Aberration Budget in Extreme Ultraviolet Lithography

摘要

It seems that the actual EUV lithography tools will have aberrations around ten times larger than those of thelatest ArF lithography tools in wavelength normalized rms. We calculated the influence of aberrations on the size errorand pattern shift error using Zernike sensitivity analysis. Mask-induced aberration restricts the specification of aberration.Without periodic additional pattern, the aberration to form 22 nm dual-gate patterns was below 8 mλ rms. Arranging theperiodic additional pattern relaxed the aberration tolerance. With periodic additional pattern, the aberration to form 22nm patterns was below 37 mλ rms. It is important to make pattern periodicity for the relaxation of the aberrationspecification.