Case study of wet chemical stain to identify implant related low yield issue

Ion implant is very important process in semiconductor manufacturing. In this study, we discuss a problem of low yield caused by an implant related defect on a specific location and structure in the device. The paper explains how general Failure Analysis (FA) techniques such as top view analysis by Scanning Electron Microscope (SEM), Passive Voltage Contrast (PVC) and cross section by Focused Ion Beam (FIB) coupled with Transmission Electron Microscopy (TEM) are unable to identify the defect which causes the gate driver failure which in turn leads to the implantation related low yield issue. It was found that Emission Microscopy (EMMI) analysis for global isolation, followed by nano-probing for electrical characterization of the gate driver was needed. Cross section wet chemical stain technique was then used to identify the localized implant junction failure.