Defect localization by Lock-in IR-OBIRCH on some recovered cases

There are some recovered cases during failure analysis (FA) process, although every FA step is performed right and very carefully. Sometimes the failure root cause still need to be identified after recovering, because the failed IC is unique and the failure root cause is very important to improve the products' quality. Sometimes the defect could be localized by Lock-in IR-OBIRCH, although the failure has disappeared. In this paper, two cases are demonstrated to show how to locate defects by Lock-in IR-OBIRCH after the failed ICs have recovered.