Computational analysis of hole placement errors for directed self-assembly

摘要

We report computational study for directed self-assembly (DSA) on morphologies' dislocation caused by block co-polymers' (BCPs') thermal fluctuation in grapho-epitaxial cylindrical guides. The dislocation factor expressed as DSA-oriented placement errors (DSA-PEs) was numerically evaluated by historical data acquisition utilizing dissipative particle dynamics simulation. Calculated DSA-PEs was compared with experimental results on two kinds of guide pattern, resist guide with no surface modifications (REF guide) and resist guide with polystyrene coated (PS-brush guide). Vertical distribution of DSA-PEs within the cylindrical guides was calculated and relatively high DSA-PEs near top region was deduced particularly in REF guide. The tendency of experimental DSA-PEs was well explained by the calculation including a fluctuation parameter on the wall particles. In PS-brush guide, calculated DSA-PEs was drastically increased with becoming the guide more fluctuating. This result indicates to fabricate hard and steady guide condition in PS-brush guide so as to achieve better placements. From the variety of guide critical dimension (CD) computation, it is suggested that smaller guide CD is better to obtain good placements. The smallest DSA-PE value in this study was observed in PS-brush guide with smaller guide CD because of the strong restriction of BCP arrangement flexibility.