Integration of STI reverse mask effect and 520C ozone-TEOS based oxide film on STI CMP process for the sub-0.15 #mu# m DRAM

摘要

The key integration and process issues of shallow trench isolation (STI) chemical mechanical polishing (CMP) process or sub-0.15 #mu# m are discussed. As DRAM cell size is scaled down, the STI trench filling and CMP reverse mask etching control are very important for filling the minimum CD size and providing wider CMP process window. And the reverse mask removal oxide depth and cell/periphery uniformity are critical for the CMP performance. The reverse mask dry etch depth is one of the key steps to influence of STI CMP polish time and uniformity. With the successful integration of 520C O3-TEOS and Reverse-mask etch, STI-CMP has gained a wide process window both in the polish-time and in the pattern-density difference in our sub-0.15 #mu# m DRAM technology.