(142k) Modeling of Multi-Layered Spin Coating Process

Spin coating is the most commonly used method in the industries to make single layer and multi-layered thin films of desired thickness and functionality. These thin films finds applications in device fabrication ranging from integrated chips in microelectronics industry to organic solar cells. In general, multilayer structure of thin films provides hardness, toughness and multifunctional character to the material for desired applications. In this paper, a lubrication theory is used to derive the evolution equations governing the flow of two layered film on a spinning disc. The set of two nonlinear evolution equations is solved using a numerical technique based on Galerkin Finite Element Method (G/FEM). With the help of numerical simulations, the effect of disc speed and physical properties of the liquids like ratios of viscosity, surface tension and density, on the uniformity of the film so form are studied. The ultimate goal of this research is to elucidate the interplay of liquid layers in the formation of layered films, and find the optimum parameter space for a given application.