A technique of fast ellipsometric measurements based on dual-drive elastic modulation is proposed in paper,for which the measurement speed of traditional mechanical rotary compensator ellipsometer is slow.The modu-lation mode of 45°dual-drive photoelastic modulator(PEM)working in pure traveling wave mode was studied by theo-retical analysis and simulation.The results show that the fast axis direction can high-speed periodic rotation and the phase delay is constant when the PEM working in pure traveling wave mode.Combined with the principle of ellipsome-try,a theoretical model of fast ellipsometric measurement based on dual drive PEM was studied in detail.The results show that the optical period of this model was less than 10µs,and the ultra-high speed optical modulation could be re-alized.With this study,it is expected to solve the problem of ultra-high speed detection of thin films in the production process of semiconductor integrated circuits,microelectronics and photovoltaic cells.It is of great significance and aca-demic value for in-line measurement of thin films.
关键词
厚度测量/光弹性/高速椭偏测量技术/弹光调制器/在线检测/Comsol有限元仿真
Key words
thickness measurement/photoelasticity/fast ellipsometric measurement technique/photoelastic mod-ulator/in-line measurement/Comsol finite element simulation
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