Patent ID: 7233072

Claim:
A surface treatment method for a connector-use connecting terminal, the method comprising: subjecting a soldered part to a three layer surface treatment of nickel, palladium and gold, wherein a palladium layer is electrolytically plated on a nickel layer under a condition where current density is 1 to 10 A/dm 2 , wherein, after forming the palladium layer, a gold layer is electrolytically plated on the palladium layer under a condition where current density is 0.05 to 0.1 A/dm 2 , wherein a thickness of the palladium layer is in a range of 0.007 to less than 0.1 μm, a thickness of the gold layer is in a range of 0.003 to less than 0.01 μm, and wherein the thickness of the gold layer is established to be less than the thickness of the palladium layer, and wherein the gold layer partially laps a palladium strike surface which forms the palladium layer.