WIRE BONDING METHOD TO DOUBLE METAL COVERED PAD SURFACE AND ELECTRIC CARD STRUCTURE CONTAINING ITS WIRE BONDING

摘要

PROBLEM TO BE SOLVED: To form a metal surface capable of connection which receives conducting wiring, by sticking a thin second metal layer on a first metal layer, and heating the first and the second metal layers up to a specified temperature for a specified time. SOLUTION: A substrate 11 with a circuit is formed of proper dielectric material (organic insulating material like epoxy glass) on which a wiring layer 13 composed of copper or the like is formed. A first metal layer 14 composed of palladium of 5 microinches thick is formed on a wiring layer 13. A second thin metal layer 15 of gold (50-200Åthick) which is different from the first metal layer 14 is arranged on the first metal layer 14. The first metal layer 14 and the second metal layer 15 which are composed of palladium and gold are heated for one hour, up to 180 deg.C. When heating, hydrogen molecules captured by a palladium layer is energized by heat and discharged in air through a gold layer. A wire 17 of wire bond is connected with the first metal layer 14 through the second thin metal layer 15.