JPH09153665A - Heat-radiation printed circuit board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To contrive to enhance adhesion between an insulation layer and a metal plate in a heat-radiation printed circuit board, and to suppress separation between the insulation layer and the metal plate at the time of post- processing and the generation of waster powders caused from the insulation layer. SOLUTION: In a heat-radiation printed circuit board comprising an insulation layer 2 on the surface of a metal plate 1, coated thereon with a copper foil 3, the insulation layer 2 is not provided with a seat-like base material as a structure material, but with a resin layer containing an inorganic filler as components. In the manufacturing method, a cost 6a of solidifying resin liquid uncontaining the inorganic filler in a copper foil 3a as components is formed and semi-solidified. A coat 6b of solidifying resin liquid containing the inorganic filler as components and not provided with the seat-like base material in this coat 6a is formed, and this cost 6b is semi-solidified to form a resinous copper foil 4a. A metal plate 1a having a through hole 7 is overlapped on this resinous copper foil 4a to form a pressed body 8, which is heated and pressurized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiation type printed circuit board in which an insulating layer is formed on the surface of a metal plate, and a copper foil is further layered on the insulation layer, and a manufacturing method thereof. The present invention relates to a heat dissipation type printed circuit board useful for manufacturing a printed circuit board in which a circuit board has a circuit formed on an insulating layer by etching a copper foil constituting the circuit board.

[0002]

2. Description of the Related Art Conventionally, a printed circuit board formed by using a metal plate as a base or a core, forming an insulating layer on the surface of the metal plate, and further laminating a copper foil on the insulating layer is known. It is used by etching a copper foil and processing it into a printed circuit board. This printed circuit board has high heat dissipation due to the thermal characteristics of the metal plate, and therefore dissipates the heat generated from the semiconductor chip mounted on the circuit to the outside of the system,
It is useful as a circuit board for preventing malfunction of semiconductor devices.

This type of printed circuit board is generally subjected to a cutting process for cutting it into a desired size, or a post-process including a drilling process for forming a through hole, if necessary.

However, the insulating layer laminated on the metal plate is
Usually, a glass cloth or glass paper consisting of glass filament is cured by heating a prepreg impregnated with a curable resin such as epoxy resin, polyimide resin, unsaturated polyester resin, vinyl ester resin, or phenol resin. In some cases, scraps of glass filament are generated during the post-processing, and these scraps may cause a short circuit when a circuit is formed on the copper foil by etching.

In order to solve such a problem, for example, two or more epoxy compounds in the molecule, a curing agent for this compound, a curing accelerator, etc., without the sheet-like base material made of the above glass filament, are used. Resin solid content as a component 10
A method of applying a curable resin solution containing 0% to a metal plate, stacking a copper foil on this coating film to form a pressed body, and thermally pressing the pressed body to produce a printed circuit board is effective. That is, the printed circuit board obtained in this manner does not generate scrap powder during post-processing.

However, the insulating layer cured by the above-mentioned curable resin liquid has a low adhesive strength with the metal plate, and when a through hole is formed by post-processing, peeling occurs at the boundary between the metal plate and the insulating layer near the through hole. In addition, when cut to the desired size, peeling occurs at the boundary between the metal plate exposed on the end surface and the insulating layer, and when the inner surface of this through hole is metal-plated, the adhesion of this metal-plated film is secured. It is not reliable in terms of performance and quality.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. An object of the present invention is to form an insulating layer on the surface of a metal plate and further coat a copper foil on the insulating layer. In the heat-dissipation type printed circuit board formed by adhering, the adhesive force between the insulating layer and the metal plate is enhanced, peeling between the insulating layer and the metal plate that occurs during post-processing is prevented, and scrap powder generated from the insulating layer Disclosed is a heat-dissipating printed circuit board that prevents generation and a method for manufacturing the same.

