Parallax method for diffraction-based single-cell overlay and film thickness measurement

Mordecai Kot; Yuval Lamhot; Alon Yagil; Tal Yaziv; Nadav Gutman; Renan Milo

doi:10.1117/12.2659163

27 April 2023 Parallax method for diffraction-based single-cell overlay and film thickness measurement

Mordecai Kot, Yuval Lamhot, Alon Yagil, Tal Yaziv, Nadav Gutman, Renan Milo

Proceedings Volume 12496, Metrology, