Global planarization of spun‐on thin films by reflow

The leveling of a thin‐liquid film on a substrate having a mesa‐like feature is analyzed by finite element analysis and lubrication theory applied to the free‐surface viscous flow problem. The height of the mesa is on the order of 1 μm and has a width on the order of 100 μm; the thin‐liquid film is initially conformal to the substrate and has a thickness on the order of 1 μm. Capillarity is found to be the primary driving force for flow. The predicted leveling times from the numerical simulations compare favorably with an analytical solution developed from lubrication theory for the leveling of a thin film on a smooth substrate.