Patent ID: 7566664

Claim:
A method for fabricating a microelectromechanical systems device comprising: providing a substrate in an etching chamber; contacting a microelectromechanical systems device formed on the substrate with a vapor phase etchant comprising a gaseous halide and a co-etchant by flowing the vapor phase etchant and the co-etchant into the etching chamber, wherein the microelectromechanical systems device comprises a target material and a structural material; the target material and the structural material are both etchable by the gaseous halide with an etching selectivity between the target material and the structural material of at least about 50:1 in the absence of the co-etchant; and the co-etchant is present in an amount effective to improve the etching selectivity between the target material and the structural material by at least about 2-times compared with the etching selectivity in the absence of the co-etchant.