Chemically tailored block copolymers for highly reliable sub-10-nm patterns by directed self-assembly

Area of Science:

• Materials Science
• Nanotechnology
• Polymer Chemistry

Background:

• Block copolymer (BCP) lithography offers theoretical potential for sub-10-nm feature fabrication.
• Practical challenges exist in developing suitable BCPs for reliable nanoscale pattern generation.

Purpose of the Study:

• To create a chemically modified BCP for directed self-assembly.
• To achieve highly reliable sub-10-nm line patterns with precise control over domain size and orientation.

Main Methods:

• Synthesized a novel block copolymer: polystyrene-block-[poly(glycidyl methacrylate)-random-poly(methyl methacrylate)] (PS-b-PGM).
• Post-functionalized the BCP with 2,2,2-trifluoroethanethiol to enhance Flory-Huggins interaction parameters (χ).
• Utilized directed self-assembly to form well-defined nanostructures.

Main Results:

• Achieved significantly higher Flory-Huggins interaction parameters (3.5-4.6 times that of PS-b-PMMA).
• Produced well-defined structures with domain spacings below 20 nm, including the smallest reported perpendicular lamellar domain size of 12.3 nm.
• Demonstrated reliable and reproducible thin-film lamellar domain alignment and vertical orientation, yielding 7.6 nm half-pitch line patterns.

Conclusions:

• The developed chemically tailored BCPs are practical for directed self-assembly.
• This method reliably produces sub-10-nm line patterns, advancing nanoscale fabrication capabilities.