therefore, the area calculation circuits 332, 333, 334 are detected every time the through hole image is detected. Then, the perimeter calculation circuit 335 and the coordinate addition circuit 336 are respectively activated, and the area and perimeter and the through hole image part coordinate addition result can be calculated.

Explaining in more detail, the coordinate adding circuit 33.
The addition results Σx and Σy of the X and Y coordinate values of the through-hole image portion from 6 and the number of pixels n corresponding to the filler from the area calculation circuit 332 are taken into the microcomputer 328, and the formula Σx / Calculation represented by n and Σy / n (Σ is
Is performed and the center of gravity is calculated, and the calculation result is
The reference value set by the comparator 328 is compared with the comparison circuit 343. As a result, the deviation amount of each of the X and Y center of gravity of the image corresponding to the filling material is calculated, and the quality of the through hole position deviation is determined and the defect type is identified.

Area calculation circuit 332, perimeter length calculation circuit 33
Similarly, the area value (number of pixels n × pixel size) and the perimeter value from each of 5 are also taken into the microcomputer 328, and after the area / (perimeter) ² operation is performed, the operation is performed. The result is compared with various reference values set by the microcomputer 328 by the comparison circuit 344, so that the quality of the filled state is determined and the defect type is identified.

Similarly, the area values from the area calculation circuits 332, 333, 334 and the reference values set by the microcomputer 328 and the comparison circuits 345, 345 respectively.
By comparing in 346 and 347, the quality of the filled state is determined and the defect type is identified.

Then, the comparison circuits 343, 344, and
The quality determination result and the defect type identification result from each of 345, 346, and 347 are associated with the position coordinates corresponding to the through holes, and are also stored in the determination result memory 348, and the stored content is the microcomputer 328. Under the control of, the data can be read out from the determination result memory 348, printed by the printer 349, and viewed.

The outline of the structure and operation of the through-hole inspection apparatus according to the present invention has been described above with reference to FIG. 17, but the histogram creation circuits 325 and 32 shown in FIG.
6,327, projection distribution generation circuits 330, 3311, 33
12, specific configurations and operations of the area calculation circuits 332, 333, 334 and the perimeter calculation circuit 335 are disclosed in Japanese Patent Laid-Open No. 63-24.
It can be easily realized by using the same one as disclosed in Japanese Patent No. 1344 or Japanese Patent Laid-Open No. 5-307006.

(II) Details of Structure and Operation of Coordinate Addition Circuit 336 Next, the structure and operation of the coordinate addition circuit 336 in the configuration of the through-hole inspection device according to the present invention will be described with reference to FIG. ,
This will be described in more detail. FIG. 18 is a block diagram showing the circuit configuration of the coordinate addition circuit 336 in the configuration of the through-hole inspection device according to the present invention.

First, the operation of the coordinate addition circuit 336 for adding through-hole coordinates in the X direction will be described. The coordinate value 337 of the coordinate generation circuit 336 and the output of the binarization circuit 322 are connected to the AND gate 401, and the output thereof is the adder 4
It is input to 02. Then, the addition result is latched by the latch 40.
3 and the output of the latch 403 is input to the adder 402. With such a configuration, AND
Since the AND operation is performed in the gate 401, the coordinate value 337 is input to the adder 402B when the binarized signal in the presence of the through hole becomes "1". On the other hand, the latch 403 stores the coordinate value added by the adder 402, and then the stored addition result is added by the adder 40.
Enter in 2A. The binarized signal is "1" in the adder 402.
The outputs of the AND gate 401 and the latch 403 having the coordinate values are sequentially added.

Also in the Y direction. Similar to the X direction, the coordinate value 338 of the coordinate length measuring circuit and the output of the binarizing circuit 322 are connected to the AND gate 404, and the output is input to the adder 405. Then, the addition result is input to the latch 406, and the output of the latch 406 is added to the adder 405.
The same operation as in the X-direction can be performed by the configuration of inputting to.

With such a configuration, the coordinate values in the X direction and the Y direction of the binary image in which the through hole exists can be added by the binarization threshold value V _H21 shown in FIG.

