Fabrication of High Aspect-Ratio Microstructure on Improved Titanium Substrate with Excellent Adhesive Strength and SU-8 Photoresist

This paper studies an anodic oxidation method (AOM) for improving the adhesion strength between SU-8 photoresist and titanium substrate. The adhesion was increased by approximately 86% through anodic oxidation treatment compared to Si wafer substrate. Moreover, the adhesion strength was further strengthened by hard baking at 110°C and its value was up to 71.64 MPa, which almost approaches the breaking strength of SU-8 polymer. The high aspect ratio (24) SU-8 micropillar arrays with 600 μm height were fabricated without any distortion, collapse and delamination. The treated titanium substrate can also serve as a seed layer for electroplating.