High-Rate Anisotropic Silicon Etching with the Expanding Thermal Plasma Technique

Abstract

Deep anisotropic silicon etching with the expanding thermal plasma (ETP) technique using fluorine-based chemistries was demonstrated for the first time. The ETP technique has a remote high-density plasma source and a good control of the downstream plasma chemistry. High etch rates between 4 and 12 µm per min were obtained while feature profiles were competitive to those obtained with the widely used inductively coupled plasma (ICP) reactors. Therefore, this novel deep anisotropic silicon etching process is an attractive, alternative fabrication technology for micromechanical devices, trench capacitors, and 3D-interconnects.