17 April 2023 Evaluation of Lines and Spaces printing and general understanding of imaging with dark field low-n mask
Author Affiliations +
Abstract

Background

One of the ways to push down resolution limits in extreme ultraviolet (EUV) lithography is to use alternative masks. New types of absorbers are being broadly investigated for current 0.33 NA as well as for high NA of 0.55.

Aim

We study the imaging performance of a low-n/low-k absorber (ABS) dark field (DF) mask for lines and spaces (LS) printing at 0.33 NA.

Approach

Experimentally and via simulations, we investigate the use of low-n DF masks for a metal direct print application and compare low-n mask performance with Ta-based ABS masks.

Results

Compared to a Ta-based ABS mask used nowadays, the low-n DF mask brings contrast gain for dense LS. Also, for low-n masks, we observe large best focus (BF) shifts for isolated features with respect to dense features and change of bias. Hence, strong mask critical dimensions (CD) control is needed. We demonstrate how adding assist features can align BF through pitch. In addition, placing subresolution assist features (SRAFs) significantly enhances exposure latitude for semi/iso and iso-LS and improves the overlapping process window for selected cases.

Conclusions

These investigations show that low-n DF masks can enhance the imaging of LS through pitch if SRAFs are used and a good mask CD control is achieved. Our work further adds fundamental understanding to advantages observed for a metal direct print application of alternative ABS masks for the current and future EUV tools.

© 2023 Society of Photo-Optical Instrumentation Engineers (SPIE)
Tatiana Kovalevich, Lieve Van Look, Joern-Holger Franke, and Vicky Philipsen "Evaluation of Lines and Spaces printing and general understanding of imaging with dark field low-n mask," Journal of Micro/Nanopatterning, Materials, and Metrology 22(2), 024401 (17 April 2023). https://doi.org/10.1117/1.JMM.22.2.024401
Received: 10 January 2023; Accepted: 27 March 2023; Published: 17 April 2023
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Printing

SRAF

Simulations

Nanoimprint lithography

Semiconducting wafers

Extreme ultraviolet

Critical dimension metrology

RELATED CONTENT


Back to Top