Defect annihilation in block copolymer nanopatterning through solvent immersion annealing

Area of Science:

• Materials Science
• Polymer Science
• Nanotechnology

Background:

• Directed self-assembly (DSA) of block copolymers (BCPs) is key for nanoscale pattern fabrication.
• Defects and processing control limit practical BCP applications.

Purpose of the Study:

• Introduce solvent immersion annealing (SIA) to improve BCP thin film alignment and reduce defects.
• Investigate SIA's effectiveness compared to solvent vapor annealing (SVA).

Main Methods:

• Applied SIA to shear-aligned polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) thin films using solvent mixtures.
• Analyzed immersion time, solvent composition, and swelling effects.
• Utilized scanning electron microscopy (SEM) and grazing-incidence small-angle X-ray scattering (GISAXS).

Main Results:

• SIA rapidly reduced defects and improved long-range ordering in BCP films within minutes.
• Optimal SIA balanced chain rearrangement and film stability.
• SIA demonstrated superior swelling control and lower sensitivity to humidity than SVA.
• Large-area SEM and GISAXS confirmed scalable fabrication of well-aligned nanopatterns.

Conclusions:

• SIA is a robust and efficient method for fabricating BCP nanopatterns with reduced defect density.
• SIA offers significant potential for advancing lithography applications.
• This technique provides enhanced control over BCP self-assembly processes.