JPH0563357A - Manufacture of metal core printed wiring board - Google Patents

Abstract

PURPOSE:To make insulation of a terminal insertion hole sure by a simple process and using a small amount of insulative resin. CONSTITUTION:As shown in figure (c), a PPS film 121 and a PPS film 122 are stuck on the upper surface and the lower surface of a metal board 11 in which a through hole 111 is formed, respectively. A copper foil 131 is stuck on the lower surface of the PPS film 122. As shown in figure (d), a metal plate 11 is arranged on a lower side press tool 141, and an upper side press tool 142 is arranged on the upper side of the metal plate 11. In this state, the press tools 141, 142 are heated. As shown in figure (e), the press tool 142 is made to descend, and a metal rod 143 is inserted into the through hole 111 while deforming the PPS film 121. Thus the PPS film 121 is deformed, and fusion bonded to the inner surface of the through hole 111 and the lower PPS film 122. Thereby the insulation of a terminal insertion hole can easily be obtained.

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 in which an electronic circuit is formed on a metal plate,
In particular, it relates to a method of manufacturing a metal core printed wiring board capable of improving the insulation of the terminal insertion hole.

[0002]

2. Description of the Related Art In recent years, the demand for printed wiring boards has increased with the increase in density and performance of electronic devices. For example, it has a high degree of dimensional stability, a rigidity that can withstand the mounting of a large number of heavy parts, and a high degree of thermal conductivity for promptly removing heat generated from the mounted parts. In order to meet such demands, conventional substrates using organic materials such as paper phenol substrates and glass epoxy substrates cannot satisfy these demands. Therefore, metal core printed wiring boards using metal plates such as aluminum and iron as cores Has been developed and put to practical use. FIG. 7 is a cross-sectional view showing such a conventional metal core printed wiring board.

In FIG. 7, reference numeral 41 is a metal plate made of aluminum. An insulating layer 42 is formed on the upper surface of the metal plate 41, and a wiring layer 43 is formed thereon. Wiring layer 43
Chip components and power transistors are mounted on the.

In the metal core printed wiring board shown in FIG. 7, the components to be mounted are limited to leadless components, and lead components such as transformers and electrolytic capacitors cannot be used. In response to this, a metal core printed wiring board provided with a terminal insertion hole for a lead component has been developed. FIG. 8 is a process diagram showing a conventional metal core printed wiring board having terminal insertion holes for lead components in the order of manufacturing steps.

First, as shown in FIG. 8A, the through hole 5
A metal plate 51 on which 11 is formed is prepared. In FIG. 8B, an insulating resin 53 (fiber reinforced plastic 54) containing a glass cloth 52 is attached to the front surface and the back surface, and a copper foil 551 to be a wiring layer 55 is formed under the fiber reinforced plastic 54 on the back surface side. Then, the metal plate 51, the fiber reinforced plastic 54 and the copper foil 551 in this state are heat-pressed,
As shown in FIG. 8C, the insulating resin 53 of the fiber reinforced plastic 54 is poured into the terminal insertion hole 511. Next, as shown in FIG. 8D, the copper foil 551 (FIG. 8B)
(See) to form a wiring layer 55 having a predetermined circuit pattern. Next, as shown in FIG. 8E, the central portion of the through hole 511 filled with the insulating resin 53 is re-drilled so that the insulating resin 53 remains on the inner wall of the previous terminal insertion hole 511. The terminal insertion hole 561 is formed.

In the metal core printed wiring board formed as described above, since the through hole 511 is filled with the insulating resin 53, the insulating resin 53 in the fiber reinforced plastic 54 must be increased, which increases the thermal resistance and heat dissipation. Equally impair sex. Correspondingly, when the amount of the insulating resin 53 is reduced, the inside of the hole cannot be completely filled and a cavity is formed, which causes a short circuit between the terminal and the metal plate 51. Further, when the central portion of the through hole 511 filled with the insulating resin 53 is re-drilled, the insulating resin 53
Cracks occur in the product, resulting in poor insulation. Moreover, since the resin is cured by hot pressing, the productivity is poor. Here, in response to the problem of increased thermal resistance, a method of inserting a cylindrical insulating resin 60 shown in the perspective view of FIG. 9 into the through hole has been developed. FIG. 10 is a process diagram showing a conventional metal core printed wiring board in which an insulating resin is inserted into the terminal insertion holes of lead components in the order of manufacturing steps.

