Analysis And Simulation Of Flow Field For Lithograph Immersion

In immersion lithography, the refractive index greater than1of liquid isfilled between the lens and wafer to obtain a large numerical aperture，whichleads to a higher resolution. Since the immersion liquid becomes a part of theimmersion system, any case that affects the optical properties of liquid must bestudied to ensure that the immersion liquid in the exposure process has opticalproperties of highly homogeneous and stable. The dissertation dwells onimmersion flow field to study the effect of immersion system structureparameters, silicon pulled unsteadily and local heat on immersion flow filed. Themain research contents and results are outlined as follows:A mathematical model of immersion flow field was established to deriveflow rate and velocity field. Here, theoretical results of mathematical modelingand numerical simulation results were compared to verify the accuracy of thetheoretical results. Study the effect of three immersion system structuralparameters on the steady flow of immersion fluid. Ultimately, obtain the bestimmersion unit structure parameters of steady flow.Dwell on step-scan exposure system which is used in the mainstreamlithography machine widely, exact distribution of velocity in the flow field undersilicon pulled unsteadily was carried out. Theoretical and numerical simulationsolution was compared to verify the correctness of result. Study the effect ofsilicon unsteady motion on immersion field flow by theoretical findings. Athree-dimensional flow field model of step-scan system was established toanalyze effect of step velocity on immersion field flow.A numerical simulation of local photo-thermal effect in single chip exposureprocess was constructed here to research on the temperature variation andthickness of heating layer when the wafer was still, pulled steadily, pulledunsteadily. The influence of temperature distribution in exposure area underwafer movement was obtained. Study the combined effect of applied pressureand motion of wafer on temperature distribution of exposure area and thicknessof the heating layer.