On the Uniformity of Thin Films: A New Technique Applied to Polyimides

Abstract

A new technique has been developed for measuring and optimizing the thickness uniformity of spun‐on films. The technique allows simple, time‐efficient, thickness profile mapping across an entire slice. This technique has been applied to a polyimide to determine the dependence of the film thickness upon dispense volume, dispense spin speed, and final spin speed. The average thickness of the film is a strong function only of the final spin speed, but the uniformity of the film is affected by all three parameters. For the 1100 cP polyimide studied, the optimum spin parameters are: 0.5 cm3 dispense volume; zero dispense spin speed; and ≥5K rpm final spin speed.