HF vapor cleaning/etching of Si surfaces

Conventionally, hydrogen fluoride (HF) wet cleaning is used to remove native oxide on Si in ULSI process. But, HF wet cleaning has some problems, for example water droplets, a lot of waste fluid, necessity of drying process, destruction of the pattern according to surface tension, etc. We consider HF vapor cleaning/etching is promissing for solving these problems. The advantages of HF vapor cleaning are drying free and eco-friendly process to etch oxide in wide range and precise control. This cleaning is effective to critical microstructure with high aspect ratio. In this paper, our purpose is to study fundamental characteristics of HF vapor cleaning. We investigated the various parameter (pressure, temperature etc) dependence of etch rates and the characteristics of Si surface after HF vapor cleaning.