SF(6) Optimized O(2) Plasma Etching of Parylene C

Parylene C is a widely used polymer material in microfabrication because of its excellent properties such as chemical inertness, biocompatibility and flexibility. It has been commonly adopted as a structural material for a variety of microfluidics and bio-MEMS (micro-electro-mechanical system) applications. However, it is still difficult to achieve a controllable Parylene C pattern, especially on film thicker than a couple of micrometers. Here, we proposed an SF(6) optimized O(2) plasma etching (SOOE) of Parylene C, with titanium as the etching mask. Without the SF(6), noticeable nanoforest residuals were found on the O(2) plasma etched Parylene C film, which was supposed to arise from the micro-masking effect of the sputtered titanium metal mask. By introducing a 5-sccm SF(6) flow, the residuals were effectively removed during the O(2) plasma etching. This optimized etching strategy achieved a 10 μm-thick Parylene C etching with the feature size down to 2 μm. The advanced SOOE recipes will further facilitate the controllable fabrication of Parylene C microstructures for broader applications.