Thermal microactuators, devices that use the principle of thermal expansion to amplify motion, have several advantages in comparison with other actuators used to motivate surface micromachined components such as rotary microengines. They provide higher output forces and have simple geometries. Accurate steady-state and transient modeling of such thermal actuators provides a tool for design optimization to obtain better actuator performance. This paper describes the development, modeling issues and results of a three dimensional multiphysics non-linear finite element model of a surface micromachined thermal actuator. The simulation results are compared with experimentally measured data. Reasonable agreement is observed for static actuator deflection response. The measured transient response is observed to be significantly slower than that predicted by the finite element model.

Volume Subject Area:
Microelectromechanical Systems
Keywords:
Thermal Actuators, Microsystems
Topics:
Actuators, Micromachining, Modeling
1.
Comtois, J.H., Bright, V.M., 1997, “Surface Micromachined Polysilicon Thermal Actuator Arrays and Applications,” Technical Digest Solid State Sensor and Actuator workshop, Hilton Head, SC, pp. 174–177.
2.
Senturia, S., 2002, Microsystem Design, Kluwer Academic Publishers.
3.
Guickel, H., Klein, J., Christenson, T., Skrobis, K., Laudon, M., Lovell, E., 1992, “Thermo-magnetic metal flexure actuators,” Technical digest, Solid State Sensor and Actuator Workshop, p. 73–75.
4.
Comtois
J. H.
,
Bright
Victor M.
,
Phipps
M. W.
,
1995
, “
Thermal microactuators for surface-micromachining processes
,”
Proc. SPIE
, Vol.
2642
, pp.
10
–
21
.
5.
Comtois
J. H.
,
Bright
V. M.
, “
Design techniques for surface-micromachining MEMS processes
,”
Proc. SPIE
, Vol.
2639
,
1995
, pp.
211
–
222
.
6.
Butler
J. T.
,
Bright
V. M.
,
Reid
R. J.
, “
Scanning and rotating micromirrors using thermal actuators
,”
Proc. SPIE
, Vol.
3131
,
1997
, pp.
134
–
144
.
7.
Reid
J.
,
Bright
V. M.
,
Comtois
J.
,
1997
, “
Arrays of thermal microactuators coupled to micro-optical components
,”
Actuator technology and Applications
, Vol.
2865
, pp.
74
–
82
.
8.
Kolesar
E. S.
,
Allen
P. B.
,
Howard
J. T.
,
Wilken
J. M.
,
Boydston
N
, “
Thermally-actuated cantilever beam for achieving large in-plane mechanical deflections
,”
Thin Solid Films
,
1999
, vol.
355–356
, pp.
295
–
302
.
9.
Allen
P. B.
,
Boydston
N. C.
,
Howard
J. T.
,
Ko
S. Y.
,
Kolesar
E. S.
, “
Theoretical and experimental characterization of the in-plane tip force and deflection achieved with asymmetrical polysilicon electro thermal microactuators
,”
Micromachined Devices and Components, Proc SPIE
, Vol.
4176
,
2000
, pp.
148
–
158
.
10.
Koester, D., Mahadevan, R., Hardy, B., Markus, K., 2001, “Multi-user MEMs processes (MUMPs) Design Handbook,” Cronos Integrated Microsystems, JDS Uniphase, NC, Revision 6.0.
11.
Reid, J.R., Silversmith, D.J., “Joule heating simulation of polysilicon thermal micro-actuators,” International Conference on Modeling and Simulation of Microsystems, vol. 2, 1999, pp. 613–616.
12.
Moulton
T.
,
Ananthasuresh
G. K.
, “
Micromechanical device with embedded electro-thermal-compliant actuation
,”
Sensors and Actuators A
, vol.
90
,
2001
, pp.
38
–
48
.
13.
Hunag
Q. A.
,
Lee
N. K. S.
, “
Analysis and design of polysilicon thermal flexure actuator
,”
Journal of Micromechanics and Microengineering
, vol.
9
,
1999
, pp.
64
–
70
.
14.
Mankame
N. D.
,
Ananthasuresh
G. K.
, “
Comprehensive thermal modeling and characterization of an electro-thermal-compliant microactuator
,”
Journal of Micromechanics and Microengineering
, vol.
11
,
2001
, pp.
1
–
11
.
15.
Mankame
N. D.
,
Ananthasuresh
G. K.
, “
Effect of thermal boundary conditions and scale on the behaviour of electrothermal-compliant micromechanisms
,”
Proc. of Modeling and Simulation of Microsystems
,
2000
, pp.
609
–
612
.
16.
Hickey
R.
,
Sameoto
D.
,
Hubbard
T.
,
Kujath
M.
, “
Time and Frequency Response of Two-Arm Micromachined Thermal Actuators
,”
J. Micromech. Microeng.
, vol.
13
,
2003
, pp.
40
–
46
.
17.
Atre, A., 2004, “Dynamic Response of Surface Micromachined Beam Flexure Actuators,” ASME International Mechanical Engineering Congress, Paper No. IMECE 2004-59040, Nov. 11–18, Anaheim, CA.
18.
Geisberger
A. A
,
Sarkar
N.
,
Ellis
M
,
Skidmore
G. D.
,
2003
, “
Electrothermal properties and modeling of polysilicon microthermal actuators
,”
Journal of Microelectromechanical Systems
, vol.
12
(
4
), pp.
513
–
523
.
19.
Messenger, R.K., 2004, “Modeling and Control of Surface Micromachined Thermal Actuators,” MS Thesis, Brigham Young University, Provo, Utah, USA.
20.
ANSYS, Version 6.1, Swanson Analysis Systems, ANSYS Inc., Pittsburgh, PA.
21.
Hickey, R., “Analysis and Optimal Design of Micromachined Thermal Actuators,” M.A.Sc Thesis, Dalhousie University, Nova Scotia, CA, 2001.
22.
Lin
L.
,
Chiao
M.
,
1996
, “
Electrothermal responses of lineshape microstructures
,”
Sensors and Actuators A
, Vol.
55
, 1996, pp.
35
–
41
.
23.
ANSYS Online Help Manual, Version 5.6.
24.
Incropera, F.P. and DeWitt, D.P. 1996, Fundamentals of Heat and Mass Transfer, 4th ed., John Wiley and Sons.
25.
Atre, A., Boedo, S., 2003, “Effect of Thermophysical Porperty Variations on Surface Micromachined Polysilicon Beam Flexure Actuators,” Modeling and Simulation of Microsystems, ISBN 0-9728422-8-4, Vol. 2, 2004, pp. 263–267.
26.
Sharpe, W. N., Jr., Eby, M. A., and Coles, G., 2001, “Effect of Temperature on Mechanical Properties of Polysilicon,” Proc. Transducers’01, p. 1366–1369.
27.
Cronos Integrated Microsystems, www.memsrus.com JDS Uniphase.
28.
Lott
C.
,
McLain
T.
,
Harb
J.
, and
Howell
L.
Modeling the Thermal Behavior of a Surface-micromachined Linear-displacement Thermomechanical Actuator
,
Sensors & Actuators: A. Physical
, Volume
101
, Number
1–2
,
2002
. pp.
239
–
250
.
29.
Manginell, R.P., 1997, “Polycrystalline-Silicon microbridge combustible gas sensor,” Ph.D Thesis, University of New Mexico, Albuquerque, NM.
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