Aberration tolerance for 130 nm lithography from view point of process latitude

Progress in optical lithography has been achieved by using shorter wavelengths and higher numerical apertures of projection lenses. KrF (245nm) lithography is the main technology for 0.25-0.15 /spl mu/m device fabrication, and ArF (193nm) lithography will be adopted for 0.13 /spl mu/m patterning. In this "sub-wavelength" region, process latitudes such as depth-of-focus and exposure latitude have been severely small. The process latitudes are affected by many factors. In particular, optical lens aberration has been studied as one of the serious factors. In this report we describe the impact of the lens aberration on the process latitude using an optical simulator. Aberration tolerance for 130 nm lithography using ArF is discussed from the viewpoint of the process latitudes.