Front side protection layer for improved reliability of wafer-level packages

This paper will describe a new technique to increase the reliability of wafer-level packages (WLPs). The technique enables the placement of a protective coating around the solder balls using a maskless process and provides improved reliability performance as compared to unprotected devices. In addition, the unbonded devices allow for easier handling. This approach also minimizes form factor requirements associated with the use of traditional capillary underfills. Feasibility studies and preliminary performance results are presented in this paper.