Bump electrodes for semiconductor devices

摘要

The electrodes are formed from an alloy wire 5 made by a rapid cooling and condensation process. The wire is inserted into the capillary tube 4 of a wire bonder and its end is heated by an electrical torch 6 to form a ball 7. The ball is attached to wiring 2 on a substrate 1 and the capillary tube is raised to sever the wire from the ball at the junction of the wire with the ball. The alloy wire comprises mainly lead, tin or indium and the wiring 2 may be provided with a metallic layer formed by vapour deposition.