[0008]

In the heat radiation type printed circuit board according to the present invention, an insulating layer 2 is formed on the surface of a metal plate 1, and a copper foil 3 is formed on the insulating layer 2. In the heat dissipation type printed circuit board formed by layering, the insulating layer 2 does not include a sheet-shaped base material as a constituent material, but is composed of a resin layer containing an inorganic filler as a component, and is bounded by the metal plate 1. The resin layer of the insulating layer 2 having the above does not generate dust during post-processing and has a large adhesive force with the metal plate 1 and the metal plating film formed on the inner surface of the through hole.

According to the manufacturing method of the heat dissipation type printed circuit board according to the fifth aspect of the present invention, the coating film 6 is formed by applying the curable resin liquid containing no inorganic filler as a component to the copper foil 3a.
After forming a, the coating film 6a is semi-cured, and then the semi-cured coating film 6a is coated with a curable resin liquid containing an inorganic filler as a component to form a coating film 6b. The resin-coated copper foil 4a is semi-cured, and the resin-coated copper foil 4a is superposed on the metal plate 1a having the through-holes 7 to form a pressed body 8. When the pressed body 8 is heated and pressed, the metal plate 1 is bounded. Semi-cured coating film 6a of resin-coated copper foil 4a having
The insulating layer 2 that strongly adheres to the metal plate 1 is formed as it hardens, and at the same time, the resin containing the inorganic filler from the coating films 6a and 6b flows into the through hole 7 of the metal plate 1, and the through hole 7 is the hardened resin. To obtain a heat dissipation type printed circuit board. When a through hole having a diameter smaller than the diameter of the through hole 7 is formed in the through hole 7 of the heat radiation type printed circuit board, the inner surface of the through hole having the small diameter is made of a resin containing an inorganic filler as a component, so that dust particles are generated. In addition, the adhesive strength of the metal plating film is improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1A is a sectional view of a heat radiation type printed circuit board according to an embodiment of the present invention.

As shown in the figure, in the heat dissipation type printed circuit board of the present invention, an insulating layer 2 is formed on the surface of a metal plate 1, and a copper foil 3 is layered on the insulating layer 2. As the metal plate 1, for example, a material type having good thermal conductivity such as an aluminum plate, a copper plate, or an alloy plate such as a SUS plate is used. This metal plate 1 is optional regardless of the presence or absence of through holes. The insulating layer 2 layered on the surface of the metal plate 1 is formed of a cured layer of a curable resin such as an epoxy resin, a phenol resin, an imide resin, a vinyl ester resin, or an unsaturated polyester resin.

The features of the present invention regarding the insulating layer 2 will be described below. The insulating layer 2 is a resin layer having a boundary with the metal plate 1 described above and does not include a sheet-shaped base material as a constituent material, and is made of an inorganic material. It is composed of a resin layer containing a filler as a component. That is, the resin layer forming the insulating layer 2 is
The resin layer obtained by heating and curing a prepreg obtained by impregnating a sheet-like base material such as a glass filament twisted cloth or a sheet of glass filament with a curable resin and drying the prepreg is excluded. That is, when this kind of base material is used as a constituent material, scrap powder is generated during post-processing such as cutting and drilling, and peeling occurs at the boundary between the metal plate 1 and the insulating layer 2. . The insulating layer 2 is a resin layer containing an inorganic filler as an essential component, and as the inorganic filler, one or more kinds of powders such as alumina, silica, mica, glass, and sulphium sulphate can be mixed and used. .

The resin forming the solid content of the resin layer forming the insulating layer 2 is, as described above, an epoxy resin, a phenol resin, an imide resin, a vinyl ester resin, an unsaturated polyester resin, a curing agent for these, and a curing accelerator. The agent is used as an ingredient.

To give a few examples of the development of the basic structure of the present invention, an inorganic filler is provided on the insulating layer 2 unless a sheet-like base material made of glass filament is further provided. It is also possible to form a second resin layer in which the resin solid content of the resin composition not containing is cured, and form the above copper foil 3 on this second resin layer to form a heat dissipation type printed circuit board. In this case, if the combined thickness of the insulating layer 2 and the second resin layer laminated on the metal plate 1 is 150 μm or more and the layer thickness of the insulating layer 2 is limited to 50 μm or more, the metal plate This is effective in producing a circuit board in which the resin filling rate in the through hole is increased and the surface is highly smooth.

