Spin coating over topography

A model for predicting film thickness profiles around topographical features during spin coating is presented. This model is applicable to features of arbitrary geometry in the two lateral dimensions. This generally permits study of the planarization of real device structures, including both isolated and neighboring features, with any orientation with respect to the wafer center. Predictions from this model agree qualitatively with measured thin-film profiles from interferograms taken during spinning. Phenomena such as pile-up and wakes result from interactions between surface tension and other driving forces in the flow.<
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