Lead finger optimization due to vibration during assembly process and transportation

Microelectronic packaging assembly has a lot of processes. After wire bonding, it may be loaded into magazine transported to molding process. During these processes or transportation, the leadframe will vibrate and potentially such vibration may cause bond wire break. Especially if some additional process is added, the risk of broken wire may increase. In this study, the leadframe experiences a surface treatment process before molding, significantly more broken wire failure was found after the process which is suspected due to leadframe vibration. To understand the failure cause and factors, an FEM simulation model of the leadframe after die attach is constructed, an excitation signal such as acceleration is applied to the system, the dynamic vibration response was analyzed through implicit dynamic simulation. The result shows that this method is good to characterize lead finger vibration. The difference of all the lead fingers at any location could be addressed, and correspondingly the potential risk of wire could be differentiated. With optimization done through simulation, the vibration of the critical lead finger is evidently reduced. And eventually a more robust design is achieved for production.