Polarized illumination is a viable technique for improving the image quality and process latitude of hyper-NA
lithography. On investigation of polarization effects, it is often assumed that the lens system can maintain the
polarization state through optical path, which may not be the case with actual lenses. These polarization changes may
cause CD variations and pattern placement errors. In this paper, we investigated a method of polarization analysis across
the pupil and showed some examples of polarization aberrations. Also, we analyzed CD sensitivity and pattern
placement errors from polarization aberrations. Specific terms of the Pauli Zernike representation have effects on CD
and pattern placement errors, like the Zernike representation of conventional aberrations. The Pauli-Zernike
representation is intuitive and useful for understanding and specifying polarization aberrations.
As ArF immersion lithography is adopted beyond the 45 nm node, the minimum mask feature size will become equal to or smaller than the wavelength of the light. For such situations, polarization by the mask will play a very important role on imaging quality. In addition, TM and TE diffraction efficiencies for very narrow grating masks will depend significantly on the mask materials. Also, they are affected by variations of absorber thickness, sidewall angle and material optical properties. In this paper, we investigate how the aquatic images with unpolarized and properly polarized illumination on binary image masks, attenuated phase shift masks (attPSM) and alternating aperture phase shift masks (altPSM) are affected by those mask parameters, using rigorous electro-magnetic field simulator. In terms of mask topography effects, there are some difficulties with phase shift mask technology with unpolarized illumination beyond 45 nm node. We will need to control absorber thickness within 2.6% for attPSM with unpolarized illumination and sidewall angle of π-shifter trenches within 1 degree for altPSM with unpolarized illumination.