Imaging Application tools for extremely low-k1 ArF immersion lithography

The k1 factor continues to be driven downward in ArF immersion lithography, even below its limit from optical theory, using various lithographic techniques such as combination of Source and Mask Optimization (SMO) and multiple patterning. Such a low k1 factor tends to lead to extremely high sensitivity tp imaging parameters such as aberrations, distortion, illumination pupilgram shape, dose, focus, etc. Therefore, fast, precise and stable settings of these parameters are crucial to make such hyper low k1 lithography practical. We introduce various kinds of imaging application tools and technique, which we have been developing, to support the imaging parameter settings and control. The application tools cover illumination pupilgram adjustment for freeform illumination, automatic aberration control, and thermal aberration parameter settings.