JP2579133B2 - Manufacturing method of multilayer printed wiring board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board, and more particularly to a method for manufacturing a multilayer printed wiring board capable of easily obtaining a high-precision multilayer printed wiring board.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become more sophisticated, the outer dimensions of electronic components have been reduced, and the density of printed wiring boards for mounting and holding electronic components and connecting the components has been increased. Higher precision, thinner and lighter weight are being developed. As methods to increase the density, precision, thinness and weight of printed wiring boards, reduction of conductor width and conductor gap, introduction of multilayer structure, thinning between layers, application of via holes, reduction of design grid Are mainly used. However, in order to introduce these techniques, it is necessary to increase the positional accuracy of the printed wiring board. In particular, in the case of a multilayer printed wiring board, it is important to accurately position each layer in order to ensure quality. FIGS. 13A to 13H and FIGS. 14A and 14B are cross-sectional views shown in the order of steps illustrating an example of a method for manufacturing a multilayer printed wiring board by a conventional pin lamination method. This example is a method for manufacturing a four-layer via-hole printed wiring board. First, a hole 2 is formed in the double-sided copper-clad laminate 1 shown in FIGS. 13A and 13E by, for example, drilling. , (F). Thereafter, for example, the plating layer 3 is formed to establish conduction between the front and back surfaces. For example, an etching mask for the circuit 4 is formed using a dry film etching resist, and then etching is performed using, for example, an aqueous ferric chloride solution. The circuit 4 is peeled off. This state is shown in FIGS.
It is. Thereafter, as shown in FIGS. 13D and 13H,
The reference hole 5 for alignment is processed to form the inner layer 7. Next, as shown in FIG. 14 (a), the inner layer 7 is attached to a steel lamination jig 8 via a laminating pin 9 with a head plate 19, an inner layer 7,
The prepreg 12 is stacked in combination, heated under pressure, and adhered as shown in FIG. 14b. Thereafter, drilling, plating, circuit formation, solder resist printing, character printing, external processing, surface treatment, and the like were performed to obtain a multilayer printed wiring board.

In contrast to the conventional method for manufacturing a multilayer printed wiring board, a method for improving the alignment accuracy of each layer is generally described as follows in the lamination shown in FIGS. 14 (a) and 14 (b). A method of increasing the number of laminated pins per unit area is used. This is based on the idea of increasing the density of the laminated pins, shortening the distance from the pins, and improving the accuracy, because the positional accuracy during lamination deteriorates as the distance from the laminated pins increases. The following method has been proposed as a similar method.

(2) In the printed circuit board laminating method disclosed in JP-A-1-136709, another reference hole is formed in a circuit formation region of an inner layer, and the reference hole has the same length as the plate thickness after lamination. A method of inserting a stacking pin and stacking under pressure.

The following method has also been proposed.

(3) In the method of manufacturing a multilayer printed wiring board disclosed in Japanese Patent Laid-Open Publication No. 4-326597, a float pin having a laminated pin fixed to a jig and a float pin that freely moves in the direction in which the material expands and contracts is used. A method of fixing the inner layers, and using a hole in the inner layer material, prepreg, or copper foil for the fixing pin as a long hole so that it can be freely expanded and contracted while maintaining the position accuracy, thereby increasing the position accuracy.

[0007]

However, in the method (1), the number of pins of the lamination jig increases. For this reason, there arises a problem that the lamination jig must be dedicated.

In the method (2), since the reference hole is formed only in the inner layer having low strength and moves due to the flow of the resin during lamination, the relative positional accuracy between the layers can be improved, but the absolute position can be improved. Accuracy cannot be improved.

Since the laminated pins are embedded in the product area, a step of removing the pins is required.

It is difficult to set the length of the laminated pins. If the length is too long, the pins come into contact with the laminating jig and the jig is deformed or the printed wiring board is damaged. If the length is too short, the inner layer comes off the pins and the positional accuracy is deteriorated. There is a risk of occurring.

There are the following problems.

In the method (3), since the float pins are movable, it is necessary to form a groove in the stacking jig, and the structure of the stacking jig becomes complicated.

[0013] Slotting is required.

Due to the structure, only one printed wiring board can be manufactured with one jig. And so on.

An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board in which a high-precision multilayer printed wiring board can be easily and inexpensively obtained.

