Siliconized silsesquioxane-based nonstick molds for ultrahigh-resolution lithography

A material approach to fabricating high-performance nonstick molds for manufacturing ultrahigh-resolution features (<8 nm) is presented. Low-viscosity liquid blends (4-121 cP) consisting of siliconized silsesquioxane acrylate (Si-SSQA) with low surface energy and difunctional acrylics were used as nonstick replica-mold materials. The cured Si-SSQA-acrylic networks showed a high UV transparency (>92% at 365 nm), high modulus and wide-range modulus tunability (0.757-4.192 GPa), high resistance to organic solvents (<1.2 wt%), low shrinkage (<3%), and high water contact angle (91-103 degrees). The Si-SSQA-acrylic blends with a nonstick property were easily transferred to high-resolution replica molds with sub-25 nm features, a pitch of 25 nm and a height of 100 nm, even if the release agent was not modified onto the master. In addition, nonstick replica molds with a low concentration of uncross-linked (meth) acrylate showed the ability to duplicate ultrasmall nanostructures with a sub-8 nm parallel line, a pitch of 17 nm and a height of 6-7 nm. Furthermore, the Si-SSQA-based replica mold prevented the formation of bubble defects during imprinting owing to sufficient gas permeability.