Asymptotic analysis of the formation of thin liquid film in spin coating

Abstract

Unsteady thin liquid film flow of non-uniform thickness on a rotating disk is analyzed by asymptotic methods. Short- and long-time-scale solutions for the transient film profile near the rotating axis are independently derived as a function of space and time. Analyses were performed for a case in which the initial film thickness is even in radial distance and the peripheral effects of the liquid film are assumed to be negligible. The result reveals the effects of the gravitational and surface tension forces, coupled with inertial force, on the film planarization and thinning process.