Compared to conventional mechatronics system design, MEMS design requires new knowledge on materials properties. This is because, materials such as silicon and many other thin films used for MEMS devices have never been used for mechanical purposes in conventional systems. Demands for characterization of materials properties in terms of design and fabrication of MEMS are discussed. Two examples of materials characterization, one for design and the other for fabrication of MEMS, are presented. Firstly, mechanical properties of thin films are evaluated. A new method for uni-axial tensile tet of film material is proposed. The test is performed on a silicon chip where the thin film specimen and the loading mechanism are integrated. Results are presented for such materials as Si, Poly-Si, SiO₂ and Si₃N₄ films sized in a range of 0.1-20 micron thick. Secondary, anisotropic etching properties of single crystal silicon are investigated. Anisotropy in etching rate is completely evaluated as a function of crystallographic orientations. Developed etch-rate database allowed to predict 3D etched profiles of silicon devices which are etched under any mask patterns, any wafer orientations, and a wide range of etching conditions. Examples of 3D structure fabrication using this system are demonstrated.

Date Published: 21 November 2001
PDF: 9 pages
Proc. SPIE 4592, Device and Process Technologies for MEMS and Microelectronics II, (21 November 2001);

Published in SPIE Proceedings Vol. 4592:
Device and Process Technologies for MEMS and Microelectronics II
Jung-Chih Chiao; Lorenzo Faraone; H. Barry Harrison; Andrei M. Shkel, Editor(s)