Optimization and monitoring of bevel removal process

• Inspecting the wafer edge issue: Wafer bevel inspection can help us to find out the root cause of yield loss from wafer edge or partial die. • Monitoring EBR/ 193 lithography performance : From the EBR monitoring results, bevel inspection find out the top EBR recipe setting is not good, and it also demonstrates the EBR performance with different bevel rinse RPM setting, it can help us to find out the optimum recipe. • Qualifying the various wafer types/sources: All condition coated in CZ wafer type show much better coating performance than that of in EPI wafer type due to CZ wafers have better wafer edge profile. Wafer edge profile vs. bevel inspection help us to improve the lithography and EBR setting with various wafer sources. • Monitoring the bevel etching performance: The bevel inspection after POLY line etch, without bevel etching process will have peeling concern from wafer edge to wafer interior area in the subsequent processes due to the under-cut defects.