<title>MEMS/NEMS mechanical characterization on different thin film materials by scanning along micro-machined cantilevers</title>

Abstract

Mechanical characterization is vital for the design of MEMS/NEMS. Many methods have been developed to measure the mechanical properties of materials; however, most of them are either too complicated, or expensive for industrial application, or not accurate. This paper describes a new characterization method to extract the mechanical properties of the materials that is simple, inexpensive and applicable to a wide range of materials. The beams of the material under tests, are patterned by laser micromachining and released by KOH etch. Surface profilometer is used to scan along μ-machined cantilevers and produce a bending profile, from which the Young’s modulus can be extracted. The errors due to initial curling and anticlastic (width) effect have been carefully studied. A new ANSYS FEA model is developed to evaluate the effects and test structure designs. SiN_x, Ni, SiC and nanocrystal diamond cantilevers have been fabricated and their mechanical properties, e.g. Young’s modulus have been evaluated as 154+/-12GPa, 202+/-16GPa, 360+/-50GPa and 504+/-50GPa, respectively. These results are consistent with those measured by nano-indentation. Residual stress gradient has also been extracted by surface profilometer, which is comparable with the results inferred from Zygo interferometer measurements. It is also possible to extract plate modulus and Poisson ratio with minimal error achieved. This method can be extended to AFM or nanometer-stylus profilometer for NEMS mechanical characterization.