Asymmetric fluid-structure dynamics in nanoscale imprint lithography

1.4 THESISFor SFIL to become a practical technology, real-time control strategiesmust be developed to in order to generate thin, parallel base layers. To betterunderstand the requirements for the specifications of an active stage systemcapable of delivering thin, parallel base layers, the fluid film interaction with thetemplate and wafer has been investigated for this thesis. A squeeze film modelof the fluid film was used to develop the analytical equations for the fluidpressure, which are a function of the template geometry, orientation, andvelocities. For a given template geometry, the pressure is then a function oforientation and velocity.p = p( x,h,θ , hD, θD) . [1.2]The solution for the pressure was obtained from the Reynolds equation,which is the fundamental equation in fluid film lubrication theory. The pressurewas then integrated over the spatial domain to obtain analytical solutions for thedamping force and torque generated by the fluid. Then, a numerical simulation ofthe equations of motion for the template assembly was performed to characterizethe dynamics of the mechanical system and its interaction with the etch barrierlayer. Finally, an experiment was designed to scientifically quantify the squeezefilm dynamics of the etch barrier layer. An improved understanding of thesqueeze film mechanics is derived from the combined efforts of theoretical,numerical, and experimental analysis.The remainder of this thesis has been organized into six chapters. Chapter2 reviews the theoretical background on modeling the squeeze film effects of theetch barrier layer. The model assumptions are explained and a derivation for theReynolds equations is given. Boundary conditions for specific geometries wereapplied to obtain appropriate analytical solutions. Chapter 3 discusses the active15