Polymer Viscoelasticity and Residual Stress Effects on Nanoimprint Lithography
Yifu Ding, Hyun Wook Ro, Jack F. Douglas, Ronald L. Jones, Alamgir Karim, Christopher L. Soles
We examine the influence of viscoelasticity on the thermal stability of nanoscale patterns imprinted into thin polymer films. For polymers with molecular masses near or below their critical entanglement threshold, simple surface tension and viscosity arguments determine the pattern decay at elevated temperatures. By contrast, high molecular mass (entangled) polymer patterns under similar conditions first decay via a rapid and substantial elastic deformation, followed by an Andrade-like power law creep regime, and finally fluid flow at longer times. These measurements indicate that the nanoimprint process can generate significant levels of residual stress, through the viscoelastic effects of the molten polymer filling the mold, in the patterns that it fabricates. Stresses can impact the structural stability of nanoimprinted polymer structures and these nonlinear effects must be considered in the development of nanoimprinting applications.
Author Info: Yifu Ding; Mentor: Christopher L. Soles; From Polymer Division, MSEL, Rm. 223, Bldg. 224; Mail Stop: 8541; Tel: 301-975-6781, Fax: 301-975-3928; Email: firstname.lastname@example.org.
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Poster Category: Materials