(576b) Examination of Line Edge Roughness of Directed Self-Assembled Block Copolymers: A Coarse-Grained Molecular Dynamics Study
In this work, we have adopted a large-scale coarse-grained molecular dynamics (CGMD) framework to analyze the LER variation for the line / space patterns formed by symmetric polystyrene-block-polymethyl methacrylate (PS-b-PMMA). Three types of substrate models have been considered to direct the BCP. 1) Flat patterned substrate 2) Wedged patterned substrate and 3) Wedged substrate with a random PS-b-PMMA polymeric brush. For the first type of substrate, the enthalpic contribution of the chemoepitaxial substrate is the driving force to form the lamellae. The wedged patterned has an entropic contribution from the topography of the substrate in addition to the patterning. The third type of substrate employs random PS-b-PMMA co-polymer brushes to mimic the neutral layer of the chemoepitaxial substrate. The BCP morphology formed by each type of the substrate has been optimized by varying the polymer and surface properties as well as the annealing conditions. The morphology obtained from large scale CGMD simulations is further processed by etching the PMMA domains resulting in the line / space patterns. Line edge roughness analysis is then performed to quantify the high and low frequency noise of the features by plotting the power spectrum density curves. We demonstrate that the correlation factors from fitting the power spectrum gives values comparable to experiments by accounting for instrumentation / measurement noise. Lastly, the effect of additives for reduction in LER and defect annihilation is also presented.