Determination of mechanical behavior of MEMS materials

In recent years, there has been explosive growth in the field of the micro-electro-mechanical system (MEMS). MEMS technologies have been found wide application in various microscale systems and devices. With the increase of usage of MEMS, higher reliability of the MEMS devices under the thermal, electric and magnetic forces are required. So the mechanical properties of the MEMS materials become more and more important. The testing methods on mechanical properties of the MEMS materials are reviewed with the discussion of both the advantages and the disadvantages, such as the nanoindentation test, the membrane bulge test, the beam bending test, the micro-Raman Spectroscopy and the uniaxial tension method. And the new developments of them are introduced simply. Some research works of the authors on the uniaxial tension method are introduced, including the details of the specimen and the grip design, the loading and the strain measurement. The finite element method was used to simulate the tension test of the samples with different shape parameters to choose the shape and dimensions of the specimen. And the interference strain/displacement gauge (interference strain/displacement gauge, ISDG) was used to measure the stain. By using the self-developed uniaxial tension testing device, the stress-strain curves of the polycrystalline copper thin film are obtained successfully.