Robust Process Development for Dislocation Free DTI Formation

Abstract

This work presents a robust process development of deep-trench isolation (DTI). The instability of DTI junction break down is largely attributed to the process-induced stress. Through TCAD and SEM analysis, the high stress point and stress-induced dislocation are found to be located at sharp DTI corners. Based on this observation, we aim to reduce the thermal/mechanical stress by optimizing the liner oxidation and oxide hard mask for DTI trench. The combined effect will eliminate the dislocation defect that is usually associated with high aspect ratio DTI and offer a significant yield gain for power devices.