Now, the timing for operating the coordinate adding circuit 336 will be described. For example, assume that the through holes are arranged at a constant pitch. In this case, the position coordinates of the through holes are stored in advance in the through hole coordinate memory 341 in a predetermined order based on the design data from the floppy disk 340. Under the control of the micro computer 328, the position coordinates read from the through-hole coordinate memory 341 in a predetermined order are the scanning position coordinates from the coordinate generation circuit 337,
The Y coordinate from the coordinate length measuring circuit 338 is compared and determined by the comparison circuit 342, and the coordinate addition circuit 336 is activated each time they match.

Even if there are several types of through-hole pitches, if the through-hole position memory is stored in the through-hole coordinate memory 341 based on the design data, regardless of the through-hole pitch. The image can be processed for each through hole that appears in a predetermined order.

(II) Details of Inspection Method in Through Hole Inspection Apparatus Next, based on the above description, details of the inspection method in the through hole inspection apparatus will be described. As described above, the multi-valued image signals from the shading correction circuits 319, 320 and 321 are binarized circuits 322, 323 and 324.
Each is binarized based on the threshold values V _H2 and V _H21 .

First, referring to FIG. 19, the threshold values V _H2 , V
A method for optimally setting _H21 will be described. FIG.
[FIG. 4] is a schematic diagram showing the signal level of the detected image signal and the state on the substrate, and a histogram showing the relationship between the occurrence frequencies thereof.

(II-1) Case of Through Hole Filled with Paste First, a method of identifying defects in the case of a through hole filled with paste will be described. That is, FIG.
As shown in (a), using the circuit board to be inspected, from the detected image signals (multi-valued image signals) from each of the line sensors 313a, 313b, 313c, the brightness frequency distribution in the entire circuit board 1 is shown. Prior to the inspection of the filled state of the through holes, it is obtained by each of the histogram creation circuits 325, 326 and 327 as shown in FIG. The brightness frequency distribution of the microcomputer 328 is shown in FIG.
As shown in (b), the signal level H _max corresponding to the circuit board
And the signal level H _min corresponding to the packing are obtained, and the threshold value V is obtained as a function of these signal levels H _max and H _min.
Each of _H2 and _VH21 is set as the optimum one by calculation.

Threshold values V _H2 , V set as described above
_By performing the binarization process by each _H21, three types of two-dimensional binarized image signals are obtained from the binarization circuits 322, 323, 324.

Furthermore, from this image signal, the area corresponding to the filling material, the area corresponding to the wall surface of the through hole, and the perimeter of the filling material are obtained, and the defect of the filling state is determined, and the defect in the case of the determination Identification is done.

The quality judgment and the defect identification will be described below with reference to specific mathematical expressions.

FIG. 14 shows two kinds of binary images for various filling states after the binarization processing with the threshold value V _H2 . From these binary image, sul - ho - area of the portion that is specularly reflected brightly corresponding to Le wall S _H201, and S _{H 202} is obtained by performing determination of the area S _{H2 01,} S _{H 202} , Deficiency defect or substrate irregularity defect is detected.

In the present embodiment, the threshold value is V _{H2 of} one kind, but when the signal level of the detected image is different for each different detection direction, the calculation shown in FIG. Different thresholds may be provided for each.

Further, FIG. 15 shows binary images for various filling states after the binarization processing with the threshold value V _H21 . From these binary images, the through-hole filling materials are shown. area (shaded display) S _H21 and its perimeter l ₂₁ and -
Obtain the central coordinate positions XL ₂₁ and YL ₂₁ of the hole filling,
Defect determination and defect type identification are performed.

[0174] Specifically, the defect determination and defect identification of type may, l ₂₁ the area S _H20, S _H210 and perimeter in case of binarizing the normal fill level with a threshold V _H2, V _H21, Using the center positions XL ₂₁₀ and YL _{210 of the} through-hole filling as reference values, as shown as a determination example in FIGS. 14 and 15, the determination is performed as follows.

