A Three-Dimensional Topography Measurement for Micro-nano Film Buckling Based on the Focusing Evaluation Function

This research focuses on observing and measuring the topography of thin film buckle in micro-nano scale, which is based on focus measure function and Shape From Focus technology, Gaussian interpolation. A PZT stepper motor which is well calibrated is used to change the distance between thin film surface and the microscope lens. Focusing-evaluation-functions elements of each image which is taken at each step are corresponded to the distance values obtained from the PZT stepper motor. Then, focusingevaluation- functions of each element at different steps can be seemed as a function of distance values. The actual distance of each element between the film and the lens, when the element is clearest, can be obtained by the Gaussian interpolation when the element focusing-evaluation-function reaches the peak value. Furthermore, this method is applied successfully to measure the full field topography of straight side buckle and telephone cord buckle.