JPH0615122B2 - Method for detecting hole drilling position in multilayer printed wiring board - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hole drilling position detecting method for detecting a hole drilling position of a hole drilled on an inner layer circuit of a multilayer printed wiring board.

[Background technology]

A multilayer printed wiring board used in electronic devices and the like is generally manufactured as follows. First, a metal foil is attached to both surfaces or one surface of the inner layer prepreg, and an inner layer circuit is formed on the metal foil to form an inner layer circuit board. The inner layer circuit board or a plurality of the inner layer circuit boards are arranged in a plane, and prepregs for outer layers are stacked on top of each other, and a metal foil is further stacked on the outer side of the prepregs, and heat and pressure molding is performed. Then, for a plurality of inner layer circuit boards arranged side by side, rough cutting is performed for each inner layer circuit. For the intermediate product of the multilayer printed wiring board formed after the molding, a hole mark indicating the reference hole drilling position, which is displayed on the surface of the inner layer circuit board, is sought out from the outermost metal foil side. The portion having the hole mark is countersunk from the upper side to expose the hole mark. A reference hole is made at the center of this hole mark. Then, by forming an outer layer circuit on the outermost metal foil with reference to the reference hole, a multilayer printed wiring board is completed.

However, the above manufacturing method has the following problems. This is because it is difficult to determine the rough cutting position in an intermediate product of a multilayer printed wiring board in which a plurality of inner layer circuit boards are arranged, because the inner layer circuit board is invisible because of the outermost metal foil. When searching for the hole mark, the hole mark is hidden by the outermost metal foil and cannot be seen, so the exact position is unknown, and there is a misalignment between the outer layer and the inner layer circuit board during heat and pressure molding. Since it is likely to occur, the exact position of the hole mark is becoming more difficult to understand.

Therefore, in order to solve the above problems, the following hole mark detection method has been developed. First, as shown in FIG. 1, after forming the inner layer circuit 1a and the hole mark 1b on the inner layer prepreg 2, a patch (guide mark) 3 is pre-applied on the hole mark 1b and then the outer layer prepreg. 4, 4 and the metal foils 5, 5 are stacked and pressure molding is performed. Finished multilayer printed wiring board intermediate product 6,
This is a method of visually observing that the portion 5a on the metal foil 5 is slightly shining up by the thickness of the patch 3.
In the figure, 1 is an inner layer circuit board. Another method is to detect the position of the hole mark by irradiating the multilayer printed wiring board with X-rays to see through the inner layer circuit (for example,
(Actual development No. 58-140665).

On the other hand, in the case of the above method, realization of full automation is strongly desired. In manufacturing a multilayer printed wiring board, which is a common form of mass production, the cost reduction merit by full automation is very large. However, in the above two methods,
There is a problem that it is difficult to realize full automation.

The former method is almost fully automated, for example, the number of steps to apply the patch increases, it is difficult for a machine to determine whether the raised portion of the metal foil is shining, and the position of the hole mark needs to be visually searched, which is very tiring. Not suitable for.

In the latter method, it is difficult to achieve both accuracy and ease of position detection, and full automation is extremely difficult.

[Object of the Invention]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a method for detecting a hole punching position in a multilayer printed wiring board that can realize full automation.

[Disclosure of Invention]

The inventor has conducted extensive studies to achieve the above object and completed the present invention.

This invention detects a hole drilling position by detecting the position of the hole mark of a multilayer printed wiring board in which hole marks indicating hole drilling positions are formed at appropriate positions on the inner layer circuit board. A method for detecting a hole punching position in a multilayer printed wiring board, comprising a plurality of rectangular bars vertically and horizontally provided with information on an xy coordinate system, which serves as a reference for determining the coordinates of the hole mark, on the peripheral portion of the inner layer circuit board. The arranged bar scale pattern is formed at the same time as the circuit pattern, at least a part of the bars of the bar scale pattern is detected, the information of the xy coordinate system is read, and the xy coordinate system is read based on the read xy coordinate system information. Is a method of detecting the position of the hole mark whose coordinate position in is known in advance. In each bar of the bar scale pattern, the vertical and horizontal sides are parallel to the x-axis and the y-axis, and the vertical and horizontal length dimensions are Ba Holes drilled position detection method of the multilayer printed wiring board, characterized by being formed as a function value of the xy coordinates of the center position of the its gist.

