Precision Measurement of Sub-50 nm Linewidth by Stitching Double-Tilt Images

Abstract

In this paper we present a stitching double-tilt image method (SDTIM) to measure sub-50 nm linewidth and to evaluate the measurement uncertainty. The SDTIM employs a parallel image method using a tilt mechanism to obtain two side scans. Moreover, the stitching method is used for linewidth determination. Experiments were performed by atomic force microscopy (AFM) using an ultrasharp tip, whose radius is smaller than 5 nm. The sample rotation axis is set parallel to the top surface of the sample in order to reduce the problem of measurement position variation. Experimental results show that the developed SDTIM can be used with an uncertainty of less than 5 nm at a confidence level of 95%. (C) 2010 The Japan Society of Applied Physics