Fundamental understanding of the interplay between target and sensor brings diffraction based overlay to the next level of accuracy

Mathijssen, Simon G. J.; Davis, Timothy J.; Boef, Arie den; Bhattacharyya, Kaustuve; Blanton, William T.

doi:10.1117/12.2584973

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…DBO is receiving the most attention because of its superior measurement accuracy [18,19]. Various methods have been proposed for DBO, such as multi-wavelength measurement [20] and DBO target design (e.g., µDBO and cDBO) [21].…”

Section: Introductionmentioning

confidence: 99%

Mitigating the Impact of Asymmetric Deformation on Advanced Metrology for Photolithography

Yang,

Yao,

Cao

et al. 2024

Applied Sciences

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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.

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