MBPA008 Front End of Line Clean - Organic Level in Oxide
Organic contamination is believed to be one of the critical factors affecting gate oxide integrity
In actual manufacturing process, time windows (1- 8 hrs) are imposed on gate oxidation after pre-gate clean, and poly deposition after gate oxidation, partly due to concerns on organic contamination
The widely used TOF-SIMS, or TD-GC-MS, only gives the info on fragments of organic species absorbed at RT on wafer surfaces, not C concentration as required by NTRS
This design for the analysis of C in oxide reflects the actual C trapped in oxide with all the thermal processing in a normal manufacturing process.
The results may be more meaningful for assessing the impact of C on the electrical performance of devices
- SIMS is used as C probe by depth profiling from Poly
- The concentration of C in oxide is calibrated against a wafer with a known C concentration prepared by ion implantation
- C concentration is given in atoms/cm2