B3.4 - Resonant Mode Detection for Fast Determination of Structural and Material Parameters of MEMS
- Event
- SENSOR+TEST Conferences 2009
2009-05-26 - 2009-05-28
Congress Center Nürnberg - Band
- Proceedings SENSOR 2009, Volume I
- Chapter
- B3 - Micro Sensors
- Author(s)
- M. Meinig, S. Kurth, T. Gessner - Fraunhofer ENAS, Chemnitz, Germany, A. Shaporin - Chemnitz University of Technology, Chemnitz, Germany, W. Bauer - Polytec GmbH, Waldbronn, Germany
- Pages
- 199 - 204
- DOI
- 10.5162/sensor09/v1/b3.4
- ISBN
- 978-3-9810993-4-8
- Price
- free
Abstract
Fast and nondestructive determination of structural and material parameters of mass-spring-damper systems is a key issue in wafer level MEMS test. The knowledge of these parameters allows the selection of defective devices before the cost intensive packaging step and the control of the fabrication process. The proposed method addresses this problem with a non-contact measurement technique based on laser Doppler interferometry. Measured frequency response functions and natural frequencies obtained from finite element simulations are used to calculate structural dimensions and material properties of the device under test. On the example of MEMS scanner arrays for Hadamard transform optics, the method is demonstrated and results are validated by scanning electron microscopy. A mean error of 3 % between the two measurement techniques was observed, which is very promising considering a measurement duration of approximately 4 seconds per device. Techniques for efficient excitation of micromechanical structures in a broad frequency range are presented, as well as algorithms for the precise determination of natural frequencies and the detection of mode interchange.