MEMS Integrated Pressure Sensor Devices and Methods of Forming Same

摘要

A method embodiment includes providing a micro-electromechanical (MEMS) wafer including a polysilicon layer having a first and a second portion. A carrier wafer is bonded to a first surface of the MEMS wafer. Bonding the carrier wafer creates a first cavity. A first surface of the first portion of the polysilicon layer is exposed to a pressure level of the first cavity. A cap wafer is bonded to a second surface of the MEMS wafer opposite the first surface of the MEMS wafer. The bonding the cap wafer creates a second cavity comprising the second portion of the polysilicon layer and a third cavity. A second surface of the first portion of the polysilicon layer is exposed to a pressure level of the third cavity. The first cavity or the third cavity is exposed to an ambient environment.

主权项

1. A method for forming a micro-electromechanical (MEMS) device comprising:
providing a MEMS wafer, wherein forming the MEMS wafer comprises:
forming a sacrificial layer over a first surface of a MEMS substrate; andforming a dielectric layer over the sacrificial layer, wherein the dielectric layer has an exposed first portion and a second portion; bonding a carrier wafer having a first cavity to MEMS wafer, wherein bonding the carrier wafer includes aligning the first cavity with the first portion of the dielectric layer; patterning the MEMS substrate; removing portions of the sacrificial layer 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 and a second cavity; bonding the cap wafer to the MEMS wafer by bonding the second plurality of metal bonds to the first plurality of metal bonds, wherein bonding the cap wafer forms a first sealed cavity comprising the second cavity aligned with the first portion of the dielectric layer and the first MEMS structure, and wherein the second MEMS structure is disposed between the second portion of the dielectric layer and the cap wafer in a second sealed cavity; and removing portions of the carrier wafer to expose the first cavity to ambient pressure.