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Proceedings Paper

Through-pellicle inspection using EUV ptychography microscope (Conference Presentation)
Author(s): Young Woong Kim; Dong Gon Woo; Yong Ju Jang; Seong Ju Wi; Jinho Ahn; Seunghyeok Shin; Whoi-Yul Kim

Paper Abstract

Extreme ultraviolet (EUV) lithography is going to be inserted into high volume manufacturing (HVM) of 7 nm technology node device. However, the insertion of EUV pellicle is still a major issue. Since particles on the pellicle larger than a critical size can act as killing defects on the final wafer pattern, through-pellicle inspection has to be preceded before applying into the lithography process. Even though non-actinic techniques which use deep ultraviolet (DUV) or e-beam light source can be used for preliminary inspection, actinic technique is still indispensable for the precise aerial image review and defect detection. In this study, through-pellicle inspection was performed by using EUV scanning lensless imaging (ESLI), which has been developed as an actinic inspection technique. ESLI uses a coherent light source generated by high-order harmonic generation (HHG) and coherent diffraction imaging (CDI) method which reconstructs the object image using the diffracted light from EUV mask. We especially adopted ptychography for large area through-pellicle inspection. Ptychography, multi-shot CDI which uses a series of diffraction patterns with redundancy, enables more accurate object reconstruction compared to conventional CDI method. We imaged EUV mask which has 128 nm half-pitch (HP) line and space (L/S) patterns. Also, mask inspection performance of ESLI was verified by comparing the reconstructed imaging results with CD-SEM image results. We also assessed defect detectability of ESLI by defect mapping of pellicle with various size defect. Furthermore, through-pellicle EUV mask imaging was executed for the study about acceptable defect size on EUV pellicle. In conclusion, we confirmed the ESLI’s feasibility for EUV pellicle qualification and defect inspection.

Paper Details

Date Published: 16 October 2019
Proc. SPIE 11147, International Conference on Extreme Ultraviolet Lithography 2019, 1114722 (16 October 2019); doi: 10.1117/12.2538720
Show Author Affiliations
Young Woong Kim, Hanyang University (Korea, Republic of)
Dong Gon Woo, Hanyang University (Korea, Republic of)
Yong Ju Jang, Hanyang University (Korea, Republic of)
Seong Ju Wi, Hanyang University (Korea, Republic of)
Jinho Ahn, Hanyang University (Korea, Republic of)
Seunghyeok Shin, Hanyang University (Korea, Republic of)
Whoi-Yul Kim, Hanyang University (Korea, Republic of)

Published in SPIE Proceedings Vol. 11147:
International Conference on Extreme Ultraviolet Lithography 2019
Toshiro Itani; Paolo A. Gargini; Patrick P. Naulleau; Kurt G. Ronse, Editor(s)

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