JPH07147485A - Manufacture of laminated printed board - Google Patents

Abstract

PURPOSE:To provide a method of manufacturing a laminated printed board, wherein the laminated printed board can be formed into a multilayered structure without taking an aspect ratio into consideration. CONSTITUTION:Intermediate layers 3 each provided with an interlayer connection hole 1 and fully covered with an insulating layer 2 excluding a land 1a around the connection hole 1 are provided, and then the intermediate layers 3 are bonded together electrically connecting the lands 1a together.

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 laminated printed circuit board.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a multilayer laminated printed circuit board, a plurality of intermediate layers having a desired pattern are bonded to each other through a prepreg, and thereafter, interlayer connection is performed by a drill or the like, or element mounting is performed. Through holes are being formed.

[0003]

However, in the above-mentioned conventional example, when the number of laminated layers of the intermediate layers is increased, the plate thickness is also increased, and as a result, it becomes difficult to reduce the hole diameter of the through hole. In addition, it has a drawback that the number of laminated layers cannot be increased.

The present invention has been made in order to solve the above drawbacks, and an object of the present invention is to provide a method for manufacturing a laminated printed circuit board which can be multilayered without considering the aspect ratio.

[0005]

According to the present invention, the above object is provided with an interlayer connecting hole 1 as shown in FIG. 1 corresponding to the embodiment, and all of the interlayer connecting hole 1 except the land portion 1a are provided. A method for manufacturing a laminated printed circuit board, in which a plurality of intermediate layers 3 each having a surface covered with an insulating layer 2 are formed, and then the land portions 1a, 1a are electrically connected to each other to join the intermediate layers 3, 3 ,. It is achieved by providing.

[0006]

The intermediate layer 3 is the land portion 1 of the interlayer connection hole 1.
The entire surface except a is covered with the insulating layer 2, and the interlayer connection holes 1 are brought into conduction by joining the intermediate layers 3 with each other by an appropriate joining means, and the wiring patterns 3b on the base 3a are Insulation is maintained by the insulating layer 2.

Since the intermediate layer 3 is generally as thin as 0.1 to 0.2 mm, the hole diameter of the interlayer connection hole 1 can be made fine without increasing the aspect ratio, and the manufacturing efficiency is improved. Is brought about.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. The manufacturing process of the laminated printed circuit board according to the present invention is shown in FIG. The intermediate layer 3 constituting the laminated printed circuit board is formed by subjecting the front and back surfaces of the base body 3a to desired patterning.

A through hole (interlayer connection hole 1) for connecting the layers and a through hole land 1a (land portion 1a) are formed in the base body 3a, and the front and back surfaces of the base body 3a have through holes. The entire surface except the land 1a is covered with the insulating layer 2 (see FIG. 1A).

A plurality of the intermediate layers 3 having the above-described structure are stacked with the through-hole lands 1a to be connected facing each other, and are bonded by the conductive adhesive 5.

In this state, interlayer connection is made between the intermediate layers 3 and 3 through the through hole 1 and the through hole land 1a, and the wiring pattern 3b between the intermediate layers 3 and 3 is the intermediate layer 3 respectively. It is insulated by the insulating layer 2 formed on the.

FIG. 2 shows the manufacturing process of the intermediate layer 3. In this embodiment, first, the through hole 1 and the wiring pattern 3b are formed in the base body 3a, and then the mask 4 is applied to the land portion 1a of the through hole 1. A photosensitive polyimide resin or the like can be used as the masking material.

Thereafter, the front and back surfaces of the base body 3a are coated with an insulating material over the entire surface. A material such as a resist is used as the insulating material, and for example, an epoxy resin or the like can be used. The thickness of the insulating material (insulating layer 2) is made slightly smaller than that of the through hole land 1a.

The intermediate layer 3 is formed by peeling the mask 4 by an appropriate means after the above steps. The mask 4 is peeled off by appropriately selecting a peeling liquid that peels off only the mask 4 and leaves the insulating material.

Next, an embodiment of a method for joining the intermediate layers 3 to each other will be described with reference to FIGS. In this embodiment, the adhesive 5
Is a sheet-like adhesive containing a plurality of small capsules 5.
are formed by mixing a, 5a ..., And each capsule 5a is formed by covering the surface layer of the conductor with the skin of the non-conductor.

The joining of the intermediate layers 3 to each other using the adhesive body 5 is performed by heating and pressing with the adhesive body 5 interposed between the intermediate layers 3 to be joined. The anisotropic conductive adhesive body 5 in which the skin of the capsule 5a is broken by the applied pressure and exhibits conductivity only in the pressing direction
Function as.

In FIG. 3, white circles indicate capsules 5a which maintain their insulating state without breaking their skins, and black circles indicate capsules 5a whose skins are broken and are in a mutually conductive state.
Is shown.

[0018]

As is apparent from the above description, according to the present invention, it is possible to form fine interlayer connection holes without increasing the aspect ratio.

Further, since the intermediate layers are formed by connecting the lands having a relatively large area as compared with the interlayer connecting holes, the alignment at the time of joining becomes easy. When using an anisotropic conductor for the adhesive,
Without considering a short circuit between adjacent interlayer connection holes,
Joining work can be performed.

[Brief description of drawings]

FIG. 1 is a diagram showing the present invention, in which (a) is a state before joining,
(B) is a figure showing a joined state.

FIG. 2 is a diagram showing a manufacturing process of an intermediate layer.

FIG. 3 is a diagram showing a conductive state of an adhesive body.

[Explanation of symbols]

 1 Interlayer Connection Hole 1a Land Part 2 Insulating Layer 3 Intermediate Layer 3a Base 3b Wiring Pattern 4 Mask

Claims (4)

[Claims] 1. A plurality of intermediate layers (3, 3) each having an interlayer connection hole (1), the entire surface of which is covered with an insulating layer (2) except for a land portion (1a) of the interlayer connection hole (1). .) Is formed, and then the land portions (1a) are electrically connected to each other to join the intermediate layers (3, 3 ...) To each other. 2. The method for producing a laminated printed circuit board according to claim 1, wherein the intermediate layers (3) are bonded together under pressure by an anisotropic conductive adhesive that exhibits conductivity only in the pressure direction. 3. A wiring pattern (3b) and an interlayer connection hole (1) are formed on a substrate (3a), and then a land portion (1a) of the interlayer connection hole (1) is masked, and then the substrate (3a). The method for manufacturing a laminated printed circuit board according to claim 1 or 2, wherein the intermediate layer (3) is manufactured by coating the insulating material on the entire surface of (1) and then removing the mask (4) of the land (1a). 4. The method for manufacturing a laminated printed circuit board according to claim 1, wherein the insulating layer (2) is formed thinner than the film thickness of the land portion (1a) of the interlayer connection hole (1).