一种在线测量微机械薄膜残余应力的新结构

提出了一种利用临界屈曲法在线测量微机械薄膜残余应力的新结构，并采用表面微加工技术制作了两种测试样品.搭建了在线观测实验装置来实时监控释放过程中结构出现的临界屈曲变形模态，由此判断出结构内部的应力状态，同时在测得临界刻蚀深度的情况下，采用有限元方法计算出残余应力大小.借助有限元方法，先研究了多个参数对临界屈曲应力的影响，然后利用这种新结构对薄膜残余应力进行了实际测量，所得结果与微旋转结构的应力测量结果基本吻合.分析及实验表明，新结构在测量薄膜残余应力方面有许多优点，具有较高的实用价值，不仅能满足大量程的应力检测要求，而且只用一个结构就可以同时测量压应力和拉应力，从而极大提高了器件版图空间的利用率.

A novel microstructure for in-situ measurement of residual stress in micromechanical thin films

A novel microstructure for in-situ measuring residual stress in micromechanical thin films by the method of critical buckling observation was proposed and two different samples were fabricated using surface micromachining technique. The experimental apparatus was built for in-situ observation of critical buckling patterns of these microstructures during sacrificial layer etching. Then, the states of residual stresses can be distinguished directly by the buckling patterns and the magnitudes can be estimated with finite element method (FEM) when the values of critical etching length have been measured. Before the measurement, effects of various parameters on the critical buckling stress were investigated in detail with FEM in advance. After that, measurements of residual stresses using the new microstructures were carried out and the results were in good agreement with that obtained from micro rotating structures. It is consequently revealed that measurement of residual stresses by this new microstructure has evident advantages over the conventional buckling observation methods. Both compressive and tensile residual stresses in wide ranges of amplitude can be measured, just using a single appropriately designed microstructure. Therefore, the usefulness of layout space can be greatly improved.