Determining the ion angular distribution of bulk titanium DRIE with overhang SU-8 mask

As an emerging technology, bulk titanium DRIE enabled devices are very attractive for in vivo and harsh environments applications. As the functionality, mobility and reliability of the micro components highly depend on the quality of microstructures, a physical etching model is necessary for better control of the DRIE profile, in which knowledge of the ion angular distribution in chlorine plasma is critical. In this report, an overhang SU-8 mask was designed and fabricated for the etching experiments, Al was deposited between two SU-8 layers to allow for separation. The etched profiles were measured by white light interferometry, which derived the ion angular distribution by data analyzing. With this distribution, a preliminary etching model was developed that could be used to forecast and optimize the titanium DRIE.