Numerical analysis by 3D finite element wire bond simulation on Cu/low-k structures

A 3D nonlinear transient dynamic finite element (FE) analysis of thermosonic wire bonding process on copper/low-k structure is investigated to understand the interfacial deformation of bond pad and responses of structure under pad respectively. The analysis is studied with finite elements at two stages, i.e. at the impacting stage of wire bond and at the end of bonding process. A methodology of bonding process with ultrasonic effects is established and is used to study the effects of parameters that are considered to be influential on the bonding performance. This FE framework is especially used to understand the deformation behavior of bond pad. Effect of variation of parameters like bond wire diameter, copper pad thickness and low-k material are investigated thoroughly for overall structural response and bond pad deformation. Also in this work, a statistical method is used to identify the parameters that are critical to the pad deformation. According to statistical analysis it is found that, type of low-k material is the most effective determinant for the bond pad deformation.