This paper describes the effectiveness of using light induced Current Imaging – Atomic Force Microscopy (CIAFP) to localize defects that are not easily detected through conventional CI-AFP. Defect localization enhancement for both memory and logic failures has been demonstrated. For advanced technology nodes memory failures, current imaging from photovoltaic effects enhanced the detection of bridging between similar types of junctions. Light induced effects also helped to improve the distinction between gated and nongated diode, as a result enhanced localization of gate to source/drain short.

This paper describes a low yield case which results in a unique 68 mm single ring wafer sort failure pattern. A systematic problem solving approach with the application various FA techniques and detailed Fab investigation resolved the issue. The root cause for the unique ring failure pattern was due to a burr at the implanter load lock. The burr scratched and toppled the photoresist resulting in subsequent blocked well implantation and memory failure.