[0016]

SUMMARY OF THE INVENTION The present invention provides an inner layer having a conductive circuit formed on both sides, an inner layer having a through hole electrically connecting the conductive circuits formed on both sides, or an inner layer having a conductive circuit on one side. Alternatively, a plurality of inner layers of an inner layer having a conductive circuit on one surface and having a through hole electrically connected to the opposite surface are formed of two copper foils or a pair of end plates disposed on the outer side by arranging the inner layer on the outside. And a step of forming a multilayer by heating and pressure bonding with a laminating jig, and a step of forming a conductive circuit and a through hole connecting the front and back and the inner layer in the copper foil or the inner layer disposed outside. In the method for manufacturing a multi-layer printed wiring board, the step of forming a plurality of layers includes positioning reference pins for positioning on the pair of end plates at predetermined positions and based on the positions corresponding to the reference pins. Inner layer holes are arranged, and insert the copper foil and the prepreg said reference hole fitted in the reference pin,
Heat and pressure bonding.

Here, the reference pin is formed on one or both sides of the end plate,
One of the pair of reference pins has a projection that is thinner than the diameter, and the other of the reference pins has a recess that fits with the projection, or a reference pin is planted on one of the opposed end plates, The other end of the head plate has a recess or a hole to be fitted with the reference pin.

[0018]

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1A to 1H and FIGS. 2A and 2B.
FIG. 3 is a sectional view showing a first embodiment of the present invention in the order of steps, FIG. 3 is a perspective view of FIG. 2A, and FIG.
FIG. 5B is a plan view of the steel lamination jig shown in FIG.
2 (b) are a plan view and a side view of the end plate with positioning reference pins shown in FIGS. 2 (a) to 2 (b) and FIG. First of the present invention
Is a method of manufacturing a four-layer surface via-hole printed wiring board as in the above-described conventional example. In the first embodiment, first, as shown in FIGS. 1A and 1E, a double-sided copper-clad laminate 1 having a size of 600 × 500 mm, a copper foil thickness of 18 μm, and a base material thickness of 100 μm is drilled. A hole 2 is made and processed as shown in FIGS. 1 (b) and 1 (f). Thereafter, as shown in FIGS.
After forming a plating layer 3 and conducting between the front and back sides, forming an etching mask for the circuit with a dry film etching resist, etching with a ferric chloride aqueous solution, and then removing the etching mask, the circuit 4 is removed. Form.
Thereafter, as shown in FIGS. 1D and 1H, a reference hole a5 having a diameter of 6.05 mm for alignment is formed.
The reference hole a5 is formed at a position corresponding to the lamination pin 9 of the lamination jig 8 made of steel in FIGS. 2 (a) and 2 (b). at the same time,
A reference hole b having a diameter of 6.05 mm is provided at a position corresponding to the positioning reference pin 10 of the end plate a11 having the positioning reference pin in FIG.
Process No. 6. Next, as shown in FIG. 2A and FIG. 3, the size shown in FIG.
1 hole for laminated pin with a diameter of 6.05 mm
3. A 6.00 mm diameter and 30 length steel stacking jig 8
5 (a) and 5 (b), a positioning reference pin 1 having a diameter of 6.00 mm and a length of 1.6 mm via a laminated pin 9 having a thickness of 1 mm.
SUS301 having a thickness of 1.55 mm and a size of 600 × 500 in which 0 is embedded and protrudes 0.1 mm only on one side.
The head plate a11 with the positioning reference pins, the inner layer 7, and the prepreg 12 are stacked. At this time, the positioning reference pin 10 and the reference hole b6 of the inner layer 7 are engaged and fixed. After this,
Pressurized and heated, and bonded as shown in FIG. Or later,
Drilling, plating, circuit formation, solder resist printing, character printing, outer shape processing, surface treatment, etc. are performed to obtain the multilayer printed wiring board of the first embodiment. At this time, the shift amount at the center of the reference hole a5 at the four corners of the multilayer printed wiring board is 70 μm at the maximum.
Met. 14 (a) and 14 (b), a multilayer printed wiring board produced by the manufacturing method using the conventional end plate 19 has a maximum shift amount of 150 μm at the same position, and the first printed wiring board has the first displacement.
According to the example, the shift amount was reduced to almost half. This reduced the reject rate from 2% to 0.5%.

