JPS61249205A - Reference hole drilling device of multilayer printed wiring board - Google Patents

Abstract

PURPOSE:To perform automatic reference hole drilling by providing a means for detecting an edge mark position by scanning the surface of a multilayer printed wiring board, a means for estimating a hole mark position and an image processing means for judging the center position of the hole mark. CONSTITUTION:Metal-made edge marks 8a-8c which become references for determining coordinates of a hole mark 1b are formed on the peripheral edge of a circuit pattern 1a which has the hole mark 1b on an inner layer circuit board 1. Then an eddy current type sensor is scanned to measure the position of the hole mark 1b, and spot facing holes 12c, 12c are formed on the surface and the back face with upper and lower end mills 12a, 12b. And these spot facing holes 12c portions are picked up by an ITV camera and an optically transmitted image is processed to detect the center point of the hole mark 1b, and substantial drilling is made with a drill. This device can perform automatic drilling work, so highly accurate drilling of a reference hole can be made.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field J] The present invention relates to a device for punching reference holes in a multilayer printed wiring board.

[Background technology 1 Electronic B! Multilayer printed wiring boards used for appliances and the like are generally manufactured as follows. First, metal foil is pasted on both sides or one side of the inner layer prepreg, and an inner layer circuit is formed thereon to produce an inner layer circuit board. Then, prepregs for the outer layer are superimposed on the top and bottom of the inner layer circuit board or a plurality of inner layer circuit boards arranged in a plane, and metal foil is further superimposed on the outside of these, followed by heating and pressure forming. .

After that, for one inner layer circuit board or a plurality of inner layer circuit boards arranged in a plane, rough cutting is performed for each inner layer circuit. By the way, for the intermediate product of the multilayer printed wiring board produced after the above-mentioned molding, the hole mark displayed on the surface of the inner layer circuit board for indicating the position of the reference hole is detected from the outermost layer metal foil side.

A spot with a hole mark is counterbored from above to expose the hole mark, and a reference hole is drilled in the center of this hole mark.

Then, by forming an outer layer circuit on the outermost layer of metal foil using this reference hole as a reference, a multilayer printed wiring board is completed.

However, the above method has the following problems. In intermediate products of multilayer printed wiring boards that are composed of a plurality of inner layer circuit boards arranged side by side,
Since the inner layer circuit board is hidden from view by the outermost layer of metal foil, it is difficult to determine the rough cutting position.b. When trying to find the hole mark, the hole mark is blocked by the outermost layer of metal foil. The exact position of the hole mark is becoming increasingly difficult to determine because the hole mark cannot be seen and the exact position cannot be determined, and because misalignment is likely to occur between the outer layer and the inner layer circuit board during C0 heating and pressure molding. In order to solve the above-mentioned problems, the following hole mark detection method has been devised.

In other words, after forming the inner layer circuit C and hole mark B on the inner layer prepreg, with a patch (lf ID mark) pasted on the hole mark B in advance, the outer layer prepreg D and metal foil E are stacked and heated and pressed. The intermediate product of the completed multilayer printed wiring board is raised by the thickness of the patch, and the part on the metal foil is visually determined to be slightly shiny. After that, counterbore the determined position and counterbore 6A.
is opened as shown in FIG. 8(a), and then the patch is peeled off to expose the hole mark B as shown in FIG. 8(b).
In this method, the adhered resin is further polished to clearly expose the peel-off hole mark B, and the center position X of the hole mark B is determined using a magnifying scope.

However, this method also requires a patching process.

Moreover, since the counterbore position is detected visually, it is difficult to counterbore at an accurate position.Furthermore, the depth to of the counterbore 9 holes A was determined by the operator's intuition, so it was difficult to counterbore to an appropriate depth. It required considerable skill to do so. Therefore, counterbore and drill holes have a problem of low positional accuracy and lack of reliability.

Furthermore, as described above, the resin adheres to the hole mark surface, which poses an aesthetic problem, and the holes also cause a decrease in positional accuracy. Furthermore, in addition to the above-mentioned patching process to indicate the hole mark position, manual work such as counterbore work, polishing to remove adhering resin, and drilling work is required, so the accuracy and quality of each work are affected. There was a problem with this, and it was extremely labor-intensive and difficult to ensure final accuracy. In other words, it was difficult to automate while ensuring accuracy.
Although we relied on the manual labor mentioned above, it turned out to be unreasonable in terms of quality and cost.

[Object of the Invention] The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a device for drilling reference holes in multilayer printed wiring boards that is automated at low cost and has high precision in the position of drilling reference holes. It is on offer.

