Effect of thickness of surface silicon oxide on liquid advancement in nanogaps between synthetic quartz mold and silicon substrate surfaces in UV nanoimprinting

Abstract

To understand the phenomenon in which shear stress increases in nanogaps between the mold and substrate surfaces during alignment in UV nanoimprinting, we investigate the liquid advancement of UV-curable droplets on modified silicon surfaces. The droplets are pressed with a flat modified surface of a synthetic quartz mold, and the transformed droplets are cured individually. Subsequently, the mold is detached and the shapes of the transformed droplets are observed. Scanning electron microscopy is performed to determine whether the transformed shapes are affected by the pressing force and holding time under a fixed applied force. The areas on which the droplets spread on the modified silicon substrates are almost independent of the pressing force and holding time, whereas the thickness of the surface silicon oxide layer affects the liquid advancement of the UV-curable droplets sandwiched between the modified mold and substrate surfaces in the nanogaps.