Xuezeng, Zhao | Search NASA

DOE OSTI2010

Effect of tip shape on line edge roughness measurement based on atomic force microscopy

Atomic force microscopy (AFM) is an important tool in line edge roughness (LER) measurements, where accuracy for line edge identification is influenced by the shape of the tip. In this article, the effect of tip shape on LER measurement based on AFM is studied theoretically. The formulas for calculating the distance between the measured and actual line edge of the sample are presented. The effects of the three kinds of tips with different shapes are experimentally compared for validation. Suggestions on how to reduce measuring error caused by tip shape are also given.

36 MATERIALS SCIENCE↗

DOE OSTI2010

Multiscale characterization method for line edge roughness based on redundant second generation wavelet transform

We introduce a multiscale characterization method for line edge roughness (LER) based on redundant second generation wavelet transform. This method involves decomposing LER characteristics into independent bands with different spatial frequency components at different scales, and analyzing the reconstructed signals to work out the roughness exponent, the spatial frequency distribution characteristics, as well as the rms value. The effect of noise can be predicted using detailed signals in the minimum space of scale. This method was applied to numerical profiles for validation. Results show that according to the line edge profiles with similar amplitudes, the roughness exponent R can effectively reflect the degree of irregularity of LER and intuitively provide information on LER spatial frequency distribution.

36 MATERIALS SCIENCE↗