In the case of orthorhombic polarization illumination / orthogonal polarization illumination detection from two directions, normal ... S _H2 <S _H20 deficiency and substrate irregularity ... S _H201 > S _H20 , while on the other hand, orthographic polarization illumination / upper polarization In case of detection, the through hole is normal ... S _H21 ≈ S _H210 , S _H21 / l ₂₁ ² ≈
S _H210 / l ₂₁ ² ≈ 1 / 4π = 0.0796 bleeding… S _H21 > S _H210 No through hole… S _H21 ≈ 0 Foreign matter adhesion / mixing… S _H21 / l ₂₁ ² <1/4 π Scattering defect… S _H21 / l ₂₁ ² <1 / 4π misalignment ... XL ₂₁ > XL ₂₁₀ , YL ₂₁ > YL ₂₁₀ .

(II-2) Case of Through Holes Next, a method of identifying defects in the case of through holes will be described. Also in the case of detecting the through through hole, the multi-valued image signal from the shading correction circuit 319 is detected by the binarization circuit 322 based on the threshold value V _H22 in the same manner as described in (II-1) above. A two-dimensional binarized image signal can be obtained by performing the binarization process.
Further, from the image signal, the area corresponding to the through-hole penetrating portion and the perimeter are obtained, and then the quality of the through-hole portion is determined, and the defect identification when it is determined to be no is performed.

The pass / fail judgment and defect identification will be described in detail below. That is, in FIG.
Then, as shown in the binary image for the through hole after the binarization processing with the threshold value V _H22 , from these binary images, the areas of the through holes (hatched lines) S _H22 and Its perimeter l ₂₂ and the center position X of the through-hole packing
L ₂₂ and YL ₂₂ are obtained, and defect determination and defect type identification are performed from them. Specifically, the defect determination and the defect type identification are performed by the area S _H220 when the normal filling state is binarized by the threshold value V _{H2 2} , and the peripheral length l ₂₂ , and the through-hole filling material. 16, the center coordinate positions XL ₂₂₀ and YL ₂₂₀ are used as reference values, and the determination is performed as follows.

That is, in the case of orthorhombic polarization illumination / upper polarization detection, the through hole is normal ... S _H22 ≈ S _H220 , S _H22 / l ₂₂ ² ≈
S _H220 / l ₂₂ ² ≈ 1 / 4π = 0.0796 No through hole ... S _H22 ≈ 0 Scraps ... S _H22 <S _H110 , S _H22 / l ₂₂ ² <1/4 π large diameter ... S _H22 > S _H220 small diameter ... S _H22 <S _H220 hole deformation ... S _H22 / l ₂₂ ² <1 / 4π position shift ... XL ₂₂ > XL ₂₂₀ , YL ₂₂ > YL ₂₂₀ .

[Inspection Target of Through Hole Inspection Device, Other Application Examples of Inspection Method] In the above description, the inspection target of the through hole inspection device is assumed to be a green sheet used for a multilayer ceramic substrate. The inspection device can be used for a printed circuit board having a foil plate or the like as a base material. In this case, the objective lens 31 of FIG.
2A, the line sensor 313a, and the polarizing plate 315a can be realized by using the inspection method shown in FIG. That is, since the base material surface such as a copper foil plate is not in a diffused state, the through-hole portion is dark and the base material portion can be detected whitish by detecting the specular reflection light by epi-illumination. A position shift detection method can be applied.

Further, the connection between the multilayer ceramic substrate after stacking and sintering the green sheets and the electronic component is performed by soldering or the like, but the connecting portion with the electronic component has a pattern such as a circle or a regular polygon. In the case of FIG. 10 or FIG.
It is obvious that the displacement detection can be performed by using the detection method shown in FIG.

[0181]

According to the method of manufacturing an electronic circuit board of the present invention, the front and back wirings of a printed wiring board having through holes (through holes) or through holes filled with a filler are connected to each other. It is possible to provide a highly reliable method for manufacturing an electronic circuit board in which the positional deviation of the through holes is small.

