JP2844584B2 - Electromagnetically shielded circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically shielded circuit board, and more particularly to a circuit board having a three-dimensional structure having a metal plate therein as an electromagnetic shield.

[0002]

2. Description of the Related Art Conventionally, as a circuit board having a three-dimensional structure having a metal plate therein as an electromagnetic shield, for example, as shown in FIG. Part is covered with an insulator layer 3 and a metal layer 4
Is formed so as to have a desired pattern, the resin 5 is injected into a mold (not shown), and the remaining portion of the surface of the metal plate 1 is subjected to secondary molding with the resin 5 to include the three-dimensional structure portion 6. There is a composite molded article 51 formed.

[0003]

However, since the above-mentioned composite molded article has only one pattern-shaped metal layer (wiring layer), the wiring cannot be rationalized, and the per-unit area of the substrate cannot be reduced. The wiring density cannot be increased.

An object of the present invention is to improve a circuit board having a three-dimensional structure having a metal plate therein so that the wiring can be rationalized effectively.

[0005]

According to the present invention, in order to improve a circuit board having a three-dimensional structure having a metal plate therein so that wiring can be effectively streamlined, a molded article is formed by: ) An electromagnetic shielding metal plate having a plurality of through holes; (2) a first insulator layer covering an inner surface of the through hole and an outer surface of the metal plate; and (3) an outer surface of the first insulating layer and a through hole. Formed on the inner surface of
A first conductor having a predetermined pattern, and (4) covering the outer surface of the first conductor and forming the first conductor.
Even after forming, at least one of the through holes remains as a through hole
Injection molded as a second insulating layer comprising a three-dimensional structure, (5) on the outer surface of the second insulator layer, and a second conductor which is formed to have a predetermined pattern, (6) The first conductor and the second conductor are formed in the remaining through holes.
The conductive member connects the two conductors . A required portion of the second conductor may be covered with a third insulator layer.

As a material for the metal plate, a material having excellent electromagnetic wave shielding properties, easy plastic working such as press punching and bending, and high strength is desirable, and, for example, steel is preferable.

[0007] Both the first insulator layer and the second insulator layer need to be formed as a layer of a conductor, usually a metal such as copper, on the surface thereof, and therefore are made of a material which can be easily bonded to the metal. It is preferable to configure. In particular, a material capable of electroless plating is preferable. In addition, since the connection between the conductor and other electric components is often performed by soldering, it is preferable to use a synthetic resin having high heat resistance, such as polyether sulfone, polyaryl sulfone, polyphenylene sulfide, or polyether imide. . To form a layer,
Any of a method of applying a liquid resin and curing or drying, a method of forming a layer by injection molding or the like, a method of attaching a sheet-like or tape-like film, and the like may be used.

The first and second conductors can be formed by various methods such as electroless plating, application of a paste, attachment of a metal foil, and vapor deposition. In the first and second conductors, a portion formed inside a through hole covered with an insulator or a conductor has a rod (pillar) or tube (tubular) shape conductive member, for example, a copper pin or It may be formed of a pipe.

[0009]

The circuit board according to the present invention has an electrode having a plurality of through holes.
The outer surface of the magnetic shielding metal plate and the inner surface of the through hole are covered with a first insulating layer, and the outer surface of the first insulating layer and the inner surface of the through hole are covered .
The surface to form a first conductor having a predetermined pattern,
While covering the outer surface of the first conductor, after molding
The second so that at least one of the through holes remains as a through hole.
Insulation layer is formed into a three-dimensional structure by injection molding
Form, the outer surface of the second insulator layer, forming a second conductor so as to have a predetermined pattern, the first conductor and the second
A conductive member for connecting to the conductor is formed in the remaining through hole.
Since composed form, a second conductor of the first conductor having a predetermined pattern on both surfaces of the first insulator layer, and having a predetermined pattern to both surfaces of the second insulating layer Can be formed respectively, and can have four conductors having a pattern, that is, four wiring layers. As a result, the wiring can be rationalized effectively, and the wiring density per unit area can be dramatically improved.

