ADHESION PROMOTION BY SURFACE-MODIFICATION AT THE PMMA-METAL INTERFACE FOR LIGA-TYPE PROCESSING

摘要

The formation of high aspect ratio Micro-Electro-Mechanical Structures (HI-MEMS) requires good adhesion of the thick microstructures to the substrate. The interfacial bond strength between PMMA and various metal substrates (Ti, Cu, Au, and Ni), in the preliminary stages of the LIGA process, was evaluated by shear stress measurement. Adhesion promotion processes have been investigated such as texturing of the surface of Ti and Cu substrates by chemical oxidation or thermal processing of the MMA sheet, and use of a positive resist as an interfacial adhesion promoter. Several fold increases in bond strength were obtained, the largest increase associated with a combination of substrate roughening, thermal treatment and use of adhesion promoters.