Analysis of the Liquid Mediated Friction during Alignment in NIL Process
S-H Kang, S-H Park, W-I Lee
Seoul national university, KR
Keywords: nano-imprint lithography, alignment, liquid-mediated adhesion, stiction, meniscus force, surface tension
Abstract:When Nano-Imprint Lithography (NIL) process is adopted in the large area applications like display, the stiction phenomenon which is the adhesion or in-plane friction between mold and substrate to disturb fine alignment process can be occurred. In this study, we analyzed this liquid-mediated stiction caused by a thin liquid layer between two parallel plates on the basis of Nano-Tribological approach, and investigated factors affecting the resisting force during alignment process in large area NIL applications. We examined the in-plane friction force variation by changing the geometric parameters (wetting area / gap height) and contact angle. It is found that the meniscus force induced from surface tension is the most critical parameter to affect stiction force. And, it was found that the sliding friction force could be remarkably reduced by changing the upper mold surface into a hydrophobic condition. This article presents the mathematical model for align-stiction problem in large area imprinting process, the parametric study of the various geometric and surface conditions, and a predictive tool for understanding and optimizing process conditions in alignment procedure of the large area imprinting application.