26 June 2003 Optimizing and enhancing optical systems to meet the low k1 challenge
Author Affiliations +
Current roadmaps show that the semiconductor industry continues to drive the usable Rayleigh resolution towards the fundamental limit (for 50% duty cycle lines) at k1=0.25. This is being accomplished through use of various resolution enhancement technologies (RETs), extremely low aberration optics with stable platforms, and resists processes that have ever-increasing dissolution contrast and smaller diffusion lengths. This talk will give an overview of the latest optical mechanisms that can be used to improve the imaging system for low k1 resolutions. We show 3 non-photoresist techniques to measure the optical parameters of a scanner: 1) a new fast phase measurement interferometer to measure aberrations is presented with an accuracy and repeatability of <3mλ, 2) we introduce a method to measure the illumination profile of the exposing source, and 3) a measurement system to monitor scattered light is presented with correlation to other techniques using a salted pellicle experiment to create controlled scattered light. The optimization of illumination and exposure dose is presented. We show the mechanism for customizing illumination based on specific mask layers. We show how this is done and compare process windows to other more conventional modes such as annular illumination or QUASAR. The optimum design is then implemented into hardware that can give extremely high optical efficiency. We also show how system level control mechanisms can be used to field-to-field and across-field exposure to compensate for lithography errors. Examples of these errors can include reticle CD deviations, wavefront aberrations, and across-field illumination uniformity errors. CD maps, facilitated by SEM and ELM, can give the prescribed changes necessary. We present a system that interfaces to new hardware to compensate these effects by active scanner corrections.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Donis G. Flagello, Donis G. Flagello, Robert John Socha, Robert John Socha, Xuelong Shi, Xuelong Shi, Jan B.P. van Schoot, Jan B.P. van Schoot, Jan Baselmans, Jan Baselmans, Mark A. van de Kerkhof, Mark A. van de Kerkhof, Wim de Boeij, Wim de Boeij, Andre Engelen, Andre Engelen, Rene Carpaij, Rene Carpaij, Oscar Noordman, Oscar Noordman, Marco H. P. Moers, Marco H. P. Moers, Melchior Mulder, Melchior Mulder, Jo Finders, Jo Finders, Henk van Greevenbroek, Henk van Greevenbroek, Martin Schriever, Martin Schriever, Manfred Maul, Manfred Maul, Helmut Haidner, Helmut Haidner, Markus Goeppert, Markus Goeppert, Ulrich Wegmann, Ulrich Wegmann, Paul Graeupner, Paul Graeupner, "Optimizing and enhancing optical systems to meet the low k1 challenge", Proc. SPIE 5040, Optical Microlithography XVI, (26 June 2003); doi: 10.1117/12.485340; https://doi.org/10.1117/12.485340

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