Patent ID: 8802473

Claim:
A method for forming a micro-electromechanical (MEMS) device comprising: providing a MEMS wafer, wherein forming the MEMS wafer includes: forming a first sacrificial layer on a first surface of a MEMS substrate; forming a dielectric layer over the first sacrificial layer, wherein the dielectric layer comprises an exposed first portion; providing a carrier wafer, wherein providing the carrier wafer includes isotropically etching a carrier substrate to form a first cavity; bonding the carrier wafer to MEMS wafer using a bonding layer, wherein the bonding includes aligning the first cavity with the first portion of the dielectric layer; patterning the MEMS substrate; removing portions of the first sacrificial layer from the MEMS substrate to form first and second MEMS structures, wherein the first MEMS structure corresponds to the first portion of the dielectric layer; forming a first plurality of metal bonds on a second surface of the MEMS substrate, wherein the second surface is opposite the first surface; providing a cap wafer including a second plurality of metal bonds; bonding the cap wafer to the MEMS wafer by bonding the second plurality of metal bonds to the first plurality of metal bonds, wherein the bonding creates a first sealed cavity including the first portion of the dielectric layer and the first MEMS structure, and wherein the second MEMS structure is disposed between a second portion of the dielectric layer and the cap wafer in a second sealed cavity; and removing portions of the carrier wafer exposing the first cavity to ambient pressure.