Thermodynamic and Kinetic Tuning of Block Copolymer Based on Random Copolymerization for High‐Quality Sub‐6 nm Pattern Formation

Abstract

The precisely controllable self-assembly phenomenon of block copolymers (BCPs) has garnered much attention because it yields well-defined periodic nanostructures with a periodicity of 5-50 nm. However, from both thermodynamic and kinetic viewpoints, it still remains a challenge to develop a BCP material that can provide sub-10 nm resolution, high pattern quality, fast pattern formation, and sufficient etch selectivity. To address these challenges, this study reports a BCP system containing a random-copolymerized block (poly(2-vinylpyridine-co-4-vinylpyridne)-bpoly(dimethylsiloxane) (P(2VP-co-4VP)-b-PDMS)) that can provide sub-6 nm resolution, 3σ line edge roughness of 0.89 nm, sub-1-min assembly time, and a high etch selectivity over 10. Calculation of the Flory-Huggins interaction parameter (χ) based on Leibler's mean-field theory and smallangle X-ray scattering measurement data confirms the gradual tunability of χ with the controlled addition of 4VP fraction in the P(2VP-co-4VP) block. While guaranteeing kinetically fast self-assembly within one minute using microwave annealing, the best pattern quality resulting from the thermodynamic suppression of line edge fluctuation is achieved with a 4VP weight fraction of 33% in the random-copolymerized block. This approach enables systematical control of sub-6 nm scale BCP self-assembly and will provide a practical patterning solution for diverse nanostructures and devices.

Shear-solvo defect annihilation of diblock copolymer thin films over a large area

“…Directed self-assembly (DSA) including graphoepitaxy ( 6 , 7 ), surface chemical patterning ( 8 , 9 ), and laser-assisted patterning ( 10 , 11 ) have achieved significant milestones in enhancing the controllability of structural orientation and ordering of the nanoscale structures of BCPs. On the basis of the processing perspective, however, DSA typically requires multistep approaches in locating and aligning nanopatterns followed by long-range orders, which are particularly expensive.…”

Fabrication of High χ-Low N Block Copolymers with Thermally Stable Sub-5 nm Microdomains Using Polyzwitterion as a Constituent Block

“…The central point to design high χ-low N BCPs is to find two polymers with quite different physical and chemical properties like surface energy, hydrophily hydrophobicity, and so on. Based on this principle, polymers containing fluorine, − silicon, − hydroxyl or amino groups, ,− carbonate groups, and crystalline/liquid crystalline structures − are frequently used as the constituent block of high χ-low N BCPs. However, above-mentioned polymers usually involve complicated monomer synthesis or polymerization.…”

Nucleobase-Containing Block Copolymers Having a High Interaction Parameter by Complementary Hydrogen Bonding

“…26,30,31 For example, χ between polydimethylsiloxane and poly[(2-vinylpyridine)-r-(4-vinylpyridne)] [P(2VPr-4VP)] blocks is in the middle of χ PS-b-P2VP and χ PS-b-P4VP . 31 Also, χ between PS and poly(isoprene-r-difluorocarbene modified isoprene) (PI-r-FPI) blocks is in the middle of χ PS-b-PI and χ PS-b-FPI . 26 The temperature dependence of χ(T) of all samples was well fitted by χ(T) = α + β/T, as shown in Figure 1f.…”