Process dependence of roughness in a positive-tone chemically amplified resist

Line edge roughness becomes an important factor in linewidth control as lithographic dimensions approach the 0.1 mu m region. In order to understand different contributions to roughness, we. explored the relationship between roughness and deprotection in the case of a positive chemically amplified resist. Experiments show that the roughness of the remaining resist depends on process history and it is not a simple function of the degree of deprotection. Scaling analysis of atomic force microscopy images shows that an equal degree of deprotection yields a self-affine rough surface with constant fractal dimensions which imply a similar surface morphology, but with a different standard deviation. The correlation between sidewall and top surface roughness is also discussed. (C) 1998 American Vacuum Society. [S0734-211X(98)17906-4].