As shown in FIG. 2, in the method of detecting the hole punching position of the multilayer printed wiring board according to the present invention, hole marks 1b indicating the hole punching positions are formed at three positions on the inner layer circuit board 1 as in the conventional case. This is a method of detecting the position of the hole by detecting the position of the hole mark 1b in the formed multilayer printed wiring board 7. The hole mark 1b indicates the position of a reference hole, which serves as a reference when forming a circuit in the outer metal foil 5 so as to correspond to the inner circuit 1a. The circuit pattern (inner layer circuit) 1a of the inner layer circuit board 1 having the hole mark 1b in advance.
Bar scale patterns 8a and 8b having information of an xy coordinate system having an origin position O ₁ which is a reference for determining the coordinates of the hole marks 1b, 1b and 1b are formed at two peripheral portions of the circuit pattern 1a at the same time. Keep it. These bar scale patterns 8a and 8b are shown in FIG. 3 in the xy coordinate system of the origin position O ₁ . The vertical and horizontal sides of each bar 38 are formed so as to be parallel to the y-axis and the x-axis. Also, each bar 38 represents the width dimension Ai as a function of x-coordinate xi in a bar center position _{O 2} Ai = A (xi), y the vertical width dimension Bj in a bar center position _{O 2}
It is represented by the function Bj = B (yj) of the coordinate yj. According to the same xy coordinate system as those of the bar scale patterns 8a and 8b, the coordinate position of each hole mark 1b is fixed before the outer layer material (outer layer prepreg and metal foil) is laminated. Next,
From the upper and lower sides of the places where the bar scale patterns 8a and 8b are formed, counterboring as shown by the chain line is performed to make a part of the bar (in the chain line circle) transparent. Then, the bar at the spot facing portion is made to transmit light, and the information of the xy coordinate system is read from the light transmission image. Read xy
From the coordinate system information, a deviation from the XY coordinate system, which serves as a reference for determining the position on the outer metal foil surface, is derived, and the position of the hole mark is detected based on that. As described above, the hole punching position detection method for the multilayer printed wiring board according to the present embodiment, the bar scale pattern having the xy coordinate system information of the inner layer circuit board is formed simultaneously with the inner layer circuit pattern, and the A part of the transmissive bar scale pattern is transmitted, the xy coordinate system information is read from the light transmission image, and the position of the hole mark that has been determined in advance is detected on the outer metal foil surface based on it. I am trying to do it. Since the bar scale pattern is used in this way, the hole mark position can be detected with high accuracy and ease, and full automation can be realized. In addition, since an inexpensive means called light transmission is used, the hole mark position, that is, the hole mark position, The automation of the detection of the drilling position can be realized at low cost. In this embodiment, the multilayer printed wiring board is mounted on an XY table that operates based on an XY coordinate system different from the coordinate system of the inner layer circuit board. With this XY table, the multilayer printed wiring board is moved to the spot where it is spotted. As shown in FIG. 4, there are end mills (bottom milling cutters) 12a and 12b on the upper and lower sides of the pedestal 11, respectively, as shown in FIG.
The pedestal 11 has a hole 11 for receiving the lower end mill 12b.
a is formed. First, the bar scale pattern 8a
Upper end mill 12a from above the part where the
Is lowered to form the spot facing hole 12c. At that time, the counterbore depth A is controlled by using the displacement of the end mill after the contact signal between the metal foil 5 and the end mill 12a is output by the conduction detector, or the elapsed time. Next, at the same position, the lower end mill 12b is raised to form the counterbore hole 12c, and the counterbore depth B is controlled in the same manner as the upper end mill 12a, although not shown. At this time, the upper counterbore 1
The distance C between the bottom surface of 2c and the bar scale pattern 8a is preferably about 0.1 to 0.3 mm, and the counterbore depth B of the lower counterbore hole 12c is preferably about 0.1 mm. However, the numerical value concerning the spot facing depth is not limited to the above numerical value. In the figure, 13 is an airtight chamber, 13a is an air jet passage for blowing off the chips adhering to the surface of the end mill 12a by spot facing, 13b is a dust collection passage for collecting chips and the like in the airtight chamber 13, and 14 is A rubber material for increasing the airtightness of the airtight chamber 13, 15 a contact pin for contacting the metal foil 5 and connecting it to the continuity detector, 15a a pin having the same shape as the contact pin 15, 16 and 16
a is a spring that biases the contact pins 15 and 15a downward, 17 is a brush for connecting the rotor 18 connected to the end mill 12a and the continuity detector, 17a is a brush holder, and 19 is an end mill 12a. Is a timing belt for rotating the.

