Nonstick, modulus-tunable and gas-permeable replicas for mold-based, high-resolution nanolithography

Abstract

A fundamental approach to fabricating a nonstick replica mold with high performance for the manufacturing of high-resolution nanostructures using mold-based lithography is presented. Low-viscosity liquid blends consisting of methacrylate multi-functionalized silsesquioxane (SSQMA), difunctional acrylics, and a small amount of silicone diacrylate (Si-DA) with low surface tension were used as nonstick replica-mold materials. The cured SSQMA/acrylic/Si-DA networks showed a high resistance to organic solvents (<1.2 wt.%), high UV transparency (>90% at 365 nm), hydrophobicity (water contact angle >90°), high modulus and wide-range modulus tunability (0.6-4.42 GPa) and small shrinkage (<3% in height). The mold materials with a nonstick property conferred by Si-DA possessed the ability to form sub-25-nm features with a high line-to-space ratio (1:1) and a high aspect ratio (4:1). In addition, a sufficiently cured replica mold with a low concentration of residual, uncross-linked (meth)acrylates was able to successfully replicate sub-25-nm features with a high line-to-space ratio (1:1) and a high aspect ratio (4:1), even if the release agent was not modified. Furthermore, replica molds can potentially be used to fabricate patterns free of bubble defects because of sufficient gas permeability.