JPH0613722A - Metal base circuit board - Google Patents

Abstract

PURPOSE:To obtain a metal base circuit board having improved withstand voltage characteristics under a high temperature by a method wherein, in a circuit board formed by laminating aluminum/copper clad foil on a metal board through the intermediary of an insulating layer, the quantity of chloride ions in the resin to be used as an insulating layer and the quantity of sodium in an inorganic component are set at the prescribed quantity or smaller. CONSTITUTION:A circuit board is formed by laminating an aluminum/copper clad foil 10, having a substitute layer 5 as an intermediate layer through the intermediary of an insulating layer 2, on a base metal board with the surface of aluminum foil 4 facing upward. Aluminum and an aluminum alloy, copper, iron, stainless steel, Invar type material and the like are used for the base board 1. Also, the insulating layer 2 is composed of an inorganic component and an organic component, and the quantity of sodium, having high ionic coupling, which is contained in the inorganic component is set at 1000ppm or smaller. Also, the quantity of chloride ions contained in resin component is set at 1000ppm or smaller. When the above-mentioned quantity exceeds 1000ppm, it becomes the cause of acceleration of deterioration in insulation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal base circuit board which has a highly reliable insulating layer at high temperatures and is used in electric equipment, communication equipment, automobiles and the like.

[0002]

2. Description of the Related Art In a conventional metal-based circuit board,
In particular, since the circuit on which the semiconductor is mounted is not required to have high withstand voltage characteristics at high temperature, impurities are particularly limited especially for the resin and the inorganic filler used for the insulating layer of the circuit board, and No quantified study has been attempted.

[0003]

Therefore, the conventional metal-based circuit board has a problem that the dielectric strength is low under high temperature and DC voltage. That is, there is a problem that the ionic impurities move and the withstand voltage is lowered in a polarity invariant voltage such as DC, AC half-wave or rectangular wave at high temperature.

The present invention has solved the above-mentioned drawbacks, and by setting the chloride ion amount in the resin used as the insulating layer and the sodium amount in the inorganic component to be not more than a specific amount, the withstand voltage characteristic at high temperature is improved. To provide a metal-based circuit board having improved characteristics.

[0005]

That is, the present invention is as follows. A circuit board in which an aluminum / copper clad foil is laminated on a metal substrate via an insulating layer, wherein the amount of sodium contained in the inorganic component in the insulating layer is 1,000 ppm or less. 2. A circuit board in which an aluminum / copper clad foil is laminated on a metal substrate via an insulating layer, wherein the amount of chloride ions contained in the resin component in the insulating layer is 1,000 ppm or less. Circuit board and 3. In a circuit board in which an aluminum / copper clad foil is laminated on a metal substrate via an insulating layer, the amount of sodium contained in the inorganic component in the insulating layer is 1,000 ppm or less,
In addition, the amount of chloride ions contained in the resin component is 1,000 ppm or less, which is a metal base circuit board, which reduces ionic impurities in the insulating layer on the metal base. By doing so, a metal-based circuit board having high withstand voltage characteristics at high temperature is provided.

[0006]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a circuit board of the present invention, in which a base metal substrate 1 is an aluminum / copper clad foil 10 having a replacement layer 5 as an intermediate layer with an insulating layer 2 in between, and an aluminum foil 4 surface of which is an upper surface. FIG.

FIG. 2 is a cross-sectional view of a circuit board with the copper foil 3 surface of the aluminum / copper clad foil 10 laminated on the insulating layer 2 as the top surface.

Further, FIG. 3 is a sectional view of a hybrid integrated circuit in which a semiconductor or the like is mounted on the circuit board of the present invention.

The base metal substrate 1 used in the present invention has good thermal conductivity and generally has a wall thickness of 0.5 mm to 3.0 m.
m and aluminum and aluminum alloys, copper,
Iron, stainless steel, invar, etc. are used.

The thickness of the insulating layer 2 is not particularly limited as long as it does not cause insulation failure, and is preferably 20 μm.
m to 500 μm, the component is composed of both inorganic and organic components and is, for example, various ceramics, a polymer resin insulating layer containing inorganic powder, or a polymer resin insulating layer containing glass fiber. As the inorganic powder, alumina,
Beryllia, boron nitride, magnesia, silica,
Silicon nitride, aluminum nitride and the like are preferable, and as the polymer resin, epoxy resin, phenol resin, polyimide resin and various engineered plastics are used.

The amount of sodium having a large ionic bond contained in the inorganic component used in the insulating layer 2 of the present invention is 1,
The amount of chloride ion contained in the resin component is 1,000 ppm or less. That is, the amount of sodium contained in the inorganic component used in the insulating layer 2 and the amount of chloride ion contained in the resin component are each 1,000 ppm.
If the voltage exceeds the range, a voltage having a constant polarity is applied to the insulating layer 2 at a high temperature, and a large amount of sodium or chloride ion impurities having an ionic bond starts to move, which causes deterioration of insulation.

