MEMS Integrated Pressure Sensor Devices Having Isotropic Cavitites and Methods of Forming Same

摘要

A method embodiment includes providing a MEMS wafer comprising an oxide layer, a MEMS substrate, a polysilicon layer. A carrier wafer comprising a first cavity formed using isotropic etching is bonded to the MEMS, wherein the first cavity is aligned with an exposed first portion of the polysilicon layer. The MEMS substrate is patterned, and portions of the sacrificial oxide layer are removed to form a first and second MEMS structure. A cap wafer including a second cavity is bonded to the MEMS wafer, wherein the bonding creates a first sealed cavity including the second cavity aligned to the first MEMS structure, and wherein the second MEMS structure is disposed between a second portion of the polysilicon layer and the cap wafer. Portions of the carrier wafer are removed so that first cavity acts as a channel to ambient pressure for the first MEMS structure.

主权项

1. A method comprising:
disposing a first surface of a membrane for a first micro-electromechanical (MEMS) device in a first sealed cavity; and exposing a second surface of the membrane to an ambient pressure level, wherein exposing the second surface comprises:
patterning one or more openings in a carrier using a first etching process;connecting bottom portions of the one or more openings using a second etching process to form a second cavity;aligning the second cavity with the second surface of the membrane; andexposing the second cavity to the ambient pressure level.