光栅平动式光调制器的残余应力自测量方法和试验

Self-measuring Method and Experiment of Residual Stress of Grating Moving Light Modulator

对微机电系统(Micro-electro-mechanical systems,MEMS)器件残余应力的测量方法大都需要有标准的测试结构。这些测试结构体积较大,一方面占用有限的光刻版面积,另一方面加电和测试时都会增加复杂性和难度。针对一种基于微光机电系统(Micro-opto-electro-mechanical systems,MOEMS)技术的光栅平动式光调制器(Grating moving light modulator,GMLM),提出一种无须外加测量结构,直接利用GMLM本身结构特性得到残余应力的测量方法。这种测量方法利用残余应力与GMLM吸合电压之间的关系,由吸合电压测量值可以计算出材料的残余应力值。推导GMLM残余应力与GMLM吸合电压之间的关系式,并考虑平行板电容的边缘效应加以修正。通过试验,给出实际GMLM采用的Al-1%Si膜的残余应力为99MPa。该方法的应用,使得GMLM器件具有残余应力自测量功能,实现测量和执行结构一体化,降低器件残余应力测量的成本和复杂度。

Most of the measuring methods of residual stress of devices of micro-electro-mechanical systems（MEMS） need standard test structures.The structures will take up a lot of space on the chip,and enhance the complication and difficulty of measuring.Aiming at a grating moving light modulator（GMLM） based on micro-opto-electro-mechanical systems（MOEMS）,a measuring method is proposed.It directly utilizes the structural characteristics of GMLM to obtain the residual stress without needing addition of measuring structure.This measuring method utilizes the relationship between residual stress and GMLM pull-in voltage,and the value of residual stress of material can be calculated from the measured value of pull-in voltage.The relationship equation between GMLM residual stress and GMLM pull-in voltage is derived,and it is modified in consideration of the fringe effects of parallel-plate capacitance.The residual stress of Al-1%Si film of GMLM is measured as 99 MPa by experiment.This method makes GMLM not only an actuator,but also a measuring structure.By integrating them all in one structure,the method decreases the price and complexity of the measurement of residual stress.