基于光学干涉技术的MEMS薄膜泊松比在线测量方法研究

Study of the Optical Interference Technique for the Measurement of the Poisson's Ratio of MEMS Thin Films

提出了一种基于光学干涉技术的MEMS薄膜泊松比在线测量方法.该方法采用直角悬臂梁作为测试结构,在上下两电极之间加上电压后,在静电力的作用下,与锚区相连的第一段直梁将发生弯曲变形和扭转变形.先由米劳干涉仪测得悬臂梁的变形,然后分离出形变中的弯曲分量和扭转分量,进而计算出薄膜材料的泊松比.用CoventorW are软件验证.结果显示该方法精度很高.

In this study, a method to measure the Poisson＇s ratio of thin MEMS film according to optical interference technical is proposed. The method makes use of a right angle cantilever beam as test structure, applies voltage between the top electrode and the bottom electrode, under the function of the electrostatic force, the first part of the cantilever beam which is connected with the anchor will become deformed with bending and torsion. First, measure the deformation with Mirau interference instrument, then separate the bending and torsion, figure out the Poisson＇s ratio of thin MEMS film, and verify the method with the software of CoventorWare. The results show that the accuracy of the method is very high.