Patent ID: 7365016

Claim:
A method of making a MEMS device containing mechanical parts, comprising: etching away a sacrificial oxide layer covering an etch-stop silicon nitride underlayer to release said mechanical parts, which are formed on said sacrificial oxide layer, by exposing the sacrificial oxide layer to anhydrous HF at a temperature of less than about 100° C. and/or at a vacuum level greater than 40 Torr, said etching away of said sacrificial oxide layer on said silicon nitride layer leaving fluorine-containing ammonium etch byproducts resulting from said anhydrous HF attacking said underlying silicon nitride layer; and subsequently subjecting said etch by-products to a temperature of more than about 100° C. and at vacuum level lower than 40 Torr without exposure to ambient air to perform an in-situ vacuum sublimation of said etch by-products.