Three-Dimensional Line Edge Roughness in Pre-and Post- Dry Etch Line and Space Patterns of Block Copolymer Lithography
In this work, we employ large-scale coarse-grained molecular dynamics (CGMD) simulations to study the three-dimensional line edge roughness associated with line and space patterns of chemo-epitaxially directed symmetric block copolymers (BCPs) on a flat substrate. The diblock copolymer chain length and interaction parameters are validated with experimental BCP period, L0 and corresponding molecular weight. Defect-free lamellae are formed, after which the system was quenched below the glass transition temperature before selectively dry-etching off one of the BCP phases. Three different values of dry etching selectivity under 10 mTorr and its effect on the remaining resist domain morphology were studied. The roughness of the polymer domain was evaluated over three process stages: anneal, pre-etch and post-etch. Power spectral density plots were then generated to elucidate the contribution of low and high frequency roughness for the three process stages. Finally, the results obtained from simulations can be shown in close agreement with experimental SEM images. The SEM images were also analyzed to obtain the roughness exponent and correlation length inherent to the process and the BCP.