Evaluation of the 3D compositional heterogeneity effect on line-edge-roughness

The controlling factors in the formation of the compositional heterogeneity at the deprotection front were investigated using 3D computer simulation. The results illustrate that the chemical composition fluctuation (CCF) formed by the photoresist deprotection reaction is an important factor contributing to the line-edge-roughness (LER) in addition to the deprotection gradient (DG) of the reaction front. The magnitude of the chemical composition fluctuation and the deprotection gradient are found to depend on the ratio of the deprotection reaction rate constant to diffusion coefficient ( k P /D ) and the number of hoping step ( n ) With this new finding, the influence on LER from various process/material parameters such as dose/contrast, diffusivity, and reactivity can all be understood through their effects on k P / D and n .