A novel micro-nano measurement method for line width using confocal microscopy with super-resolution image restoration

Abstract

A novel micro-Nano measurement method using confocal microscopy with super-resolution image restoration is proposed to achieve the measurement of all of the lateral dimensions of the line width step sample including the dimension that is smaller than the diffraction limit. In this method, first, the step is over-sampling scanned to obtain the intensity image data at focal plane; and then using the respective restoration to obtain super-resolution restoration images of the flat region and the bevel region; finally, the ideal profile is estimated from the restoration images and used to locate the edges of the structures to measure. Maximum likelihood estimation algorithm based on Markov filed is adopted for the image restoration. Experimental results of the measurement for the lateral dimensions of TGZ02 100nm height standard show that this method can accurately measure the period and all of the lateral dimensions of the step. The method reaches an average measurement value of 0.162μm for the bevel edge, and it is 0.015μm smaller than that measured by AFM.