Different roughness parameters, such as the root mean square deviation (rms or σ), the correlation length Lcor, the fractal dimension D and the Fourier spectrum, are presented and compared. The scaling behavior of σ determining the Lcor as well as the dependence of σ 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 σ and D which is not predicted by theory, and elucidates the dependence of Lcor on the exposure dose.