JPH0441235A - Treatment of low thermal expansion metal plate and metal base board and metal base wiring board using same metal plate - Google Patents

Abstract

PURPOSE:To inexpensively and easily obtain the above low thermal expansion metal plate having excellent adhesion by roughening the surface of the low thermal expansion metal plate having the coefficient of thermal expansion of a specific value or less by mechanical grinding so as to obtain specific depth and treating the ground surface with a silane coupling agent. CONSTITUTION:The surface of a low thermal expansion metal plate having the coefficient of thermal expansion of 7X10<-6>/ deg.C or less is roughened by mechanical grinding so as to obtain 3-10mum depth and the ground surface is treated with a silane coupling agent to make it possible to obtain the low thermal expansion metal plate having excellent adhesiveness. When the low thermal expansion metal plate having the coefficient of thermal expansion of 7X10<-6>/ deg.C or more is used, the sufficient reliability of the connection part with an element is not obtained when said metal plate is formed into a wiring board. As a low thermal expansion metal, a 42 alloy or invar being an iron-nickel alloy is suitably used. A method using sand paper is suitably used in the mechanical grinding roughening the surface of the metal plate. When the depth of a roughened surface is below 3mum, adhesive strength is insufficient and, when the depth exceeds 10mum, a time is required in surface roughening and a resin having good flowability must be used at the time of the formation of an insulating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of processing a low thermal expansion metal plate, and a metal base substrate and a metal base wiring board using the metal plate obtained by the treatment method.

Z. The method for treating a low thermal expansion metal plate according to claim 1, wherein the low thermal expansion metal plate is an iron-nickel alloy plate.

3. The method for treating a low thermal expansion metal plate according to claim 1 or 2, wherein the silane coupling agent is an aminosilane coupling agent.

[Conventional technology]

In order to improve the reliability of the connection between the element and the wiring board when mounting an element with low thermal expansion such as a silicon chip or ceramic chip carrier, a low thermal expansion metal plate such as 42 alloy or invar is used. A metal-based wiring board has been proposed. However, because there is a large difference in thermal expansion between the low-expansion metal and the organic resin material used as the insulating layer, thermal stress is likely to occur at the interface between the metal plate and the insulating layer, and these metals have poor adhesive properties compared to aluminum, etc. There is a problem in that the adhesive strength between the metal plate and the insulating layer is not sufficient due to poor performance. Therefore, as a method for improving the adhesive strength between these metal plates and an insulating layer made of an organic resin material, Japanese Patent Laid-Open No. 61-2
As shown in Japanese Patent Publication No. 95693, a method of attaching aluminum, iron, zinc, etc. to the surface of an Invar plate by rolling, electrolysis, vapor deposition, etc., and as shown in Japanese Patent Application Laid-Open No. 63-261863, There is a method in which aluminum layers are laminated on both sides of an iron-nickel alloy layer.

[Problem to be solved by the invention]

The method disclosed in JP-A-61-295693 is not necessarily suitable for mass production because aluminum is attached to the surface of a metal plate by rolling, electrolysis, vapor deposition, etc.

Furthermore, the method disclosed in JP-A No. 63-261863 uses a multi-layered metal plate consisting of an aluminum layer and a low thermal expansion metal plate such as 42 alloy. It is not commercially available and requires expensive manufacturing equipment to manufacture. Furthermore, since it takes time to stack the layers, even if it is mass-produced, it will be expensive.

The present invention allows low thermal expansion metal plates to be easily processed at low cost.
The present invention provides a method for processing a low thermal expansion metal plate, in which a low thermal expansion metal plate having excellent adhesive properties can be obtained by the treatment, and a metal base substrate and a metal base wiring board using the metal plate subjected to the treatment.

[Means to solve the problem]

The inventors of the present invention have conducted intensive research to solve the above problem, and have found that the problem can be solved by roughening the surface of a low thermal expansion metal plate to a specific depth using a specific method, and then performing a specific treatment. Z has discovered that the problem can be solved, and based on this knowledge, he has completed the present invention.

That is, the present invention has a thermal expansion coefficient of 7 x 10-"/'C
The surface of the following low thermal expansion metal plate is mechanically ground to 3 to 10
The present invention provides a method for treating a low thermal expansion metal plate, which is characterized in that after roughening the surface to a depth of μm, the ground surface is treated with a silane coupling agent.

A low thermal expansion metal plate with a coefficient of thermal expansion of 7 x 10-''/'C or less is used. If a metal plate exceeding this value is used, sufficient reliability of the element and the connecting portion cannot be obtained when used as a wiring board.

As the low thermal expansion metal, 42 alloy, which is an iron-nickel alloy, Invar, or the like is suitably used.

Methods for roughening the surface of a metal plate include sandblasting, chemical roughening, mechanical grinding, etc., and in the present invention, mechanical grinding is used. Mechanical grinding is preferably carried out by using sandpaper. Sandblasting and chemical roughening cannot achieve the same effect as mechanical grinding, even if they form a rough surface of the same degree. The degree of roughening of the surface of the metal plate by grinding is 3 to 10 μm in depth, more preferably 5 to 8 μm.
The depth should be m. . If the depth of the roughening is less than 3 μm, the adhesive force will not be sufficient, and if the depth exceeds 10 μm, it will take time to roughen the surface, and a resin with good fluidity will be required when forming the insulating layer. Restrictions arise, such as having to use . Better adhesion is obtained with a depth of 5-8 μm.

