US Patent 7261230 Wirebonding insulated wire and capillary therefor

An improved method of bonding an insulated wire (14) that has one end connected to a first bond pad (16) to a second bond pad (18) includes moving a tip of a capillary (20) holding the bond wire (14) over the surface of the second bond pad (18) such that the bond wire (14) is rubbed between the capillary tip (20) and the second bond pad (18), which tears the bond wire insulation so that at least a portion of a metal core of the wire (14) contacts the second bond pad (18). The wire (14) is then bonded to the second pad (18) using thermocompression bonding. The tip of the capillary (20) is roughened to enhance the tearing of the bond wire insulation.