Study of Demolding Characteristics in Step-and-Repeat Ultraviolet Nanoimprinting

Abstract

Ultraviolet (UV) nanoimprinting includes a contact process necessary for transferring nanoscale features from a mold to a UV-curable resist coated on a substrate. The demolding that comes with the contact process is a source of defects, and an obstacle to be overcome for nanodevice fabrications. In this study, we aim to execute more than 10000 times of step-and-repeat UV nanoimprinting with a single mold, tracing demolding forces and water contact angles of the mold surface as the indication of mold-resist/substrate interface and mold degradation. A condensable gas, a UV-curable resist, and a fluorosurfactant were considered in this study. It was revealed that 1,1,1,3,3-pentafluoropropane (PFP) or HFC-245fa, which is the common industrial name, as a condensable gas and a type of fluorosurfactant played an important role in minimizing the demolding impact and thus helped in increasing mold lifetime. The surfactant-added resists performed 6500 imprinting steps in PFP.

Effect of Fluorosurfactant contained in Resin for Anti-sticking Layer Free UV Nanoimprinting

“…The fluorosurfactants in the resin segregate to the resin surface and induce the release property. So far, we confirmed that the deterioration rate of ASL delayed by step and repeat UV nanoimprinting using UV nanoimprint resin added with fluorosurfactant [11]. This result indicates that the fluorosurfactant in UV nanoimprint resin operates to prevent the ASL deterioration.…”

The Photopolymer Science and Technology Award

“…The results suggest over 2000 demolding cycles can be performed without fatal defects or damage. Using synthetic UV resin, the 22-nm convex resist lines had a best value of LER(3σ) = 1.2 nm and the best value of LWR(3σ) = 1.8 nm, and over 20,000 repeated imprints were achieved with a single mold [10,11]. Furthermore, a fluorescent UV-curable resin is proposed for the in-situ observation of imprinted patterns after demolding, allowing the quantitative evaluation of performance [12].…”

Breakthrough Achievement In Nanoimprint Lithography Using PFP Condensable Gas

“…We aimed to execute more than 10,000 steps of UV nanoimprinting without significant imprint defects with a single mold. In this study, we focused on the condensable gas PFP, and a fluorosurfactant as an inner release agent [52,53]. As a means to improve the durability of the antisticking layer in the mold surface, a fluorosurfactant was tested.…”