Surface Tension Effects In Microlithography - Striations

Surface tension plays a role in many areas of lithography. One of them has been found to be formation of Benard cells in photoresist coatings at the center of a wafer. A relationship between these cells and ,'riations is proposed. Observations of the effects of evaporation, gravity, radius, dispense flow, spiv, lme, spin speed, type of solvent, type of solute and concentration of surfactant suggest that the formation of cells and striations follows the same principles that are active in conventional thick coatings. Surface tension measurements are reported that support this conclusion.