JPH0897556A - Metal core printed wiring board manufacturing method - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method of manufacturing a metal core printed wiring board capable of releasing heat accumulated in a metal, which is a core, to the outside. [Constitution] After forming a hole having a diameter larger than the hole diameter defined in the through hole in the core metal and filling at least a part of the hole with a conductive material, a prepreg is formed on both sides of the metal and further on the outer surface thereof. A copper foil is laminated and formed, and then a through hole that passes through the center of a hole having a diameter larger than the hole diameter defined by the through hole formed in the metal and penetrates through the laminated plate is formed, and then copper plating is applied to form an inner layer. Connect the metal to the outer copper foil.

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 metal core printed wiring board, and more particularly to a method for manufacturing a metal core printed wiring board which efficiently releases heat accumulated in a metal which is a core to the outside.

[0002]

2. Description of the Related Art Conventionally, to make a metal core printed wiring board, as shown in FIG. 9, a hole 2 for through hole is made in a metal (aluminum plate) 1 to be a core, the metal 1 is pretreated, and then, As shown in FIG. 10, a prepreg 3 is built up on both sides of the metal 1, and a copper foil 4 is further built up on the outer surface thereof, and then laminated and formed as shown in FIG. 11, then as shown in FIG. The hole 5 was pierced from the outer layer and penetrated, then electroless copper plating and electrolytic copper plating 6 were applied as shown in FIG. 13, and then the circuit pattern 7 was formed in the outer layer as shown in FIG. . By the way, the metal 1 embedded in the metal core substrate shown in FIG. 11 is mostly aluminum or silicon steel (iron-based) at present, and copper is rarely used. Aluminum is an amphoteric metal that is very soluble in acids and alkalis and cannot be plated well by ordinary plating. There are two little known: Special electroless nickel plating method. A method of electroplating after substituting zinc in a zincate bath. Therefore, it is possible to plate with aluminum alone, but it is not possible to plate directly on the metal 1 embedded in the metal core substrate, and even if both are exposed, it is a composite material. Can not be plated, (reason: glass epoxy resin is degreased →
Sensitization → Catalyst treatment is required. ), When trying to treat other things, the aluminum will melt. Therefore, in the metal core printed wiring board, the heat accumulated in the metal which is the core cannot be released to the outside.

[0003]

Therefore, the present invention is to provide a method of manufacturing a metal core printed wiring board capable of releasing the heat accumulated in the metal, which is the core, to the outside.

[0004]

A method of manufacturing a metal core printed wiring board according to the present invention for solving the above-mentioned problems is to open a hole larger than a hole diameter defined by a through hole in a metal serving as a core, and at least one of the holes. After filling the part with a conductive material, prepreg is formed on both sides of the metal, and a copper foil is laminated on the outer surface of the metal, and then the metal is passed through the center of a hole larger than the hole diameter specified by the through hole. It is characterized in that a through hole is formed through the laminated plates, and then copper plating is performed to connect the metal in the inner layer and the copper foil in the outer layer. As the metal used above, aluminum, iron, magnesium and the like are used, but aluminum is particularly preferable. Also, the diameter of the hole to be drilled in the metal is smaller than the hole
It should be large in the range of 0.2 to 1.0 mm. Further, as the conductive material to be filled in the hole having a diameter larger than the hole diameter defined by the through hole formed in the metal, nickel paste, nickel rod, copper paste, silver paste, copper rod, etc. are used, but especially nickel paste Is preferable because it has good compatibility with aluminum used as the core metal. In the above-described method of manufacturing a metal core printed wiring board, there are the following two methods for filling the conductive material into the holes formed in the metal serving as the core. A nickel paste, a copper paste, or a silver paste is screen-printed on the metal, and any excess material on the surface is polished and removed to make it smooth. Cut nickel rods and copper rods to the required diameter and length, and crimp them into the holes.

[0005]

The metal core printed wiring board manufactured as described above has a conductive material in which the metal embedded inside is filled in the hole for the connecting through hole and the copper on the inner surface of the hole formed in the conductive material. Since the metal is connected to the outer layer by plating, the heat accumulated in the metal is quickly transferred to the surface and released to the outside. If the diameter of the hole formed in the metal to be the core is not larger than the diameter specified by the through hole by 0.2 mm or more, the metal is exposed with a slight misalignment, which is not preferable. However, if the hole diameter is too large and exceeds 1.0 mm, high-density wiring cannot be achieved, which is also undesirable.

