H. S. Lin, C. M. Chen, UMC, Hsin-Chu City, Taiwan

Summary: The importance of understanding mismatched behavior in SRAM has increased as the technology node shrinks below 100nm. Using the nanoprober technique [1-3], MOS characteristics of failure bits in actual SRAM cells had been measured directly. After transistors that are failing had been identified, proper physical analyses actions were determined and taken to observe tiny defects. In this study, several types of nanoscopic defects such as offset spacer residue, salicide missing from active area, doping missing from the channel, gate oxide defects, contact barrier layer residue, and broken poly-gate silicide were successfully discovered.