Theoretical and numerical analysis of the effect of constant velocity on thermosonic bond strength

A new effective method is presented in this study to investigate the effect of constant velocity on the thermosonic bond strength. The proper relationship between the bond strength and results of FE analysis was introduced with some related theoretic equations in solid state welding. A transient non-linear dynamic finite element framework was developed, and the strain rate sensitivity of the gold ball and pad was considered. The effective normal pressure and bond surface exposure were all calculated, thus the bond strength was estimated approximately. It can be found that the bond strength increases with the increase of constant velocity, and then decreases after it exhibits the maximum. In addition, the strength distribution in bond interface was also studied. At last, the application range of the present method was discussed.