[0010]

The present invention will be described in more detail with reference to the following examples. Embodiment 1 FIG. 1 shows an example of a circuit board having a three-dimensional structure having a metal plate therein according to the present invention. In FIG. 1, a metal plate 1 has a through hole 2, and both surfaces and an inner surface of the through hole 2 are covered with an insulator layer 3. A metal layer 4 is formed on both surfaces of the insulator layer 3 so as to have a predetermined pattern, and the metal layer 4 is also formed on the inner surface of the through hole 2 covered with the insulator layer 3. Insulator layer 3 or insulator layer 3
To cover both sides of the metal plate 1 covered with the metal layer 4,
The resin 5 is molded, and the through hole 2 covered with the insulator layer 3 and the metal layer 4 is also filled with the resin 5 except for the through hole 2a. The molded part of the resin 5 has a three-dimensional structure 6. The conductor pin 8 is fitted into the through hole 2a. A metal layer 7 is formed on a predetermined portion on the outer surface of the molded resin 5.

The metal plate 1 is a stainless steel plate, the insulator layer 3 is an epoxy resin coating, the resin 5 is a polyether sulfone, the metal layers 4 and 7 are copper plating layers, and the conductor pins 8 are copper.

The circuit board according to this embodiment is manufactured according to the manufacturing process shown in FIG. First, as shown in FIG. 2A, a metal plate 1 having a through hole 2 is prepared. As shown in FIG. 2B, both surfaces of the metal plate 1 and the inner surface of the through hole 2 are covered with an insulating layer 3 of epoxy resin. Next, FIG.
As shown in (C), a metal layer 4 is formed by electroless plating on predetermined portions on both surfaces of the insulator layer 3 and on the inner surface of the through hole 2 covered with the insulator layer 3. The electroless plating was performed through steps of applying a solution containing a plating catalyst, forming a resist film using a photoresist, and etching. Next, as shown in FIG. 2 (D), the resin 5 is put into the mold 21 and the cavity is filled with the resin 5, and the insulating layer 3 or both surfaces of the metal plate 1 covered with the insulating layer 3 and the metal layer 4 are coated. Is formed so as to cover the resin. The mold 21 has a fixing pin 21a penetrating through the through hole 2a.
Since a is inserted into the receiving hole 21c provided on the inner surface 21b of the opposite mold beyond the metal plate 1, the through-hole 2a is not filled with the resin 5. In this way, as shown in FIG. 2E, a composite molded product 22 including the three-dimensional structure 6 is formed.

[0013] As shown in FIG.
A metal layer 7 is formed on a predetermined portion of the outer surface of the substrate by electroless plating. The electroless plating is performed in the same manner as in the case of the metal layer 4. Since the resin 5 is not filled in the through holes 2a (covered with the insulator layer 3 and the metal layer 4), the copper pins 8 are fitted. Thus, the composite molded article 23 including the metal plate 1, the metal layers 4 and 7, and the three-dimensional structure 6, that is, the circuit board of FIG. 1 is formed.

A metal layer 4 having a predetermined pattern formed on both surfaces of a metal plate 1 with an insulator layer 3 interposed therebetween, and a metal layer 7 having a predetermined pattern formed outside with a resin 5 therebetween. Thus, four wiring layers are formed, and the metal plate 1 functions as an electromagnetic wave shield.

Embodiment 2 Another example of the circuit board of the present invention is shown in FIG. As in the first embodiment, both surfaces of the metal plate 1 having the through holes 2 and the inner surface of the through holes 2 are covered with the insulator layer 3, and the metal layers 4 are formed on both surfaces of the insulator layer 3 so as to have a predetermined pattern. Have been. The metal layer 4 is also formed on the inner surface of the through hole 2 covered with the insulator layer 3. Insulator layer 3
Alternatively, the resin 5 is formed so as to cover both surfaces of the metal plate 1 covered with the insulator layer 3 and the metal layer 4, and the through hole 2 covered with the insulator layer 3 and the metal layer 4 also has The resin 5 is filled except for the through hole 2a. The molded part of the resin 5 has a three-dimensional structure 6. A metal layer 7 is formed on a predetermined portion on the outer surface of the molded resin 5. Metal layer 7
Is also formed on the inner surface of the through hole 2a covered with the insulator layer 3 and the metal layer 4, and is continuous with the metal layer 7 on the outer surface of the resin 5. The metal layer 7 is covered with an insulator layer 9 except for the vicinity of the through-hole 2a, and a metal layer 10 is formed on the outer surface of the insulator layer 9 except for the peripheral portion. The metal layer 10 is a through hole 2
It is continuous with the metal layer 7 near a. Unlike the first embodiment, it has six wiring layers and does not use the conductor pins 8.