As shown in FIG. 10A, a metal plate 61 is prepared. Next, as shown in FIG. 10B, through holes 62, 62 are formed in the metal plate 61. Next, FIG.
In (c), an insulating layer 64 is attached to the upper surface of the metal plate 61, and a copper foil 651 to be the wiring layer 65 is further formed on the upper surface of the insulating layer 64. Then, as shown in FIG. 10D, the through holes 62, 62 have the insulating resins 60, 60 shown in the perspective view of FIG.
Then, as shown in FIG. 10E, the copper foil 651 (see FIG. 10C) is etched to form a wiring layer 65 having a predetermined circuit pattern. Next, as shown in FIG. 10 (f), the central portion of the through hole 62 filled with the insulating resin 65 is re-drilled, and the insulating layer 64 and the wiring layer 65 are bored in communication with the through hole 62 to insulate A new terminal insertion hole 66 is formed so that the resin 65 remains on the inner wall of the front through hole 62.

In such a printed wiring board, when there are a large number of through holes 62 into which the insulating resin 60 is inserted, the insulating resin 60 must be inserted individually, which is troublesome. Further, when the central portion of the through hole 62 filled with the insulating resin 60 is re-drilled, a crack is generated in the insulating resin 60, resulting in poor insulation.

[0009]

SUMMARY OF THE INVENTION In the conventional metal core printed wiring board device described above, in order to ensure the insulation of the terminal insertion hole with a small amount of fiber reinforced plastic, an insulating resin is inserted into the through hole to insert the terminal insertion hole. However, if a large number of terminal insertion holes are required, it is necessary to insert the insulating resin separately for each, which is time-consuming, and the center portion of the terminal insertion hole filled with the insulating resin must be re-drilled. When doing
In many cases, the insulating resin was cracked.

SUMMARY OF THE INVENTION An object of the present invention is to provide a metal core printed wiring board device which eliminates the above problems and is capable of obtaining a reliable insulating property of a terminal insertion hole with a simple process and a small amount of insulating resin.

[0011]

The present invention provides a metal core printed wiring board in which a metal plate is used as a core, a through hole for inserting a terminal of a lead component is formed in the metal plate, and an insulating layer is formed on the inner surface thereof. In the manufacturing method, after forming the through-hole in the metal plate, a thermoplastic insulating film is disposed on one surface of the metal plate, and the rod-shaped member having a diameter smaller than the through-hole is heated to the metal plate. It is characterized in that the thermoplastic insulating film is inserted from the one surface side into the through hole while sandwiching the thermoplastic insulating film, and the thermoplastic insulating film is fused to the inner surface of the through hole.

[0012]

With this structure, the thermoplastic insulating film is fused to the inner surface of the through hole to form the terminal insertion hole, so that the terminal insertion hole can be securely formed with a simple process and a small amount of insulating resin. Insulation is obtained.

[0013]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. 1 and 2 are process diagrams showing an embodiment of a method of manufacturing a metal core printed wiring board according to the present invention in the order of manufacturing steps.

