Patent ID: 8927312
Filing Date: 2015-01-06
Classification: H01H,H01L,H03K

Abstract:
1. A method for fabricating a MEMS (micro-electromechanical systems) transistor in a far back end of line (FBEOL) level of a CMOS (complementary metal-oxide-semiconductor) integrated circuit, said method comprising: forming a first cavity within a first oxide layer in said FBEOL level of said CMOS integrated circuit; filling said first cavity with a sacrificial material; covering said first oxide layer and said first cavity with a first dielectric layer; covering said first dielectric layer with a second oxide layer; forming a second cavity in said first dielectric layer and said second oxide layer, said second cavity being at least in part contiguous with said first cavity; lining side walls of said second cavity with said sacrificial material; forming a third cavity and a fourth cavity next to one of said side walls of said second cavity in said first dielectric layer and said second oxide layer in a direction parallel to the plane of said FBEOL level of said CMOS integrated circuit, said sacrificial material on said one of said side walls of said second cavity separating said second cavity from said third and fourth cavities; filling said second, third, and fourth cavities with an electrically conducting material to form a MEMS cantilever switch, a gate, and a drain, respectively; covering said second cavity, including said side walls and said MEMS cantilever switch, with said sacrificial material; covering said second oxide layer, said sacrificial material, and said gate and said drain with a second dielectric layer; covering said second dielectric layer with a third oxide layer; providing a vent hole at least through said second dielectric layer and said third oxide layer to said sacrificial material; and removing said sacrificial material, including said sacrificial material on said one of said side walls of said second cavity, through said vent hole with a solvent to release said MEMS cantilever switch and to provide a gap between said MEMS cantilever switch and said gate and said drain.