title: Effect of surface tension and coefficient of thermal expansion in 30 nm scale nanoimprinting with two flexible polymer molds.
abstract: We report on nanoimprinting of polymer thin films at 30 nm scale resolution using two types of ultraviolet (UV)-curable, flexible polymer molds: perfluoropolyether (PFPE) and polyurethane acrylate (PUA). It was found that the quality of nanopatterning at the 30 nm scale is largely determined by the combined effects of surface tension and the coefficient of thermal expansion of the polymer mold. In particular, the polar component of surface tension may play a critical role in clean release of the mold, as evidenced by much reduced delamination or broken structures for the less polarized PFPE mold when patterning a relatively hydrophilic PMMA film. In contrast, such problems were not notably observed with a relatively hydrophobic PS film for both polymer molds. In addition, the demolding characteristic was also influenced by the coefficient of thermal expansion so that no delamination or uniformity problems were observed when patterning a UV-curable polymer film at room temperature. These results suggest that a proper polymeric mold material needs to be chosen for patterning polymer films under different surface properties and processing conditions, providing insights into how a clean demolding characteristic can be obtained at 30 nm scale nanopatterning.
authors.affiliation: School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, Korea.
authors.forename: Jae Kwan
authors.initials: JK
authors.lastname: Kim
authors.forename: Hye Sung
authors.initials: HS
authors.lastname: Cho
authors.forename: Ho-Sup
authors.initials: HS
authors.lastname: Jung
authors.forename: Kipil
authors.initials: K
authors.lastname: Lim
authors.forename: Ki-Bum
authors.initials: KB
authors.lastname: Kim
authors.forename: Dae-Geun
authors.initials: DG
authors.lastname: Choi
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: Jeong
authors.forename: Kahp-Yang
authors.initials: KY
authors.lastname: Suh
mesh_terms: D003460:Crystallization / Q000379:methods*; D055119:Elastic Modulus; D006358:Hot Temperature; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D054802:Molecular Imprinting / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D013499:Surface Properties; D013500:Surface Tension; D013814:Thermal Conductivity
chemical_list: D046911:Macromolecular Substances; D011108:Polymers