[0006]

EXAMPLE 1 An example of a method for manufacturing a metal core printed wiring board (having a through hole diameter of 0.8 mm) according to the present invention will be described with reference to the drawings. As shown in FIG.
1.2 mm larger than a through hole on a 1 mm aluminum plate
A hole 2 of mm is formed by pressing (drilling or etching may be used). Next, as shown in FIG. 2, the conductive material 8 is filled in a part of the hole 2 formed in the core metal. In the case of this example, a copper paste is screen-printed, and the excess material exposed on the surface is polished and smoothed by a belt sander or the like as shown in FIG. Next, as shown in FIG. 4, a prepreg 3 is built up on both sides of the aluminum plate 1, and a copper foil 4 is built up on the outer surface thereof. Next, as shown in FIG. 5, lamination molding is performed. Then, as shown in FIG. 6, a through hole 5 having an inner diameter of 0.8 mm, which is smaller than the through hole 2, formed in the metal 1 is perforated from the outer layer. Next, as shown in FIG. 7, electroless copper plating and electrolytic copper plating 6 are applied to the outer layer and the through hole 5 to connect the inner layer 1 and the outer layer with the conductive material 8 and the copper plating 6, and after that, A circuit pattern 7 was formed on the outer layer as shown in Fig. 3 to produce a metal core printed wiring board. The metal core printed wiring board of Example 1 thus produced and the metal core printed wiring board of the same size and made of the same material produced by the conventional method shown in FIGS.
A thermal shock test was conducted by repeating 100 cycles from 65 ° C, 30 minutes to + 125 ° C, 30 minutes as one cycle. When the change rate of through-hole resistance was + 10% or less, there was no through-hole cracking or peeling, and printed wiring board Both had good impact resistance. Also, use through-hole solder at 260 ° C ± 5 ° C.
The solder heat resistance test was carried out for 20 seconds, and neither of them had a through hole crack or interlayer peeling. However, in the metal core printed wiring board of the example, the conductive material 8 filled in the hole 2 in which the heat accumulated in the metal, which is the core, is exposed to the metal, and the through hole formed in the conductive material 8 are formed. Although it is transmitted to the through hole lands and the circuit pattern 7 on the surface through the copper plating 6 on the inner surface of 5 and is released to the outside, in the conventional metal core printed wiring board, the heat accumulated in the metal that is the core is released to the outside. I couldn't.

[0007]

[Embodiment 2] Embodiment 1 is the same as Embodiment 1 except that nickel paste is used as a conductive material to fill a hole having an inner diameter larger than a through hole formed in an aluminum plate.
A metal core printed wiring board was made by the same process as in. The thus-produced metal core printed wiring board of Example 2 was subjected to the same thermal shock test and solder heat resistance test as in Example 1, and the same good results as those of the metal core printed wiring boards of Example 1 and the conventional example were obtained. . Furthermore, in the metal core printed wiring board of Example 2, the compatibility between the core metal aluminum and the nickel paste was good, and the heat accumulated in the core metal could be radiated to the outside even better than the metal core printed wiring board of Example 1. .

[0008]

As can be seen from the above description, according to the method of manufacturing a metal core printed wiring board of the present invention, the metal which is the core is connected to the surface through hole land and the circuit pattern through the connecting through hole which is different from the through hole. Connected,
The heat accumulated in the core can be easily transferred to the surface and released to the outside, and a reliable metal core printed wiring board can be easily obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 2 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 3 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 4 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 5 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 6 is a diagram showing steps of a method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 7 is a diagram showing steps of a method of manufacturing a metal core printed wiring board according to the present invention.

FIG. 8 is a diagram showing steps of a method of manufacturing a metal core printed wiring board according to the present invention.

FIG. 9 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

FIG. 10 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

FIG. 11 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

FIG. 12 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

FIG. 13 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

FIG. 14 is a diagram showing steps of a conventional method for manufacturing a metal core printed wiring board.

[Explanation of symbols]

 1 Aluminum plate (metal) 2 Hole drilled in core metal 3 Prepreg 4 Copper foil 5 Through hole 6 Copper plating 7 Circuit pattern 8 Conductive material

Claims (6)

[Claims] 1. A core metal is provided with a hole having a diameter larger than a hole diameter defined by a through hole, at least a part of the hole is filled with a conductive material, and then a prepreg is formed on both sides of the metal, and further an outer surface thereof. Copper foil is laminated and formed, and then a through hole that passes through the center of a hole having a diameter larger than the hole diameter defined by the through hole formed in the metal and penetrates the laminated plate is formed, and then copper plating is applied to the inner layer. A method for manufacturing a metal core printed wiring board, which comprises connecting the metal of claim 1 to an outer layer of copper foil. 2. The diameter of the hole larger than the diameter defined by the through hole is 0.2 than the diameter defined by the through hole.
2. Larger in the range of mm to 1.0 mm.
A method for producing a metal core printed wiring board as described. 3. The method for manufacturing a metal core printed wiring board according to claim 1, wherein the metal is aluminum, iron or magnesium. 4. The production of a metal core printed wiring board according to claim 1, 2 or 3, wherein the conductive material with which the holes larger than the hole diameter defined by the through holes are filled is a copper paste, a silver paste or a copper rod. Method. 5. The method for manufacturing a metal core printed wiring board according to claim 1, 2 or 3, wherein the conductive material with which the hole having a diameter larger than the hole diameter defined by the through hole is filled is a nickel paste or a nickel rod. 6. The method for producing a metal core printed wiring board according to claim 1, wherein the copper plating is electroless copper plating and then electrolytic copper plating. .