Further, according to the present invention, a through hole having a positional deviation or a printed wiring board having a through hole having a positional deviation after the through hole is filled with a filling material is eliminated, Fill the through hole of the good printed wiring board with the filling material to form the wiring pattern,
It is possible to provide a highly reliable manufacturing method of an electronic circuit board, which is manufactured by stacking and sintering only good printed circuit boards.

Next, according to the through-hole inspection method and inspection apparatus of the present invention, the displacement of the through-holes formed in the printed wiring board or the through-holes filled with the filling material can be corrected at high speed. It is possible to provide a through-hole inspection method and inspection device that enable accurate measurement.

According to the present invention, the non-defective through hole and the defective through hole of the through hole (through hole) formed in the printed wiring board or the through hole filled with the filling material are distinguished from each other and inspected. However, it is possible to provide a through-hole inspection method and apparatus capable of measuring the positional deviation of non-defective through-holes with high accuracy.
Further, according to the present invention, when inspecting a printed wiring board having a through-hole, it is possible to provide an inspecting method for an electronic circuit board, which allows the board to be held flat and inspected.

[Brief description of drawings]

FIG. 1 is a flow chart schematically showing an example of a manufacturing process from a printed wiring board of the present invention to an electronic circuit board.

FIG. 2 is a flow chart for explaining the manufacturing process shown in FIG.

FIG. 3 is a green sheet 1 having through holes 2 formed therein.
FIG.

FIG. 4 is a perspective view schematically showing how the screen mask 5b and the green sheet 4 are aligned.

FIG. 5 is a graph showing the relationship between the positional deviation amount of through holes in the X direction and the occurrence frequency (in the conductor paste filling step), wherein the horizontal axis represents the positional deviation amount in the X direction and the vertical axis represents the frequency. .

FIG. 6 is a side view of a green sheet being laminated, showing n + on the n-th green sheet GV _1.
The first layer green sheet GV ₂ and the (n + 1) th layer green sheet GV ₃ on the (n + 1) th layer green sheet GV ₂
It is shown that they are laminated.

FIG. 7 is a graph showing the relationship between the positional deviation amount of the through hole in the X direction and the occurrence frequency (in the stacking process), wherein the horizontal axis represents the positional deviation amount in the X direction and the vertical axis represents the frequency.

FIG. 8 is a schematic diagram and image of the image detection method comparing the case of polarized illumination / polarization detection (including epi-illumination and ring-shaped illumination) from above and the case of oblique polarization illumination / polarization detection. It is the figure which put together the signal diagram and the cross-sectional view of a board | substrate in tabular form.

FIG. 9 compares the case where a through hole is filled and the case where a through hole is not filled, and divides the polarized illumination from above and the obliquely polarized illumination from one side into the image signal lines. It is the figure which put together the figure and the projection view of the through hole by a binary image in the tabular form in order to explain the gap between the signal and the projection view.

FIG. 10 is a perspective view of a main part of an optical inspection device in the case of upward polarized illumination / polarized light detection, and a diagram listing defects detected by the optical inspection device.

FIG. 11 shows a filling state, an image signal, a binary image, and a judgment example of a through hole filled with a conductor paste in a normal case and each defective case in the case of upward polarized illumination / polarization detection. FIG. 3 is a schematic diagram that enables comparison in a tabular format.

FIG. 12 shows a filling state, an image signal, a binary image of a state of a through through hole in the case of upward polarized illumination / polarized light detection.
FIG. 6 is a schematic diagram that enables comparison in a tabular form between a determination example and a normal case and each defective case.

FIG. 13 is a perspective view of a main part of an optical inspection device in the case of oblique polarization illumination / polarized light detection and a diagram listing defects detected by the optical inspection device.

FIG. 14 shows a filling state, an image signal, a binary image, and a judgment example of a through hole filled with a conductor paste in the case of normal polarization and lack of unevenness of the substrate when the polarized polarized light is detected and polarized. FIG. 9 is a schematic diagram that allows comparison in tabular form at times.

FIG. 15 is a perspective view of a through-hole filled with a conductor paste in oblique polarization illumination / polarization detection, showing a filled state, an image signal, a binary image, and a judgment example in a normal case and each defective case. FIG. 2 is a schematic diagram that enables comparison in a tabular format.