Further, the aluminum / copper clad foil 10 used in the present invention includes aluminum plated with nickel via nickel, zinc or tin, aluminum / copper bonding foil by a rolling method, and the like. The thickness of the aluminum / copper clad foil 10 is generally in the range of 0.5 μm to 1 mm.

Next, in the metal base circuit board of the present invention, the aluminum foil 4 and the copper foil 3 of the clad foil 10 are etched to form an arbitrary pattern, and the conductive circuit 1 made of the copper foil is formed.
2 and the pad 11 for wire bonding. After that, a semiconductor 8 or the like which is a chip component is mounted, and if necessary, bonding is performed with a wire 9 using an aluminum wire or a gold wire to manufacture a circuit component. The present invention is described in detail below with reference to examples.

Example 1 An aluminum substrate having a thickness of 1.5 mm was used as an insulating layer with a thickness of 150 μm.
A thick epoxy resin containing alumina powder was laminated. The content of chloride ion in the epoxy resin at this time is 10
ppm, and the amount of sodium in alumina powder is 10,000 pp
I used m. Next, 15 μm using zinc as a substitution layer
Using an aluminum / copper clad foil made by laminating a 35 μm thick electrolytic copper foil on a thick aluminum foil, the conductive circuit and bonding pad pattern are formed by etching, and after the chip parts are mounted, wire bonding is performed. went. 125 of 10 products made in this way
As a result of applying a DC voltage of 1,000 V (+ on the pattern side) at ℃, the average dielectric breakdown time was 10,000 hours.

Example 2 Insulation having the same constitution as that of the substrate used in Example 1, in which the amount of chloride ions contained in the epoxy resin is 10,000 ppm and the amount of sodium contained in the alumina powder is 10 ppm. A layer of substrate was used. The average dielectric breakdown time was 1,000 hours as a result of applying a DC voltage of 1,000 V (pattern side +) to these 10 products at 125 ° C.

Example 3 An insulating layer having the same structure as the substrate used in Example 1 and containing 10 ppm of chloride ions contained in the epoxy resin and 10 pm of sodium contained in the alumina powder. The substrate of was used. About 10 of this product, 125 ℃, DC voltage 1,
As a result of applying 000V (pattern side +), the average dielectric breakdown time was 100,000 hours.

Comparative Example 1 Insulation having the same structure as that of the substrate used in Example 1, in which the amount of chloride ions contained in the epoxy resin is 10,000 ppm and the amount of sodium contained in the alumina powder is 10,000 ppm. A layer of substrate was used. The average dielectric breakdown time was 100 hours as a result of applying a DC voltage of 1,000 V (pattern side +) to these 10 products at 125 ° C.

[0018]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, by reducing the amount of ionic impurities in the resin and the inorganic component used as the insulating layer, it is possible to extend the dielectric breakdown time at high temperature, and to mount semiconductors. It is used as a circuit in electric equipment, communication devices, automobiles, etc., and can solve the problems that have been encountered in the past.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a circuit board of the present invention with an aluminum foil of an aluminum / copper clad foil as an upper surface.

FIG. 2 is a cross-sectional view of the circuit board of the present invention with the copper foil of aluminum / copper clad foil as an upper surface.

FIG. 3 is a cross-sectional view of a semiconductor-mounted hybrid integrated circuit in which a conductive circuit is formed on the circuit board of the present invention and a semiconductor or the like is mounted.

[Explanation of symbols]

 1 Base Metal Metal 2 Insulation Layer 3 Copper Foil 4 Aluminum Foil 5 Zinc Substitution Layer 6 Solder 7 Heat Spreader 8 Semiconductor 9 Wire 10 Aluminum / Copper Clad Foil 11 Pad 12 Conductive Circuit

Claims (3)

[Claims] 1. A circuit board in which an aluminum / copper clad foil is laminated on a metal substrate via an insulating layer, wherein the amount of sodium contained in the inorganic component in the insulating layer is 1,000 ppm or less. Base circuit board. 2. A circuit board in which an aluminum / copper clad foil is laminated on a metal board via an insulating layer, wherein the amount of chloride ions contained in the resin component in the insulating layer is 1,000 ppm.
A metal-based circuit board characterized in that: 3. A circuit board in which an aluminum / copper clad foil is laminated on a metal substrate via an insulating layer, wherein the amount of sodium contained in the inorganic component of the insulating layer is 1,000 ppm or less, and the resin component is contained in the resin component. The amount of chloride ion contained
Metal-based circuit board characterized by 1,000ppm or less.