Fabrication of Sub-3 nm Feature Size Based on Block Copolymer Self-Assembly for Next-Generation Nanolithography

Abstract

For Ultrahigh-density storage media and D-RAM, the feature size of lithography should be much reduced (say less than 10 nm): Though some-research groups reported feature site of 5-6 rim, further reduced feature size is needed. for next generation lithography. We synthesized, via a reversible addition-fragmentation chain-transfer polymerization, polydihydroxystyrene-block-polystyrene (PDHS-b-PS) copolymers showing lamellar and cylindrical microdomains by adjusting the volume fraction of PS block-Ups). We found that the Flory-Huggins interaction parameter (chi) between PDHS and PS was very large, 0.7 at 170 degrees C. Because of-the hugex chi, the lamellar domain spacing (L) of PDHS-b-PS with a total molecular weight of 2.1 kg mol(-1) and f(PS) = 0.5 was only 5.9, nm thus, a sub-3 nm feature size (half-pitch) was successfully obtained, Furthermore, PDHS-b-PS with a molecular weight of 4.2 kg mol(-1) and f(PS) = 0.79 showed hexagonally packed cylinders with 4 nm diameter. We also obtained thin films of PDHS-b-PS with cylindrical microdomains, showing 8.8 nm center-to-center spacing, Furthermore, we fabricated ultrahigh-density ZrO2 nanowire arrays from the cylindrical monolayer thin films via atomic layer deposition, indicating an applicability of PDHS-b-PS for next-generation lithography.