Paper
10 April 2024 EUV source pole control for LCDU and CD ellipticity handling in hexagonal contact arrays
Author Affiliations +
Abstract
Improving local critical dimension uniformity (LCDU) as well as productivity in the extreme pitch of EUV layers is the most important challenge in DRAM device. In general, automated source optimization (SO) process is limited to investigate all possible candidates for the best LCDU performance, like fixing the amount of mirror in specific sigma and generating uncommon pole shapes. In this paper, we present LCDU improvement method in hexagonal contact array patterns based on controlling the center sigma position in the EUV pupil. We demonstrated that the LCDU was improved when the source points were located on the outer edge side of pupils regardless of normalized image log slope (NILS). This indicated the mirror location in the source is significant for LCDU in the similar NILS conditions. Moreover, it was confirmed that the CD along the critical direction increased as source points moved toward the center of the 3-beam imaging area, thus the changed CD ellipticity could further improve LCDU or cut down ACI defect source. The results showed a similar tendency in both the binary mask (BIN) and phase shift mask (PSM) even to differ type of resist. Overall, we verified the correlation of LCDU and ADI CD ellipticity through the sigma center position control, and we believe this approach will contribute to future research on improving LCDU.
(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.
Jieun Song, Janghun Kim, Hyung Jong Bae, Sudeok Kim, Soonmok Ha, Woojin Jung, Seokwon Cho, Jeounghun Park, Dohyeon Park, Eunji Lee, Minseung Song, Hyunseung Ha, Giseon Han, Young Joo Choi, Gyeongseok Park, Seongbo Shim, and Chan Hwang "EUV source pole control for LCDU and CD ellipticity handling in hexagonal contact arrays", Proc. SPIE 12953, Optical and EUV Nanolithography XXXVII, 1295309 (10 April 2024); https://doi.org/10.1117/12.3010718
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KEYWORDS
Extreme ultraviolet

Light sources and illumination

Mirrors

Semiconducting wafers

Simulations

Nanoimprint lithography

Critical dimension metrology

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