A modified Bosch-type process for precise surface micromachining of polysilicon

摘要

We report on the study of a new plasma process for precise surface micromachining of polysilicon. The principle is based on the adaptation of the well-known Bosch process to polysilicon, alternating etch and passivation steps under inductively coupled plasmas (ICPs). However, instead of using ICPs for both steps, we chose to keep a C4F8-based ICP for the passivation step, while using a standard RF plasma with SF6 chemistry during etching. The effect of ICP power and gas flux over etch rates, etch profiles and selectivity was studied. It showed the ability to easily control the anisotropy angle using very few parameters, and was dedicated to the realization of micromechanical structures. [References: 11]