HighAspect-Ratio Inductively Coupled Plasma Etching of Bulk Titanium

Titanium is a promising new material system for the bulk micromachining of MEMS devices. Titanium-based MEMS have the potential to be used for applications involving harsh environments, high fracture toughness requirements, or biocompatibility. The bulk titanium etch rate and TiO2 mask selectivity in an Inductively Coupled Plasma (ICP) as a function of various process parameters is presented, and optimized conditions are used to develop the Titanium ICP Deep Etch (TIDE) process. The TIDE process is capable of producing high-aspect-ratio structures with smooth sidewalls at etch rates in excess of 2 µm/min, thus providing a powerful new means for the microfabrication of titanium-based MEMS devices