Highly anisotropic silicon and polysilicon room-temperature etching using fluorine-based high density plasmas

A highly anisotropic Si and Polysilicon plasma etching process at room temperature has been developed in an inductively coupled plasma (ICP) reactor using SF6/CHF3 gas mixtures. The etching rates achieved are much higher than those obtained in a reactive ion etching reactor (RIE), using a similar F-based room temperature process. Etched structures are analysed by SEM and surface chemical analysis (ESCA), while the plasma gas phase is analysed by Optical Emission Spectroscopy (OES).