MEMS Seminar Today at 3:45pm in CISX Aud.

Maryam Ziaei-Moayyed maryamzm at stanford.edu
Wed Oct 11 10:01:24 PDT 2006


Fall 2006 MEMS Seminar Series


WHEN:    Wednesday 10/11/06  4-5pm
         Refreshments at 3:45 pm

WHERE:   CISX Auditorium


TITLE:   Metal-Organic MEMS Packaging Based on Decomposable Polymers

SPEAKER: Dr. Pejman Monajemi
         Silicon Clocks, Inc.


WEBSITE: http://www.stanford.edu/~maryamzm/memsseminar


Abstract:

The development of low-cost, high-volume packaging technique for
microelectromechanical systems (MEMS) is an important challenge. In this
talk, an approach to low-cost, wafer-level packaging of resonators and
inertial sensors is presented.  The process does not require wafer-to-wafer
alignment and bonding, high temperature thin film deposition, or etching of
sacrificial thin films. A thermally-decomposable sacrificial polymer
placeholder is first patterned on top of the MEMS component, followed by
spin coating and exposure of a low-k polymer overcoat. The sacrificial
polymer decomposes at temperatures below 260C and the volatile
gaseous products permeate through the overcoat leaving an embedded
air-cavity, which eliminates the steps needed to seal a perforated or
porous cover. The polymer overcoat can be made as thin as few microns (for
resonators) or as thick as 150µm (for accelerometers). Cavities as small as
0.00015 mm3 (for resonators) and as large as 1 mm3 (for inertial sensors)
were fabricated. The Q factor of a series of 2.5 MHz beam resonators and
the static sensitivity of an in plane accelerometer did not change
significantly after packaging. Hermeticity and vacuum operation are
obtained by thin-film deposition of a metal layer. Thermal cycling and
stress measurement of the metal-organic capsules including chromium, gold
and aluminum have been performed to obtain the optimum conditions including
temperature and pressure of decomposition, metal deposition, and final
package curing.



Bio:

Pejman Monajemi received PhD in Electrical and Computer Engineering from
Georgia Institute of Technology, Atlanta, GA in April 2006. His research
was on the development of wafer-level packaging methods for low-loss MEMS
varactors, resonators and inertial sensors. He is currently working for
Silicon Clocks, Inc, Fremont, CA.





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