Determination of line profiles on photomasks using DUV, EUV, and x-ray scattering

F. Scholze; B. Bodermann; S. Burger; J. Endres; A. Haase; M. Krumrey; C. Laubis; V. Soltwisch; A. Ullrich; J. Wernecke

doi:10.1117/12.2065941

17 October 2014 Determination of line profiles on photomasks using DUV, EUV, and x-ray scattering

F. Scholze, B. Bodermann, S. Burger, J. Endres, A. Haase, M. Krumrey, C. Laubis, V. Soltwisch, A. Ullrich, J. Wernecke

Proceedings Volume 9231, 30th European Mask and Lithography Conference; 92310M (2014) https://doi.org/10.1117/12.2065941
Event: 30th European Mask and Lithography Conference, 2014, Dresden, Germany

Abstract

Non-imaging techniques like X-ray scattering are supposed to play an important role in the further development of CD metrology for the semiconductor industry. GISAXS provides directly assessable information on structure roughness and long-range periodic perturbations. The disadvantage of the method is the large footprint of the X-ray beam on the sample due to the extremely shallow angle of incidence. This can be overcome by using wavelengths in the extreme ultraviolet (EUV) spectral range which allow for much steeper angles of incidence but preserve the large range of momentum transfer that can be observed. At the Physikalisch-Technische Bundesanstalt (PTB), the available photon energy range extends from 50 eV up to 10 keV at two adjacent beamlines. PTB commissioned a new versatile Ellipso-Scatterometer which is capable of measuring 6” square substrates in a clean, hydrocarbon-free environment with full flexibility regarding the direction of the incident light polarization. The reconstruction of line profiles using a geometrical model with six free parameters, a finite element method (FEM) Maxwell solver and least-squares optimization yielded consistent results for EUV and deep ultraviolet (DUV) scatterometry. For EUV photomasks, the actinic wavelength EUV scatterometry yields particular advantages. A significant polarization dependence of the diffraction intensities for 0^th and +1^st orders in the geometry with the grating lines perpendicular to the plane of reflection is observed and the 0^th order intensity shows sufficient sensitivity to the line width such that a CD-resolution below 0.1 nm is within reach. In this contribution we present scatterometry data for line gratings using GISAXS, and EUV and DUV scatterometry and consistent reconstruction results of the line geometry for EUV and DUV scatterometry.

Citation Download Citation

F. Scholze, B. Bodermann, S. Burger, J. Endres, A. Haase, M. Krumrey, C. Laubis, V. Soltwisch, A. Ullrich, and J. Wernecke "Determination of line profiles on photomasks using DUV, EUV, and x-ray scattering", Proc. SPIE 9231, 30th European Mask and Lithography Conference, 92310M (17 October 2014); https://doi.org/10.1117/12.2065941

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