上海科技大学知识管理系统

In the process of patterning phase change material on 300 mm wafer it is important to address the potential chemical and physical damage that occurs to the material to improve the yield of the memory devices. In this study the mechanism of plasma etching damage of phase change material was investigated. The etching analysis was performed on both the plain and patterned carbon-doped GeSbTe phase change material that was subjected to consecutive HBr plasma etching, oxygen stripping, and HF cleaning steps. The HBr etching procedure resulted in physical and chemical damage to the phase change material with residual Ge element. The subsequent oxygen stripping led to the oxidation of Ge, Sb, and Te elements which were effectively removed in the optimized cleaning process. The additional high-temperature process after plasma etching exhibited minimal impact on the phase change material. The patterned pitch lines of down to 80 nm wide tended to shrink in width after HF cleaning, which is beneficial to reduce the thermal crosstalk in the high-density memory array. The understanding of etching damage in the patterning of phase change materials is crucial for the development of highly reliable phase change memory in the high-density three-dimensional integration. © 2024 Elsevier B.V.