Characterization and simulation of surface and line-edge roughness in photoresists

The problem of surface and line-edge roughness characterization and prediction is discussed. Different roughness parameters, such as the root mean square deviation (rms or σ), the fractal dimension, and the Fourier spectrum, are presented and compared. These roughness parameters for three negative tone resists (wet and plasma developed) are analyzed versus exposure dose, photoacid generator concentration, and plasma development conditions. Finally, a molecular type simulator is used to predict the experimental roughness behavior.