Asymmetric fluid-structure dynamics in nanoscale imprint lithography

Chapter 7: Closing Remarks7.1 SUMMARY OF RESEARCHThis research has encompassed a broad range of areas including analyticalmodeling, numerical simulations, and experimental analysis. It has alsoincorporated a medley of software/hardware issues and spectral analysis. Byinterpreting the analytical models, numerical simulations, and experimentalresults, it has been shown that the Reynolds equations for squeeze film dampingis a valid and useful tool for understanding the dynamics of the mechanicalsystems in SFIL.The fluid pressure plays a significant role to orient the passively compliantstages used in the multi-imprint stepper and the single imprint machines. It hasbeen shown that the pressure tends to correct the angular misalignments bygenerating a damping torque and the pressure asymmetry cannot be ignored.Thus, the original intent of the passive stage designs has been proven to work.The passive stages self-correct due to the coupling between the mechanicalsystem and the liquid etch barrier. Although presence of the etch barrier aides incorrecting the misalignment, it also limits the rate at which imprinting can bedone since, thinner base layers require more time to achieve. However, with anappropriate control scheme, based on a two s-curve motion profile, this problemcan be solved. Furthermore, the theoretical and measured forces can be achievedby the actuation systems currently implemented.An additional contribution of this research work has been the applicationof a real-time gap-sensing tool in measuring the film thickness of the fluid duringthe squeezing process. In developing an active stage system to perform SFIL, this99