FIG. 16 is a view showing a through-hole in a filled state, an image signal, a binary image, when oblique polarization illumination / polarization detection is performed.
FIG. 6 is a schematic diagram that enables comparison in a tabular form between a determination example and a normal case and each defective case.

FIG. 17 is a block diagram schematically showing the structure and operation of the through-hole inspection device according to the present invention and its relationship, and is an enlarged view of an optical main part in particular.

FIG. 18 is a block diagram showing a circuit configuration of a coordinate adder circuit 336 in the configuration of the through-hole inspection device according to the present invention.

FIG. 19 is a schematic diagram showing a signal level of a detected image signal and a state on a substrate, and a histogram showing a relation between the occurrence frequencies thereof.

FIG. 20 is a cross-sectional view of the green sheet and the suction holder, showing the conditions for flattening the green sheet having the through holes penetrating therethrough.

FIG. 21 is a cross-sectional view of a multilayer wiring board after laminated sintering.

FIG. 22 is a cross-sectional view of a wiring board having a through hole and an image signal obtained by illuminating the wiring board and a detected image for comparison.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Green sheet, 2 ... Through hole, 3 ... Optical inspection device, 5 ... Conductor filling printing machine, 6 ... Green sheet filled with conductor paste, 7 ... Optical inspection device, 9 ... Circuit pattern printing machine, 10 ... Circuit Pattern-printed green sheet, 11 ... Optical inspection device, 13 ... Laminating process, 15 ...
Sintering furnace, 16 ... Multilayer ceramic, 17 ... Optical inspection device,
20 ... Electronic circuit board, 301 ... Circuit board, 310a, 3
10b ... Point light source, 311a, 311b ... Condenser lens, 312a, 312b, 312c ... Objective lens, 31
3a, 313b, 313c ... Line sensor, 314a,
314b, 315a, 315b, 315c ... Polarizing plate, 3
16, 317, 318 ... Image detection circuit, 319, 32
0, 321, ... Shading correction circuit, 322, 32
3, 324 ... Binarization circuit, 328 ... Micro computer, 329 ... Contour extraction circuit, 330, 3311, 331
2 ... Projection distribution creation circuit, 332, 333, 334, ...
Area calculation circuit, 335 ... Circumference length calculation circuit, 336 ... Coordinate addition circuit, 337 ... Coordinate generation circuit, 338 ... Coordinate length measurement circuit, 341 ... Through hole coordinate memory, 343, 34
4, 345, 346, 347 ... Comparison circuit, 348 ... Judgment result memory.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shiro Hoshi 1 Horiyamashita, Hadano City, Kanagawa Prefecture

Claims (19)

