An intelligent imaging system for ArF scanner

The k1 factor continues to be driven downwards, even beyond its theoretical limit 0.25, in order to enable the 32 nm feature generation and beyond. Due to the extremely small process-window that will be available for such extremely demanding imaging challenges, it is necessary that not only each unit contributing to the imaging system be driven to its ultimate performance capability, but also that the final integrated imaging system apply each of the different components in an optimum way with respect to one another, and maintain that optimum performance level and cooperation at all times. Components included in such an integrated imaging system include the projection lens, illumination optics, light source, in-situ metrology tooling, aberration control, and dose control. In this paper we are going to discuss the required functions of each component of the imaging system and how to optimally control each unit in cooperation with the others in order to achieve the goal of 32 nm patterning and beyond.