Practical resolution limit of KrF lithography

Since lithography represents a major part of chip manufacturing costs it is desirable to extend KrF optical lithography to 0.15 μm design rules and beyond. This paper discusses the resolution limits that can be achieved with state-of-the-art 0.68 NA exposure systems and optical enhancement techniques such as modified illumination, phase shift masks and optical proximity corrections. The goal is to optimize the imaging process to achieve process windows large enough for use in a manufacturing environment