JPH0559869U - Metal base wiring board - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention aims to provide a metal base wiring board capable of exhibiting excellent withstand voltage characteristics. A metal base substrate, a high-thermal-conductivity double-sided substrate arranged on the metal base substrate via an adhesive layer, and a high-thermal-conductivity double-sided substrate juxtaposed on the metal base substrate via an adhesive layer. A high thermal conductivity double-sided substrate, the insulating layer being filled with an inorganic filler, and the first surface formed on the entire surface of one surface of the insulating layer.
And a patterned second metal layer formed on the other surface of the insulating layer, the first metal layer being disposed on the metal base substrate via an adhesive layer. It is characterized by

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a metal base wiring board.

[0002]

[Prior Art]

 In general, power modules and the like are required to have high withstand voltage and high heat dissipation. Therefore, as shown in FIG. 8A, a metal base substrate 80 mainly made of aluminum or the like is mainly made of copper or the like with an adhesive insulating layer 81 filled with an inorganic filler at a high ratio on the entire surface. A metal base wiring board formed by forming a circuit pattern 82 is used. This metal-based wiring board has a problem in that the mounting density cannot be increased because other types of wiring boards that do not require high withstand voltage and high heat dissipation cannot be laminated to form a multilayer.

Conventionally, in order to solve this problem, as shown in FIG. 8B, a print made of glass epoxy or the like is provided on a predetermined region of an insulating layer 81 on a metal base substrate 80 via an adhesive layer 83. A metal base wiring board formed by arranging a wiring board 84 and a flexible printed wiring board (hereinafter, abbreviated as FPC), or an adhesive layer on a predetermined area on the metal base board 80 as shown in FIG. 8C. A metal base wiring board has been devised in which the printed wiring board 84 and the FPC are directly arranged via 83 so as not to overlap each other.

[0004]

[Problems to be solved by the device]

 However, the metal base wiring board shown in FIG. 8 (B) cannot effectively secure a region requiring high withstand voltage and high heat dissipation, and the metal base wiring board shown in FIG. 8 (C). The plate has not been put to practical use because of problems such as poor pressure resistance and poor flowability of the material for forming the adhesive layer.

The present invention has been made in view of the above points, and an object of the present invention is to provide a metal base wiring board that can exhibit excellent dielectric strength.

[0006]

[Means for Solving the Problems]

 The present invention provides a metal base substrate, a high thermal conductive double-sided substrate disposed on the metal base substrate via an adhesive layer, and a high thermal conductive double-sided substrate juxtaposed to the metal base substrate to form an adhesive layer. The double-sided substrate having high thermal conductivity comprises an insulating layer filled with an inorganic filler, and a first metal formed on the entire surface of one surface of the insulating layer. And a patterned second metal layer formed on the other surface of the insulating layer, the first metal layer being disposed on the metal base substrate via an adhesive layer. Provided is a metal base wiring board.

Here, as the material of the metal base substrate, aluminum, copper, iron, nickel, copper-invar or the like can be used.

The adhesive used for the adhesive layer is not particularly limited as long as it has adhesiveness, but it is preferable to use inorganic powder, inorganic fiber or metal powder, metal fiber, etc. having excellent thermal conductivity. Is desirable. In particular, it is preferable to use a conductive adhesive so that the metal layer formed on the entire surface of one surface of the high thermal conductive double-sided substrate is not electrically isolated.

Epoxy resin, phenol resin or the like can be used as a material for forming the insulating layer of the high thermal conductive double-sided substrate. As the inorganic filler filled in the insulating layer, alumina, silica, boron nitride or the like can be used. The filling rate of this inorganic filler is preferably 60 to 90% by weight. In addition, it is not preferable to use an insulating film or the like for the insulating layer because sufficient thermal conductivity cannot be obtained.

As the metal of the metal layer of the high thermal conductivity double-sided substrate, copper, copper-aluminum clad or the like can be used.

As the circuit board arranged in parallel with the high thermal conductivity double-sided board, a single-sided or double-sided printed wiring board using glass epoxy or the like as a board material can be used.

[0012]

[Action]

 According to the metal base wiring board of the present invention, it is possible to secure an insulating layer having a dielectric strength and a high thermal conductivity by using a preformed high thermal conductivity double-sided board. That is, it is possible to solve the problem that a sufficient dielectric strength cannot be obtained in the method of forming a temporarily dried adhesive insulating layer on one surface of the metal layer and curing and integrating them. Furthermore, different types of circuit boards can be mounted in a relatively small area.

[0013]

【Example】

 Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

First, as shown in FIG. 1A, alumina powder of about 80 is formed on one surface of each of the electrolytic copper foil 10 having a thickness of 35 μm and the electrolytic copper foil 11 for circuit having a thickness of 105 μm. A high thermal conductive insulating layer 12 is formed by applying an insulating epoxy resin filled in a weight percentage and temporarily drying at about 90 ° C. so that the high thermal conductive insulating layers 12 come into contact with each other under vacuum pressure. Then, both copper foils were bonded together to produce a double-sided board. At this time, the thickness of the high thermal conductive insulating layer 12 was 120 μm.

