JPH04332193A - Multilayer circuit forming body and manufacture of the same - Google Patents

Abstract

PURPOSE:To realize a small size forming body which does require troublesome procedures for assembling and connection by forming an internal circuit forming body consisting of a conductive part of the predetermined shape, an insulating body formed outside thereof by an injection molding and a conductive layer in the predetermined region on the surface of such insulating body. CONSTITUTION:A copper plate is punched into a predetermined shape to obtain an internal layer circuit 1. It is then put into a metal die and polyester sulfone is ejected for molding to form a molded body 5. Since a projection extended up to the internal layer circuit 1 is provided at the internal surface of metal die in such a position as corresponding to a through hole 3, after necessary preprocessing is conducted to the surface of the molded body 5, a plating catalyst is adhered to the necessary part of the surface and the internal surface of a through hole 3, electroless copper plating is conducted to this portions to form a metal layer 4 operating as an external layer circuit, thereby completing a double-layer circuit forming body 6. Accordingly, troublesome procedures are not required for assembling and connection, realizing reduction in size.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer circuit molded body and a method for manufacturing the same, and more particularly to a multilayer circuit molded body having predetermined circuits inside and on the surface thereof, and a method for manufacturing the same.

0002

[Prior Art] Generally used wiring boards are flat, and when multiple wiring boards are used in a three-dimensional combination, the wiring boards are cut in advance to a size that matches the housing of the product into which they are installed. After fixing key points to each other with reinforcing materials, the individual boards are connected using electric wires.

0003

However, such a conventional multilayered wiring board composite requires time and effort to assemble the board and connect the wiring. Furthermore, the wiring between the boards is often complicated, which makes it difficult to miniaturize.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to realize a multilayer circuit structure which requires no effort in assembly and connection and which is miniaturized.

Another object of the present invention is to realize a method for manufacturing a miniaturized multilayer circuit structure that does not require much effort for assembly and connection.

[0006]

[Means for Solving the Problems] In the present invention, in order to realize a miniaturized multilayer circuit structure that does not require effort in assembly and connection, the multilayer circuit structure is formed into a conductive material of a predetermined shape. The device consists of an internal circuit-forming body made up of parts, an insulator injection molded on the outside of the body, and a conductive layer formed on a predetermined part of the surface of this insulator.

[0007] Furthermore, in the present invention, in order to realize a manufacturing method of a miniaturized multilayered circuit-forming body that does not require labor for assembly and connection, an internal circuit-forming body having a conductive portion of a predetermined shape is molded. A molded body was formed by injection molding an insulating material into the mold, and a conductive layer was formed on a predetermined portion of the surface of this molded body.

[0008] In order to electrically connect the internal circuit forming body and the conductive layer, it is desirable to provide a through hole communicating with the internal circuit forming body in a predetermined portion of the molded body.
Preferably, this through hole is formed using a mold having a corresponding protrusion during molding.

The internal circuit forming body is, for example, a metal plate such as a copper plate punched into a predetermined shape, a conductive layer formed on a predetermined part of the surface of an insulator, a printed wiring board, etc.
Can be configured.

[0010] The insulating material constituting the insulator must be able to be injection molded, and usually thermoplastic or curable resin is used. It is preferable to use so-called engineering plastics, which have excellent rigidity, dimensional stability, electrical properties, and thermal properties.

In order to form a conductive layer on a predetermined portion of the surface of an insulating material, injection molding of the insulator is performed by composite molding (two-shot molding) of a resin that can be plated and a resin that is difficult to plate. A method of plating metal on the exposed parts of the resin, a method of applying a catalyst to the entire surface of the insulator, and covering the parts not requiring plating with a permanent mask can be used.

[0012] Methods of plating metal on the surface of a composite molded resin that can be plated include a method of adding a plating catalyst to the resin to make it plating possible, and a method of roughening exposed parts of the resin that are easily roughened by etching. Then, there is a method of applying a catalyst to this surface and plating it.

