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US 5,309,632 AGranted
Process for producing printed wiring board
AssigneeHitachi Chemical Company, Ltd.
InventorsHiroshi Takahashi, Shin Takanezawa, Masao Kanno, Yorio Iwasaki, Toshirou Okamura, Akishi Nakaso, Kiyoshi Hasegawa
Life of this patent
Estimating the term…
Abstract
A process for producing a printed wiring board characterized by forming a nickel layer by electroless plating and a copper layer formed thereon by electroless plating, or forming a copper undercoating layer before the nickel layer by electroless plating can produce printed circuit boards excellent in resistance to electrolytic corrosion and suitable for mounting parts in high density.
Claims9
A process for producing a printed wiring board, which comprises
- (i-a) forming an adhesive layer containing an electroless plating catalyst on surfaces of an insulating substrate containing an electroless plating catalyst,
- (ii-b) drilling through-holes in the resulting insulating substrate,
- (iii-c) masking portions except for the through-holes and circuit forming portions with a first resist for electroless plating,
- (iv-d) dipping the resulting substrate in a chemical roughening solution to selectively roughen the portions not masked with the resist,
- (v-e) dipping the thus treated substrate in an electroless nickel plating solution to form nickel plated layers on the roughened portions not masked with the first resist,
- (v-ef) masking portions except for the through-holes and circuit forming portions with a second resist for electroless plating, the second resist forming a circuit forming pattern that is 5 to 10 .mu.m narrower than that of the first resist, so that the second resist covers a portion of the nickel plated layers, and
- (vi-f) dipping the nickel plated substrate in an electroless copper plating solution to conduct copper plating on exposed portions of the nickel plated layers.
4 more elements
A process for producing a printed wiring board, which comprises
- (i-a') forming an adhesive layer on surfaces of an insulating substrate,
- (ii-b) drilling through-holes in the resulting insulating substrate,
- (iii-d') dipping the resulting substrate in a chemical roughening solution to roughen the whole surfaces,
- (iv-d) masking portions except for the through-holes and circuit forming portions with a first resist for electroless plating,
- (v-e) dipping the thus treated substrate in an electroless nickel plating solution to form nickel plated layers on the roughened portions not masked with the first resist,
- (v-ef) masking portions except for the through-holes and circuit forming portions with a second resist for electroless plating, the second resist forming a circuit forming pattern that is 5 to 10 .mu.m narrower than that of the first resist, so that the second resist covers a portion of the nickel plated layers, and
- (vi-f) dipping the nickel plated substrate in an electroless copper plating solution to conduct copper plating on exposed portions of the nickel plated layers.
4 more elements
A process for producing a printed wiring board, which comprises
- (i-a) forming an adhesive layer of surfaces of an insulating substrate,
- (ii-b) drilling through-holes in the resulting insulating substrate,
- (iii-c) masking portions except for the through-holes and circuit forming portions with a first resist for electroless plating,
- (iv-d) dipping the resulting substrate in a chemical roughening solution to selectively roughen the portions not masked with the first resist,
- (v-H) dipping the resulting substrate in an aqueous solution containing palladium ions,
- (v-i) dipping the resulting substrate in a reducing agent solution,
- (vii-e) dipping the thus treated substrate in an electroless plating solution to form nickel plated layers on the roughened portions not masked with the first resist,
- (v-ef) masking portions except for the through-holes and circuit forming portions with a second resist for electroless plating, the second resist forming a circuit forming pattern that is 5 to 10 .mu.m narrower than that of the first resist, so that the second resist covers a portion of the nickel plated layers, and
- (viii-f) dipping the nickel plated substrate in an electroless copper plating solution to conduct copper plating on exposed portions of the nickel plated layers.
6 more elements
A process for producing a printed wiring board, which comprises
- (i-a) forming an adhesive layer containing an electroless plating catalyst on surfaces of an insulating substrate containing an electroless plating catalyst,
- (ii-b) drilling through-holes in the resulting insulating substrate,
- (iii-c) masking portions except for the through-holes and circuit forming portions with a first resist for electroless plating,
- (iv-d) dipping the resulting substrate in a chemical roughening solution to selectively roughen the portions not masked with the first resist,
- (v-e) dipping the thus treated substrate in an electroless plating solution to form plated layers of nickel, a nickel alloy, or a mixture thereof on the roughened portions not masked with the first resist,
- (v-ef) masking portions except for the through-holes and circuit forming portions with a second resist for electroless plating, the second resist forming a circuit forming pattern that is 5 to 10 .mu.m narrower than that of the first resist, so that the second resist covers a portion of the nickel plated layers, and
- (vi-f) dipping the thus nickel plated substrate in an electroless copper plating solution to conduct copper plating on exposed portions of the nickel plated layers.
4 more elements
Dependencies are inferred from the claim text.