Mechanical properties of MEMS structures
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Author (Corporation)
Publication date
2005
Typ of student thesis
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Type
04B - Conference paper
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Editor (Corporation)
Supervisor
Parent work
11th International Conference on Fracture 2005 (ICF11)
Special issue
DOI of the original publication
Link
Series
Series number
Volume
5
Issue / Number
Pages / Duration
3800-3805
Patent number
Publisher / Publishing institution
Place of publication / Event location
Turin
Edition
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Programming language
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Practice partner / Client
Abstract
Mechanical characterization of MEMS (micro electromechanical systems) materials is increasingly important in view of improving reliability and assessing the life time of new miniaturized devices. In this paper first a number of testing methods are described. These methods include tensile, torsion and fatigue testing of specially designed microstructures. Difficulties arise from manufacturing and handling of small structures and the determination of its geometrical dimensions which directly affect the accuracy of material parameters extracted from the experiments. In addition, the measurement of mechanical parameters like small forces and torques or strains poses a challenge. This paper focuses on size effects in rolled copper foils of thickness between 10 and 250 microns as determined from tensile testing. Tensile testing was chosen as a testing method in order to minimize strain gradients. Depending on the size the copper foils are tested in a classical setup or in a special tensile apparatus which is adapted to the small size of the specimens. The special setup consists of a balance to measure the applied force. The specimens are strained with a lead screw driven translation stage. In order to take care of slip and elasticity in the fixations the strain is measured optically directly on the sample using a least square template matching algorithm. It was found that depending on the thickness of the foils the average fracture strain decreases from about 15% down to .5 % for the 250 and 10 micron specimens, respectively. In order to find a reason for this dramatic change many efforts have been undertaken in order to characterize the specimens more precisely. The microstructure of the samples was determined using various methods including conventional micrographs, hardness measurements and X-ray diffraction.
Keywords
Copper, Elasticity, Fatigue testing, Lead screws, Materials testing apparatus, Microstructure, Strain, Template matching, Tensile testing, Torsion testing, X ray diffraction, 10 micron, Applied forces, Conventional micrographs, Copper foils, Forces and torques, Fracture strain, Geometrical dimensions, Hardness measurement, Least Square, Life-times, Material parameter, Mechanical characterizations, Mechanical parameters, MEMS-structure, Micro electro mechanical system, Miniaturized devices, Screw-driven, Size effects, Strain gradients, Template-matching algorithms, Testing method, Translation stage, Fracture
Subject (DDC)
Event
11th International Conference on Fracture 2005 (ICF11)
Exhibition start date
Exhibition end date
Conference start date
20.03.2005
Conference end date
25.03.2005
Date of the last check
ISBN
978-1-61782-063-2
ISSN
Language
English
Created during FHNW affiliation
No
Strategic action fields FHNW
Publication status
Published
Review
Peer review of the abstract
Open access category
Closed
License
Citation
Dual, J., Simons, G., Villain, J., & Weippert, Chr. (2005). Mechanical properties of MEMS structures. In International Congress on Fracture (ICF) (Ed.), 11th International Conference on Fracture 2005 (ICF11) (Vol. 5, pp. 3800–3805). https://irf.fhnw.ch/handle/11654/49557