An anisotropic dry etch process with fluorine chemistry to create well-defined titanium surfaces for biomedical studies

We present a highly anisotropic dry etch process for bulk Titanium (Ti), based on a conventional parallel plate reactor system and the nontoxic feed gases SF6, CHF3 and O2. This combination is commonly used for reactive ion etching of silicon, but to our knowledge has not yet been reported for etching bulk Ti. The influence of the process parameters total gas flow, gas composition, and process pressure on the Ti structures is discussed along with their optimization. With the optimized process we achieved an anisotropy of 0.9 with an etch rate of 40 nm/min, and a resulting slope of the sidewalls of 85°.

Figure optionsDownload as PowerPoint slideHighlights
► The fabrication of well-defined micro-structured titanium surfaces is reported.
► Bulk titanium substrates for biological studies of cell–interface-interactions.
► The titanium structures are fabricated by an SF6-based anisotropic RIE process.
► Nearly vertical sidewalls were achieved.
► Very high anisotropy of the dry etch process (up to 0.94) is demonstrated.