| 摘要 |
PURPOSE:To coat a copper wire with a chemically stable gold plating layer, and to prevent a contact with air by forming a surface-preparation plating layer onto the surface of the copper wire while shaping the gold plating layer on the outside of the surface-preparation plating layer. CONSTITUTION:A small-gage metal wire 1 for wire bonding is constituted of a copper wire 2, a nickel plating layer 3 as a surface-preparation plating layer formed onto the surface of the copper wire 2 and a gold plating layer 4 shaped outside the nickel plating layer 3. The outer diameter of the small-gage metal wire 1 is set so as to be equalized with conventional gold wires. The copper wire 2 is manufactured through a wire drawing working method through which a long-sized wire rod composed of high-purity copper is drawn by a wire drawing machine, and the outer diameter of the copper wire 2 is set at a value slightly smaller than conventional gold wires. The nickel plating layer 3 is shaped onto the whole surface of the copper wire 2 through a known nickel plating method. The gold plating layer 4 is formed through a known gold plating method. A diffusion into the copper wire 2 of the gold plating layer 4 is prevented by the nickel plating layer 3. |
