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- Title
Mitigating the Impact of Asymmetric Deformation on Advanced Metrology for Photolithography.
- Authors
Yang, Wenhe; Yao, Shuxin; Cao, Jing; Lin, Nan
- Abstract
Controlling overlay in lithography is crucial for improving the yield of integrated circuit manufacturing. The process disturbances can cause undesirable morphology changes of overlay targets (such as asymmetric grating), which can significantly impact the accuracy of overlay metrology. It is essential to decouple the overlay target asymmetry from the wafer deformation, ensuring that the overlay metrology is free from the influence of process-induced asymmetry (e.g., grating asymmetry and grating imbalance). Herein, we use an asymmetric grating as a model and show that using high-diffraction-order light can mitigate the impact of asymmetric grating through the rigorous coupled-wave analysis (RCWA) method. In addition, we demonstrate the diffraction efficiency as a function of the diffraction order, wavelength, and pitch, which has guiding significance for improving the measurement accuracy of diffraction-based overlay (DBO) metrology.
- Subjects
INTEGRATED circuits manufacturing; PHOTOLITHOGRAPHY; METROLOGY
- Publication
Applied Sciences (2076-3417), 2024, Vol 14, Issue 11, p4440
- ISSN
2076-3417
- Publication type
Article
- DOI
10.3390/app14114440