Manipulating self-assembled thin film hierarchical patterns through in-film polymerization

NU 2017-185

INVENTORS

Muzhou (Mitchell) Wang*

Zhe Qiang

SHORT DESCRIPTION

This technology illustrates a new way to create multiple different block copolymer patterns on a surface through a three-step process.

BACKGROUND

The bottom-up patterning of polymers, particularly through directed self-assembly of block copolymers (BCPs), has garnered attention for its cost-effectiveness and spontaneous nanoscale order. Directed self-assembly is recognized as a next-generation lithographic technique, offering uniform generation of well-defined nanodomains across large areas. However, applications such as electronic circuits and magnetic storage media necessitate versatile patterns with distinct features in different regions on a single substrate. Existing methods for generating hierarchical BCP nanopatterns involve patterned substrates, kinetic trapping, control of interfacial surface energy, or adjustment of interaction parameters. Nevertheless, these approaches are limited in altering only the orientation or ordering degree of nanodomains, as the underlying BCP chemistry dictates the morphology of each region. The need for true on-demand synthesis integrated with self-assembly arises to achieve precise hierarchical control over morphology, functionality, and properties in polymer films.

ABSTRACT

Northwestern researchers have introduced a groundbreaking three-step process enabling spatial modification of BCP patterns on surfaces, facilitating iterative film patterning modifications and hierarchical patterning of different areas. The incorporation of monomers and light into pre-formed BCP patterns adds a dynamic element, allowing the creation of hierarchical structures across a surface. Through careful deposition and the introduction of monomer vapor, specific pattern formations are induced, and localized light exposure triggers polymer formation, leading to swelling in the associated block. This precise and controlled local modification in the pattern allows for the creation of a hierarchical pattern, enhancing the versatility of BCP patterning. The in-film polymerization method demonstrated integrates photoinitiated polymer synthesis with simultaneous BCP self-assembly via solvent vapor annealing processes, providing a new route for on-demand nanopattern manipulation, and enabling hierarchical control over morphology and functionality through local irradiation of films.

APPLICATIONS

• Semiconductors and lithography
• Optical coatings
• Mesoporous materials

ADVANTAGES

• Largely compatible with existing equipment
• Fewer steps (three vs. many steps for competing technologies)
• Generalizable to most polymer systems
• Sequential application possible to create very complex patterns

PUBLICATION

Qiang Z, Akolawala S. and Wang M, 2018. Simultaneous in-film polymer synthesis and self-assembly for hierarchical nanopatterns. ACS Macro Letters, 7(5), pp.566-571.

IP STATUS

US Utility Patent Application Issued;  PCT Application Issued

Block copolymer (BCP) synthesis process on films and subsequent self-assembly into nanopatterns