[0013] In order to electrically connect the internal circuit forming body and the conductive layer, a conductive layer is formed on the inner surface of a through hole that is provided in a predetermined portion of the molded body and that leads to the internal circuit forming body in the same manner as described above. A method of forming layers can be used. Examples are shown below to provide a more detailed explanation of the present invention.

[0014]

[Example 1] Fig. 1 shows an example of a multilayer path forming body according to the present invention.
Shown below. The multilayer circuit structure shown in FIG. 1 consists of an inner layer circuit 1 formed by punching a copper plate into a predetermined shape, an insulating material 2 formed by injection molding polyether sulfone on the outside thereof, and a metal layer 4. A through hole 3 passes through the insulating material 2, and a metal layer 4 is also formed on the inner surface of the through hole 3.

A method for manufacturing this multilayer circuit structure is shown in FIGS. 2(A) to 2(C). First, a copper plate is punched out into the shape shown in FIG. 2(A) to form the inner layer circuit 1. This is placed in a mold (not shown) and polyether sulfone is injection molded to produce a molded article 5 shown in FIG. 2(B). Since a protrusion reaching the inner layer circuit 1 is provided on the inner surface of the mold at a position corresponding to the through hole 3, a through hole 3 penetrating through the insulating material 2 is formed as shown in FIG. 2(B). . After performing necessary pretreatment on the surface of the molded body 5, a plating catalyst is attached to the required portions of the surface and the inner surfaces of the through holes 3, and electroless copper plating is performed on these portions to form a metal that acts as an outer layer circuit. The layer 4 is formed to form a two-layer circuit forming body 6 shown in FIG. 2(C).
completed. FIG. 1 is a cross section taken along cutting line II in FIG. 2(C).

Another example of the multilayer circuit structure according to the present invention is shown in FIG. In the inner layer circuit 31, instead of the copper plate in Example 1, a copper layer 33 is formed on the entire both surfaces of the polyethersulfone molded body 32 by electroless copper plating. Components other than the inner layer circuit are made in the same manner as in Example 1.

[0017]

Effects of the Invention The multilayer circuit structure of the present invention requires less effort to assemble and connect than conventional wiring board composites. Further, it is possible to downsize the device. Further, according to the method for manufacturing a multilayer circuit formed body of the present invention, a miniaturized multilayer circuit formed body can be manufactured without requiring any effort for assembly and connection.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of a multilayer circuit structure according to the present invention.

FIGS. 2(A) to 2(C) are cross-sectional views showing one embodiment of the method for manufacturing a multilayer circuit formed body according to the present invention.

FIG. 3 is a sectional view showing another embodiment of the multilayer circuit structure according to the present invention.

[Explanation of symbols]

1 Inner layer circuit 2 Insulating material 3 Through hole 4 Metal layer 5 Molded body 6 Two-layer circuit forming body 31 Inner layer circuit 32 Polyethersulfone molded body 33
copper layer

Claims (4)

[Claims] [Claim 1] Consisting of an internal circuit forming body consisting of a conductive portion having a predetermined shape, an insulator injection molded on the outside thereof, and a conductive layer formed on a predetermined portion of the surface of this insulator. A multilayer circuit forming body characterized by: 2. An internal circuit forming body consisting of a conductive portion having a predetermined shape, an insulator injection molded on the outside thereof, and a conductive layer formed on a predetermined portion of the surface of the insulator,
A multilayer circuit-forming body characterized by comprising a conductive member that connects the conductive portion of the internal circuit-forming body and the conductive layer on the surface of the insulator through the insulator. 3. The multilayer structure of claim 2, wherein the conductive member comprises a conductive layer formed on the inner surface of a through hole in the injection molded insulator that communicates with the internal circuitry. circuit formation. 4. An internal circuit forming body made of a conductive portion having a predetermined shape is fixed in a mold that contacts the internal circuit forming body at a predetermined part of the inner surface, and an insulating material is injection molded into the mold. , forming a molded body having a through hole corresponding to the predetermined portion between the surface and the internal circuit forming body, and forming a conductive layer on the surface of the molded body and a predetermined portion of the inner surface of the through hole. A method for producing a multilayer circuit formed body, characterized by: