JPH01143295A - Manufacture of multilayer printed wiring board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Field of Application) The present invention relates to a method for manufacturing a multilayer printed wiring board, and particularly to manufacturing a multilayer printed wiring board with blind pier holes and high pattern accuracy. Regarding the method.

(Prior Art) Conventionally, as a method for manufacturing a high-density multilayer printed wiring board having blind peer holes, the following method has been used.

(1) The outer layer board, which has through-holes formed in advance and a circuit pattern formed on the inner layer surface, is stacked on the inner layer board via the prepreg, heated and pressurized to form an integral layer, and then the through-holes are formed by a conventional method. A method for forming an outer layer circuit pattern.

(2) After manufacturing a multilayer printed wiring board without blind peer holes using a conventional method, non-through holes are drilled at desired locations on the multilayer printed wiring board using a laser or a drill, and then A method of forming an outer layer circuit pattern by a method.

(Problems to be Solved by the Invention) However, in method (1) among these methods, the outer layer is plated in two steps: through-hole plating during the production of the outer layer board and through-hole plating after lamination. 2 layer planes
Since the conductor is plated multiple times and the conductor thickness becomes too thick at 60 μm or more, it is difficult to control the pattern width and gap of the outer layer circuit pattern, making it impossible to form a highly accurate circuit pattern.

Further, in the method (2), there was a problem that not only the process was complicated and workability was poor, but also a highly reliable blind pier hole could not be formed.

The present invention has been made to solve these problems, and provides a method for manufacturing a multilayer printed wiring board that can form highly accurate circuit patterns and can respond to high-speed and high-density demands. With the goal.

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a multilayer printed wiring board of the present invention includes providing through holes in a double-sided copper-clad laminate and forming a circuit pattern only on the inner layer surface, and then forming a circuit pattern only on the inner layer surface. Multilayer printed wiring in which a wiring board has an inner layer board with a circuit pattern formed on both sides, and the inner layer surface is placed inside through a prepreg, and the through holes and the outer layer circuit pattern are formed after they are laminated together by heating and pressing. The method for manufacturing the board is characterized in that the double-sided copper-clad 8 yen scrap board is made of copper foil on the outer layer surface that is thinner than that on the inner layer surface.

Note that the copper foil thickness on the outer layer surface is 18 to 70 mm thick on the inner layer surface.
In the μm range, it is desirable that the amount is in the range of 5 to 18 μl.

(Function) In the method for producing a multilayer printed wiring board of the present invention, a laminate in which the thickness of the copper foil on the outer layer surface is thinner than that on the inner layer surface is used as the double-sided steel-clad laminate for producing the outer layer board. Even if this surface is plated twice in the through-hole plating process when manufacturing the outer layer board and the plating process when forming the through-holes in the laminate, the outer layer copper foil will not become too thick.

Therefore, an outer layer circuit pattern with high precision in pattern width, pattern gap, etc. can be formed by ordinary etching.

(Example) Hereinafter, a method for manufacturing a multilayer printed wiring board of the present invention will be explained based on the drawings.

As shown in FIG. 1, through-holes 4 are formed at predetermined positions in a double-sided copper-clad laminate 3 made by pasting copper foil 1 with a thickness of 5 μl and copper foil 2 with a thickness of 18 μl on both sides of an insulating plate. After setting, the second
As shown in the figure, a copper plating layer 5 is provided on the entire surface including the inner wall surface of the hole 4. Next, the thicker copper foil 2 (18
A circuit pattern 6 was formed on the surface of the thin copper foil 1 by a conventional method to produce an outer layer board 7 having the thin copper foil 1 side as the outer layer surface.

Next, as shown in FIG. 3, these 72 outer layer plates and inner layer plates 9 each having an inner layer circuit pattern 8 formed on both sides,
A plurality of prepregs 10 are inserted between them and overlapped,
It was heated and pressurized and laminated into one piece.

Next, a fourth layer was placed at a predetermined position on the thus obtained multilayer board.
As shown in the figure, after providing a through hole 11, a copper plating layer 12 is formed on the entire inner wall surface and outer layer surface of the hole 11, and then, as shown in FIG. 5, a circuit is formed on the outer layer surface by a conventional method. Pattern 13 was formed.

According to the method of the embodiment configured as described above, since the conductor knob on the outer layer of the multilayer board obtained by lamination molding is thin,
Even if the copper plating layer 12 is formed thereon during through-hole plating, the overall outer layer conductor thickness will not become too thick. Therefore, a highly accurate circuit pattern 13 can be formed by etching this outer layer conductor.

[Effects of the Invention] As is clear from the above explanation, in the method for manufacturing a multilayer printed wiring board of the present invention, since the conductor thickness of the outer layer is thin,
It is possible to form an outer layer circuit pattern with high precision in pattern width, gap, etc., and to obtain a high precision multilayer printed wiring board that can respond to high speed and high density.

[Brief explanation of the drawing]

FIGS. 1 to 5 are cross-sectional views for explaining an embodiment of the method for manufacturing a multilayer printed wiring board according to the present invention in the order of steps. 3・・・・・・・・・Double-sided copper-clad FA layer board 5.12
...Copper plating layer 6.8...Inner layer circuit pattern 9...Inner layer board 10...Prepreg 13...・・・
......Outer layer circuit pattern applicant
Toshiba Corporation Representative Patent Attorney Sasa Suyama - Figure 3 Figure 4

Claims (1)

[Claims] (1) After providing through holes in a double-sided copper-clad laminate and forming a circuit pattern only on the inner layer surface, this wiring board is combined with an inner layer board with circuit patterns formed on both sides, and a prepreg with the inner layer surface inside. In the manufacturing method of a multilayer printed wiring board in which through-holes and outer layer circuit patterns are formed after the two-sided copper-clad laminate is laminated together through heat and pressure and then laminated together, the copper foil thickness on the outer layer side is A method for producing a multilayer printed wiring board characterized by using a layer thinner than that of the layer surface.