Mask error enhancement factor for sub 0.13μm lithography

Abstract

Mask Error Enhancement Factor (MEEF) has become one of the critical concerns with the recent technology progress into producing pattern features far smaller than the wavelength of light, as in the case of 0.13 μm lithography and below. In this paper, we present MEEF study on different illumination conditions for 0.13 μm technology using 248nm KrF Lithography. Both simulation results using Prolith/2 tool and experimental results using 248nm DUV scanner, for varying the illumination conditions namely, annular versus conventional with different Numerical Aperture (NA) and Partial Coherent (PC) settings will be discussed. The study shows MEEF varies for different illumination conditions. MEEF was lower with high NA setting as compared to low NA, and annular illumination shows slight improvement of MEEF. In addition, experiments using different types of reticle specifically; Binary mask, 6% half tone Phase Shift Mask (PSM) and 18% High Transmittance Mask (HTM) were also analysed to characterise its relationship with MEEF.