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This study developed a stitching process for unit element nanotemplates based on step and repeat imprinting for use in enlarged soft mold fabrication. This mold was subsequently used for the custom-developed roll-to-plate UV nanoimprint process. The distinctive features of roll UV imprinting include the following: (1) the UV source is embedded within a roll mold made of quartz so that it can illuminate a resist coated on either a transparent or an opaque substrate, (2) the press-contact between the resist and soft mold wrapped around the quartz mold was designed to synchronize the rolling operation with the linear motion of the substrate, which helped minimize the residue thickness, and (3) a compressed pneumatic force was applied along the contact line of the roll imprint, which helped attenuate any possible level mismatch on the stitched mold surface.

In conventional nanoimprinting using acrylate-based resists, the imprinted resist acts as a sacrificial barrier for the underlayer etch. However, the imprinted patterns can be directly used for electronic device structures immediately after removal of the residual layers if electrically conductive functional resists are used. In this work, we used a UV-curable monomer, hydroxyethyl methacrylate mixed with a highly concentrated nanosilver colloid, for direct imprinting. The imprinted patterns were heat-treated to cause sintering of the nanosilver particles, and to shrink the cured polymer matrix. Then silver etchant was applied to remove the residual layer before a thorough rinsing. Pattern shrinkage was investigated at each process stage as a function of nanosilver concentration. Shrinkage depended slightly on pattern width, and had a strong correlation with Ag loading in the range of 40–60 wt %. The electrical resistivity was estimated at 40.8 nΩm, which is quite close to that of bulk silver, 15.87 nΩm.