[Claims] 1. A method of manufacturing an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of the board using a through hole, wherein the electronic circuit board is formed in a multilayer structure. A means for irradiating the board with light, a means for detecting the image signal measured by irradiating the light, a means for calculating a positional deviation correction amount, and an electronic circuit board alignment based on the positional deviation correction amount. And means for irradiating the electronic circuit board with light, irradiating the electronic circuit board with light, and detecting the image signal measured by irradiating the light By detecting the image signal measured by irradiation and calculating the positional deviation correction amount, the positional deviation correction amount of the through hole between the electronic circuit boards is calculated by the image signal, A method of manufacturing an electronic circuit board, characterized in that the position of the electronic circuit board is adjusted based on the calculated misregistration correction amount by means of adjusting the position of the board. 2. A through hole processing step, a step of filling a filling material into a through hole, a step of filling a filling material into a through hole, and a step of forming a circuit pattern by the mask, after at least one of these steps has passed. An image measured by irradiating the electronic circuit board with light by the means for irradiating the electronic circuit board with light, and by irradiating the light with the means for detecting an image signal measured by the light. By detecting a signal, detecting the positional deviation amount of the through hole in each step from the image signal, and calculating the positional deviation correction amount, the electronic signals formed in multiple layers from the detected positional deviation amount. The positional deviation correction amount is calculated so as to minimize the positional deviation error between the circuit boards, and is calculated by the means for aligning the electronic circuit boards. The method of manufacturing an electronic circuit board according to claim 1, wherein the aligning between the electronic circuit board based on the position deviation correction amount. 3. A method of manufacturing an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of the board using a through hole, and means for irradiating the electronic circuit board with light, and irradiating the light. Means for detecting an image signal measured by the following method, means for calculating a positional deviation correction amount, and means for aligning the electronic circuit board and a mask for patterning the electronic circuit board based on the positional deviation correction amount. Having a through hole processing step, a step of filling a through hole with a filling material, a step of filling a through hole with a filling material, and a step of forming a circuit pattern by the mask, after at least one of these steps, The electronic circuit board is illuminated with light by means for illuminating the electronic circuit board, and the light is illuminated by means for illuminating the light and detecting an image signal measured. The image signal measured by the above is detected, the through hole position deviation amount in each process is detected from the image signal, and the position deviation correction amount is calculated by the means for calculating the position deviation correction amount. A means for calculating a positional deviation correction amount so as to minimize a positional deviation error with respect to a reference through hole position or a through hole position of a mask forming a through hole or a pattern, and performing alignment between the electronic circuit board and the mask. According to the method, the electronic circuit board is aligned with the mask based on the calculated positional deviation correction amount. 4. A method of manufacturing an electronic circuit board having wiring, wherein when an electronic circuit component is mounted by electrically connecting to the wiring of the electronic circuit board, light is applied to the electronic circuit board. A means for irradiating, a means for detecting an image signal measured by irradiating the light, a means for calculating a positional deviation correction amount, and an alignment of the electronic circuit board and the electronic circuit component based on the positional deviation correction amount. And irradiating the electronic circuit board on which the electronic component is mounted with light by means of irradiating the electronic circuit board with light, and detecting an image signal measured by irradiating the light. Detecting the image signal measured by irradiating the light, detecting the position deviation amount of the electronic circuit component from the image signal, and calculating the position deviation correction amount, the position detected by the means. Amount of deviation From the above, the positional deviation correction amount is calculated so that the positional deviation error with the predetermined mounting position of each electronic component is minimized, and the calculated by the means for aligning the electronic circuit board and the electronic circuit component. A method for manufacturing an electronic circuit board, characterized in that the electronic circuit board and the electronic circuit component mounted on the electronic circuit board are aligned based on the positional deviation correction amount. 5. A method of manufacturing an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of the board using a through hole, and means for irradiating the electronic circuit board with light and means for irradiating the light. And a means for detecting an image signal measured by a through hole processing step, a step of filling the through hole with a filling material, and a step of filling the through hole with a filling material and then forming a circuit pattern by the mask. Then, the allowable amount of through-hole displacement in each of the above steps is defined, and the electronic circuit board is irradiated with light after at least one of the steps is passed through the electronic circuit. By irradiating the substrate with light and detecting the image signal measured by irradiating the light, the image signal measured by irradiating the light is detected. A through hole position deviation amount in each step is detected, and an electronic circuit board in which the detected through hole position deviation amount is larger than an allowable through hole position deviation amount in each step is excluded, A method of manufacturing an electronic circuit board, characterized in that only an electronic circuit board having a through hole positional deviation amount within an allowable range is used in a subsequent process. 