Roughness characterization in positive and negative resists

Different roughness parameters, such as the root mean square deviation (rms or sigma), the correlation length L-cor, the fractal dimension D and the Fourier spectrum, are presented and compared. The scaling behavior of sigma determining the L-cor as well as the dependence of sigma and D on the exposure dose for two negative tone (wet- and plasma-developed) and one positive tone resist are investigated. The experimental analysis reveals an interesting interrelation (inverse behavior) between sigma and D which is not predicted by theory, and elucidates the dependence of L-cor on the exposure dose. (C) 2002 Elsevier Science B.V. All rights reserved.