Development of testing system for evaluating the mechanical properties of thin microelement

为了在服务操作中开发可靠的微机械和MEMS，必须非常小心地进行微机械评估，即，包括疲劳行为的μ m尺寸的微元件的机械性能。然而，评价方法还没有很好地建立。本研究开发了薄微构件的力学性能测试系统，对薄微构件的拉伸强度、弹性模量、疲劳强度等力学性能进行了评价，建立了薄微构件的评价方法。该系统由压电陶瓷驱动的定位平台驱动的微机械拉伸试验机、微操作系统、双视场显微镜辅助的非接触应变测量系统组成。该系统基本上是针对厚度为3.5μm、宽度为10μm的多晶硅薄微元件设计的。在进行单轴拉伸试验时，最重要也是最困难的是试样夹持方法的确定。在本研究中，开发了一种带胶水的夹持方法，并成功地应用于单轴拉伸试验，在夹持处没有任何滑动。此外，将该测试系统安装在AFM工作台上，成功地对样品表面进行了原位观察。对试验机和控制程序进行了改进，使之既能在实验室空气中又能在水中进行薄微元件的疲劳试验。

In order to develop a reliable micro machine and MEMS in a service operation, much care must be taken into micro mechanical evaluation, i.e., mechanical properties of μm-sized microelements including fatigue behavior. However, the evaluation method has not been well established yet. In this study, the testing system of a thin microelement has been developed to evaluate the mechanical properties; the tensile strength, elastic modulus, fatigue strength and so on, and the evaluation methods for thin microelement are established. The system consists of a micromechanical tensile testing machine actuated by a PZT driven positioning stage, a micro manipulation system, a non-contact strain measurement system with a help of a double field of view microscope. The system is basically designed for poly-Si thin microelement with 3.5μm thick and 10μm wide. When conducting the uni-axial tensile test, the most important and difficult thing is to establish the method of gripping the specimen. In this study, a gripping method with glue is developed and successfully applied to the uni-axial tensile test without any slipping at the grip. Moreover the testing system is installed on an AFM stage and in situ observation of specimen surface is successfully done. The testing machine and a control program are improved to conduct the fatigue tests of thin microelement not only in laboratory air but also in water.