6. A through-hole inspection method for an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of a board using the through-holes, when the through-holes are penetrated. It has means for irradiating the electronic circuit board with light, and means for irradiating the light to detect an image signal measured, and the means for irradiating the electronic circuit board with light causes the electronic circuit board to move upward or downward. By irradiating light obliquely from above, by means for detecting the image signal, the image signal measured by irradiating light is detected from above or obliquely above the point where the light is irradiated, and in a normal through hole in advance. Image signal threshold V
_H11 and a reference position are determined. Based on the threshold value V _{H11 of the} image signal and the reference position, the area of the detected through hole is S _H11 , and the peripheral length is l.
When the _11, these areas S _H11, perimeter l _11, based on the reference position, without through-hole defects, debris jam defect, large defects, small defects, the defect through hole in a state that the hole deformation defect defect A through-hole inspection method characterized in that the type is detected in an identified state, or a positional deviation from a normal through-hole is detected. 7. A method of irradiating the electronic circuit board with light from above or obliquely above by means for irradiating the electronic circuit board with light, wherein the linearly polarized illumination light is emitted from above or obliquely above. The polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and the image signal detected by the means for detecting the image signal is irradiated with light. 7. The through-hole inspection method according to claim 6, wherein the method of detecting from above or diagonally above the point is from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. . 8. A through-hole inspection method for an electronic circuit board, which is formed by electrically connecting wirings on the front and back of the board using the through-holes, wherein the through-holes are filled with an electrically conductive substance. And a means for irradiating the electronic circuit board with light, and a means for detecting the image signal measured by irradiating the light, and the electronic circuit board is irradiated with the light. The image signal measured by irradiating light from above or obliquely above is detected by the means for detecting the image signal from above or obliquely above the point where the light is irradiated, and the normal Image signal threshold V in through hole
_H1 and a reference position are determined, and when the area of the detected through hole is S _H1 and the peripheral length is 1, based on the threshold value V _{H1 of the} image signal and the reference position, these areas S 1 _H1, perimeter l _1, based on the reference position, bleeding defect, no through-hole defects, foreign matter defects detected in the state of the identified defect type of the defect through holes with scattering defects, the state or normal A through-hole inspection method characterized in that a positional deviation from the through-hole is detected. 9. A method of irradiating the electronic circuit board with light from above or obliquely above by means of irradiating the electronic circuit board with light, wherein the linearly polarized illumination light is irradiated from above or obliquely above. The polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and the image signal detected by the means for detecting the image signal is irradiated with light. 9. The through-hole inspection method according to claim 8, wherein the method of detecting from above or diagonally above the point is from above or diagonally above by the light of the polarization component orthogonal to the polarization direction of the linearly polarized illumination light. . 10. A method for inspecting a through hole of an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of the board by using the through hole, wherein the through hole is filled with an electrically conductive substance. And a means for irradiating the electronic circuit board with light, and a means for detecting the image signal measured by irradiating the light, and the electronic circuit board is irradiated with the light. By irradiating light obliquely from above, the image signal detected by the means for detecting the image signal is detected from obliquely above the point where the light is irradiated, and the image in the normal through hole is detected in advance. Signal threshold V
_H1 and a reference position are defined, and when the area of the detected through hole is S _H2 based on the threshold value V _{H2 of the} image signal, the electronic circuit based on this area S _H2 A through-hole inspection method, characterized in that a concave-convex defect of a substrate and a defect of an electrically conductive substance filled in the through-hole are detected. 11. A method for irradiating the electronic circuit board with light from obliquely above by means for irradiating the electronic circuit board with light, the linearly polarized illumination light being irradiated with linearly polarized illumination light from obliquely above. The polarized light component in the same direction as the polarized light direction is shielded, and the image signal measured by irradiating the image signal by the means for detecting the image signal is obliquely above the point where the light is irradiated. 11. The through-hole inspection method according to claim 10, wherein the more detecting method includes detecting the light having a polarization component in a direction orthogonal to the polarization direction of the linearly polarized illumination light from diagonally above. 12. A through-hole inspection apparatus for an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of a board using the through-holes, when the through-holes are penetrated. It has means for irradiating the electronic circuit board with light, and means for irradiating the light to detect an image signal measured, and the means for irradiating the electronic circuit board with light causes the electronic circuit board to move upward or downward. By irradiating light obliquely from above, by the means for detecting the image signal, the image signal measured by irradiating light is detected from above or obliquely above the point where the light is irradiated, and in a normal through hole in advance. Image signal threshold V