[Disclosure 1 of the Invention The present invention provides a circuit pattern in which a hole mark indicating a reference hole drilling position is formed at an appropriate location on an inner layer circuit board, and an edge mark is formed on the surface of the inner layer circuit board to predict the formation position of the hole mark. a multilayer printed wiring board formed of metal foil on the peripheral edge thereof; an edge mark detection means for scanning the surface of the multilayer printed wiring board to detect the position of the edge mark based on a change in eddy current loss; A prediction means for predicting the position of the hole mark from the detection position of the hole mark, and a counterbore hole of a constant depth that is moved to a predetermined position on the upper and lower surfaces of the multilayer printed wiring board based on the prediction result of the prediction means. upper and lower end mills to be installed, a light projecting means for irradiating a light rope to the counterbore holes on either the top or bottom of the multilayer printed circuit board drilled by the end mills, and counterbore holes from the opposite side of the light projecting side. an imaging means arranged correspondingly to take a light transmission image, an image processing means for determining the center position of the hole mark from the image obtained by the imaging means, and a center position of the hole mark determined by the image processing means. The present invention is characterized in that it is equipped with a drill device that is moved to the center and drills reference holes in the multilayer printed wiring board.

This will be explained below using examples.

K19 FIG. 1 shows the inner layer circuit board 1 used in this embodiment,
On the inner layer circuit board 1, hole marks 1 b, 1 b,
Metal edge marks 8a=8b and 8c, which serve as references for determining the coordinates of 1b, are formed at the same time as the circuit pattern 1a. These edge marks 8a=8
b-8e is for determining the X and Y coordinate axes of the inner layer circuit board 1 as shown in FIG.
A straight line that is perpendicular to Tsumugi and passes through the center point of edge mark 8c is x
It is the axis. Each hole marker 21 according to these xy coordinates
The edge mark 8 a, which determines the coordinate position of b
, 8 b, and 8 c, as shown in FIG. 2, an eddy current sensor 9 is inserted inward (in the direction of the arrow, also shown in FIG. 1) while keeping a certain distance from the surface of the outer metal foil 5. The position is measured by scanning. This method uses eddy current loss to detect conductors. In this embodiment, since the eddy current loss due to the outer layer metal foil is constant, the change in eddy current loss when the outer layer metal foil and the metal edge mark overlap is detected. As shown in the graph of FIG. 2, when the eddy current sensor 9 that scans the surface of the outer metal foil 5 is located on the edge marks 8 a, 8 b, and 8 c where the first magnetic field change occurs, the sensor output is the first. It is designed to form a waveform to the peak point. Therefore, based on the change in the output of the eddy current sensor 9 that forms the first waveform peak point A, the positions of the plurality of edge marks 81LtBb, 8c are measured. and x defined on the inner layer circuit board 1.
The y-seat axis emerges on the surface of the outer layer metal foil 5. Therefore, the position of each hole mark 1b whose coordinates have been determined in advance along the xy coordinate axis can also be automatically known on the surface of the outer layer metal M5.

Once the position of the hole mark is detected, counterboring is then performed at that position.
If the y-coordinate of the hole mark 1b on the inner layer circuit board 1 is automatically replaced with the corresponding position on the outer layer metal foil by arithmetic processing or the like, automation of the counterboring process can be realized.

For example, as shown in FIG. 3, the XY coordinate axes are placed on the outline of the roughly cut multilayer printed wiring board 7 whose outermost layer is a metal foil for forming an outer layer circuit. X on one side of the outline
Take the axis, and take the Y-axis on the side perpendicular to the - side. And now Edgemark 8a.

8 b, 8 c XY)! ! ! Let each coordinate on the Ume system be (X
atYa), (Xb, Yb), and (Xc, Ye), the inclination θ between the xy coordinate axes of the inner layer circuit board 1 and the outer shape of the multilayer printed wiring board 7 is determined by the following equation 0.

The above coordinates (X , , Y o) are determined by the following equations 0 and 0.

X o ” X bcos2θ−YbsinθCO8θ
+X csin2θcosθ・・・・・・■Xcsin
θcosθ+ Yccos2θ0°...°°■Then, xyP of hole mark 1b that has been determined in advance! A mark wo (XLyi
), then the XY coordinates (X
i, Y i) can be obtained using the following formula 0 and ■.