Further, a heat dissipation type printed circuit board in which a plurality of metal plates 1 are used to form a multilayer structure may be used.

The manufacturing method of the heat dissipation type printed circuit board according to claim 5 of the present invention, which is the development of the heat dissipation type printed circuit board in the embodiment of the present invention, is shown in FIG. 1 (b).
Explanation will be made with the help of

A curable resin liquid containing no inorganic filler as a component is applied to the copper foil 3a to form a coating film 6a, the coating film 6a is semi-cured, and the inorganic filler is added to the semi-cured coating film 6a. After coating a curable resin solution contained as a component to form a coating film 6b, the coating film 6b is semi-cured to form a resin-coated copper foil 4a, and a metal plate 1a having a through hole 7 is coated with the resin-coated copper foil 4a. The cured coating film 6b is overlaid to form a pressure-receiving body 8, and the pressure-receiving body 8 is heated and pressed to be manufactured. The curable resin liquid containing an inorganic filler as a component in the copper foil 3a is, for example, an epoxy resin, a phenol resin, an imide resin, a vinyl ester resin, an unsaturated polyester resin, a resin solid content of these curing agents and curing accelerators. , And alumina, silica, mica, glass, one or more kinds of powder such as sulphate valium as a component, and the curable resin which does not contain an inorganic filler as a component in the copper foil 3b is an epoxy resin obtained by removing the inorganic filler.
The resin solid content is composed of a phenol resin, an imide resin, a vinyl ester resin, an unsaturated polyester resin, a curing agent for these, and a curing accelerator. in this case,
When a copper foil having a roughened adhesive surface is used as the copper foil 3a to which these curable resin liquids are applied, it is effective in preventing peeling at the time of post-processing because the adhesive strength with the insulating layer is increased.

[0019]

【Example】

(Embodiment 1) A metal plate 1 having a through hole 7 was used.
An 8 mm aluminum plate was used, and the aluminum plate was subjected to AC electrolytic treatment with an aqueous solution (PH = 10) in which caustic soda and sodium carbonate were mixed to roughen the adhesive surface. The following curable resin liquid was applied to both surfaces of this aluminum plate to form a coating film 6b. Parts mean parts by weight. Composition of resin solids: Tetrabromobisphenol A type epoxy resin (epoxy equivalent = 500): 100 parts Dicyandiamide (hardening agent): 1.2 parts 2-Ethyl 4-methylimidazole (hardening accelerator): 0.1 parts This resin solids 100 60 parts of mica powder having an average particle size of 20 μm was blended as an inorganic filler with respect to 10 parts to prepare a curable resin liquid. The aluminum plate on which the coating film 6b of the above curable resin liquid is formed is dried at 120 ° C. for 30 minutes to semi-cure the coating film 6b, and then the copper foil 3a having a thickness of 18 μm is arranged at 170 ° C. and 5 ° C.
It was heated and pressed at 0 kg / cm ² for 70 minutes to obtain a heat dissipation type printed circuit board having a double-sided copper foil and provided with an insulating layer 2. The layer thickness of this insulating layer 2 was 200 μm.

This circuit board was subjected to a through-hole processing by an NC having a diameter smaller than that of the through-hole 7 of an aluminum plate by a conventional method, and then through-hole plating and copper foil were etched to obtain a heat radiation type printed circuit board. (Embodiment 2) 1. As a metal plate 1 having through holes 7.
A 0 mm aluminum plate was used, and the aluminum plate was subjected to AC electrolytic treatment with an aqueous solution (PH = 10) in which caustic soda and pyrophosphoric acid were mixed to roughen the adhesive surface. After coating the curable resin liquid having a resin solid content of 100% described in Example 1 on one surface of the copper foil 3a to form a coating film 6a, the coating film 6a is coated with 12
It was semi-cured at 0 ° C. for 20 minutes under a reduced pressure of 80 Torr. Next, the curable resin liquid of Example 1 was applied onto the semi-cured coating film 6a to form a coating film 6b, which was then semi-cured at 120 ° C. for 30 minutes under a reduced pressure of 80 Torr. The layer thickness of the upper and lower coating films 6a and 6b was 150 μm.

