Image-based pupil plane characterization for anamorphic lithography systems
Autor: | Bruce W. Smith, Zac Levinson |
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Rok vydání: | 2017 |
Předmět: |
Physics
Basis (linear algebra) Zernike polynomials business.industry Extreme ultraviolet lithography Phase (waves) 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Metrology 010309 optics symbols.namesake Interferometry Optics 0103 physical sciences symbols Computer vision Artificial intelligence 0210 nano-technology business Lithography De facto standard |
Zdroj: | SPIE Proceedings. |
ISSN: | 0277-786X |
Popis: | Next-generation EUV lithography systems will use anamorphic optics to achieve high-NA. The well-known Zernike circle polynomials do not describe the sixteen primary aberrations of these anamorphic optical systems though. We propose to use a basis which does describe the primary aberrations. We examine the properties of this new basis and how they impact lithographic processes through analogies to isomorphic aberrations. We have developed an application to use the proposed basis in existing lithography simulators. There is an additional importance in EUVL placed on understanding how pupil variation evolves during system operation. Interferometric methods are the de facto standard of pupil phase metrology but are challenging to implement during tool use. We have previously presented an approach to measure both the pupil amplitude and phase variation of isomorphic EUVL systems from images formed by that system. We show how this methodology can be adapted to anamorphic optical systems. More specifically, we will present a set of binary metrology targets sensitive to the anamorphic primary aberrations. |
Databáze: | OpenAIRE |
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