PHOTOLITHOGRAPHY ON MICROMACHINED 3D SURFACES USING ELECTRODEPOSITED PHOTORESISTS

Photolithography on micromachined 3D surfaces is becoming a key proces s for the fabrication of a wide range of novel micromechanical devices . Due to the surface tension, photoresists deposited as a liquid cause problems at sharp corners, which occur commonly in micromachined sili con devices. This paper describes the application of an electrodeposit able ultraviolet sensitive photoresist, which is commercially availabl e and which is already used in printed circuit board production. Proce ss considerations are discussed to apply this technology successfully to silicon substrates. The results show the feasibility of photolithog raphy on surfaces with anisotropically etched 200 mu m deep cavities i n (100) silicon.