MEMS resonant load cells for micro-mechanical test frames: feasibility study and optimal design

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Torrents A., Azgin K., Godfrey S. W. , Topalli E. S. , AKIN T., Valdevit L.

JOURNAL OF MICROMECHANICS AND MICROENGINEERING, vol.20, no.12, 2010 (Peer-Reviewed Journal) identifier identifier

  • Publication Type: Article / Article
  • Volume: 20 Issue: 12
  • Publication Date: 2010
  • Doi Number: 10.1088/0960-1317/20/12/125004
  • Journal Indexes: Science Citation Index Expanded, Scopus


This paper presents the design, optimization and manufacturing of a novel micro-fabricated load cell based on a double-ended tuning fork. The device geometry and operating voltages are optimized for maximum force resolution and range, subject to a number of manufacturing and electromechanical constraints. All optimizations are enabled by analytical modeling (verified by selected finite elements analyses) coupled with an efficient C++ code based on the particle swarm optimization algorithm. This assessment indicates that force resolutions of similar to 0.5-10 nN are feasible in vacuum (similar to 1-50 mTorr), with force ranges as large as 1 N. Importantly, the optimal design for vacuum operation is independent of the desired range, ensuring versatility. Experimental verifications on a sub-optimal device fabricated using silicon-on-glass technology demonstrate a resolution of similar to 23 nN at a vacuum level of similar to 50 mTorr. The device demonstrated in this article will be integrated in a hybrid micro-mechanical test frame for unprecedented combinations of force resolution and range, displacement resolution and range, optical (or SEM) access to the sample, versatility and cost.