Patent ID: 8129805
Filing Date: 2012-03-06
Classification: B81B,B81C

Abstract:
1. A method for fabricating a microelectromechanical system (MEMS) device, comprising: providing a semiconductor substrate comprising a semiconductor layer and an interconnect structure formed over the semiconductor layer; sequentially forming a passivation layer and a photoresist layer over the interconnect structure; forming a plurality of openings in the photoresist layer, wherein the openings expose a portion of the passivation layer; performing a first etching process, using the photoresist layer as an etching mask, to remove the passivation layer exposed by the openings and the interconnect structure thereunder, forming a plurality of first trenches exposing a portion of the semiconductor layer; removing the photoresist layer to expose the passivation layer; performing a second etching process, using the passivation layer as an etching mask, removing a portion of the semiconductor layer exposed by the first trenches, and forming a plurality of second trenches in the semiconductor layer; attaching an upper capping substrate to the passivation layer to form a first composite substrate; thinning a surface of the semiconductor layer of the first composite substrate in areas where the second trench is not formed, leaving a thinned semiconductor layer; and performing a third etching process to partially remove the thinned semiconductor layer and form a third trench therein, wherein the third trench exposes and connects the second trenches, such that a suspended micromachined structure is defined in a region between the first trench, the second trenches, and the third trench.