Metal foil for printed wiring board and production thereof
AssigneeHitachi Chemical Company, Ltd.
InventorsNaoyuki Urasaki, Kouichi Tsuyama, Kiyoshi Hasegawa, Shuichi Hatakeyama, Akinari Kida, Akishi Nakaso, Hiroshi Nomura
Life of this patent
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Abstract
A metal foil for printed wiring boards comprising a first copper layer to be adhered to a resin, a second copper layer having a sufficient strength as a metal layer and a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus formed between the first and second copper layers is suitable for producing printed wiring boards having excellent heat resistance, particularly during production procedures.
Claims19
A process for producing a metal foil for printed wiring boards, which comprises
- a step of roughening a surface of a second copper layer having sufficient strength to provide a supporting metal layer,
- a step of forming a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus on the roughened surface of the second copper layer, and
- a step of forming a first copper layer on the nickel-phosphorus alloy layer, followed by roughening of the surface of the first copper layer to provide a roughness finer than roughness of the second copper layer.
A process for producing a printed wiring board which comprises:
- (a) a step of providing a prepreg on a roughened first copper layer of a metal foil for printed circuit boards, said metal foil comprising a first copper layer having a surface roughness suitable for adhering to the prepreg, a second copper layer having sufficient strength to provide a supporting metal layer and a coarser surface roughness than the first copper layer, and a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus formed between the first copper layer and the second copper layer, followed by pressing with heating to give an integral structure,
- (b) a step of removing the second copper layer by etching,
- (c) a step of removing the nickel-phosphorus alloy layer by etching, and
- (d) a step of forming a circuit conductor by etching the first copper layer.
A process for producing a printed wiring board which comprises:
- (a) a step of forming a resin layer on a roughened first copper layer of a metal foil for printed circuit boards, said metal foil comprising the first copper layer having a surface roughness suitable for adhering to the resin layer, a second copper layer having sufficient strength to provide a supporting metal layer and a coarser surface roughness than the first copper layer, and an intermediate layer formed between the first copper layer and the second copper layer and made of a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus, followed by heating,
- (b) a step of removing the second copper layer by etching,
- (c) a step of removing the nickel-phosphorus alloy layer by etching, and
- (d) a step of forming a circuit conductor by etching the first copper layer.
A process for producing a printed wiring board which comprises:
- (a) a step of forming a prepreg on a roughened first copper layer of a metal foil for printed circuit boards, said metal foil comprising a first copper layer having a surface roughness suitable for adhering to the prepreg, a second copper layer having sufficient strength to provide a supporting metal layer and a coarser surface roughness than the first copper layer, and a nickel-phosphorus alloy layer containing 1.1% by weight or more of phosphorus formed between the first copper layer and the second copper layer, and providing a copper foil on the prepreg, followed by pressing with heating to give an integral structure,
- (b) a step of removing the second copper layer by etching while retaining the copper foil,
- (c) a step of removing the nickel-phosphorus alloy layer by etching, while retaining the copper foil, and
- (d) a step of forming circuit conductors by etching the first copper layer formed on one side of the prepreg and the copper foil formed on another side of the prepreg.
Dependencies are inferred from the claim text.