Patent ID: 7956428

Claim:
An electromechanical device comprising: a substrate layer; a first insulation layer over the substrate layer; a buried polysilicon layer over the first substrate layer; a first plurality of alignment marks placed adjacent the buried polysilicon layer over the first substrate layer and for aligning equipment for epitaxy and polish processing; a chamber including a first encapsulation layer having at least one vent; a mechanical structure, wherein at least a portion of the mechanical structure is disposed in the chamber and the at least one vent is disposed over the mechanical structure; a protective layer over the buried polysilicon layer, wherein the buried polysilicon layer includes conductive paths and at least one electrode, wherein the protective layer forms at least part of a separating layer between the chamber and the buried polysilicon layer, wherein the protective layer comprises a nitride; a second insulation layer over the protective layer; the first encapsulation layer encapsulating the mechanical structure, wherein the first encapsulation layer is etched to provide the at least one vent so that the mechanical structure can be released; a second plurality of alignment marks aligned to the first plurality of alignment marks and formed within the first encapsulation layer by growing monocrystalline areas defining the second plurality of alignment marks and growing a first epitaxy polysilicon layer over the protective nitride layer; and a second encapsulation layer comprised of a semiconductor material formed by a second and relatively thick epitaxy polysilicon layer deposited over the first epitaxy polysilicon layer to line an inner surface of an evacuated area surrounding the mechanical structure, and to encapsulate the released mechanical structure and seal the at least one vent, and wherein final alignment marks corresponding to the second plurality of alignment marks are formed in the second encapsulation layer.