After grinding the metal plate in this manner, it is treated with a silane coupling agent. Commercially available silane coupling agent solutions are typically
The silane coupling agent is diluted with an organic solvent such as methanol or ethanol.

Silane coupling agent treatment further increases this solution by 0.5 to 5
After diluting with water to about % by weight, it is applied to the metal surface by immersion in this liquid, brushing or spraying, and then dried. As the silane coupling agent, an epoxysilane coupling agent, an aminosilane coupling agent, etc. are used, and among these, an aminosilane coupling agent is preferably used.

The metal base substrate of the present invention is produced by using a metal plate subjected to such treatment and providing a conductive foil on the metal plate via an organic resin or a composite material of an organic resin and an inorganic material to serve as an insulating layer. Organic resins include epoxy, polyimide,
Resins with excellent electrical properties such as polyamide are suitable.

As the inorganic material, alumina powder, silica powder, etc., woven cloth such as glass cloth, alumina paper, etc. are used.

As the conductor foil, copper foil, a composite foil of copper and other metals, etc. are used.

The metal base wiring board of the present invention is produced by etching the thus obtained metal base substrate to form wiring.

[Effect]

Since the low expansion metal plate, metal base substrate, and metal base wiring board of the present invention have a low coefficient of thermal expansion, the reliability of the connection between the element and the wiring board when mounting an element with low thermal expansion is low. Furthermore, the surface of the low thermal expansion metal plate is roughened to a depth of 3 to 10 μm and treated with a silane coupling agent, resulting in a mechanical bond (anchoring effect) between the insulating layer and the metal surface. , adhesion is improved.

〔Example〕

Hereinafter, the present invention will be explained in detail based on Examples, but the present invention is not limited thereto.

Example 1 The surface of a low thermal expansion metal plate 1 made of alloy 42 (coefficient of thermal expansion 4.5 x 10-6/''C) was polished using a belt-type surface grinder (commonly known as a belt sander) equipped with No. 240 sandpaper. A low thermal expansion metal plate having a treated surface 11 as shown in FIG. This is shown in Figure (a).This material was immersed in a 1% by weight solution of an aminosilane coupling agent (A1100 manufactured by Nippon Unicar Co., Ltd.) and then dried and treated with an amino coupling agent.Then, the copper foil was coated with an alumina filler. An epoxy resin varnish containing about 50% by volume of A metal base board was obtained.A sample was prepared by leaving only the 20-square copper foil of this board and etching the other parts of the copper foil, and floating it in a solder bath at 320°C to measure the time it takes for the copper foil to swell. When measured, the average value for 10 samples was about 3 minutes.

When the metal base substrate is etched, a metal wiring board having a circuit-formed conductor foil as shown in FIG. 3 is obtained.

Comparative Example 1.2.3 ■ After grinding the surface with No. 400 sandpaper (depth of the rough surface approximately 1 μm), a 42 alloy plate treated with an amino coupling agent in the same manner as in Example 1 (the surface roughness was As shown in Figure 4 et al.
), ■After sandblasting the surface (depth of rough surface 4μm),
A 42 alloy plate treated with an aminosilane coupling agent in the same manner as in Example 1 (the surface roughness is shown in Figure 4 (C)); A ground 42 alloy plate (not treated with silane coupling agent) was obtained.

Metal base substrates were prepared in the same manner as in Example 1, except that the above-mentioned (1), (2), and 0042 alloy plates were used, and the same tests as in Example 1 were conducted. As a result, 1
．． 5 minutes, 2 minutes for ■, and 1.5 minutes for ■, all values 1/2 to 2/3 compared to Example 1. Note that since the same resin is used here, the time it takes for the soldering pass to swell reflects the adhesive strength between the layers.

〔Effect of the invention〕

The surface treatment method of the present invention does not require any treatment such as adhering aluminum, and simply grinds the 42 alloy plate using a general-purpose method and treats it with a silane coupling agent.It has excellent adhesive properties and low thermal expansion. You can get metal plates. Therefore, it has excellent productivity and its industrial value is extremely large.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a low thermal expansion metal plate subjected to a low thermal expansion metal plate processing method showing an embodiment of the present invention, and FIG. 2 is a sectional view of a metal base substrate showing an embodiment of the present invention. FIG. 3 is a sectional view of a metal base wiring board showing an embodiment of the present invention. FIG. 4 is a measurement diagram showing the degree of roughening of the surface of a metal plate. Explanation of symbols 1 Low thermal expansion metal plate 11 Processed surface of low thermal expansion metal plate 2 Insulating layer 3 Conductor foil 31 Conductor foil with circuit formed

Claims (5)

[Claims] 1. After roughening the surface of a low thermal expansion metal plate with a coefficient of thermal expansion of 7 x 10^-^6/℃ or less by mechanical grinding to a depth of 3 to 10 μm, the ground surface is treated with a silane coupling agent. Characteristic processing method for low thermal expansion metal plates. 2. 2. The method for treating a low thermal expansion metal plate according to claim 1, wherein the low thermal expansion metal plate is an iron-nickel alloy plate. 3. The method for treating a low thermal expansion metal plate according to claim 1 or 2, wherein the silane coupling agent is an aminosilane coupling agent. 4. A metal base substrate characterized by using a low thermal expansion metal plate obtained by the treatment method according to any one of claims 1 to 3. 5. A metal base wiring board characterized in that wiring is formed on the metal base substrate according to claim 4.