Process optimization by advanced process control with fault detection system for flash memory

Plasma damaged 0.18 μm flash memory device has been resolved by integrating advanced process control with fault detection and classification (APC FDC) system in ILD HDP PSG process. PSG plasma damage to device was detected by real-time monitoring APC control system with multivariate statistically calculation to detect out-of-control conditions within five minutes. The unhealthy recipe contents and the hardware healthy status are detected by integrating APC FDC system. After we analyzing the fault detection and classification function, APC system successfully predicts the same results as wafer acceptance test and wafer sort yield. Recipe and hardware are modified to eliminate the plasma damage according the analysis results.