Patent ID: 8093087

Claim:
A method for fabricating microelectromechanical system (MEMS) device, comprising: providing a substrate, having a first surface and a second surface; forming a MEMS structure over the first surface of the substrate, forming a structural dielectric layer over the first surface of the substrate, wherein the structural dielectric layer has a dielectric member and a space surrounding the MEMS structure is filled with the dielectric member; patterning the substrate by an etching process from the second surface of the substrate to expose a portion of the dielectric member filled in the spaces surrounding the MEMS structure; forming an wettable layer to cover an exposed portion of the substrate at the second surface; and performing at least an etching process on the dielectric member filled in the spaces surrounding the MEMS structure, wherein the MEMS structure is exposed and released, wherein the etching process comprises an isotropic etching process with an wet etchant, wherein at least a portion of the dielectric member in the spaces surrounding the MEMS structure is removed by the isotropic etching from the second side of the substrate.