A NOVEL SEIF CLEANING PROCESS FOR HIGH ASPECT RATIO SILICON ETCH

摘要

This paper presents a novel SP_6/HBr/O_2 process to perform high aspect ratio (HAR) anisotropic silicon etch. Design of experiments (DOE) and single variable experiments were used to determine the principle input factors and main effects with SF_6/HBr/O_2 plasma. The process was optimized to perform HAR anisotropic etch on mask patterns having both line and contact hole structure with CD ranging from 0.35μm to >10μm. The SF_6/HBr/O_2 process was also utilized to perform trench etch on silicon-on-insulator (SOI) structures. A two step process scheme was utilized to resolve the issues related to the notching of bottom (at the buried oxide interface) on SOI wafers. The self cleaning nature and production worthiness of the HAR silicon etch process were also demonstrated during a marathon process run over 70 plasma hours.