In this embodiment, first, as shown in FIG. 1A, a metal plate 11 is prepared. The metal plate 11 has a thickness of approximately 1 to
Made of 3mm aluminum. Next, as shown in FIG. 1B, through holes 1 for inserting terminals are formed in the metal plate 11.
After forming 11, the pretreatment such as degreasing and alumite treatment is performed if necessary. Next, as shown in FIG.
Polyphenylene sulfide films (hereinafter referred to as PPS films) 121 and 122 each having a thickness of 0.1 mm are attached to the upper surface and the lower surface of the metal plate 11 as thermoplastic insulating films, and the lower surface of the PPS film 122 has a thickness of 3.5 mm. × pasting copper foil 131 of 10 ^-2 mm. Next, as shown in FIG. 1D, the lower press forming metal fitting 14
1, the metal plate 11 is installed with the surface on which the copper foil 131 is attached facing down, and the upper press forming metal fitting 14
2 is arranged above the metal plate 11. In this case, the lower press forming metal member 141 is formed of a metal such as iron in a plate shape. On the other hand, the upper press forming metal fitting 142 has a radius of P
A metal rod 143, which is a rod-shaped member having a small diameter corresponding to the thickness of the PS film 121, is provided on a metal plate 144 so as to project downward, and is vertically moved by a driving device. In this state, the press forming metal fittings 141 and 142 are heated, and the press forming metal fitting 142 is lowered to deform the PPS film 121 and insert the metal rod 143 into the through hole 111.
To insert. Then, as shown in FIG. 1 (e), P
The PS film 121 is deformed and fused to the inner surface of the through hole 111 and also fused to the PPS film 122 below. Also, in this case, the PPS films 121, 12
2 is also fused with the flat surface portion of the metal plate 11. After that, the press forming metal fitting 142 is raised, and as shown in FIG.
Metal plate 11 with PPS films 121 and 122 fused
2 is removed from the press forming metal fittings 141 and 142, and FIG.
As shown in (g), the copper foil 131 (see FIG. 1C) is etched to form the wiring layer 13 forming a predetermined circuit pattern. After this, as shown in FIG. 2H, a position corresponding to the center of the through hole 111 of the PPS films 121 and 122 and the wiring layer 13 is bored, and a new terminal insertion hole 161 is formed.
To form. The metal core printed wiring board is manufactured as described above.

According to such an embodiment, the through hole 111
PPS film 121 whose inner surface is softened by heat
An insulating resin (in this case, the PPS film 121) that can easily and surely insulate the terminal insertion hole 161 by covering it with natural cooling and insulates the through hole 111.
There is no concern that cracks will occur on the surface, and it also helps reduce the amount of insulating resin. In addition, the PPS film 121 fused to the through hole
, It is not necessary to heat-cure, and the insulating layer can be formed only by natural cooling, which improves productivity. Furthermore, when a plurality of through-holes 111 are formed in the metal plate 11, a plurality of metal rods 143 corresponding to the plurality of through-holes 111 in the press forming metal fitting 142 are provided on the metal plate 144 so as to project a plurality of metal rods 143. Since the through hole 111 can be covered with the PPS film 121 at the same time, the manufacturing cost can be reduced. FIG. 3 shows another embodiment according to the present invention for reinforcing the wiring layer.

In FIG. 3, a fiber reinforced resin layer 17 is provided between the copper foil 131 and the PPS film 121. In this state, the copper foil 131 (see FIG. 1C) is etched to form a wiring layer that forms a predetermined circuit pattern, and then PP
The S films 121 and 122, the fiber reinforced resin layer 17 and the wiring layer are provided at positions corresponding to the central portions of the through holes 111,
A new terminal insertion hole is formed. Other configurations are shown in FIG.
It is similar to the embodiment. According to such a modification, the wiring layer can be reinforced by the fiber reinforced resin layer 17 as well as the same effect as the embodiment of FIG. FIG. 4 shows another embodiment of the present invention, which further reinforces the wiring layer.

In FIG. 4, instead of using a pure PPS film as a film attached to the lower side of the metal plate 11, a fiber reinforced resin film 1 made of glass fiber and PPS is used.
8 is used. The other structure is the same as that of the embodiment of FIG.

According to such a modification, the same effect as the embodiment of FIG. 3 can be obtained, and the copper foil 131 can be heat-sealed to the fiber reinforced resin film 18, so that the wiring layer is further reinforced. be able to. FIG. 5 shows another embodiment of the present invention, which further ensures the insulation of the terminal insertion hole.

