Iterative optimization of tail breaking force of 1mil wire thermosonic ball bonding processes and the influence of plasma cleaning

An online tail breaking force measurement method is developed with a proximity sensor between wire clamp and horn. The wire under the tensile load measures about 1.5cm extending from the bond location to the wire clamp. To increase the sensitivity, the bondhead speed is reduced to 2mm/s during breaking the tail bond. It takes roughly 10ms to break the tail bond. The force resolution of the method is estimated to be better than 5.2mN. An …