_H11 and a reference position are determined. Based on the threshold value V _{H11 of the} image signal and the reference position, the area of the detected through hole is S _H11 , and the peripheral length is l.
_{In the case of 11} , defects based on the area S _H11 , the perimeter length l ₁₁ , and the reference position are defects having no through hole, defects including a scrap residue, a large diameter defect, a small diameter defect, and a hole deformation defect. A through-hole inspection device characterized by detecting a type in an identified state or detecting a positional deviation from a normal through-hole. 13. When irradiating the electronic circuit board with light from above or obliquely above by means for irradiating the electronic circuit board with light, the electronic circuit board is irradiated with linearly polarized illumination light from above or obliquely above. The polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and the image signal detected by the means for detecting the image signal is irradiated with light. 13. The through-hole inspection device according to claim 12, wherein when detecting from above or diagonally above a point, the light of a polarization component orthogonal to the polarization direction of the linearly polarized illumination light is detected from above or diagonally above. . 14. A through-hole inspection device for an electronic circuit board, which is formed by electrically connecting wirings on the front and back sides of a board using the through-holes, wherein the through-holes are filled with an electrically conductive substance. And a means for irradiating the electronic circuit board with light, and a means for detecting the image signal measured by irradiating the light, and the electronic circuit board is irradiated with the light. The image signal measured by irradiating light from above or obliquely above is detected by the means for detecting the image signal from above or obliquely above the point where the light is irradiated, and the normal Image signal threshold V in through hole
_H1 and a reference position are determined, and when the area of the detected through hole is S _H1 and the peripheral length is 1, based on the threshold value V _{H1 of the} image signal and the reference position, these areas S 1 _H1, perimeter l _1, based on the reference position, bleeding defect, no through-hole defects, foreign matter defects detected in the state of the identified defect type of the defect through holes with scattering defects, the state or normal A through-hole inspection device characterized by detecting a positional deviation from the through-hole. 15. When irradiating the electronic circuit board with light from above or obliquely above by means for irradiating the electronic circuit board with light, the electronic circuit board is irradiated with linearly polarized illumination light from above or obliquely above. The polarization component in the same direction as the polarization direction of the linearly polarized illumination light is shielded, and the image signal detected by the means for detecting the image signal is irradiated with light. 15. The through-hole inspection apparatus according to claim 14, wherein when detecting from above or diagonally above the point, light is detected from above or diagonally above by light having a polarization component orthogonal to the polarization direction of the linearly polarized illumination light. . 16. A through-hole inspection device for an electronic circuit board, which is formed by electrically connecting wirings on the front and back of the board by using the through-holes, wherein the through-holes are filled with an electrically conductive substance. And a means for irradiating the electronic circuit board with light and a means for irradiating the light with an image signal to be measured, and the electronic circuit board is irradiated with the light. By irradiating light obliquely from above, by the means for detecting the image signal, the image signal measured by irradiating the light is detected obliquely above the point where the light is irradiated, and the image in the normal through hole Signal threshold V
_H1 and a reference position are defined, and when the area of the detected through hole is S _H2 based on the threshold value V _{H2 of the} image signal, the electronic circuit based on this area S _H2 A through-hole inspection apparatus, which detects irregularities on a substrate and defects on an electrically conductive substance filled in the through-hole. 17. When the electronic circuit board is irradiated with light from obliquely above by means for irradiating the electronic circuit board with light, the linearly polarized illumination light is irradiated with linearly polarized light from obliquely above. The polarized light component in the same direction as the polarized light direction is shielded, and the image signal measured by irradiating the image signal by the means for detecting the image signal is obliquely above the point where the light is irradiated. 17. The through-hole inspection apparatus according to claim 16, wherein, when further detecting, the linearly polarized illumination light is detected obliquely from above by light having a polarization component in a direction orthogonal to the polarization direction. 18. An electronic circuit board inspecting method for inspecting an electronic circuit board having a through hole formed therethrough, comprising: a means for sucking air from one surface of the electronic circuit board, wherein the suction holder for holding the electronic circuit board is provided. An electronic circuit board characterized by mounting an electronic circuit board, placing a sheet on the surface of the electronic circuit board facing the electronic circuit board, sucking air from one surface of the electronic circuit board, and then inspecting the electronic circuit board. Inspection method. 19. The method for inspecting an electronic circuit board according to claim 18, wherein the sheet is a member that transmits light.