Develop a novel thermal switch through CMOS MEMS fabrication process

You Liang Lai*, Lei Chun Chou, Ying Zong Juang, Hann Huei Tsai, Sheng-Chieh Huang, Jin-Chern Chiou

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


This paper focuses on implementing two novel CMOS-MEMS type switches: buckling type and thermal type, by using commercially available TSMC 0.35 μm two-poly four-metal (2P4M) CMOS process. There are two novel designs in these two type switches: first, the soft contact structure with post-processing fabrication; second, using residual stress to achieve large structural deformation in buckling type and thermal type switches. To create the soft contact structure, residual gradient stress effect has been utilized to make bending-down curvatures. According to the experiments, the layer Metal1 has the largest negative residual gradient stress [1] effect that can achieve the largest negative deflection in z-axis. Because the structure will bend down after post-processing release, larger lateral contact area are set up to gain the lower contact miss ability. In the post-processing fabrication, 0.3μm thickness gold will be deposited on the contact tips. Due to the essence of gold, comparing with aluminum, has no oxidation issue, gold also has the advantage of higher conductivity to reduce the electrical power loss. In the buckling type design, the switch uses residual stress to achieve lateral buckling effect to solve long distance problem. In the thermal type design, this paper design a folded-flexure [2, 3] with the electro-thermal excitation to turn the switch on or off. In the prototype, the device size is 500 μm × 400 μm and the gap between two contact pads is 9 μm in offstate. on the experimental results, the switch can work stably at 3 volts, and the displacement of the thermal type switch can achieve 2.7μm, which is sufficient for the mechanism of switching-on or switching-off.

Original languageEnglish
Title of host publicationMicromachining and Microfabrication Process Technology XVI
StatePublished - 2011
EventMicromachining and Microfabrication Process Technology XVI - San Francisco, CA, United States
Duration: 25 Jan 201127 Jan 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


ConferenceMicromachining and Microfabrication Process Technology XVI
Country/TerritoryUnited States
CitySan Francisco, CA


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