JP2521187B2 - Method for manufacturing multilayer wiring board - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer wiring board having blind through holes.

2. Description of the Related Art A conventional multi-layer wiring board having blind through holes (non-through blind hole type through holes) is a multilayer circuit board in which a plurality of circuit-formed wiring boards and prepregs are alternately laminated, and heat molding is performed to integrate them. After manufacturing the wiring board, drill through to make non-penetrating through-holes at specified locations, perform seeder dipping for activation in chemical plating, apply plating resist, and then perform chemical plating. It goes on to manufacture a multilayer wiring board having blind through holes.

As shown in the drawings, the blind through hole 1 of the conventional multilayer wiring board is a drill 4 process for forming a blind blind hole for connecting between the circuits 3 of the multilayer wiring board 2 integrated and laminated. Is going. At this time, if the length between the stacked circuit 3 and l ₁ relationship depth L of the hole by the drill is L> l ₁ Otherwise, the through-holes obtained by subsequent chemical plating high reliability It is said that you cannot get it.

The deeper the drilling depth, the more difficult the machining becomes.
There is a problem that the stacked upper layer circuit may be damaged and it is difficult to remove the cut dust.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention forms an outer layer wiring board and inner layer wiring in which a circuit is formed and through holes are previously formed at positions where blind through holes are to be formed. In the method of manufacturing a multilayer wiring board in which the board and the board are pressure-bonded and integrated with each other with an adhesive, a blind through hole is formed by drilling up to the entrance of the final through hole of the inner wiring board, and then chemical plating is performed. The present invention provides a method for manufacturing a multilayer wiring board characterized by forming blind through holes by performing the steps.

The above case is a method for manufacturing a multilayer wiring board provided with blind through holes for connecting the multilayer wiring board and the inner layer wiring board, but the present invention is also for connecting circuits between a plurality of inner layer wiring boards. The present invention provides a method for manufacturing a multilayer wiring board having a blind through hole. That is, the outer layer wiring board having circuits and through holes formed therein and a plurality of inner layer wiring boards having circuits and through holes formed in advance at positions where blind through holes are to be formed are pressure-bonded and integrated with an adhesive. In the method for manufacturing a multilayer wiring board described above, after the inner layer wiring boards for which blind through holes are to be formed are pressure-bonded together with an adhesive, the final through hole of the inner layer wiring board for forming blind through holes is formed up to the entrance of the through hole. It is intended to provide a method for manufacturing a multilayer wiring board, which comprises forming a blind through hole by performing a drilling process and then a chemical plating process.

Action A method for manufacturing a multilayer wiring board according to the present invention includes a blind through hole connecting circuits between an inner wiring board and another inner wiring board, or a blind through hole connecting circuits between an outer wiring board and an inner wiring board. When forming a through hole, a through hole is provided in advance at a place where a blind through hole is formed. After the outer layer wiring board and the inner layer wiring board or the inner layer wiring boards are pressure-bonded and integrated with each other, a hole is drilled up to the entrance of the through hole of the final inner layer wiring board to be connected by the blind through hole. That is, since the drill is not passed through the through hole of the final inner wiring board, the circuit provided on the side opposite to the entrance of the through hole in this inner wiring board is not affected by the drilling process and is not damaged. In addition, work efficiency is improved.

Depending on the composition of the chemical plating solution, if the thickness of the adhesive is about 100 μm, the outer layer wiring board and the outer layer wiring board can be formed by the next chemical plating treatment regardless of the thickness of the outer layer wiring board and the inner layer wiring board. The through holes previously formed in the inner wiring board serve as nuclei, plating is deposited on the inner wall of the holes made in the adhesive by the drill, the through holes are connected, and the blind through holes are formed.

Depending on the type of adhesive, a part of the adhesive may enter the through hole of the final inner layer wiring board. However, even if this adhesive is not completely removed by the drill, if the adhesive is removed and the through hole is exposed only at the entrance part of the through hole, the exposed part becomes the core and Deposition of plating that can connect holes.

EXAMPLE An example of a method for manufacturing a multilayer wiring board according to the present invention will be described with reference to the drawings.

