Thermally induced change in deformation of multimorph MEMS structures

David C. Miller; Martin L. Dunn; Victor M. Bright

doi:10.1117/12.443016

Translator Disclaimer

2 October 2001 Thermally induced change in deformation of multimorph MEMS structures

David C. Miller; Martin L. Dunn; Victor M. Bright

Author Affiliations +

Proceedings Volume 4558, Reliability, Testing, and Characterization of MEMS/MOEMS; (2001) https://doi.org/10.1117/12.443016
Event: Micromachining and Microfabrication, 2001, San Francisco, CA, United States

Abstract

Exposure to elevated temperatures can cause permanent alteration of the shape of a multimorph MEMS device. In particular, the cantilever beam structure has been characterized extensively for the bimorph polysilicon and gold materials combination. Environments even briefly elevated above 110 C can induce change in structural displacement. That is, when observed at some reference temperature, the displacement is different from the original shape prior to baking, when monitored at the same reference temperature. Thermal exposure can cause the magnitude of displacement to increase in excess of two or threefold. Structural bifurcation can magnify the displacement of a plate-like structure. The process used to increase deformation of a multimorph MEMS structure will be described, and characterized according to the part's geometry. Such change in shape is not entirely permanent and is subject to relaxation. Change in deformation has been characterized throughout the time-span of approximately one-year. Lastly the implications of the so-called heat-treatment (or energy storage) mechanism are discussed in terms of MEMS device reliability, manufacture and packaging, as well as design.

Citation Download Citation

David C. Miller, Martin L. Dunn, and Victor M. Bright "Thermally induced change in deformation of multimorph MEMS structures", Proc. SPIE 4558, Reliability, Testing, and Characterization of MEMS/MOEMS, (2 October 2001); https://doi.org/10.1117/12.443016