S. T. Liu, T. C. Liu, M. L. Chang, J. Lin, Integrated Service Technology Inc., Hsin-chu, Taiwan

Summary: To sum up, the results reported in this paper have demonstrated that the limitation of re-building of WLCSP after complete a FIB editing can be overcome via direct FIB milling. The developed innovative methodologies can be implemented to modify the designed circuit in both chip and package level on a fully-packaged WLCSP device. In spite of the difficult tasks facing a FIB operator, CE and creation of probe pads on not only IC metal line but RDL is indeed possible. The techniques yielded here can offer a wide range of application to circuit design, debugging, and failure analysis.