The Welding Institute

Michael H Scott

Keith I Johnson

Donald A Edson

To permit ball-bonding of wires of aluminium or aluminium alloy to small electrical circuits or components, a spark discharge is created between the end of the wire and an electrode in a shielding atmosphere with a peak current density in the wire section which is from 40 to 450 times that used for ball-bonding gold wire. In this way oxidation of the ball is prevented.

Electrical inter-connection method

Difficulties in forming a ball on the end of a wire of aluminium or aluminium alloy for ball bonding are overcome by applying between the wire and an electrode a low voltage, typically 30 volts, and bringing the wire and electrode into temporary contact to fuse the wire and initiate a spark discharge which results in the formation of a ball on the wire end. The spark discharge takes place in a shielding gas to avoid oxidation of the ball.

Growing community of inventors

Cambridge, United Kingdom

Michael H Scott