This resin-coated copper foil 4a was placed on both sides of the aluminum plate of Example 1, heated and pressed at 170 ° C., 50 kg / cm ² for 20 minutes in a reduced pressure atmosphere of 15 torr, and then 50
The heating and pressurization was performed for 1 minute in an atmospheric pressure atmosphere to obtain a heat dissipation type printed circuit board provided with the insulating layer 2. The total thickness of the insulating layer formed of the coating films 6a and 6b is 200 μm, and the thickness of the insulating layer formed of the coating film 6b containing an inorganic filler is 60 μm.
Met.

On this circuit board, under the same conditions as in the first embodiment,
A heat-radiating printed circuit board was obtained by performing through-hole processing by NC having a diameter smaller than that of an aluminum plate, and then performing through-hole plating and etching copper foil. (Example 3) The aluminum plate of Example 2 was used as the metal plate, and the copper foil of Example 2 was used. After coating the curable resin liquid having a resin solid content of 100% described in Example 1 on one surface of the copper foil 3a to form a coating film 6a, the coating film 6a is coated with 12
It was semi-cured at 0 ° C. for 20 minutes under a reduced pressure of 80 Torr. Next, the curable resin liquid of Example 1 was applied onto the semi-cured coating film 6a to form a coating film 6b, which was then semi-cured at 120 ° C. for 30 minutes under a reduced pressure of 80 Torr. The layer thickness of the upper and lower coating films 6a and 6b was 150 μm.

This resin-coated copper foil 4a was placed on both sides of the aluminum plate of Example 1, heated and pressed in a reduced pressure atmosphere of 15 torr for 20 minutes at 170 ° C. and 50 kg / cm ² , and then 50
The heating and pressurization was performed for 1 minute in an atmospheric pressure atmosphere to obtain a heat dissipation type printed circuit board provided with the insulating layer 2. The total thickness of the insulating layer formed from the coating films 6a and 6b is 100 μm, and the thickness of the insulating layer formed from the coating film 6b containing an inorganic filler is 10 μm.
Met.

On this circuit board, under the same conditions as in the first embodiment,
A heat-radiating printed circuit board was obtained by performing through-hole processing by NC having a diameter smaller than that of an aluminum plate, and then performing through-hole plating and etching copper foil. (Example 4) An aluminum plate of the metal plate 1 was used, and a roughened 35 μm copper foil was used. A circuit board including an insulating layer in which the same two-layer coating films 6a and 6b as in Example 2 were semi-cured on one surface of the copper foil 3a was manufactured. A circuit was formed on this resin-coated copper foil 4a under the same etching conditions as in Example 1 to obtain an inner layer circuit board. This inner layer circuit board is provided on both sides of an aluminum plate with a glass base material (116E manufactured by Nitto Boseki Co., Ltd.) and an epoxy resin amount of 5
Two prepregs (R-1661J manufactured by Matsushita Electric Works, Ltd.) composed of 3% by weight were stacked on top of each other, and the above-mentioned circuit board was further stacked thereon as an outer layer circuit board. In this case, the above-mentioned prepreg manufactured by Matsushita Electric Works, Ltd. was overlaid by the pin lamination method to form the pressure-receiving body 8, which was used in Example 2.
By heating and pressurizing under the conditions described above, a multilayer heat radiation type printed circuit board was obtained.

This multilayer heat dissipation type printed circuit board has a diameter smaller than that of the through hole of the aluminum plate under the same conditions as in the first embodiment.
Through hole processing by NC was performed, and then through hole plating and copper foil were etched to obtain a multilayer heat dissipation type printed circuit board.

