Metal foundation construction to consolidate electroplated structures for successful removal of SU-8 mould

Abstract

For integrating thick microstructures with microfabricated circuitry on the same chip, a metal foundation method to consolidate adhesion of the electroplated microstructures to the substrate for successful removal of SU-8 mould is proposed. Along with multilevel interconnections microfabrication or other required metal deposition, the metal foundations are constructed and then tamped by interlevel dielectric. With metal foundations formed along with fabrication of interconnections and thin film electrodes, the electroplated Ni structures of an electrostatically levitated rotational microgyro, with thickness of 200 µm after lapping the whole wafer, are successfully released by removing the SU-8 mould using the fuming sulphuric acid oxidising method.