The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 06, 2012
Filed:
Jul. 16, 2010
John R. Martin, Foxborough, MA (US);
Timothy J. Brosnihan, Natick, MA (US);
Craig Core, North Andover, MA (US);
Thomas Kieran Nunan, Carlisle, MA (US);
Jason Weigold, Newburyport, MA (US);
Xin Zhang, Acton, MA (US);
John R. Martin, Foxborough, MA (US);
Timothy J. Brosnihan, Natick, MA (US);
Craig Core, North Andover, MA (US);
Thomas Kieran Nunan, Carlisle, MA (US);
Jason Weigold, Newburyport, MA (US);
Xin Zhang, Acton, MA (US);
Analog Devices, Inc., Norwood, MA (US);
Abstract
A micromachined microphone is formed from a silicon or silicon-on-insulator (SOI) wafer. A fixed sensing electrode for the microphone is formed from a top silicon layer of the wafer. Various polysilicon microphone structures are formed above a front side of the top silicon layer by depositing at least one oxide layer, forming the structures, and then removing a portion of the oxide underlying the structures from a back side of the top silicon layer through trenches formed through the top silicon layer. The trenches allow sound waves to reach the diaphragm from the back side of the top silicon layer. In an SOI wafer, a cavity is formed through a bottom silicon layer and an intermediate oxide layer to expose the trenches for both removing the oxide and allowing the sound waves to reach the diaphragm. An inertial sensor may be formed on the same wafer, with various inertial sensor structures formed at substantially the same time and using substantially the same processes as corresponding microphone structures.