FIG. 6 is a side view of the end plate 6 with positioning reference pins used in the second embodiment of the present invention.
(B) is sectional drawing shown in order of process explaining the 2nd Example of this invention. In the second embodiment of the present invention, a positioning reference pin 10 having a diameter of 6.00 mm and a length of 1.7 mm as shown in FIG. 600x500 S
A head plate b14 with positioning reference pins made of US301 was used. As in the first embodiment, an inner layer 7 was formed as shown in FIGS. Next, as shown in FIG. 7 (a), a steel stacking jig 8 having a size of 600 × 500 mm, a thickness of 15 mm and a hole 13 for a stacking pin having a diameter of 6.05 mm at four places in a peripheral portion has a diameter of 6.00 mm. First, a positioning reference pin 10 having a diameter of 6.00 mm and a length of 1.6 mm is embedded at the bottom through a laminated pin 9 having a length of 30 mm, and has a thickness of 1.5 mm protruding 0.1 mm only on one side. An end plate a11 having a positioning reference pin made of SUS301 and having a size of 600 × 500 mm is set, and then stacked on the inner layer 7, the pregleg 12, and the inner layer 7. Next, a head plate b14 with positioning reference pins is used, and the inner layer 7, prepreg 12,
The inner layer 7, the end plate a11 with the positioning reference pin, and the steel jig 8 are overlapped. After that, it is heated and pressed and bonded as shown in FIG. 7 (b). After that, as in the first embodiment, drilling, plating, circuit formation, solder resist printing, character printing, outer shape processing, surface treatment, etc. are performed and the second processing is performed. The multilayer printed wiring board of Example was obtained. A maximum of 10 multilayer printed wiring boards were produced with this stacked structure, but the amount of displacement was 70 μm at maximum, as in the first embodiment.

FIGS. 8A and 8B are sectional views showing a third embodiment of the present invention in the order of steps for explaining the third embodiment, and FIGS.
8B is a plan view and a side view of the end plate b of FIGS. 8A and 8B, and FIG. 10 is a perspective view of FIG. Third of the present invention
In the embodiment of the present invention, a positioning reference pin 10 having a diameter of 6.00 mm and a length of 2.5 mm shown in FIGS. 8A and 8B and FIG. SUS30 of 0.5mm, size 600x500mm
End plate C15 with 1 positioning pin and FIGS. 9 (a) and 9 (b)
At the position corresponding to the positioning reference pin 10 shown in FIG.
6 and a mirror plate b16 having a laminated pin hole (each having a diameter of 6.05 mm) 13 at a position corresponding to the laminated pin 9. First, as in the first embodiment, FIGS.
An inner layer 7 was formed as shown in (h). Next, FIG.
(A) and as shown in FIG.
0mm thickness 15mm, diameter 6.00mm at 4 places in the periphery
The diameter of the steel lamination jig 8 having the lamination pin hole 13 is 6.0
First, a positioning reference pin 10 having a diameter of 6.00 mm and a length of 2.5 mm is embedded at the bottom through a laminated pin 9 having a length of 0 mm and a length of 30 mm, and a 1.0 mm pin protrudes only on one side. A 1.5 mm thick 600 × 500 SUS301 end plate C with positioning reference pins, inner layer 7, pregreg 12, and inner layer 7 are stacked. The end plate b16 is used thereon and overlaid with the steel jig 8. On this occasion,
A hole having a diameter of 6.05 mm is formed at a position corresponding to the positioning reference pin 10 and the lamination pin 9 of the inner layer 7 and the pre-leg 12. After that, heat and pressure are applied to bond as shown in FIG. Thereafter, drilling, plating, circuit formation, solder resist printing, character printing, outer shape processing, surface treatment, and the like are performed to obtain the multilayer printed wiring board of the third embodiment. At this time, the amount of deviation at the center of the reference hole a5 at the four corners of the multilayer printed wiring board was 70 μm at the maximum as in the first embodiment.

FIGS. 11 (a) and 11 (b) are a plan view and a side view of a convex positioning reference pin and a concave positioning reference pin of a fourth embodiment, respectively, and FIGS. FIG. 14 is a cross-sectional view illustrating a fourth embodiment in the order of steps for explaining the same. In the fourth embodiment of the present invention, FIGS.
A convex positioning reference pin 17 in which a pin having a diameter of 3.00 mm and a length of 2.0 mm is embedded in a pin having a diameter of 6.00 mm and a length of 1.6 mm, and a corresponding 6.01 mm diameter and a length of 1 3.05mm diameter on a 0.6mm pin,
1.5 mm in thickness with a concave positioning reference pin 18 having a 1.0 mm deep hole embedded therein
A head plate b16 with a convex positioning reference pin 17 and a head plate b16 with a concave positioning reference pin 18 made of SUS301 of 0 × 500 mm were used. As in the first embodiment, first, FIG.
As shown in (a) to (h), an inner layer 7 was formed. Next, as shown in FIG.
A steel lamination jig 8 having a thickness of 15 mm and a lamination pin hole 13 having a diameter of 6.05 mm at four locations in the peripheral portion is 6.00 mm in diameter.
First, the end plate b16 with the concave positioning reference pin 18 at the bottom, the inner layer 7, the pregreg 12, and the inner layer 7 are stacked via the laminated pin 9 having a length of 30 mm. Next, the end plate b16 having the convex positioning reference pins 17 thereon is used, and is stacked on the steel lamination jig 8. After that, heat and pressure,
Adhesion is performed as shown in FIG. Thereafter, drilling, plating, circuit formation, solder resist printing, character printing, outer shape processing, surface treatment, and the like are performed to obtain the multilayer printed wiring board of the fourth embodiment. At this time, the amount of displacement at the center of the reference hole a5 at the four corners of the multilayer printed wiring board was 70 μm at the maximum as in the first embodiment.

