An unique sample pretreatment method for circuit edit on WLCSP devices

In the present work, the thick organic passivation layer of WLCSP products was uniformly removed before the focused ion beam (FIB) circuit edit (CE) process. By this approach, the cycle time of the whole CE process can be remarkably decreased and the successful rate can be effectively increased. In addition, the suggested flows for successful CE under solder bumps and RDLs have been proposed.