As the numerical aperture (NA) increasing and process factor k1 decreasing in 193nm immersion lithography, polarization aberration (PA) of projection optics leads to image quality degradation seriously. Therefore, this work proposes a new scheme for compensating polarization aberration. By simulating we found that adjusting the illumination source partial coherent factors σout is an effective method for decreasing the PA induced pattern critical dimension (CD) error while keeping placement error (PE) within an acceptable range. Our simulation results reveal that the proposed method can effectively compensate large PA in actual optics.
As the numerical aperture (NA) of 193nm immersion lithography projection optics (PO) increasing, polarization
aberration (PA) leads to image quality degradation seriously. PA induced by large incident angle of light, film coatings
and intrinsic birefringence of lens materials cannot be ignored. An effective method for PA compensation is to adjust
lens position in PO. However, this method is complicated. Therefore, in this paper, an easy and feasible PA
compensation method is proposed: for ArF lithographic PO with hyper NA (NA=1.2), which is designed by our
laboratory, the PA-induced critical dimension error (CDE) can be effectively reduced by optimizing illumination source
partial coherent factor σout. In addition, the basic idea of our method to suppress pattern placement error (PE) is to adopt anti-reflection (AR) multi-layers MgF2/LaF3/MgF2 and calcium fluoride CaF2 of  crystal axes. Our simulation results reveal that the proposed method can effectively and quantificationally compensate large PA in the optics. In particular, our method suppresses the dynamic range of CDE from -12.7nm ~ +4.3nm to -1.1nm ~ +1.2nm, while keeping PE at an acceptable level.