Polymer Viscoelasticity and Residual Stress Effects on Nanoimprint Lithography


  • Official contribution of the National Institute of Standards and Technology (NIST); not subject to copyright in the United States. The error bars presented throughout this manuscript indicate the relative standard uncertainty of the measurement. Certain commercial materials and equipment are identified in order to specify adequately the experimental procedure. In no case does such identification imply recommendation by the National Institute of Standards and Technology nor does it imply that the material or equipment identified is necessarily the best available for this purpose. This work is partially funded by the NIST Office of Microelectronic Programs. Use of the Advanced Photon Source was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. W-31–109-ENG-38. Supporting Information is available online at Wiley InterScience or from the author.


original image

The decay kinetics of polystyrene (PS) gratings are monitored by tracking the intensity of the first-order laser diffraction peak as a function of annealing time. For low-molecular-mass PS (24 kg mol–1, blue circles), an exponential response suggests that the pattern decay is a surface-tension- driven viscous flow. In high-molecular-mass PS (1007 kg mol–1, green circles) a complicated response includes a rapid elastic recovery, a power-law creep, and a viscouslike flow (see figure).