(552d) Computational Simulation of Different Topography Substrates Effects on Critical Dimension and Line Space Variation in Block Copolymer Directed Self-Assembly

Directed self-assembly (DSA) of block copolymer (BCP) is a promising and economic method of manufacturing periodic lamellar patterns on wafer that is widely used in semi-conductor and electronic fields. At such a small length scale that below 20 nm, same as defective free and smooth edges, an evenly distributed width line space pattern is also critical for the following usage in producing next generation microelectronic devices but in lack of relative research. A coarse grained molecular dynamic (CGMD) simulation on polystyrene-b-poly (methyl methacrylate) (PS-b-PMMA) block copolymer DSA process using chemoepitaxial method was carried out through modifying some parameters that are difficult to control accurately in experiments to fill this blank. The template topography has been proved to have large influence on BCP lamellae formation, it should be used to optimize the acquired structure instead of being eliminated. By changing substrate properties including 1) gap between raised level pinned area and unpinned area, 2) pinned width, 3) inclined wall distance and 4) interaction strength, their effects on produced lamellae critical dimension (CD), line space variation and roughness were investigated and an optimized template design direction was found. A pinned width close to PS L₀ (15 nm) is preferred; the gap between raised level of pinned area and unpinned area has an optimized value around 3 to 4 nm; the interaction strength should be kept at a small value. The templates which have the pinned area edge been covered by the neutral brushes also shows great properties in terms of CD variation, if the available pinned width does not go too low, the system will have a low CD variation and can also avoid PS domains’ tapering effect. On top of that, the PS/PMMA ratio was found critical for line space variation, the mass ratio of 0.925:1 performs the best currently. Based on the analysis of effect, some suggestions on substrate properties are given.