[0023]

As described above, according to the present invention, it is possible to improve the positional accuracy by drilling holes in a high-strength end plate and implanting positioning reference pins in the same manner as increasing the number of pins of the lamination jig. I can do it. As a result, the position accuracy can be almost doubled compared with the related art. In addition, since the stacking can be performed by disposing the positioning reference pins on both sides, there is an effect that a large number of high-precision multilayer printed wiring boards can be manufactured at the same time.

[Brief description of the drawings]

FIGS. 1A to 1H are cross-sectional views illustrating a first embodiment of the present invention in the order of steps for explaining the same.

FIGS. 2A and 2B are cross-sectional views illustrating a first embodiment of the present invention in the order of steps for explaining the first embodiment.

FIG. 3 is a perspective view of FIG.

FIG. 4 is a plan view of the steel lamination jig shown in FIGS. 2 (a) to 2 (b) and FIG.

FIGS. 5A and 5B are a plan view and a side view of the end plate with the positioning reference pin shown in FIGS. 2A and 2B and FIG. 3, respectively.

FIG. 6 is a side view of a head plate b with positioning reference pins used in a second embodiment of the present invention.

FIGS. 7 (a) and 7 (b) are cross-sectional views shown in the order of steps for explaining a second embodiment of the present invention.

FIGS. 8A and 8B are cross-sectional views illustrating a third embodiment of the present invention in the order of steps for explaining the same.

FIGS. 9 (a) and 9 (b) are a plan view and a side view of the end plate (b) of FIGS. 8 (a) and 8 (b).

FIG. 10 is a perspective view of FIG.

FIGS. 11A and 11B are a plan view and a side view of a convex positioning reference pin and a concave positioning reference pin of a fourth embodiment, respectively.

FIGS. 12 (a) and 12 (b) are cross-sectional views showing a fourth embodiment of the present invention in the order of steps for explaining the same.

13 (a) to 13 (h) are cross-sectional views shown in the order of steps illustrating an example of a method for manufacturing a multilayer printed wiring board by a conventional pin lamination method.

14 (a) and 14 (b) are cross-sectional views shown in the order of steps illustrating an example of a method for manufacturing a multilayer printed wiring board by a conventional pin lamination method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Double-sided copper-clad laminate 2 Hole 3 Copper plating layer 4 Circuit 5 Reference hole a 6 Reference hole b 7 Inner layer 8 Steel lamination jig 9 Lamination pin 10 Positioning reference pin 11 Mirror plate a with positioning reference pin 12 Pregreg 13 For lamination pin Hole 14 End plate b with positioning reference pin 15 End plate c with positioning reference pin 16 End plate b 17 Convex positioning reference pin 18 Recessed positioning reference pin 19 End plate

Claims (5)

(57) [Claims] An inner layer having conductive circuits formed on both sides, an inner layer having through holes electrically connecting conductive circuits formed on both sides, an inner layer having conductive circuits on one side, or a conductive circuit on one side. A plurality of inner layers of an inner layer having a through hole electrically connected to the opposite surface are sandwiched between two copper foils or a pair of end plates and a laminating jig via a pre-greg with the inner layer disposed outside. And a step of forming a conductive circuit and a through hole for connecting the front and back and the inner layer to the copper foil or the inner layer disposed on the outside. The step of forming a plurality of layers comprises positioning a reference pin for positioning at a predetermined position on the pair of end plates, and forming a reference hole at a position corresponding to the reference pin; A method for manufacturing a multilayer printed wiring board, comprising: inserting a foil and a prepreg into the reference pin by fitting the reference hole into the reference pin, and bonding by heating and pressing. 2. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein said reference pins are planted on one side of a mirror plate. 3. The method according to claim 1, wherein the reference pins are planted on both sides of the mirror plate. 4. The device according to claim 1, wherein one of the pair of reference pins has a projection smaller than a diameter, and the other of the reference pins has a recess fitted with the projection. Of manufacturing a multilayer printed wiring board. 5. The printed wiring board according to claim 1, wherein a reference pin is erected on one of the opposed end plates, and a recess or a hole is provided on the other end of the end plate to be fitted with the reference pin. Method.