Prediction of film thickness of Bottom Anti-reflective Coating based on in-line viscosity measurement

Tighter fim thickness control is required as the linewidth of semiconductor devices gets smaller. Viscosity is one of the most important parameters to determine film thickness during spin coating. In this paper, we show strong and repeatable correlation between viscosity and film thickness for a Bottom Anti-reflective Coating (BARC) material. Based on results of this work, we have developed a mathematical model, which allows Process Engineers to predict film thicknes by measuring the viscosity of the material. It is now possible to automatically target a desired film thickness of BARC onto the wafer by targeting BARC viscosity during manufacturing.