A circuit 12 is formed by etching the copper layer 11 using a copper-clad laminate having a copper layer 11 formed on both sides of a polyimide resin substrate 10.
Then, the through hole 13 is formed to form the outer wiring board 14, and the inner wiring board 18 having the circuit 15 and the through hole 16 is manufactured through the same steps as the outer wiring board 14. The outer wiring board 14 is arranged on the outer side and the inner wiring board 18 is arranged on the inner side, and the wiring boards 14 and 18 are pressure-bonded and integrated with each other with an adhesive 19 made of a polyimide resin to manufacture a multilayer wiring board 20.

Before manufacturing this multilayer wiring board 20, a plurality of inner layer wiring boards
In order to form blind through holes for connecting between the through holes 16 of the circuit 15 of 18, the inner layer wiring board 18 is pressure-bonded and integrated with an adhesive 19 made of a polyimide resin to produce a multilayer wiring board 22. , To connect the through holes 16A and 16B, by drilling with a drill 23 having a diameter slightly larger than the inner diameters of the through holes 16A and 16B, the resin that has entered the holes for the through holes 16 at the time of crimping is removed, and the adhesive A hole is made in 19 and a part of the entrance portion 25 of the through hole 16B is cut to expose the through hole 16B. The tip portion 24 of the drill 23 does not have to be opened through the next through hole 16B, and the vicinity of the inlet portion 25 is sufficient. If chemical plating is then performed, the through holes 16A and 16B can be connected to form a complete through hole 16C (FIG. 2). After that, if it is laminated and integrated with another wiring board, it can be provided as a blind through hole 16 between the inner wiring boards as shown in FIG.

FIG. 3 shows a multilayer wiring board 30 in which through holes 13A and 13B are preliminarily formed in an outer wiring board 14 and an inner wiring board 8 and integrated with an adhesive 19 to form each through hole 13A,
Drill a hole with a drill 23 for connecting between 13B.
At this time, the tip portion 24 of the drill 23 is the next through hole 13B.
It does not have to pass through the through hole 13B as in the conventional case, as it may be stopped near the entrance 25 of the. After this, chemical plating is performed to form blind through holes 13 for connecting through holes 13A and 13B. Naturally, the blind through hole 13 may be formed after the multilayer wiring board 20 is integrated with the inner and outer wiring boards 14 and 18, as shown in FIG.

EFFECTS OF THE INVENTION The present invention has the structure as described above, and the through holes formed by chemical plating can be formed with sufficiently high reliability without performing the seeder treatment. Conventionally, when forming a through hole, the drilling has been performed through the place where the through hole is to be provided, so that problems such as reliability deterioration of the through hole due to smear can be solved.

[Brief description of drawings]

1 to 3 are sectional views of the present invention, and FIG. 4 is a conventional sectional view. 12: Circuit, 13, 16: Blind Through Hole, 14: Outer Layer Wiring Board, 18: Inner Layer Wiring Board, 19: Adhesive, 20: Multilayer Wiring Board, 23: Drill, 24: Drill Tip, 25: Through Hole Inlet Department.

Claims (2)

(57) [Claims] 1. A multilayer wiring board in which a circuit is formed and a through hole is previously formed at a position where a blind through hole is to be formed, and an outer wiring board and an inner wiring board are pressure-bonded and integrated with each other with an adhesive. In the manufacturing method, a blind through hole is formed by drilling up to the entrance portion of the through hole of the final inner layer wiring board forming the blind through hole, and then a blind through hole is formed by chemical plating. Manufacturing method. 2. An outer layer wiring board having a circuit and a through hole formed therein and a plurality of inner layer wiring boards having a circuit and a through hole previously formed at a position where a blind through hole is formed. In the method of manufacturing a multilayer wiring board that has been crimp-integrated with each other, the inner through-holes of the inner wiring board, which are intended to form blind through holes, are crimped together with an adhesive, and then the blind through holes are formed. A method for manufacturing a multilayer wiring board, characterized in that a blind through hole is formed by forming a blind through hole by drilling a hole up to the entrance of the.