Tunable daughter molds from a single Si master grating mold.

After the cost of ownership of tool, the next significant cost involved in nanoimprint lithography is that of mold fabrication. The cost of mold fabrication is proportional to the area of pattern and follows an inverse relationship with the pattern resolution. In this work, the authors demonstrate proof-of-concept fabrication of Si and SiO₂ grating molds of variable feature sizes, spacings, densities, and aspect ratios that can be generated from a single Si master mold of ₂μm line and space features. This process utilizes "SiO₂ resin," which can be imprinted via in situ thermal free radical polymerization. Heat-treatment of the patterned resin resulted in loss of organics, formation of SiO_x and gave rise to known feature size reduction (~65%). After the pattern transfer using SiO_x as the etch mask, a Si daughter mold containing 0.7μm wide gratings with 3.3μm spacing was generated. The process of imprinting and heat-treatment was repeated using the daughter mold, which regenerated a mold that approximates the master mold feature profile. Our technique demonstrates that submicron-sized features can be achieved from Si molds containing micron-sized features and vice versa. Such flexibility may lead to substantial reduction in the cost of mold fabrication. [ABSTRACT FROM AUTHOR]