Effect of resolution enhancement techniques on aberration sensitivities of ArF immersion lithography at 45 nm node

The impact of resolution enhancement technologies (RET) on aberration sensitivities are studied in the conditions of different pattern density, numerical aperture (NA) and polarized light with ArF immersion lithography at 45 nm node. The results show that the aberration sensitivity of all order astigmatism, coma, and spherical aberration is much small when the dense line is printed. The aberration sensitivities are higher when strong alternating phase shift mask (altPSM) and chrome-less (Cr-less) PSM are employed. The low order aberration sensitivity is much bigger when polarization effect is no longer neglected in hyper NA system. RET and aberration should be accounted in conjunction with polarization effect during the design stage since minimization of negative effects is a primary goal. These results reveal that RET, pattern type, size, NA and polarized illumination impact the aberration sensitivity significantly in hyper NA lithography. Tool designer and device maker should pay more attention on this for 45 nm node and below.