First, in FIG. 5A, the metal plate 21
After forming the through holes 211 for inserting terminals, the PPS films 221 and 222 are formed on the upper and lower surfaces of the metal plate 21.
Stick each one. The metal plate 21 in this state is placed on the press forming metal member 241 in which the through hole 245 having a radius smaller than the thickness of the PPS film 222 is formed. An upper press forming metal member 242 similar to the upper press forming metal member 142 of FIG. 1 is arranged on the upper side of the metal plate 21. Next, FIG.
As shown in (b), the press forming metal member 241 and the press forming metal member 242 are heated, the press forming metal member 242 is lowered, and the metal rod 243 is inserted into the through hole 211 while deforming the PPS film 222. Then, PPS
The film 222 is deformed and fused to the inner surface of the through hole 211 and also fused to the PPS film 221 below. Further, in this case, the PPS films 221 and 222 are also fused with the flat surface portion of the metal plate 21. After this, FIG. 5 (c)
As shown in, the press forming metal member 242 is further lowered. As a result, the metal rod 243 is inserted into the through hole 245, the PPS films 221 and 222 are pushed out, and the PP
The positions corresponding to the through holes 245 of the S films 221 and 222 are penetrated. The metal plate 21 to which the PPS films 221 and 222 are fused is removed from the press forming metal members 241 and 242 as shown in FIG.
As shown in (e), the fiber-reinforced resin layer 27 is formed on the lower surface of the PPS film 221, and the copper foil 281 is formed on the lower surface of the fiber-reinforced resin layer 27. Copper foil 2 in this state
81 is etched to form a wiring layer forming a predetermined circuit pattern, and then a position corresponding to the center of the through hole 211 of the fiber reinforced resin layer 27 and the wiring layer is bored to form a new terminal insertion hole. ..

According to this structure, the same effects as those of the embodiment shown in FIG. 3 are obtained, and the PPS films 221 and 221 are formed.
Since the through holes can be formed in 22 at once, it is possible to further reduce the manufacturing cost.

In the embodiment shown in FIGS. 1 to 6, the metal plate 1 is used.
Although aluminum is used for 1 and 21, other metals such as iron and stainless steel may be used. Although PPS is used as the material of the thermoplastic insulating film, other materials such as polyether sulfone, polycarbonate, polyether ether ketone, etc. may be used. Further, although the metal rods 143 and 243 are used as the rod-shaped members, another rod-shaped member made of a material having high heat resistance, such as ceramics, may be used. In addition, the rod-shaped member and the metal plates 11 and 21
The gap between the through holes 111 and 211 is the same as the thickness of the thermoplastic insulating film.
The gap may be changed within a range in which the PPS films 221 and 222 on the inner surface of No. 1 do not cause cracking and defective fusion.

[0022]

As described above, according to the present invention,
By fusion-bonding the thermoplastic insulating film to the inner surface of the through hole to form the terminal insertion hole, a reliable insulating property of the terminal insertion hole can be obtained by a simple process and a small amount of insulating resin. Further, the thermoplastic insulating film fused to the through hole does not need to be thermoset, and the insulating layer can be formed only by cooling, so that the productivity is improved.

[Brief description of drawings]

FIG. 1 is a process diagram showing a method of manufacturing a metal core printed wiring board according to an embodiment of the present invention until a PPS film is fused to the inner surface of the through hole.

FIG. 2 is a process drawing of a process of forming a terminal insertion hole in the method of manufacturing the metal core printed wiring board of FIG.

FIG. 3 is a process drawing showing another embodiment of the method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 4 is a process drawing showing another embodiment of the method for manufacturing a metal core printed wiring board according to the present invention.

FIG. 5 is a process drawing until a thermoplastic insulating film of still another embodiment of the method of manufacturing a metal core printed wiring board according to the present invention is fused to the inner surface of the through hole.

FIG. 6 is a process drawing of a process of forming a terminal insertion hole in the method of manufacturing the metal core printed wiring board of FIG.

FIG. 7 is a cross-sectional view showing a conventional metal core printed wiring board.

FIG. 8 is a process drawing showing a manufacturing process of a conventional metal core printed wiring board provided with terminal insertion holes for lead components.

FIG. 9 is a perspective view showing an insulating resin used in a conventional metal core printed wiring board.

FIG. 10 is a process drawing showing a manufacturing process of a conventional metal core printed wiring board using the insulating resin of FIG.

[Explanation of symbols]

 11 Metal Plate 111 Through Hole 121 PPS Film 143 Metal Rod

Claims (1)

[Claims] 1. A method of manufacturing a metal core printed wiring board, comprising using a metal plate as a core, forming through holes for inserting terminals of lead components in the metal plate, and forming an insulating layer on the inner surface of the through hole. After forming the through hole, a thermoplastic insulating film is provided on one surface of the metal plate, and the thermoplastic insulating film is applied from the one surface side of the metal plate in a state where a rod-shaped member having a diameter smaller than that of the through hole is heated. A method of manufacturing a metal core printed wiring board, characterized in that the thermoplastic insulating film is fused to the inner surface of the through hole by inserting the thermoplastic insulating film into the through hole while sandwiching.