X i = X o + xieosθ ten yisinθ river...
・■Y for Yi, -xisinθ+yicosθ...
...X of hole mark 1b found as above 0
By inputting the Y coordinate (Xi, Yi) into an arithmetic control means such as a computer, and controlling the counterbore means provided to move relatively according to the XY coordinates based on the information, the counterbore hole is formed. It is automatically formed at a position on the outer layer metal RTI.

In addition, in the above embodiment, the metal edge mark 8
The number of edge marks 8a, 8b, and 8c formed is not particularly limited, and the positions of edge marks 8a, 8b, and 8c do not have to be located on the xy coordinate axis.

FIG. 4 shows the configuration of a counterbore means consisting of a counterbore positioning NC feeding device, in which a multilayer printed wiring board 7 is placed on an XY table (not shown) that operates based on an XY coordinate system. . The multilayer printed wiring board 7 is moved to the counterbore location using this XY table. At this spot facing point, the end mill 12a serving as a spot facing means is provided on both the upper and lower sides of the table 11.
, 12b, and the lower end mill 12b is mounted on the stand 11.
A hole 11a is formed into which the receiver is inserted. Then, the end mill 12a is lowered from above and the counterbore hole 12c is cut into the fifth hole.
Form as shown in the figure. At this time, the counterbore depth Ll is controlled using the downward displacement of the end mill or the passage of time after the contact signal between the metal foil 5 and the end mill 12a is output by the continuity detector 28.

Next, the lower end mill 12b is raised at the same position to form the counterbore hole 12c, and the counterbore depth t2 is controlled in the same manner as the upper end mill 12a. At this time, the upper counterbore hole 1
The distance t between the bottom surface of the hole mark 2e and the hole mark 1b is approximately 0.1 to 0.
．． lam is desirable, and the counterbore depth j+*h is approximately 0.
．． The airtight chamber 13, which is preferably 25a in diameter, is connected with a dust collection path 13b for collecting dust, etc. inside, and a rubber material 14 is provided around the opening to improve airtightness.
Contact pin 15 and pin 1 for further metalization
5a, these contact pins 15, and a spring 16.16a that biases the bottle 15a downward.

The end mill 12 is rotationally driven by a timing belt 19.
A brush 17 connected to a continuity detector 28 is in sliding contact with a rotor 18 that rotates a, and this brush 17 is held by a brush holder 17a.

Now, when the counterbore processing from the front and back sides of the multilayer printed wiring board 7 is completed, the upper counterbore hole 12a portion of the multilayer printed wiring board is moved below the ITV camera 21 as shown in FIG. 6 using the XY table.

At this time, illumination by light 71 and IPA 20, 20 is applied obliquely from below the lower counterbore hole 12c, and a light transmission image appearing on the bottom surface of the upper counterbore hole 12c is imaged by the ITV camera 21 as shown in Figures #&7. If this light transmission image is subjected to image processing, the center point 26 of the hole mark 1b can be directly derived, so that the drilling position of the reference hole can be detected with high precision without error.

Then, the image processing device 29 binarizes the video signal obtained by imaging, and uses conventionally known methods such as centroid measurement method and long side 1/2 division method from the binarized image data. The center coordinates of the hole marker 21b are determined by the method, and the multilayer printed wiring board 7 is moved by controlling and driving an XY table (not shown) so that the drill bit 22 is positioned below the center coordinates. After that, the actual drilling begins. As a result, a reference hole with extremely high positional accuracy can be obtained. in this case,
The center axis of the drill 22 may be aligned with the center point of the hole mark 1b by attaching the drill rotation part to another fine movement XY table (not shown) and controlling and driving the fine movement XY table. Incidentally, sometimes the multilayer printed wiring board 7 is placed on the stand 11 and pressed from above by the pressing member 23, so that the front side is set in a sealed state. A transparent glass 23b is fitted on the upper surface of the holding member 23, and the ITV camera 21 captures a light transmission image through the transparent glass 23b. In addition, chips generated when drilling a hole with the drill 22 are blown away by the air jet passage 23a,
The chips are collected by the dust collection path 25.

As described above, the position detection of the hole marker 21b and the counterbore hole 12 are performed.
c, drilling 12c, further detecting the center point of hole mark 1b,
By automatically performing the work up to drilling the reference hole, it is possible to drill the reference hole with high precision.As a method for detecting the position of the hole mark 1b, the eddy current sensor 9 can be used as described above. Nick marks 8 a, 8 b,
In addition to the method of detecting 8c, there is also a method of capturing a light transmission image in the same way as detecting the center point of the hole mark 1b, or a method of forming the edge marks 8a, 8b, 8c with a magnetic material and using an outer layer of a non-magnetic material. Edge mark 8 at B b is detected from the surface of metal W5 by a magnetic sensor.

