MEMS材料力学性能的测试方法

介绍国内外MEMS(micro-electro-mechanical system)材料力学性能的测试方法,包括纳米压痕法、薄膜打压法、梁弯曲试验、微拉曼光谱法、单轴拉伸法等.分析各种测试方法的优缺点、基本原理和最新进展.详细介绍单轴拉伸试验方法的试验原理、特点及发展现状, 在此基础上介绍作者们在MEMS材料单轴拉伸试验方面的阶段性研究成果,包括单轴拉伸试样设计、夹具设计、加载方法及应变测量技术等.试样和夹具的设计采用有限元方法模拟不同形状参数试样的拉伸试验过程,确定试样的外形和尺寸.应变测量采用的是激光干涉应变计法(interference strain /displacement gauge, ISDG),并用所研制的微小试样拉伸试验机,成功测得多晶铜薄膜材料的应力-应变曲线.

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.