Alternative reticles for low-k1 EUV imaging

M.-Claire van Lare; Frank J. Timmermans; Jo Finders

doi:10.1117/12.2536415

26 September 2019 Alternative reticles for low-k1 EUV imaging

M.-Claire van Lare, Frank J. Timmermans, Jo Finders

Proceedings Volume 11147, International Conference on Extreme Ultraviolet Lithography 2019; 111470D (2019) https://doi.org/10.1117/12.2536415
Event: SPIE Photomask Technology + EUV Lithography, 2019, Monterey, California, United States

Abstract

Alternative reticles have the potential to improve EPE for low-k1 EUV lithography on multiple aspects, by reducing mask 3D effects and improving optical contrast. We study the application of high-k masks and attenuated phase-shift masks at diffraction level and show that mitigation of mask 3D effects, such as contrast fading, is crucial for both good performance of both alternative-reticle types. We present optimum embodiments for both mask types. We find that the optimum attenuated phase-shift mask (PSM) results in a phase shift of 1.2 π. The extra 0.2 π phase shift required for the EUV mask compared to its DUV counterpart is needed to compensate the strong mask 3D effects; the 1.2 π phase shift is crucial for good performance at small pitch and was found for all 3 materials studied in this work: Ru, Pd, and Mo. We show that our Rubased attenuated PSM embodiment results in a strong gain in normalized image log slope (NILS). <30% NILS gain can be achieved compared to a Ta-based reference mask. To demonstrate the generic applicability of the mask, we show NILS gain using the same attenuated PSM embodiment for different use cases for 0.33 and 0.55-NA EUV lithography, including regular contacts, DRAM patterns, and contacts through pitch. We show that the optimum mask-type choice is application dependent and present our recommendations in a mask-decision tree. We discuss the implications of using new reticle absorbers for scanner integration.

Conference Presentation

Citation Download Citation

M.-Claire van Lare, Frank J. Timmermans, and Jo Finders "Alternative reticles for low-k1 EUV imaging", Proc. SPIE 11147, International Conference on Extreme Ultraviolet Lithography 2019, 111470D (26 September 2019); https://doi.org/10.1117/12.2536415

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available