8c may be detected.

[Effect of the invention 1] The present invention provides a circuit in which a hole mark indicating the position of a reference hole is formed in an appropriate dark place on an inner layer circuit board, and an edge mark is formed on the surface of the inner layer circuit board to predict the formation position of the hole mark. Edge mark detection means uses a multilayer printed wiring board formed of metal foil on the peripheral edge of the pattern, scans the surface of the multilayer printed wiring board to detect the position of the edge mark without contact; Since it is equipped with a prediction means for predicting the hole mark position from the detection position, the position of the hole mark can be automatically detected with high accuracy, and the upper and lower surfaces of the multilayer printed wiring board can be detected based on the prediction result of the prediction means. Equipped with upper and lower end mills that are each moved to a predetermined position to drill a counterbore hole of a constant depth, so the machine automatically countersinks 9.
In addition to obtaining a counterbore hole with a certain depth, the finish of the bottom surface of the counterbore hole can be unified without variation, improving the appearance. A light projection means for irradiating a light beam onto a counterbore hole on either the upper or lower side of a printed wiring board; an imaging means arranged corresponding to the counterbore hole from the opposite side of the light projection side for capturing a light transmitted image; and an imaging means Since it is equipped with an image processing means that determines the center position of the hole mark from the image obtained by the image processing means, the center point of the hole mark can be automatically detected with high precision. It is possible to drill a reference hole at a highly accurate position using a drill device that is moved to a certain position.As mentioned above, since everything is automated, it improves accuracy and productivity that cannot be obtained from manual and visual work. This results in a significant improvement in the finish of the product, and also eliminates the need for patching, which eliminates defects such as scratches and foreign matter contamination caused by patching, and eliminates wire breaks and scratches that would otherwise occur due to these factors. This has the effect of significantly reducing the occurrence rate of serious defects in multilayer printed wiring boards such as boards, etc., and providing highly reliable products.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one aspect of the inner layer circuit board of the multilayer printed wiring board used in the embodiment of the present invention, FIG. The hole mark position is automatically set to W1! on the outer layer metal foil.
Figure 4 is a cross-sectional view of the same end mill part, Figure 5 is a cross-sectional view of the counterbore part value of a multilayer printed wiring board obtained by the same end mill, and Figure 6 is a cross-sectional view of the same hole. A cross-sectional view of the ITV camera that detects the mark and the drill part for drilling the reference hole, Figure 7 is an enlarged plan view of the counterbore hole according to the above, and Figures 8 (a) and (b) are the conventional multilayer A cross-sectional view and a plan view of counterbore hole values of a printed wiring board,
1 is an inner layer circuit board, 1a is an inner layer circuit, 1b is a hole mark, 5
is outer layer metal foil, 7 is multilayer printed wiring board, 8 a, 8 b
, 8c is Etsuno mark, 12a and 12b are end mills, 12c is counterbore hole, 20 is Hikari 7 fiper, 21 is IT
26 is a hole mark center position, and 29 is an image processing device. Agent Patent Attorney Ishi 1) Chief Figure 7 Figure 1 a C Figure 2 Figure 3 Figure 7 Procedural Amendment (Voluntary) June 10, 1985

Claims (1)

[Claims] 1) A hole mark indicating the position of the reference hole is formed at an appropriate location on the inner layer circuit board, and an edge mark to predict the formation position of the hole mark is formed on the surface of the inner layer circuit board.A metal is attached to the peripheral edge of the circuit pattern. An edge mark detection means for detecting the position of an edge mark without contact by scanning the surface of the multilayer printed wiring board using a multilayer printed wiring board formed of foil, and a detection position from the edge mark detection means. A prediction means for predicting the position of the hole mark, and a counterbore hole for drilling a counterbore hole of a constant depth by moving to a predetermined position on the upper and lower surfaces of the multilayer printed wiring board, respectively, based on the prediction result of the prediction means. An end mill, a light projecting means that irradiates a light beam onto a counterbore hole on either the upper or lower side of the multilayer printed wiring board drilled by these end mills, and a light projector that is arranged corresponding to the counterbore hole from the opposite side of the light emitter. an imaging means for taking a transmitted image; an image processing means for determining the center position of the hole mark from the image obtained by the imaging means; and a reference hole that is moved to the center position of the hole mark determined by the image processing means. 1. A reference hole drilling device for a multilayer printed wiring board, comprising: a drill device for drilling holes in a multilayer printed wiring board.