After finishing the counterbore processing from both sides of the bar scale pattern, the counterbore portion of the multilayer printed wiring board is moved to below the ITV camera (industrial television camera) by the XY table. Illumination by an optical fiber is applied to the spot facing portion from below, and a light transmission image of the bar in the spot facing portion is captured by the ITV camera. If this light transmission image is processed,
As shown in FIG. 3, the inclination θ between the xy coordinate system of the inner layer circuit board and the XY coordinate system which is the coordinate system of the XY table is calculated. In addition, the positional deviation between the xy coordinates (xi, yj) of the center position of the bar and the coordinates (Xi, Yj) of the same distance position in the XY coordinate system is calculated. Therefore, if the inclination θ and the positional shift are input to a computer and calculated, the origin of the xy coordinate system can be calculated as the coordinates (X ₀ , Y ₀ ) on the XY coordinate system. And this coordinate (X ₀ ,
The position of the hole mark can be known on the surface of the outer-layer metal foil by tracing the distance from Y ₀ ) to the position of the hole mark which is determined in advance based on the xy coordinate system. As shown in FIG. 2, another bar scale pattern 8b is formed on the peripheral portion of the inner layer circuit board 1. With respect to the bar scale pattern 8b as well, if the spot facing processing and the image processing of the light transmission image of the spot facing portion are performed in the same manner as described above, the inclination between the xy coordinate system and the XY coordinate system of the internal circuit board will be described. And the shift can be calculated more accurately. If the position of the hole mark is detected,
The multi-layer printed wiring board is moved by the XY table, and a reference hole is formed in the hole mark with a drill.

In a multilayer printed wiring board, the position of the inner layer circuit board may deviate from the outer layer material by several millimeters or tilt when laminating the outer layer material on the inner layer circuit board or when performing heat and pressure processing thereafter. It is easy to do. Therefore, the deviation of the inner layer circuit board and the inclination of the inner layer circuit board are known by the above-described method, so that the error in the position of the reference hole is suppressed to 0.05 mm or less.
However, the inner layer circuit board may expand and contract during heat and pressure molding. Therefore, in order to further improve the accuracy of the reference hole drilling position, the multi-layer printed wiring board is moved by the XY table, and the counterbore processing is performed from both front and back positions of the hole mark in the same manner as the counterboring process of the bar scale pattern. I do. Further, as shown in FIGS. 5 and 6, the hole mark 1b is illuminated from below by the optical fibers 20 and 20, and the ITV camera 21 captures a light transmission image of the hole mark 1b. If this light transmission image is subjected to image processing, the hole mark 1
Since the center point 26 of b is calculated, the drilling position of the reference hole can be detected with high accuracy. Therefore, the multilayer printed wiring board 7 is moved based on the XY table (not shown),
The center point of the hole mark 1b is installed directly above the center axis of the drill 22. Thereby, the reference hole can be formed with high accuracy. In FIG. 5, 11 is a pedestal and 23
Is a holding member for forming a hermetically sealed state on the surface of the multilayer printed wiring board 7 and holding the wiring board 7, and 23a is a drill 2
After air is blown out to blow off the chips after the hole is formed by 2, 23b is transparent glass, 24 is a counterbore hole, 25 is a chip collecting path, and 27 in FIG. 6 is a field of view of the ITV camera.

The hole mark detected by the hole punching position detecting method of the multilayer printed wiring board according to the present invention indicates the position of the reference hole for forming the outer layer circuit in the embodiment. But,
The present invention is not limited to this, and for example, holes for through-hole plating may be shown. Also,
There is no particular limitation on the number of hole marks formed. The same applies to the bar scale pattern.

