초록 |
Immersion lithography has the potential to extend 193nm exposure systems to 45nm line widths. However, undesirable effects on photoresist patterning are occurred when small water droplets are left on the photoresist. In this study, to advance the fundamental understanding in formation process of stains from evaporating of water droplets on the surface of photoresist, the evaporation process and microfluid flows in evaporating water droplets on polymer surfaces are characterized. There were three distinct stages in evaporation process independent of both the initial quantity of water droplets and the hydrophobic properties of polymer surfaces. Inside the evaporating water droplets, the directions of microfluid flows are changed depends on the evaporation stages. The contaminants in stains on polymer surfaces were found to be concentrated at the perimeter of the stains, in agreement with the observed outward microfluid flow in the last stage of the evaporation process of water droplets. |