Paper Info
Title
SU-8 Electrothermal Actuators: Optimization of Fabrication and Excitation for Long-Term Use.
Abstract
In this paper we examine the suitability of SU-8 2000 as a construction material for electrothermal actuators and the actuator stability for long-term operation. The fabrication of SU-8 was optimized for mechanical and thermal stability. Samples with different softbake duration, exposure dose and postbake temperature were evaluated using Fourier-Transform IR-spectroscopy and dynamic-mechanical analysis. The exposure dose and postbake temperature proved to have a strong influence on the cross-linking and the glass transition temperature. A final hardbake levels the effects of the process history. A high degree of crosslinking, a low drop of the dynamic modulus over temperature (30%) up to the glass transition temperature 100-140 degrees C were achieved for SU-8 with an exposure dose of 1500 mJ/cm(2), a postbake temperature of 95 degrees C and hardbake of 240 degrees C. Electrothermal actuators proved to be stable until the end of the experiment after 2400 duty cycles. Actuator deflections up to 55 mu m were measured (actuator length: 4 mm) for input powers up to 160 mW and a maximum operating temperature of 120 degrees C. Higher temperatures led to permanent deformations and failure. An offset drift of up to 20% occurs during actuation, but converges after a burn-in phase of about two hours.
Year
DOI
Venue
2014
10.3390/mi5041310
MICROMACHINES
Keywords
Field
DocType
electrothermal actuator,SU-8,long-term stability,pseudo-bimorph,glass transition temperature
Operating temperature,Deflection (engineering),Glass transition,Electronic engineering,Excitation,Thermal stability,Dynamic modulus,Materials science,Fabrication,Actuator
Journal
Volume
Issue
Citations 
5
4
0
PageRank 
References 
Authors
0.34
0
6
Name
Order
Citations
PageRank
Thomas Winterstein110.70
Matthias Staab200.34
Christian Nakic300.34
Hans-Jürgen Feige400.34
Jürgen Vogel500.34
Helmut F. Schlaak632.39