In the embodiment, when the light transmission image of the bar scale pattern or the hole mark is picked up, the ITV camera is picked up from above so that the illumination is applied from the lower side. However, the positions of the illumination and the ITV camera are not limited to those in the embodiment. In addition, a device for capturing a light transmission image is an ITV.
The image capturing device is not limited to the camera and may be another image capturing device.

〔The invention's effect〕

Since the present invention is configured as described above, it is possible to detect the hole mark position in the multilayer printed wiring board with high accuracy and easily, and it is possible to realize the full automation of the hole mark position detection. Play.

In the present invention, the reason why the hole mark position can be detected with high accuracy in the multilayer printed wiring board is that the hole mark position is detected based on the position information of the bar in the bar scale pattern. Due to.

The bar scale pattern according to the present invention is made up of a large number of minute bars. The bar scale pattern is provided with information on the xy coordinate system that serves as a reference for determining the coordinates of the hole mark, that is, each bar has a hole. The position information is accurately associated with the mark position, and the position of the hole mark can be accurately determined based on the position information of this bar.

Large marks cannot have position information accurately associated with hole mark positions, but in the case of a bar scale pattern, since individual bars are very small marks, they are accurately associated with hole mark positions. Location information can be added to the bar. According to the present invention, the hole mark position can be detected with high accuracy by using the bar scale pattern utilizing the above-mentioned property of the minute mark.

In the present invention, the reason why the hole mark position in the multilayer printed wiring board can be easily detected is that the hole mark position can be easily calculated by calculation after obtaining the position information of the bar. This is because it is easy to obtain information in the case of the present invention.

In order to obtain the position information of the bar, it is necessary to search for a minute bar that cannot be seen from the surface. However, in the case of the present invention, it is not necessary to search for all the bars of the bar scale pattern, and some and unspecified A bar is sufficient, and as a result, the bar is searched for not the individual minute bar but the bar scale pattern itself larger than the hole mark. As a result, the search can be automatically performed easily. The bar to be searched may be a partial and unspecified bar, of course, because each bar has position information accurately associated with the hole mark position.

In the case of the bar scale pattern, there is no limitation on the method of capturing the image of the bar, the hole mark position can be detected with high accuracy and easily in the multilayer printed wiring board, and the hole mark position detection is fully automated, and the entire hole drilling process is performed. The present invention can be said to be very useful because it can be automated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view for explaining a conventional example of a hole punching position detecting method for a multilayer printed wiring board, and FIGS. 2 to 4 are one example of a hole punching position detecting method for a multilayer printed wiring board according to the present invention. 2 is a plan view showing a multilayer printed wiring board, FIG. 3 is an enlarged view showing an example of a bar scale pattern, FIG. 4 is a cross-sectional view showing a spot facing process, FIG. FIG. 5 is a cross-sectional view illustrating a method of capturing a light transmission image of a spot facing portion, and FIG. 6 is a plan view showing the spot facing portion above the hole mark. 1 ... inner layer circuit board, 1a ... inner layer circuit, 1b ... hole mark, 5 ... outer layer metal foil, 7 ... multilayer printed wiring board, 8a,
8b: bar scale pattern, 26: hole mark center position

Claims (1)

[Claims] 1. A hole forming position of a multilayer printed wiring board, wherein hole marks indicating hole forming positions are formed at appropriate positions on an inner layer circuit board, by detecting the position of the hole marks. A method for detecting a hole punching position of a multilayer printed wiring board for detecting, wherein a plurality of rectangular bars having information of an xy coordinate system, which is a reference for determining the coordinates of the hole mark, is previously provided in the peripheral portion of the inner layer circuit board. An individually arranged bar scale pattern is formed at the same time as the circuit pattern, at least a part of the bars of the bar scale pattern is detected, the information of the xy coordinate system is read, and the xy coordinate system is read based on the read xy coordinate system information. This is a method of detecting the position of a hole mark whose coordinate position in the system is known in advance, and each bar of the bar scale pattern has vertical and horizontal sides parallel to the x-axis and the y-axis, and a vertical and horizontal length dimension. Each bar Holes drilled position detection method of the multilayer printed wiring board, characterized by being formed as a function value of the xy coordinates of the center position of the.