JPH0221001B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a suitable drilling control method applied when drilling holes in a multilayer printed circuit board using an NC drilling machine.

Recently, this type of printed circuit board has become more dense,
Although there is a trend toward finer patterns, conventionally when drilling holes in such substrates using an NC drilling machine, the drilling machine was controlled using the drilling information set in advance at the design stage. However, with these control methods, it is not possible to correct the variations that occur during the process in each substrate, that is, the overall deviation of the pattern as a whole, and the deviation due to expansion and contraction of the base material that occurs in the intermediate layer during lamination, and it is not possible to correct the deviation that occurs in the process of each substrate. There is a drawback that so-called intermediate layer land breakage failure occurs in which the opening position deviates from the target intermediate layer land pattern.

Therefore, the present invention forms a plurality of target patterns on the intermediate layer of a printed circuit board, and calculates the total amount of deviation from the difference between the designed coordinates of the target patterns and the actual coordinates, and calculates the designed pitch between each pattern. A drilling control method for an NC drilling machine that eliminates the above-mentioned drawbacks by calculating the base material expansion/contraction amount from the actual pitch difference, and correcting the coordinates of the drilling position in the drilling information based on these amounts. The purpose is to provide the following.

Hereinafter, the present invention will be specifically explained based on an embodiment shown in the drawings.

As shown in FIG. 1, the NC drilling machine 1 consists of a data processing device 2 storing drilling information, a numerical control device 3, and a main body 5. The main body 5 has a frame 6.
have. A table 7 is provided on the frame 6 so as to be movable and driven in the directions of arrows A and B by a motor 9. Furthermore, a head 10 is mounted on the upper part 6a of the frame 6, and a table 7 is mounted by a motor 11 to move at right angles to the directions of arrows A and B. It is provided so that it can be freely moved and driven in the directions of arrows C and D. A sub-head 12 is provided in the head 10 and is movably driven by a motor 13 in the directions of arrows E and F, which are perpendicular to the directions of arrows A, B, C, and D, that is, in the vertical direction in the figure. are provided with drilling devices 15, 15 and a pattern reading device 16. The reading device 16 has a laser 17 and a sensor 19 that captures the light from the laser 17, as shown in FIG. As shown in FIG.
20c and 20d are formed, respectively.

Since the NC drilling machine 1 has the above-described configuration, when drilling a hole in the multilayer printed circuit board 20, first, the board 20 is counterbore, and four dummy land patterns 20a, 20b, 20c, 20 are formed.
The substrate 20 is set on the table 7 with the portion d exposed. Next, dummy land patterns 20a, 20b, 20c, 20d included in the drilling information
Based on the positional information of
Read each coordinate position of 0b, 20c, and 20d. At this time, as shown in FIG. 2, a laser beam 21 is emitted from the laser 17 of the reading device 16 toward the printed circuit board surface 20e, and the sensor 19 captures the reflected light 22, but due to the movement of the table 7 etc. When the laser beam 21 reaches the counterbore 20f, the reflection point 21a of the beam 21 shifts to the lower patterns 20a, 20b, 20c, and 20d in the figure, so the reflected light 22 no longer enters the sensor 19, and at that point So patterns 20a, 20b,
The coordinates of 20c and 20d are calculated by the data processing device 2. In this way, each pattern 20a, 2
The actual coordinates of 0b, 20c, 20d are drill press 1
With the origin G as a reference, as shown in Figure 3,
(X′ ₁ , Y′ ₁ ), (X′ ₂ , Y′ ₂ ), (X′ ₃ , Y′ ₃ ), (
_X'4 ,
Y′ ₄ ), the difference between the actual coordinates and the designed coordinates of the dummy lands 20a, 20b, 20c, and 20d, that is, the total amount of deviation _Z
Z _Y is calculated in the X and Y directions using equations (1) and (2). Each pattern 20a, 20b, 20c, 20d
The design coordinates of (X ₁ , Y ₁ ), (X ₂ , Y ₂ ), (X ₃ ,
_{Y 3} ) _{, ( X 4 , Y 4 ) , Z Y} = ( _Y'1 + _Y'2 + _Y'3 + _Y'4 )/4- ( _Y1 + _Y2 + _Y3 + _Y4 )/4...(2) Next, patterns 20a, 20b, 20c, 20
From the coordinates of d, the actual pitch P′ _X1 between each pattern,
Calculate P′ _X2 , P′ _Y1 , P′ _Y2 in the X and Y directions,
The average difference between the design pitches P _X and P _Y is calculated using equations (3) and (4)
, and the base material expansion/contraction amounts L _X and L _Y between the intermediate layer patterns on the substrate 20 are calculated in the X and Y directions.

