Comparison of CHARM-2 and Surface Potential Measurement to Monitor Plasma Induced Gate Oxide Damage

Abstract Plasma process induced gate oxide damage was found in early process development stages. Device data showed unacceptable burn-in failure. By utilizing multiple test vehicles, the underlying cause of oxide damage was identified. This study showed that no single methodology is adequate for controlling the damage. A combination of the monitoring techniques is required to understand root cause of damage and how to optimize the process or equipment. The plasma process was optimized and verified with CHARM-2 monitor response. Further device data verification indicated no gate oxide damage was found with new improved process. The fast turn around time of plasma monitors were essential to understand and determine the plasma damage source. Understanding the relationship between plasma monitor response and plasma process is a key point to identify the source of damage. A fingerprint of plasma process is very useful for process control and defect reduction