Patent ID: 9604843
Date: 2017-03-28
CPC Classifications: B81B,B81C

Claim:
1. A microelectromechanical systems (MEMS) device comprising: a MEMS wafer comprising at least one MEMS structure; a first sealed cavity in the MEMS wafer, the first sealed cavity having a first pressure; a cap wafer bonded to a first side of the MEMS wafer; a second cavity between the MEMS wafer and the cap wafer, the second cavity having a second pressure, the second pressure being greater than the first pressure; a carrier wafer bonded to a second side of the MEMS wafer, the second side being opposite the first side; a third cavity between the carrier wafer and the MEMS wafer, the third cavity having a third pressure, the third pressure being greater than the second pressure; and a polysilicon layer between the third cavity and the first sealed cavity, the polysilicon layer comprising a first MEMS structure.