Effect of shifter edge angle and lens aberration on the pattern profile in the edge-line phase-shift method

摘要

Abstract: Origin of asymmetrical resist patterns, which had been observed in the edge-line phase shift lithography, has been investigated by simulations and experiments concerning the affects of shifter edge angle and stepper lens aberration. It has been found that the asymmetry of resist patterns has been caused by coma aberration of stepper projection lens and enhanced as the shifter width becomes narrower. Furthermore, the effect of shifter edge angle has been proved equivalent to the effect of narrowing the shifter width. !7