Use of the in-process bond shear test for predicting gold wire bond failure modes in plastic packages

A strong relationship is found between in-process (post wirebond) bond shear test results on gold ball bonds and post-process, post-board mount wire pull results. The shear test results detect clear differences in shear strength and failure mode between two types of bond pad structures. Significant variation due to the level of ultrasonic power used in bonding was also found. The subsequent wire pull results obtained from units receiving full package assembly and simulated customer board mount agreed with the in-process shear findings of both pad structure and bonding process effects. The results have promising implications for the use of in-process bond shear as a tool for improving ball bond reliability through wirebond process control and bonding parameter optimization.<>