Selective Removal of Dry-Etching Residue Derived from Polymer Sacrificial Layer for Microelectromechanical-System Device Fabrication

A selective removal of dry-etching residue using hydrofluoric acid (HF) vapor is described in relation to the fabrication of microelectromechanical-system (MEMS) devices. Auger electron spectroscopy (AES) analysis of residue after dry etching of polymer sacrificial layers reveals that the residue is mainly composed of silicon oxides. HF vapor removes the dry-etching residue, and raising the vapor temperature enables the selective removal of the residue without damaging silicon dioxide (SiO2), which is often used as the insulator for MEMS devices. Direct-contact-type MEMS switches with SiO2 insulators fabricated using polymer sacrificial layers demonstrate the effectiveness of removing the dry-etching residue selectively. (C) 2012 The Japan Society of Applied Physics