Asymmetric fluid-structure dynamics in nanoscale imprint lithography

Figure 6.6 shows that the force due to the squeeze film pressure follow thesame trend for the simulation and the experiments. The maximum force in theexperimental data was 1.75 lbs. The maximum force in the simulation was 1.35lbs. The relative difference between the two results is 23%, which is quitesignificant. This discrepancy could be due to several possibilities.First, compliance estimates for the mechanical system contribute todifference in the actual and expected forces. In the actual setup, there are certaincompliances that are not modeled, for example, the substrate is modeled as rigid,however, the chuck, which holds the chromium substrate has compliance.Second, there existed some topography due to macroscopic scratches on thechromium substrate. Since chromium is a fairly soft material, maintaining aclean, flat surface was extremely difficult. The third cause relates to the previousin that there were particles observed on the substrate and template surfaces underthe magnification of a microscope. These particles could not be eliminated due tohandling of these components. The combined effects of all these factors are notfully understood and more research is needed in this area.4000380036003400film thickness, nm32003000280026002400220020000 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1time, sFigure 6.7 Average film thicknesses from simulation results (solid line) andexperimental results (circles). Correlation set.88