JPS5983771A - Manufacture of etched copper-coated metal substrate - Google Patents

Abstract

PURPOSE:To facilitate liquid waste disposal, while making an etching time constant, in pattern etching a copper layer on a metal substrate prepd. by laminating a copper foil through an insulating layer onto a metal plate, by using an etchant based on sulfuric acid and H2O2. CONSTITUTION:In the metal substrate prepd. by laminating a copper foil through an insulating layer composed of an organic macromolecule such as epoxy resin, inorganic substance or these mixture onto a metal plate such as an Al material or stainless steel, said copper foil is pattern etched. Hereon, an etchant based on sulfuric acid and H2O2 is used. Hence, etching is performed by converting copper into copper sulfide with said etchant without damaging Al. Consequently, copper can be easily removed as the crystal of copper sulfide by cooling said liquid etchant, and the etching can be continually performed under the same condition by supplying sulfuric acid and H2O2 in response to their consumptions.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an etched copper-clad metal substrate. In recent years, copper-clad metal substrates with good heat dissipation properties, especially copper-clad aluminum substrates, have become popular in hybrid eco
It is attracting attention as a substrate for This copper-clad aluminum substrate usually has an insulating adhesive layer on the aluminum plate.
Since the structure is such that copper foil is bonded on top of that, aluminum is exposed on the back side of the board. For this reason, etching agents such as ferric chloride, cupric chloride, and alkaline etchants, which have been conventionally used for copper pattern etching on paper phenol and glass epoxy copper-clad laminates, are used to remove the copper on copper-clad aluminum substrates. In order to perform pattern etching, it was necessary to (1) protect the back surface of the substrate with a film or the like, and (2) form a layer on the back surface of the substrate that would not be attacked by etching agents, such as an alumite treatment. However, these two methods have the disadvantage that it is difficult to protect the sides of the substrate.

Therefore, when etching a copper pattern on a copper-clad metal board where the metal is exposed on the back side of the board, as in the etching of this copper-clad aluminum board, it is best to use an etching agent that does not attack the metal that is the board material. preferable. In other words, for copper pattern etching on copper-clad aluminum substrates, ammonium persulfate aqueous solution has long been known as an etching agent that etches copper without damaging aluminum irregularities, but it is difficult to dispose of waste liquid and the etching time varies greatly. There were other drawbacks.

The present invention solves these drawbacks, and by using sulfuric acid and hydrogen peroxide as the main ingredients as a pattern etching agent for copper foil, it does not attack aluminum, the etching time is constant, and waste liquid treatment is easy. The present invention provides a method of manufacturing an etched copper-clad metal substrate that can be etched. That is, the present invention uses an etching agent containing sulfuric acid and hydrogen peroxide as main components when pattern etching the steel foil in a metal substrate in which a copper foil is laminated on a metal plate via an insulating layer. It is characterized by

Etching of copper using an etching agent mainly composed of sulfuric acid and hydrogen peroxide in the present invention proceeds according to the following chemical formula.

Cu+H3S04+H2O2→CuSO4+2H20 Therefore, copper is removed from the etching agent as copper sulfate crystals,
By replenishing the consumed sulfuric acid and hydrogen peroxide, etching can always be performed under the same etching conditions. In addition, crystallization of copper sulfate can be easily performed by cooling the etching solution, so it cannot be removed immediately. However, unlike the ammonium persulfate-based etching agent, ammonia and copper ions form a complex salt, making it difficult to remove the copper ions. Nor. In addition to these main ingredients, the sulfuric acid-hydrogen peroxide based etching agent of the present invention may contain an etching accelerator, an additive for stabilizing hydrogen peroxide, etc. , aluminum and its alloys,
Furthermore, there are corrosion-resistant metals such as stainless steel. The surface of the aluminum may still be subjected to alumite treatment or the like.

As the insulating layer of the metal substrate that can be used in the present invention, organic polymers such as epoxy resins, phenol resins, silicone resins, and polyimide resins, inorganic substances, and composite materials of organic polymers and inorganic substances such as glass epoxy are used. .

The present invention will be further explained below with reference to Examples and Comparative Examples.

Example 1 Alkali was applied by screen printing onto [Denka H-Technology TT Plate] (trade name of Denki Kagaku Kogyo), which was made by laminating a 35 μm copper foil on a 1.5 column thick aluminum plate through an 80 μm insulating layer. Removable Elatin Breath) D A 200
Print B (Sanf Chemical ■Product name) in a pattern and 8
It was dried for 0°010 minutes. After that, an etching agent consisting of 20 volumes of sulfuric acid and 12 volumes of Perma-Etch (Ebara Electric Co., Ltd.'s product name; mainly composed of 50 volumes of hydrogen peroxide) was used at a copper concentration of 20 Y/l. Spray etched for 12 minutes at °C. The aluminum surface on the back of the board was not attacked, and only the copper foil could be etched in a pattern. Also, by cooling the etching solution to 10°C, copper sulfate could be recovered as sword-shaped crystals.

Comparative Example 1 For the same substrate as in Example 1, 30% by weight of ferric chloride
When etched with an aqueous solution at 40°C,
In addition to etching the copper, the aluminum on the back surface of the substrate was dissolved with hydrogen generation.

Comparative Example 2 25% of ammonium persulfate was used on the same substrate as in Example 1.
When 09/ was etched with an aqueous solution at 40°C, not only the copper was etched in 7 minutes, but also the aluminum on the back surface of the substrate turned white.

Comparative Example 6 In Comparative Example 2, the copper concentration was 35! When similarly etched with an aqueous ammonium persulfate solution under the condition of i'/l,
Even after 15 minutes or more, the copper was not completely etched and copper remained in spots. Furthermore, the aluminum on the back surface of the substrate turned white as in Comparative Example 2.

As described above, by using the etching agent containing sulfuric acid and hydrogen peroxide as main components according to the present invention, it is possible to etch a copper pattern on a copper-clad metal substrate without damaging the back surface of the substrate.

Patent applicant: Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] In a metal substrate in which copper foil is laminated on a metal plate via an insulating layer, an etching agent containing sulfuric acid and hydrogen peroxide as main components is used to pattern-etch the copper foil. A method for manufacturing a copper-clad metal substrate.