Friday, October 10 4:30 pm 5:30 pm
Session E Micromachining (Invited Papers)
E-1 MEMS (Microelectromechanical Systems) Audio DevicesDreams and RealitiesJohn J. Neumann, Jr., Carnegie Mellon University. Pittsburg, PA, USA
MEMS (microelectromechanical systems) technology is more than a scientific curiosity. Commercial MEMS products are being produced using semiconductor manufacturing techniques. What kind of audio devices can be made using this technology? Surveillance, hearing aids, and directional microphones spring to mind. Less obvious are ultrasonics, in-ear translators, and surround-sound wallpaper.
The small size of MEMS devices brings up issues of physical limits and appropriate size scales for acoustic applications. MEMS microphone/speaker design involves many of the same issues as conventional microphones/speakers, but the scale difference changes their relative importance. Over the past four years, the MEMS lab at Carnegie Mellon University has developed both microphones and speakers using CMOS-MEMS micromachining, and the technology is being commercialized by Pittsburgh startup Akustica.
E-2 Surface-Micromachined MEMS MicrophoneGary W. Elko, Avaya Labs, Basking Ridge, NJ, USA; Flavio Pardo, Daniel Lopez, David Bishop, Bell Labs, Lucent Technologies, Muray Hill, NJ, USA; Peter Gammel, Agere Systems, Allentown, PA, USA
The term MEMS is an acronym for MicroElectroMechanical Systems. During the past decade numerous novel sensor devices based on MEMS technologies have been made: accelerometers for air-bag deployment detection, MEMS mirror arrays for Digital Light Processing (DLP) projectors, and inkjet printer heads to name a few well known devices. MEMS devices have been developed for data storage, wireless communication, displays, optical switching, as well as microfluidics, aerospace, and biomedical applications. The application of MEMS technology to audio has been primarily focussed on microphones. There are two major application areas that are driving the interest in MEMS microphones: hearing aids where size and integration with signal processing are important, and consumer devices where there is interest in reducing costs by integrating a complete systems solution on an integrated circuit and packaging of devices to allow standard robotic pick-and-place manufacturing. This paper describes a MEMS microphone that was built at Bell Labs which was the first all-surface machined MEMS microphone. We also describe some fundamental issues in the design of MEMS microphones.