[0026]

[Comparative example]

Comparative Example 1 A 0.1 mm glass cloth was impregnated with the curable resin liquid of Example 1 and dried to obtain a prepreg having a resin amount of 55% by weight. This is placed on both sides of the aluminum plate of Example 1, and the copper foil of Example 1 is further placed on it to form a body to be pressed, which is heated and pressed under the same conditions as in Example 1, and a heat radiation type printed circuit. It was used as a substrate. The thickness of the cured resin layer was 200 μm. A printed circuit board was manufactured on this printed circuit board under the same conditions as in Example 1. (Comparative Example 2) The curable resin liquid having a resin solid content of 100% of Example 1 was applied to the aluminum plate of Example 1 to form a coating film, and then the coating film was cured under the same conditions as in Example 1 to release heat. Printed circuit board. A printed circuit board was manufactured on this printed circuit board under the same conditions as in Example 1.

Evaluation method of quality (1) Presence or absence of scrap powder generation: 300 pieces of test pieces obtained by cutting the obtained printed circuit board into a 100 mm square and chamfering the end face.
From the height of mm, it was dropped on a black paper table 5 times, and the presence or absence of powder on the table was visually confirmed. (2) Adhesive force between through hole and metal plating: 0.9 mm
A piano wire having a diameter was soldered to the metal plating in the through hole and evaluated by a tensile test. (3) Adhesive force between metal plate and insulating layer: A portion including a through hole was cut into a 50 mm square to form a test piece, which was immersed in a solder bath at 260 ° C. for 5 seconds as one cycle and subjected to thermal shock for 5 cycles. Then, it was cut along a line passing through the center of the through hole, and the cut surface was observed with a microscope for the presence or absence of peeling between the metal plate and the insulating layer. The number of test pieces was set to n = 10.

The measurement results of the respective qualities of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in (Table 1).

[0029]

[Table 1]

[0030]

According to the heat dissipation type printed circuit board according to the first to fourth aspects of the present invention, the adhesive force between the insulating layer and the metal plate is high, and the insulating layer and the metal plate are generated during the post-processing. Is not peeled off, and the generation of scrap powder generated from the insulating layer is improved.

Further, according to the method of manufacturing the heat dissipation type printed circuit board of the present invention, the adhesive force between the insulating layer and the metal plate is high, the insulating layer and the metal plate are not separated from each other, which is caused during the post-processing, and the insulating layer is not formed. It is possible to obtain a heat-dissipation type printed circuit board in which the generation of dust particles caused by the above is improved.

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a heat dissipation type printed circuit board according to an embodiment of the present invention, and FIG. 1B is a manufacturing method of the heat dissipation type printed circuit board according to an embodiment of the present invention. FIG. 3 is a sectional view mainly showing a layer structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal plate 2 Insulating layer 3 Copper foil 3a Copper foil 3b Copper foil 4a Copper foil with resin 4b Copper foil with resin 6a Coating film 6b Coating film 7 Thru hole 8 Pressure body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location H05K 3/44 H05K 3/44 A

Claims (5)

[Claims] 1. A heat dissipation type printed circuit board comprising an insulating layer (2) formed on the surface of a metal plate (1) and a copper foil (3) layered on the insulating layer (2). The layer (2) does not include a sheet-shaped base material as a constituent material, but is composed of a resin layer containing an inorganic filler as a component, which is a heat radiation type printed circuit board. 2. The heat radiation type printed circuit board according to claim 1, wherein the insulating layer (2) has a thickness of 50 μm or more. 3. The metal plate (1) is an aluminum plate.
Alternatively, the heat dissipation type printed circuit board according to claim 2. 4. The heat dissipation type printed circuit board according to claim 1, wherein the resin layer of the insulating layer (2) is composed of an epoxy resin. 5. A coating film (6a) is formed by applying a curable resin liquid that does not contain an inorganic filler as a component to a copper foil (3a), and then the coating film (6a) is semi-cured, and then this semi-cured. A curable resin liquid containing an inorganic filler as a component is applied to the formed coating film (6a) to form a coating film (6b), and then the coating film (6b) is semi-cured to form a resin-coated copper foil (4).
a), the resin-coated copper foil (4a) is superposed on a metal plate (1a) having a through hole (7) to form a pressure-receiving body (8), and the pressure-receiving body (8) is heated and pressurized. A method of manufacturing a heat dissipation type printed circuit board.