3D mask effects of absorber geometry in EUV lithography systems

Riaz R. Haque; Zac Levinson; Bruce W. Smith

doi:10.1117/12.2219708

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18 March 2016 3D mask effects of absorber geometry in EUV lithography systems

Riaz R. Haque, Zac Levinson, Bruce W. Smith

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Proceedings Volume 9776, Extreme Ultraviolet (EUV) Lithography VII; 97760F (2016) https://doi.org/10.1117/12.2219708
Event: SPIE Advanced Lithography, 2016, San Jose, California, United States

Abstract

The non-zero chief ray angle at the object (CRAO) in EUVL systems introduces azimuthally asymmetric phase shifts. Understanding and characterizing these effects is critical to EUVL system and mask design. The effects of 3D mask absorber geometry on diffraction phase were examined through rigorous simulation. The diffraction phase distribution was split into even and odd components to enable analogies between the well-known effects of lens aberrations and EUV 3D mask effects. Specifically, this analysis reveals that the odd component of the phase distribution is non-zero in off-axis optical systems. We have found that 3D mask effects in EUVL systems can be partially compensated in the pupil plane to minimize aerial image effects, such as best focus shifts, horizontal-vertical CD bias, and image placement error.

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Riaz R. Haque, Zac Levinson, and Bruce W. Smith "3D mask effects of absorber geometry in EUV lithography systems", Proc. SPIE 9776, Extreme Ultraviolet (EUV) Lithography VII, 97760F (18 March 2016); https://doi.org/10.1117/12.2219708

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