Patent ID: 8187723

Claim:
A chromate-free surface-treated copper foil comprising: an electrodeposited copper foil; a rust-proofing treatment layer comprising: a non-alloyed nickel layer on top and in direct contact with the electrodeposited copper foil; and a non-alloyed tin layer on top and in direct contact with the nickel layer; and a silane coupling agent layer on top of and in direct contact with the tin layer, wherein the nickel layer has a thickness by weight of 5 to 40 mg/m 2 and the tin layer has a thickness by weight of 5 to 40 mg/m 2 , wherein the sum of thickness by weight of non-alloyed nickel and non-alloyed tin layers is 10 to 50 mg/m 2 , and wherein the non-alloyed nickel and non-alloyed tin layers combined have a [nickel weight/tin weight]ratio of ⅓ to 3.