Adhesive layer for bonding the resin to a copper surface

A bonding layer (2) for contacting of resin is provided, which is formed on a surface of copper (1) and an alloy of (a) copper, (b) tin, and (c) at least one type of metal (third metal ) selected from the group consisting of silver, zinc, aluminum, titanium, bismuth, chromium, iron, cobalt, nickel, palladium, gold and platinum, contains. The copper is in an amount of 1 to 50 atomic%, the tin contained in an amount of 20 to 98 atomic% and the third metal in an amount of 1 to 50 atomic%. The bonding layer (2) has a thickness of not less than 0.001 microns and not more than 1 .mu.m. Thus, the adhesion between copper and the resin can be improved.