Dry release process of anhydrous HF gas-phase etching for the fabrication of a vibrating microgyroscope

摘要

Abstract: A micro gyroscope, which vibrates in two orthogonal axes on the substrate plane, is designed and fabricated. Fabrication processes of the micro gyroscope are composed of anisotropic silicon etching by RIE, dry release by newly developed anhydrous HF gas-phase etching (GPE) of the buried sacrificial oxide layer, stress relief by multi-step annealing, metal electrode formation. The GPE process was verified as a very effective method for the release of compliant microstructures of micro gyroscope. The developed GPE system with anhydrous HF gas and CH$-3$/OH vapor was characterized and its etching properties were discussed. We successfully fabricated micro gyroscope with no virtually process-induced stiction and no residual products after GPE of TEOS, LTO, and thermal oxide on silicon substrates. !11