The Structural Dyanmic Modeling And Simulation Of The Lithography

The lithography is one of electromechanical integration equipment with the highest precision and the most advanced technology in the Integrated Circuit manufacture field. The mechanical system of the lithography is a typical and complicated multi-body system, which consists of the base frame, the mainplate, the reticle stage, the wafer stage, the lens, the illumination, the alignment system and so on, with the couple of gas-bearings, magnetic and the couplings. With many assemblies and complicated connections, the dynamic characteristic is very important for the improvement of the lithography precision. It is a challenge to set up the structural dynamic model for the complicated mechanical system of the lithography.In this thesis, based on a rational simplification of the lithography's complicated structure, the dynamic mathematic models of wafer stage system and linear motor system are set up with the Lagrange Method, in which exist many coupling phenomenon. On the basis of the analysis of the subsystem's dynamic behaviors, the multi rigid-body and parametric dynamic simulation model with 135 DOFs is founded for the entire lithography structure with the virtual prototype software ADAMS. The identification of the dynamic parameters is the key to the dynamic model. The dynamic parameters of the key subsystems such as the air-bearings system are identified and calculated depending on the vibration test and the dynamic simulation. According to these parameters, the multi rigid-body dynamic model is modified to establish a more accurate simulation model. Based on the simulation model, the inherent vibration characteristic of the lithography is analyzed detailedly and the distribution of the natural frequencies of the lithography system is obtained. To check the dynamic simulation model, the vibration tests with the hammer impact on lithography key assemblies are carried out in the entire lithography system. The deviation between the natural frequencies gained from the test data and from the simulation results is reasonable and the simulation model is accepted.In the thesis, based on the test and analysis, the multi rigid-body simulation model is set up for the lithography system. The simulation model can gain dynamic characteristic. These research results will provide theoretical guidelines for structural design & betterment and control strategy, as well as great references for improving the precision for the lithography.