JPS63168072A - Metal base printed circuit substrate - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a printed circuit board based on an aluminum plate (hereinafter referred to as an Al plate), in which an A1 board and an insulating layer are in strong contact with each other. For this purpose, the surface of the Al plate is treated with phosphoric acid alumite.

(Prior art) As shown in Fig. 2, a conventional printed circuit board based on an Al board is made of a first board (4), a circuit metal foil (6) made of copper, aluminum, etc., and an insulating layer (such as prepreg). 5).

In more detail, in order to obtain adhesive strength, the surface of the Al plate is roughened by physical methods such as polishing, or made porous by sulfuric acid alumite treatment or oxalate alumite treatment, and the insulating layer is They used prepreg, which is a base material such as glass fiber cloth, impregnated with thermosetting resin such as epoxy resin, phenol resin, or silicone resin, or thermoplastic resin film.

Circuit boards based on such Al plates cannot be said to fully satisfy various required characteristics under harsh usage conditions in recent years, and further improvements are desired.

In particular, various studies have been made regarding the adhesion between the Al plate and the insulating layer from both sides of the Al plate and the insulating layer, but no satisfactory results have been obtained yet.

(Object of the invention) The present invention improves the adhesion between the A1 board and the insulating layer in a printed circuit board based on an Al board, which has excellent heat resistance and withstand voltage, and is resistant to harsh processing and usage conditions. The purpose of this invention is to provide a printed circuit board that can withstand

[Structure of the invention]

The present invention provides a metal-based printed circuit board consisting of an Al plate and an insulating layer provided on the surface thereof, as shown in FIG. An alumite film (1a) is provided on which an insulating layer (2
) and, if necessary, a metal foil layer (3) in this order.

The present invention has a thickness of 0.1 to 1.5μ on the surface as an A1 plate.
The main feature is that a phosphoric acid alumite film of m is used.

A method for providing a phosphoric acid alumite film will be explained. Phosphoric acid concentration 50-200g/j! Use a treatment solution of The liquid temperature is room temperature to 45℃, and the current density is 30 to 100A/TIt.
, by performing electrolysis for 2 to 15 minutes, the Al plate was coated with 0.
A film of aluminium phosphate 1 to 1 to 1.5 μm thick can be provided.

The phosphoric acid alumite film has a strength of about 300, compared to other alumites, for example, about 200. Therefore, the insulating layer to be bonded can easily penetrate into the pores of the phosphoric acid alumite, and the adhesion between the insulating layer and the Al plate is improved.

In addition, sulfuric acid alumite and oxalic acid alumite are easily hydrated by water, making the film brittle and inhibiting adhesion, but phosphoric acid alumite has a film that is difficult to hydrate, so it has good adhesion.

When the film thickness of phosphoric acid alumite is less than 0.1 μm, the pores are shallow;
Sufficient adhesion cannot be obtained. On the other hand, if the thickness exceeds 1.5 μm, the adhesion force is comparable to that of 0.1 to 1.5 μm, and higher adhesion force cannot be obtained. Furthermore, when a molded substrate is bent, cracks occur in the alumite film, resulting in a decrease in adhesion and insulation. Furthermore, when drilling holes, the wear of the drill is large, which shortens the life of the drill.
This is not preferable because it will cause cracks in the alumite film, reducing adhesion and insulation.

Next, the materials used for the insulating layer include a prepreg in which a fibrous base material is impregnated with a thermosetting resin, a thermoplastic resin film, a thermosetting resin applied to an Al plate, a thermoplastic resin, and the like.

Thermosetting resins include phenol resins, epoxy resins, unsaturated polyester resins, polyimide resins, etc.
Epoxy resins and polyimide resins are preferred in order to fully exhibit the excellent adhesive properties of the phosphoric acid alumite on the surface of the plate.

Furthermore, preferably, the fibrous plugging material used when impregnating a fibrous base material with a fibrous base material on the alumite treatment to form a prepreg includes paper, synthetic fiber cloth, glass fiber cloth, etc. A glass fiber woven fabric or a glass fiber nonwoven fabric made of E glass, which has excellent electrical properties and the like, is preferable.

The proportion of resin in the thermosetting resin-impregnated fibrous base material is usually 30
The content is 60% by weight, but from the viewpoint of thermal conductivity and heat resistance, the smaller the content is, the more desirable it is, as long as it satisfies the properties required for subsequent processing steps, such as the adhesive strength between each layer.

Further, for the same reason, it is preferable not to use an adhesive between the Al plate and the prepreg, but in the present invention, since the Al plate has a porous phosphoric acid alumite film, it is possible to avoid using the adhesive. realizable.

AI, a predetermined number of prepreg sheets, and metal foil if necessary are laminated and molded under heat and pressure.

When a thermosetting resin is applied to an Al plate, usually a liquid resin is directly applied to the Al plate, and after drying, a metal foil is layered if necessary, and the resin is heated and press-molded.

