Patent ID: 9725305
Date: 2017-08-08
CPC Classifications: B81B,B81C,G01P

Claim:
1. A method comprising: forming a trench in a first side of a first silicon wafer; forming a cavity connected to the trench in the first side of the first silicon wafer; forming an oxide layer on the first side and in the trench; bonding the first side of the first silicon wafer to a second silicon wafer; forming a MEMS (micro-electro-mechanical systems) structure in the second silicon wafer; bonding the second silicon wafer to a third silicon wafer, removing a portion of a second side of the first silicon wafer, wherein the removing exposes the oxide layer; setting a pressure within the trench and the cavity; and forming a layer on the second side of the first silicon wafer, wherein the layer seals the trench, the cavity, and the MEMS structure.