Paper
29 September 2023 Actinic patterned mask inspection for EUV lithography
Toshiyuki Todoroki, Hiroki Miyai
Author Affiliations +
Abstract
In 2019, Lasertec successfully developed ACTIS™, the world’s first actinic patterned mask inspection (APMI) system, and has since been providing it as a solution to customers for use in EUV lithography production processes. APMI, is a type of inspection that utilizes the same 13.5nm EUV light used in EUV lithography. ACTIS can perform high-resolution, high-throughput inspection of EUV photomasks and detect all types of printable defects, the mask defects that would be printed on wafers in the EUV lithography process. DUV inspection can detect some of the printable defects. However, DUV inspection cannot detect phase defects, whereas APMI can. A comparison between the inspection performance of DUV and APMI for several defects, including phase defects, is provided in this paper. High-NA lithography is expected to be used for the EUV process at the technology nodes of N3 and beyond. High-NA lithography will be achieved by utilizing anamorphic optics, where magnification scales of projection differ along the horizontal and vertical axes. ACTIS has the extendibility to meet the requirements of high-NA lithography as it can be modified to have the NA on the mask extended along a single axis. Lasertec is developing a new generation ACTIS for use in high NA EUV lithography with higher NA projection optics. In this paper, we present the progress of ACTIS inspection technology, suitable characteristics of the Light Source Required for APMI, and simulation results generated by a rigorous optical simulator using electromagnetic calculations which shows performance improvement of new generation ACTIS with higher NA projection optics.
© (2023) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Toshiyuki Todoroki and Hiroki Miyai "Actinic patterned mask inspection for EUV lithography", Proc. SPIE 12915, Photomask Japan 2023: XXIX Symposium on Photomask and Next-Generation Lithography Mask Technology, 1291502 (29 September 2023); https://doi.org/10.1117/12.2685011
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KEYWORDS
Inspection

Extreme ultraviolet

Extreme ultraviolet lithography

Pellicles

Light sources

Defect detection

Lithography

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