The impact of lenses aberration on CD and position for low kl lithography

Abstract

In low $\mathrm{k}_{1}$ regime, the lithography resolution is close to the optical diffraction limit. Ignoring the impact of lenses aberration for such precise lithography processes is questionable. The aberration of lithography lenses in circular pupil is typically represented by Zernike polynomials. In theory, even Zernike aberrations mainly induce pattern critical dimension (CD) variation and odd Zernike aberrations mainly induce pattern position variation. We study the CD and position simulations in various lithography configurations, such as numerical aperture (NA), illumination sigma, defocus, wafer stack, and pattern pitch. Based on the above data, this paper comprehensively discusses the impact of each Zernike aberration on pattern CD and position. The conclusion is useful to accurately predict pattern CD and position variations and to further implement aberration-aware optical proximity correction (OPC) for actual lithography lenses.