JPH0761638B2 - Drilling method for multi-layer printed wiring board reference holes - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drilling method for a multilayer printed wiring board, and more particularly to a positioning method for a drilling position of a reference hole that serves as a reference for the drilling position during through-hole processing. is there.

(Prior art) A multilayer printed wiring board, if necessary, a plurality of inner layer circuit boards on which inner layer circuits are formed are aligned and superposed by a prepreg, and further, on one side or both sides via a prepreg, It is manufactured by stacking outer layer materials (single-sided copper clad laminate or copper foil) and heating and pressing. Thereafter, in order to electrically connect circuits of different layers, a hole (through hole) penetrating the conductor portion of each layer is formed, and the inner wall of the hole is plated. If the drilling position of the through hole is not correct, electrical connection will not be possible. Therefore, a reference hole is formed at a fixed position on the multilayer printed wiring board, and a hole for a through hole is formed on the basis of this hole. This reference hole is provided with a reference hole position indicating mark on the inner layer circuit board and the reference hole position indicating mark is exposed by means such as end mill cutting, or the position is confirmed by X-ray fluoroscopy and a hole is formed at the center. It is opened.

(Problems to be Solved by the Invention) Recently, a plurality of multilayer printed wiring boards have been manufactured by one press. That is, a multilayer printed wiring board including a plurality of unit multilayer printed wiring boards (this is referred to as a multi-sided multilayer printed wiring board) is manufactured, cut into unit printed wiring boards, and then subjected to required processing.

When the inner layer circuit board, the prepreg and the outer layer material are stacked and heated and pressed, the resin in the prepreg melts and flows,
It is well known that inner circuit boards have dimensional changes.
In a multi-faced multilayer printed wiring board, the dimensional change after molding is not uniform and varies depending on the position. For example, at the end of the printed wiring board with multiple faces, the deformation shown in FIG. 1 is performed.

In the modified printed wiring board, a reference hole is formed at the center of the reference hole position display mark as in the conventional case, and a through hole is formed at the design position with reference to the reference hole. It will be out of position.

Therefore, it was attempted to perform a number of molding experiments, obtain the average value of the displacement amount of the circuit in advance, and open a reference hole at a position displaced from the position of the reference hole position display mark. However, it is necessary to perform a large number of molding experiments, and the amount of displacement may not be constant due to changes in molding conditions.
It has not been adopted yet.

It is an object of the present invention to provide a simple method for determining a position for making a reference hole.

(Means for Solving the Problems) In the present invention, at least a pair of reference hole position indicating marks are provided, and one of the marks is used as an origin of orthogonal coordinates, and a straight line connecting the mark and another mark passes through the origin. The position (coordinates) of the reference hole position display mark and the position of a specific portion of the inner layer circuit are seen through an X-ray through a multilayer printed wiring board having an inner layer of a circuit board having a straight line orthogonal to the y axis as the x axis. Knowing (x coordinate, let this be x), and regarding the position (coordinate) of a specific portion of the inner layer circuit, the design position (x coordinate,
Displacement from this (X) (x-axis displacement | x−X
|) To obtain the correction value S such that S <| x−X |
From the position of the reference hole position display mark, when the correction value S is the designed x-coordinate X and the corrected design x-coordinate is X ', parallel to the x-axis direction so that X'is between x and X. The feature is that a reference hole is formed at the moved position.

As the position (x) of the specific portion of the inner layer circuit, the end portion of the circuit board is selected so that the maximum displacement amount | x−X | is known, and the correction value S is 1/2 of the maximum displacement amount. Then, the deviation of the drilling position due to the different displacement amount depending on the position in the circuit board can be reduced. In the xy coordinates in FIG. 1, p _n (x _n , B) in the first quadrant has a relationship with the designed drilling position X _n because the inner layer circuit board is displaced in the positive direction of the x axis. _n > X _n ,
To set S <| x-X |, set _Go (0,0) as the origin of the coordinates to x
The reference hole is G _o ′ (S, 0) translated in the positive direction of the axis.

Hereinafter, description will be given with reference to the drawings.

Consider a case where a reference hole is formed in a multilayer printed wiring board which is deformed as shown in FIGS. 1 and 3. The coordinates of the pair of reference hole position display marks provided on this printed wiring board are
Let G ₀ (0,0) and G ₁ (0, A). In addition, a specific portion of the inner layer circuit is defined as a clearance hole or pad at the substantially central end of the inner layer circuit board, and the actual measurement value of the coordinate is set to p _n (x _n , B), and the design coordinate value of this clearance hole or pad is set. To P _n
Let (X _n , B). Drill a reference hole at G ₀ (0,0), G ₁ (0, A),
When drilling this clearance hole or pad with reference to this reference hole, the hole for this clearance hole or pad should be drilled at a position (x _n -X _n ) displaced from the actual position of the clearance hole or pad. become. This deviation is small in the clearance hole or pad near the reference hole, and becomes large as the distance from the reference hole increases. Therefore, a reference hole is formed at a position translated (x _n -X _n ) / 2 in the x-axis direction, and the reference hole is used as a reference to form a design position. Then, in the vicinity of the reference hole, a hole is drilled at a position shifted by + (x _n -X _n ) / 2 from the regular position (measured value), and p _n is shifted by-(x _n -X _n ) / 2. Drilled in position. After all, the maximum value of the deviation is the absolute value of (x _n -X _n ) / 2. That is, the reference hole position indication marks G ₀ , G ₁
The holes located in the vicinity are shifted by the correction value S and increase from zero to S, and the displacement of the holes near xn is reduced from | x _n -X _n | to | x _n -X _n | / 2. . Since the absolute value of the deviation is nearly half in the present invention, the positions of the clearance hole and the pad have a smaller variation from the designed position, and the electrical insulation or connection can be improved with reliability.

