Impact of the EUV mask phase response on the asymmetry of Bossung curves as predicted by rigorous EUV mask simulations

Christof G. Krautschik; Masaaki Ito; Iwao Nishiyama; Katsura Otaki

doi:10.1117/12.436666

20 August 2001 Impact of the EUV mask phase response on the asymmetry of Bossung curves as predicted by rigorous EUV mask simulations

Christof G. Krautschik, Masaaki Ito, Iwao Nishiyama, Katsura Otaki

Author Affiliations +

Proceedings Volume 4343, Emerging Lithographic Technologies V; (2001) https://doi.org/10.1117/12.436666
Event: 26th Annual International Symposium on Microlithography, 2001, Santa Clara, CA, United States

Abstract

EUV masks generally mandate rigorous scattering models as the thickness to wavelength ratio is typically on the order of 30:1. In addition, boundary conditions at the absorber/air interface lead to non-zero electric fields even in the absorber region while the phase itself generally experiences a complex cross mask behavior that is pattern type as well as size dependent. Using two different types of rigorous simulators that are based on the differential method (LithoLand) and the time-domain finite-element method (EMFLEX) we explore and quantify the subtleties associated with the EUV mask when compared to a thin mask obeying the Kirchoff approximation. Both rigorous simulators predict that 30 nm isolated pattern, especially for NA >0.20 experience a focus shift of about 50 nm relative to best focus for the thin mask case. This effect occurs even when the illumination is normally incident to the mask. Furthermore, the Bossung curve for isolated patterns show an asymmetry through focus that is absent for the thin mask case and is sensitive to the partial coherence condition of the illuminator. Nested features seem to be far more immune to this unexpected anomaly. The origin of the predicated focus shift and asymmetry is explained through the complex phase behavior for the EUV mask which is fundamentally different from the thin mask case.

Citation Download Citation

Christof G. Krautschik, Masaaki Ito, Iwao Nishiyama, and Katsura Otaki "Impact of the EUV mask phase response on the asymmetry of Bossung curves as predicted by rigorous EUV mask simulations", Proc. SPIE 4343, Emerging Lithographic Technologies V, (20 August 2001); https://doi.org/10.1117/12.436666

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