Large Area Directed Self-Assembly of Sub-10 nm Particles with Single Particle Positioning Resolution

Directed self-assembly of nanoparticles (DSA-n) holds great potential for device miniaturization in providing patterning resolution and throughput that exceed existing lithographic capabilities. Although nanoparticles excel at assembling into regular close-packed arrays, actual devices on the other hand are often laid out in sparse and complex configurations. Hence, the deterministic positioning of single or few particles at specific positions with low defect density is imperative. Here, we report an approach of DSA-n that satisfies these requirements with less than 1% defect density over micrometer-scale areas and at technologically relevant sub-10 nm dimensions. This technique involves a simple and robust process where a solvent film containing sub-10 nm gold nanoparticles climbs against gravity to coat a prepatterned template. Particles are placed individually into nanoscale cavities, or between nanoposts arranged in varying degrees of geometric complexity. Brownian dynamics simulations suggest a mechanism in which the particles are pushed into the template by a nanomeniscus at the drying front. This process enables particle-based self-assembly to access the sub-10 nm dimension, and for device fabrication to benefit from the wealth of chemically synthesized nanoparticles with unique material properties.