L _X = {( _{P ′ X1} −P _{X ) + (} P′ _{X2 −P} /2...(4) Using the total deviation amounts Z _X , Z _Y and the base material expansion/contraction amounts L _X , L _Y obtained in this way, the coordinates (x, y)
is corrected using equations (5) and (6), and the coordinates (x′, y′) of the drilling position are calculated by taking into account the total amount of deviation and the amount of expansion and contraction of the base material.
Calculated as

x′ ₌ x+( _x /P _x ) _{L X} + _Z Then, the numerical control device 3 drives the table 7 and the head 10, sets the drill device 15 at the corrected drilling position coordinates (x', y'), lowers the sub-head 12 in the F direction, and lowers the sub-head 12 to the substrate. Drill a hole on 20.

Note that the above-mentioned embodiment is based on the pattern reading device 1.
Although a case has been described in which a target pattern such as the dummy land pattern 20a 6 is detected using the laser beam 21, various other methods can be considered as a method for detecting the target pattern. That is, the fourth
As shown in the figure, X-rays 25 are emitted from the X-ray generator 23.
A method of irradiating light 29 onto the substrate 20 with a half mirror 28 and capturing the pattern 27 by projecting it on a screen 30 as shown in FIG. 5. can also be considered.

Furthermore, as shown in Fig. 3, the number of target patterns is not limited to four, but two or more can be provided, and in the case of two, the amount of expansion and contraction of the base material can be captured only in one direction. The correction may be made in a simple manner, and if there are five or more blocks, the substrate 20 may be divided into several blocks to perform more precise correction.

As explained above, according to the present invention, the dummy land pattern 20 is provided in the intermediate layer of the printed circuit board 20.
A, 20b, etc. are formed, and the design coordinates (X ₁ ,
Y ₁ ), (X ₂ , Y ₂ )...and the actual coordinates (X′ ₁ , Y′ ₁ ),
(X′ ₂ , Y′ ₂ )...and the actual pitch between each pattern P′ _X1 , P′ _X2 , P′ _Y1 , P′ _P2 and the designed pitch
_{Calculate the difference between P _} y) is corrected, it becomes possible to accurately drill holes in the multilayer printed circuit board 20 while taking into account the variations in the board 20, thereby preventing the occurrence of land breakage defects, etc., and making the board 20 even better. This can contribute to higher density.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of an NC drilling machine to which the present invention is applied, FIG. 2 is a view showing a pattern reading device, FIG. 3 is a plan view showing a printed circuit board, and FIGS. 4 and 5 are patterns It is a figure which shows another example of a reading device. 1... NC drilling machine, 20... Printed circuit board,
20a, 20b, 20c, 20d...Target pattern (dummy land pattern), 27...Target pattern, _PX , _PY ...Design pitch, _P'X1 , _P'X2 ,
P′ _Y1 , P′ _Y2 ...Actual pitch, (X ₁ , Y ₁ ), (X ₂ ,
Y ₂ ), (X ₃ , Y ₃ ), (X ₄ , Y ₄ )...Design coordinates,
(X′ ₁ , Y′ ₁ ), (X′ ₂ , Y′ ₂ ), (X′ ₃ , Y′ ₃ ), (
_X'4 ,
Y′ ₄ )...Actual coordinates.

Claims (1)

[Claims] 1. In an NC drilling machine that drills holes in a multilayer printed circuit board based on drilling information, multiple target patterns are formed in the intermediate layer of the printed circuit board, and the total number of target patterns is calculated based on the difference between the designed coordinates and the actual coordinates of the target patterns. The amount of deviation is calculated by calculating the amount of expansion and contraction of the base material from the difference between the designed pitch and the actual pitch between each pattern.
A drilling control method for an NC drilling machine configured by correcting the coordinates of the drilling position in the drilling information based on these quantities.