Development of a new simulation model of spin coating process and its application to optimize the 450 mm wafer coating process

A new one-dimensional simulation model to predict the surface coverage and average thickness of coating films obtained from spin coating processes is developed adopting moving mesh technique. The effects of initial profile, dispensed volume, solvent vapor pressure, relative humidity and initial viscosity on the coating film geometry are investigated numerically. The initially dispensed volume, solvent vapor pressure, initial viscosity and wafer rotation speed are found to be effective parameters to control the surface coverage and average film thickness. The relations between spin coating process parameters and the film geometry parameters, surface coverage and average film thickness, are derived from the new model. It is found that the photoresist solution consumption per a given size of chips could be reduced by optimizing the operation parameters.