Dynamic Modeling And Analysis Of Reticle Stage Applied In Lithography

As one of the key subsystems of the lithography, reticle stage is designed to precisionpositioning with high velocity, so it is required to have high performance of dynamiccharacteristics. But the dynamic modeling and analysis are difficult, because there are manyassemblies and complicated connections in reticle stage.Structure of reticle stage is rationally simplified and divided into substructures in thisthesis, based on multi-rigid-body discrete element method, modeling strategy of reticle stageis put forward. The multi-rigid-body discrete element models of the substructures are buildreference to finite element analysis result, and models are validated with modal experimentalresults. Dynamic parameters of air bearings are identified by fluid finite element analysismethod, and dynamic parameters of air springs are calculated with theoretical formula.Dynamic simulation model of the entire reticle stage is established in ADAMS.The inherent vibration characteristics of reticle stage are obtained by modal analysis withthe built model. In order to optimize model frequency, structure improvement approaches areproposed by parameter sensitivity analysis. Analysis on the pitching vibration of reticle stagewhen step by step moving is taken, based on the analysis results, improvement approaches oflinear motor drive mode and vibration isolation system design are proposed.The dynamic simulation model based on finite element analysis, theoretical calculationand experimental test, can show the nature dynamic characteristic of reticle stage. Throughdynamic simulation analysis, the vibration characteristics of reticle stage are obtained, and theresults could support the optimization to improve reticle stage.