title: Real-time shape evolution of nanoimprinted polymer structures during thermal annealing.
abstract: The real-time shape evolution of nanoimprinted polymer patterns is measured as a function of annealing time and temperature using critical dimension small-angle X-ray scattering (CD-SAXS). Periodicity, line width, line height, and sidewall angle are reported with nanometer resolution for parallel line/space patterns in poly(methyl methacrylate) (PMMA) both below and above the bulk glass transition temperature (T(G)). Heating these patterns below T(G) does not produce significant thermal expansion, at least to within the resolution of the measurement. However, above T(G) the fast rate of loss in pattern size at early times transitions to a reduced rate in longer time regimes. The time-dependent rate of polymer flow from the pattern into the underlying layer, termed pattern "melting", is consistent with a model of elastic recovery from stresses induced by the molding process.
authors.affiliation: Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA. ronald.jones@nist.gov
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Jones
authors.forename: Tengjiao
authors.initials: T
authors.lastname: Hu
authors.forename: Christopher L
authors.initials: CL
authors.lastname: Soles
authors.forename: Eric K
authors.initials: EK
authors.lastname: Lin
authors.forename: Ronald M
authors.initials: RM
authors.lastname: Reano
authors.forename: Stella W
authors.initials: SW
authors.lastname: Pang
authors.forename: Diego M
authors.initials: DM
authors.lastname: Casa
mesh_terms: D003198:Computer Simulation; D003199:Computer Systems; D003460:Crystallization / Q000379:methods*; D006244:Hardness; D006358:Hot Temperature; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D044367:Phase Transition; D019904:Polymethyl Methacrylate / Q000032:analysis / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D019904:Polymethyl Methacrylate