Patent ID: 7842397

Claim:
A printed wiring board copper foil, comprising: a nickel plating layer comprising a nickel-cobalt alloy plating layer, a total deposit amount of nickel and cobalt on a side to be bonded to a printed wiring board base material being 5 μg/cm 2 or more to 20 μg/cm 2 or less, a cobalt concentration being 60 mass % or more to 80 mass % or less, wherein said nickel plating layer is applied to said copper foil by using an insoluble anode and a nickel plating solution comprising water, 100 g/L or more and less than 200 g/L of nickel sulfate, and 10 g/L or more and less than 30 g/L of sodium citrate or 8 g/L or more and less than 25 g/L of citric acid dissolved in the water, but no nickel chloride and boric acid added therein, wherein a pH of the solution is adjusted to 2 or more and less than 4.