Next, as shown in FIG. 1B, a through hole is formed in a glass epoxy double-sided copper-clad laminate in which the insulating layer 13 has a thickness of 0.1 mm and the copper foil 14 has a thickness of 35 μm. A perforating process was performed, a through-hole plating process was performed on this, and one surface was patterned by a usual method to produce a single-sided circuit board as shown in FIG. 1 (C).

Next, as shown in FIG. 2, the double-sided board and the single-sided circuit board are cut into a predetermined size, and the double-sided board has the circuit electrolytic copper foil 11 on the upper surface through the conductive adhesive 20. As described above, the single-sided circuit board was placed on the aluminum plate 22 having a thickness of 2 mm so that the surface not formed with the pattern was the upper surface through the insulating glass epoxy prepreg sheet 21.

After that, as shown in FIG. 3, the copper foils 11 and 30 on the upper surfaces of the double-sided board and the single-sided circuit board are patterned by a usual method, and an insulating treatment is performed on the copper foils 11 and 30 with a solder resist ink or the like to form a main body. The invented metal-based wiring board was produced.

It has been confirmed that the obtained double-sided substrate of the metal-based wiring board exhibits superior pressure resistance as compared with the conventional metal-based wiring board.

The present invention is not limited to the above-described embodiment, and as shown in FIG. 4, a double-sided substrate 40 is placed on an aluminum plate 22 via a conductive adhesive 20, and a double-sided substrate is further provided. A circuit board 41, one surface of which is patterned so as to be juxtaposed with 40, is placed on the aluminum plate 22 via an insulating adhesive 42, and then the exposed surfaces of the double-sided board 40 and the circuit board 41. It may also be patterned.

Further, as shown in FIG. 5 or 6, the same adhesive may be used when the double-sided board 40 and the circuit board 41 are placed on the aluminum plate 22. That is, as shown in FIG. 5, both may be bonded by using the conductive adhesive 20, or both may be bonded by using the insulating adhesive 42 as shown in FIG. When the conductive adhesive 42 is used as shown in FIG. 5, the wiring 43 and the wiring 43 are electrically connected to the area corresponding to the circuit board 41 so as not to short-circuit between the wiring 43 on the lower surface of the circuit board 41 and the aluminum plate 22. The insulating adhesive 42 needs to be interposed between the insulating adhesive 42 and the insulating adhesive 20.

Further, as shown in FIG. 7, solder 50 may be used instead of the conductive adhesive 20 of the metal base wiring board shown in FIG. In this case, it is necessary to interpose a metal foil 51 for soldering between the insulating adhesive 42 and the solder 50.

[0022]

[Effect of the device]

 As described above, the metal base wiring board of the present invention can secure the thickness of the insulating layer having high withstand voltage and high heat dissipation, so that it can exhibit excellent dielectric strength and improve reliability. be able to. Further, since the unpatterned metal foil is formed on the entire surface of one surface of the insulating layer, it is easy to evaluate the characteristics and electrically stable.

Further, the high thermal conductive double-sided board according to the present invention can be manufactured by simply applying an insulating adhesive on the surfaces of two metal foils, tentatively drying and then bonding them together. The process can be simplified.

Further, since the metal base wiring board of the present invention can exhibit sufficient dielectric strength, it can be applied to metal base boards having different thicknesses and types. For example, in the past, there was a problem that it was difficult to print cream solder due to the difference in level between the mounting surfaces of the high thermal conductive double-sided board and the circuit board, but the metal-based wiring board of the present invention makes it possible to adjust the thickness. Therefore, such a problem can be easily solved.

[Brief description of drawings]

1A to 1C are cross-sectional views for explaining a method for manufacturing a metal-based wiring board according to the present invention.

FIG. 2 is a cross-sectional view for explaining a method of manufacturing the metal base wiring board of the present invention.

FIG. 3 is a cross-sectional view for explaining a method of manufacturing the metal base wiring board of the present invention.

FIG. 4 is a cross-sectional view showing another embodiment of the metal base wiring board of the present invention.

FIG. 5 is a cross-sectional view showing another embodiment of the metal base wiring board of the present invention.

FIG. 6 is a cross-sectional view showing another embodiment of the metal base wiring board of the present invention.

FIG. 7 is a cross-sectional view showing another embodiment of the metal base wiring board of the present invention.

FIG. 8 is a cross-sectional view for explaining a conventional metal base wiring board.

[Explanation of symbols]

10 ... Electrolytic copper foil, 11, 30 ... Electrolytic copper foil for circuit, 12 ...
High thermal conductive insulating layer, 13 ... Insulating layer, 14 ... Copper foil, 20 ...
Conductive adhesive, 21 ... Glass epoxy prepreg sheet, 22 ... Aluminum plate, 40 ... Double-sided board, 41 ... Circuit board, 42 ... Insulating adhesive, 43 ... Wiring, 50 ... Solder, 51 ... Metal foil.

Claims (1)

[Scope of utility model registration request] 1. A metal base substrate, and a high thermal conductive double-sided substrate disposed on the metal base substrate via an adhesive layer,
A circuit board arranged side by side on the high thermal conductive double-sided board via an adhesive layer on the metal base substrate, wherein the high thermal conductive circuit board is an insulating layer filled with an inorganic filler; A first metal layer formed on the entire surface of one surface of the insulating layer, and a patterned second metal layer formed on the other surface of the insulating layer.
A metal-based wiring board, wherein the metal layer is disposed on the metal-based substrate via an adhesive layer.