The metal plate 1 is a stainless steel plate, the insulator layers 3 and 9 are epoxy resin coatings, the resin 5 is polyether sulfone, the metal layers 4 and 7 are copper layers formed by electroless plating, and the metal layer 10 is a copper paste. It is a copper layer formed from.

To manufacture the circuit board according to the present embodiment,
First, the composite molded product 22 is formed by the steps shown in FIGS. 2A to 2E, and the composite molded product 22 is further formed as shown in FIG.
Through the steps shown in FIGS.

As shown in FIG. 4A, the composite molded article 22
A metal layer 7 is formed on a predetermined portion of the outer surface of the substrate by electroless plating. Since the inside of the through-hole 2a (covered with the insulator layer 3 and the metal layer 4) is not filled with the resin 5, the metal layer 7 is also formed in this portion. And FIG.
As shown in (B), an insulator layer 9 is formed on the surface of the metal layer 7 using an epoxy resin except for the vicinity of the through hole 2a. Further, as shown in FIG. 4C, a copper paste is applied to the outer surface of the insulator 8 except for the peripheral portion to form the metal layer 10, and the composite molded article 41, that is, the circuit board of FIG. Be composed.

The circuit board shown in FIG. 3 has a metal layer 4 having a predetermined pattern formed on both sides of a metal plate 1 with an insulator layer 3 interposed therebetween, and a metal layer 4 formed on the outside with a resin 5 interposed therebetween. A total of six wiring layers, a metal layer 7 having a predetermined pattern and a metal layer 10 having a predetermined pattern formed on the outside thereof with an insulating layer 9 interposed therebetween, are formed. Acts as a shield.

In the present embodiment, the metal layer 10 is formed using a copper paste, but electroless plating may be used.

[0021]

According to the present invention, a circuit board having a three-dimensional structure having a metal plate therein has a multi-layered wiring layer and a conductor is connected between the layers to effectively reduce the wiring. As a result, the wiring density per unit area of the substrate can be dramatically increased.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a cross section of one embodiment of a circuit board with an electromagnetic shield according to the present invention.

FIG. 2 is an explanatory view showing a manufacturing process of an embodiment of a circuit board with an electromagnetic shield according to the present invention.

FIG. 3 is an explanatory view showing a cross section of another embodiment of a circuit board with an electromagnetic shield according to the present invention.

FIG. 4 is an explanatory view showing a part of the manufacturing process of another embodiment of the electromagnetically shielded circuit board according to the present invention.

FIG. 5 is an explanatory view showing a cross section of a conventional electromagnetically shielded circuit board.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 metal plate 21 mold 2 through hole 21 a fixing pin 2 a through hole 21 a fixing pin 3 insulating layer 21 b inner surface 4 metal layer 21 c receiving hole 5 resin 22 composite molded product 6 three-dimensional structural part 41 composite molded product 7 metal layer 51 composite Molded product 8 Conductor pin

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takanobu Ishibashi 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Power System Research Laboratories, Hitachi, Ltd. (56) References JP-A-2-98192 (JP) (A) JP-A 1-236685 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H05K 9/00 H05K 1/02 H05K 3/46

Claims (2)

(57) [Claims] An electromagnetic shielding metal plate having a plurality of through holes; a first insulator layer covering an inner surface of the through hole and an outer surface of the metal plate; an outer surface of the first insulating layer; Formed on the inner surface of the through hole
It is a first conductor having a predetermined pattern, as well as covering the outer surface of the first conductor, after the molding
So that at least one of the through holes remains as a through hole
Injection-molded, a second insulator layer containing a three-dimensional structure, an outer surface of the second insulator layer , a second conductor formed to have a predetermined pattern, and the remaining Formed in the through-hole, the first conductor and
An electromagnetically shielded circuit board, comprising a conductive member for connecting to the second conductor . 2. The electromagnetically shielded circuit board according to claim 1, wherein said second conductor has a required portion covered with a third insulator layer.