Dynamic Nano-scale Surface Profilometry Using Stroboscopic Interferometry

Abstract

Dynamic 3-D nano-scale surface profilometry using stroboscopic interferometry was successfully developed. An optical microscopy based on stroboscopic interferometry was developed to achieve full-field vibratory out-of-plane surface profilometry and system characterization. To increase the measurement bandwidth of the developed system, an innovative image processing algorithm based on deconvolution principle was developed to improve the signal to noise ratio of the detected interferometric data. The method provides an excellent way to increase the measurement bandwidth without adding any significant hardware in a stroboscopic interferometric framework. Meanwhile, an innovative detection algorithm based on image contrast measure was developed for automatic identification of accurate resonant modes. To verify the effectiveness of the developed methodology, a cross microbeam was measured to analyze the full-field resonant vibratory modes and dynamic characteristics. The experimental results confirm that the dynamic behavior of the tested microcantilever beams can be accurately characterized and 5 nm of vertical measurement accuracy as well as tens micrometers of vertical measurement range can be achieved. The measured results were satisfactorily consistent with the theoretical simulation outcomes from ANSYS.