The Effect of Ultrasonics on Deformation

The basis for our understanding of the ultrasonic bonding mechanism was first presented by B. Langenecker. This paper will explain Langenecker's contribution, with a description of the ultrasonic wirebonding mechanism based on his theory. Descriptions of the mechanisms that occur at the bonding interface will also be included. Recently a new theory has been presented by K. Otsuka that significantly adds to Langenecker's work. This paper will also cover Dr. Otsuka's contribution and describe mechanisms for both 60KHz and 120 KHz wedge bonding based on a modified theory. Dr. Otsuka emphasizes dislocation theory, the effects of strain rate on material behavior, and provides a better explanation of how new metal surfaces are exposed and where oxides and contamination are trapped. His theories explain the significant differences between wedge bonding with 60KHz and 120 KHz ultrasonics and add significantly to our understanding of the process.