Status of EUV reflectometry at PTB

Frank Scholze; Christian Laubis; Christian Buchholz; Andreas Fischer; Sven Ploeger; Frank Scholz; Heike Wagner; Gerhard Ulm

doi:10.1117/12.598728

6 May 2005 Status of EUV reflectometry at PTB

Frank Scholze, Christian Laubis, Christian Buchholz, Andreas Fischer, Sven Ploeger, Frank Scholz, Heike Wagner, Gerhard Ulm

Author Affiliations +

Proceedings Volume 5751, Emerging Lithographic Technologies IX; (2005) https://doi.org/10.1117/12.598728
Event: Microlithography 2005, 2005, San Jose, California, United States

Abstract

The development of EUV lithography is critically based on the availability of suitable metrological equipment. To meet the industry's requirements, the Physikalisch-Technische Bundesanstalt (PTB) operates an EUV reflectometry facility at the electron storage ring BESSY II. It is designed for at-wavelength metrology of full-sized EUVL optics with a maximum weight of 50 kg and a diameter of up to 550 mm. A micro-reflectometry station was installed for reflectometry with high spatial resolution for, e.g., structured masks. A photon beam size of 10 μm FWHM has presently been achieved. To meet the increasing demands of metrology for future lithography production tools, the measurement uncertainty was permanently reduced. For peak reflectance, a total uncertainty of 0.10 % is achieved with a reproducibility of 0.05 %. The uncertainty of 2 pm in the center wavelength is given mainly by the uncertainty for the reference wavelength of the Kr 3d5/2-5p resonance. A long-term reproducibility of 0.8 pm has been demonstrated over a period of about 4 years. We have recently demonstrated repeatability below 0.06 pm. This good repeatability is important for the determination of the coating-thickness gradient in alpha-tool optics. We present a long-term series of measurements at a set of EUV mirrors and discuss our recent results in improving wavelength reproducibility.

Citation Download Citation

Frank Scholze, Christian Laubis, Christian Buchholz, Andreas Fischer, Sven Ploeger, Frank Scholz, Heike Wagner, and Gerhard Ulm "Status of EUV reflectometry at PTB", Proc. SPIE 5751, Emerging Lithographic Technologies IX, (6 May 2005); https://doi.org/10.1117/12.598728

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