摘要
介绍了一种基于哈特曼传感器的薄膜应力在线检测系统。哈特曼透镜阵列将待测量表面划分成若干小区域,通过测量每个小区域成像光斑的相对位置变化来获得整个测量表面的变形量,将测得的变形量代入到薄膜应力与基板表面变形的关系式中,求得薄膜应力。通过对影响光斑质心探测精度的各种因素进行分析,提出使用加阈值的一阶矩法,精确计算光斑质心,结合高灵敏度的CMOS探测器,使系统的面形测量精度达到15.7nm,应力测量灵敏度优于3.3MPa,实现了薄膜应力测量的高灵敏度与在线测量的统一。最后通过对TiO2,SiO2单层膜的在线测量,验证了系统的灵敏度与稳定性,能够完全满足薄膜应力分析的需要。
A thin film stress measurement system on-line based on the Hartmann- Shack wavefront sensor technique was introduced. The Hartmann-Shack micro-lens array divided the sample surface into several parts and the sample surface curvature or bows could be achieved by calculating the relative change of the image position. The film stress could be obtained subsequently by transforming the curvature or bow into the stress using the stress-deformation expressions. Using the high-sensitivity CMOS camera and threshold weighted pixel average （TWPA） method, the measuring precision of wave front had reached to 15.7 nm. With the stress measuring sensitivity superior to 3.3 MPa, the system combined the high sensitivity and measurement on-line together. The experiments of depositing TiO2 and SiO2 monolayer were used to validate the system＇s capabilities. The results indicate that the system meets design needs.
出处
《红外与激光工程》
EI
CSCD
北大核心
2009年第1期120-125,共6页
Infrared and Laser Engineering
关键词
薄膜应力
在线测量
哈特曼传感器
Thin film stress
Measurement on line
Hartmann-Shack wave front sensor