FIG. 2 shows an apparatus for carrying out the method of the present invention. The XY table 1 has a measuring function such as a magnetic measuring scale, on which a product 2 to be punched is placed, and the product 2 is fixed by a clamp 3. XY table 1
The table surface of is made of glass or plastics with little X-ray attenuation. This table surface contains a mark or guide parallel to the xy axis so that rough positioning can be performed when the product 2 is placed. Align each central axis on one vertical line on the table surface of the XY table 1.
An X-ray irradiation tube 4 and an image pickup tube 5 are arranged across the XY table 1. The drill 6 is arranged parallel to the central axis of the image pickup tube 5 at a distance 1 from the image pickup tube 5. The XY table 1, the X-ray irradiation tube 4, the image pickup tube 5 and the drill 6 are housed in an X-ray shielding box 8. The X-ray image captured by the image pickup tube 5 is displayed on the screen of the monitor television 7.

The procedure of the actual drilling work will be described below.

The position of the center of the image captured by the image pickup tube 5 on the screen of the monitor TV 7 is checked in advance.
Place the product 2 with the end face aligned with the marked line of the XY table 1,
Fix with clamp 3. Move the XY table 1 so that the reference hole position display mark G ₀ is located just below the image pickup tube 5, and X
Finely adjust the XY table 1 so that the center of the image of the reference hole position display mark G ₀ coincides with the center of the image captured by the image pickup tube 5 by irradiating a line, and reset the value of the magnetic measurement scale. To (0,0). Next, the XY table 1 is moved to obtain the coordinates (0, A) of the reference hole position display mark G ₁ . Next, the coordinates (x _n , B) of a certain pattern p _n that have been determined in advance
Ask for. Then, as compared with the design coordinates (X _n , B), as described above, the correction value S is S <| x _n from the positions of G ₀ and G _1.
S is calculated to be -X _n |, and when the x coordinate by correcting the design x coordinate X is X ', the reference hole is shifted to a position where X'is translated between x and X. Open Actually, since the position of the drill is a distance l away from the image pickup tube 5, when making a reference hole in the reference hole position display mark G ₀ , when the reading of the magnetic measurement scale is x _n > X _n ,
When making a reference hole at (l + S, 0) or at the reference hole position display mark G ₁ , the reading on the magnetic measuring scale should be (l + S
Move the XY table 1 so that it becomes S, A) and make a hole. When x _n <X _n , the reference hole of G ₀ is (1−S, 0), and when the reference hole position display mark G ₁ is to be formed,
X so that the reading of the magnetic measuring scale becomes (l-S, A)
Move the Y-table 1 to make a hole.

EFFECTS OF THE INVENTION According to the present invention, the coordinates of the reference hole position display mark and the coordinates of a certain pattern are obtained by X-ray fluoroscopy to determine a correction value, and the deformation of the multilayer printed wiring board to be drilled is known, and the reference hole position display The reference hole is used as a reference for drilling by shifting it from the mark, and the hole is drilled at the designed position based on the hole so that the deviation of the drilling position due to the deformation of the multilayer printed wiring board can be averaged. The gap disappears.

[Brief description of drawings]

FIG. 1 is a plan view of a modified multilayer printed wiring board for explaining the present invention, and FIG. 2 is a side view in which a device for carrying out the present invention is cut away. FIG. 3 is a plan view of a multilayer printed wiring board including symbols in FIG. 1 for explaining the present invention. Explanation of code 1 …… XY table 2 …… Product 3 …… Clamp 4 …… X-ray irradiation tube 5 …… Sensor tube 6 …… Drill 7 …… Monitor TV 8 …… X-ray shielding box

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kaname Takee Kaname Takegawa, Shimodate, Ibaraki 1500 Ogawa, Shimodate, Hitachi Chemical Co., Ltd. (72) Fumio Miyata, Ogawa, Shimodate, Ibaraki 1500 Hitachi Chemical Company Shimodate Factory

Claims (2)

[Claims] 1. An inner layer circuit and an inner layer circuit board on which reference hole position indicating marks are formed, if necessary, aligned by a plurality of prepregs to be superposed, and further, single-sided copper on both sides or one side via a prepreg. In the method of stacking the laminated laminates or copper foil, heating and pressurizing the whole and integrally laminating it, then making a hole in the reference hole position indication mark and making a hole at the design hole position based on this hole A circuit having at least a pair of reference hole position indicating marks in which one of the marks is the origin of Cartesian coordinates, the straight line connecting this mark and another mark is the y-axis, and the line passing through the origin and orthogonal to the y-axis is the x-axis The X-ray is used to see through the multilayer printed wiring board having the board as the inner layer, and the coordinates of the reference hole position display mark and the x-coordinate of a specific portion of the inner-layer circuit (this is referred to as x) are known.
Regarding the coordinates of a specific portion of the inner layer circuit, the displacement amount | x−X | in the x-axis direction is calculated from the designed x-coordinate (this is X), and the correction value S becomes S <| x−X | And the design x-coordinate X is defined as the corrected design x-coordinate, then X'is x.
And X, a position where the correction value S is translated in parallel with the x-axis direction from the position of the reference hole position display mark is set as a reference hole position, and the reference hole position is formed. 2. The x coordinate of a specific portion of the inner layer circuit,
1/2 of the value obtained by subtracting the design value X from the measured value x is the correction value (S = |
x-X | / 2), The method for drilling a reference hole of a multilayer printed wiring board according to claim 1, wherein