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Proceedings Paper

Line-edge roughness performance targets for EUV lithography
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Paper Abstract

Our paper will use stochastic simulations to explore how EUV pattern roughness can cause device failure through rare events, so-called "black swans". We examine the impact of stochastic noise on the yield of simple wiring patterns with 36nm pitch, corresponding to 7nm node logic, using a local Critical Dimension (CD)-based fail criteria Contact hole failures are examined in a similar way. For our nominal EUV process, local CD uniformity variation and local Pattern Placement Error variation was observed, but no pattern failures were seen in the modest (few thousand) number of features simulated. We degraded the image quality by incorporating Moving Standard Deviation (MSD) blurring to degrade the Image Log-Slope (ILS), and were able to find conditions where pattern failures were observed. We determined the Line Width Roughness (LWR) value as a function of the ILS. By use of an artificial "step function" image degraded by various MSD blur, we were able to extend the LWR vs ILS curve into regimes that might be available for future EUV imagery. As we decreased the image quality, we observed LWR grow and also began to see pattern failures. For high image quality, we saw CD distributions that were symmetrical and close to Gaussian in shape. Lower image quality caused CD distributions that were asymmetric, with "fat tails" on the low CD side (under-exposed) which were associated with pattern failures. Similar non-Gaussian CD distributions were associated with image conditions that caused missing contact holes, i.e. CD=0.

Paper Details

Date Published: 24 March 2017
PDF: 10 pages
Proc. SPIE 10143, Extreme Ultraviolet (EUV) Lithography VIII, 101430E (24 March 2017); doi: 10.1117/12.2258660
Show Author Affiliations
Timothy A. Brunner, GLOBALFOUNDRIES Inc. (United States)
Xuemei Chen, GLOBALFOUNDRIES Inc. (United States)
Allen Gabor, GLOBALFOUNDRIES Inc. (United States)
Craig Higgins, GLOBALFOUNDRIES Inc. (United States)
Lei Sun, GLOBALFOUNDRIES Inc. (United States)
Chris A. Mack, Fractilia (United States)

Published in SPIE Proceedings Vol. 10143:
Extreme Ultraviolet (EUV) Lithography VIII
Eric M. Panning, Editor(s)

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