Asymmetric fluid-structure dynamics in nanoscale imprint lithography

The one degree-of-freedom template orientation stage was designed toexperimentally study the imprinting forces and gap sensing tool as well as tovalidate the numerical model of the squeeze film flow of the etch barrier. Thetorsional stiffness of this stage was designed to be similar to the template stagesfrom the multi-imprint stepper. The stiffness coefficient for each of the templateorientation stage (Figure 3.3) from the stepper was approximately 55 N-m/rad.From equation B.1, the radius (R) for the notched flexure was chosen as 1.27 mm,the equivalent depth (b) was 8.9 mm, and the minimum cross-sectional thickness(t) was 1 mm. This results in a torsional stiffness of 64 N-m/rad.As of the writing of this thesis, the design of a complete templateorientation stage to provide the appropriate kinematics for the active stage testbed has not been finalized.3.2.3 High-Resolution Actuation SystemIn order to minimize undesirable grinding motion, each actuation legconsists of a revolute flexure joint (R), a motorized micrometer (P), a.k.a. DC-Mike actuators, a quartz force sensor, and a universal joint (U) connected inseries. One RPU actuation leg is shown in Figure 3.5. Each actuation leg isconnected in parallel with a distributed flexure ring to the active stage basestructure. Three actuation legs form a tripod for an RPU stage, where the threeattachment locations on the distributed flexure ring specify the orientation plane.Each component of the actuation system must be stiff in the lateral directions.46