Comprehensive investigation on improvement of local CDU for sub-20nm DRAM devices

Zhong Zhang; Yang Zhang; Liang Zhu; Yi Cheng; Hui Dong; Kaige Gong; Jingjing Zhao; Jun Xu; Alex Ren

doi:10.1117/12.2657250

28 April 2023 Comprehensive investigation on improvement of local CDU for sub-20nm DRAM devices

Zhong Zhang, Yang Zhang, Liang Zhu, Yi Cheng, Hui Dong, Kaige Gong, Jingjing Zhao, Jun Xu, Alex Ren

Proceedings Volume 12494, Optical and EUV Nanolithography XXXVI; 124941H (2023) https://doi.org/10.1117/12.2657250
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Conference Poster

Abstract

Improving local critical dimension uniformity (LCDU) is always significant for enlarging process windows and reducing defect rates in lithography, especially for more scaling sub-20nm nodes in DRAM devices. In this study, various strategies are evaluated to improve both ADI and AEI LCDU on one of multiple patterning processes, Litho-Etch-Litho-Etch (LELE) process. Firstly, different advanced photoresists and track recipe optimization methods are explored and evaluated. The best result shows ADI LCDU is improved by 10.0%, and AEI LCDU by 10.3%. Secondly, several source mask optimization (SMO) solutions are tested and ADI and AEI LCDU is improved by 5.5% and 5.7%. Thirdly, new type of photomask, 30% high transmission phase shift mask (HT PSM), is introduced to optimize NILS and MEEF performances. The result shows ADI and AEI LCDU are enhanced by 13.7% and 14.2%. Additionally, etch advanced vertical profile approach can further improve on-device AEI LCDU by 19.0%.

Citation Download Citation

Zhong Zhang, Yang Zhang, Liang Zhu, Yi Cheng, Hui Dong, Kaige Gong, Jingjing Zhao, Jun Xu, and Alex Ren "Comprehensive investigation on improvement of local CDU for sub-20nm DRAM devices", Proc. SPIE 12494, Optical and EUV Nanolithography XXXVI, 124941H (28 April 2023); https://doi.org/10.1117/12.2657250

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