A Micromachined Knudsen Pump for On-Chip Vacuum

Post Doctorate Research Fellow
University of Michigan

ABSTRACT:
This presentation will describe a single-chip micromachined implementation of a Knudsen pump a type of vacuum pump that works by the principle of thermal transpiration, has no moving parts, and consequently offers high reliability. A 6-mask process was used to fabricate the pump from a glass substrate and a silicon wafer. A single stage pump and two integrated pressure sensors occupy 1.5 mm x 2 mm. Measurements show that this device can evacuate a cavity to 0.46 atm while operating at atmospheric pressure and using 80 mW input power. Temperature measurements show thermal isolation on the order of 10^4 K/W between the polysilicon heater used to operate the pump and the rest of the device.

BIO:
Shamus McNamara received a B.S. and M.S. degree in Electrical Engineering from Rensselaer Polytechnic Institute in 1994 and 1996, respectively. He received a Ph.D. in Electrical Engineering in March 2002 from the University of Wisconsin under Professor Guckel and Professor Yogesh Gianchandani. He was an adjunct lecturer at the University of Michigan during the Fall 2002 semester, teaching EECS 320, Introduction to Semiconductor Devices . He is currently a research fellow at the University of Michigan working on a variety of projects involving micromechanics.