When thermoplastic resin is used as an insulating layer, crosslinked polyolefin, high melting point polyolefin, polyether sulfone, polyetherimide, fluororesin, etc. are commonly used.
It is laminated in the form of a film on an Al plate, or it is made into an emulsion, applied to the Al plate, and dried. In this case as well, metal foils are laminated as necessary, and an adhesive is used between each layer as necessary. Thereafter, it is heated and press-molded at a temperature equal to or higher than the resin softening point.

The metal foil is made of copper, aluminum, nickel, etc., and the adhesive surface is preferably chemically or physically treated to improve adhesion. In addition, an oil film is provided,
Since no adhesive is required for adhesion to the prepreg, in order to improve thermal conductivity, it is preferable not to apply adhesive to the metal foil in the present invention.

〔Effect of the invention〕

The metal-based printed circuit board obtained according to the present invention is A
It has excellent properties such as adhesion between the l-plate and the insulation diagram, thermal conductivity, heat resistance, and voltage resistance, so it is suitable for processing and use under harsh conditions.

(Examples and Comparative Examples) Examples 1 to 3, Comparative Examples 1 to 3 Glass fiber woven @ (Nittobo WEA-106 [)] was impregnated with epoxy resin varnish to a resin content of 41% by weight and dried to produce prepreg. (Wa-da.

The formulation of the epoxy resin varnish is as follows.

Brominated epoxy resin (Epicote EP1035) 10
000 hydrogen cyandiamide 4 u2 4-methylimidazole 0.15 N solvent 100, /
One sheet of the prepreg and the A shown below on each side on its - side.
1 plate (thickness 1m) and electrolytic copper foil (35μTrL) with one side roughened on the other side, heated at 175℃, 9ONff.
/cffl, heated and pressure molded for 130 minutes and AI! A board-based laminate was obtained.

(Comparative Example 1) Al plate (JIS 1-(4000, A1050P,
One side of H-24) was roughened by ball polishing. The surface roughness Rmax was 15 μm.

(Comparative Example 2) Al plate (JISH4000, A1050P, 1-1-2
4> was treated with sulfuric acid alumite under the following conditions to form a film with a thickness of 1.5 μm.

Liquid composition 15% sulfuric acid Liquid temperature 25°C Electrolysis conditions 1 A/d TIi, 2 minutes [Comparative Example 3
] Af plate (JIS4000, A1050P, H-24>
One side of the sample was treated with phosphoric acid alumite under the following conditions to form a film with a thickness of 10 μm.

Liquid composition: Phosphoric acid 100g# Liquid temperature: 30°C Electrolysis conditions: 1A/d for 45 minutes and 7 hours (Examples 1 and 2) AJ2 plate (J I 34000. A1050P, H
-24> was subjected to phosphoric acid alumite treatment under the following conditions to obtain films of 1.5 μm and 0.5 μm, respectively.

Liquid composition: Phosphoric acid 100g# Liquid temperature: 30°C Electrolysis conditions: 0.5A/d for 15 minutes 0.5A/d
Trt, 5 minutes (Example 3) Al plate (J I 54000. A3052P, l-1
-34> was treated with phosphoric acid aluminium 1 to 19 under the same conditions as in Example 1 to form a 1.5 μm film.

A prepreg was obtained by impregnating and drying.

Thereafter, a Δ) board-based laminate was obtained in the same manner as in the case of the epoxy resin described above.

[Example 4] It was used.

[Comparative example 4] It was used.

Table 1 shows the properties of the Al plate-based laminates obtained in these Examples and Comparative Examples.

As is clear from Table 1, All obtained in each example
The II-S laminate has excellent properties such as adhesion between the Al plate and the prepreg (insulating layer), thermal conductivity, heat resistance, and voltage resistance. In addition, drill wear is small and bending workability is good.

In addition, in Table 1, the measurement method for each item is as follows.

Adhesive strength: The obtained laminate was treated in boiling water for 2 hours,
It was examined whether or not there was peeling between the insulating layer and the Al plate.

The insulating layer is destroyed without peeling. Q Peel off.
X Thermal conductivity: Showa Den IE QTM
Hot wire thermal conductivity was measured using a type rapid thermal conductivity meter.

Tril wear nitrile diameter 1.1, rotation speed 60.000r
Drilling was performed under the conditions of ptn and feed rate of 3 TrL/min.

Bending workability: R-2# bending was performed with the A1 plate facing inside.

There is delamination between the layers and cracks in the alumite film × No abnormality
OOther characteristics are J l5C
6481.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an A1 board-based printed circuit laminate obtained by the present invention. FIG. 2 is a cross-sectional view of a conventional AI board-based printed circuit laminate. 1.4...Al plate 1a...Phosphate alumite film 2.5...Insulating layer 3.6...Metal cage patent applicant Sumitomo Bakelite Co., Ltd. Showa Aluminum Co., Ltd.

Claims (1)

[Claims] In a metal-based printed circuit board consisting of an aluminum plate and an insulating layer provided on its surface, the aluminum plate has a phosphoric acid alumite film of 0.1 to 1.5 μm on the surface on which the insulating layer is provided. Characteristic metal-based printed circuit board.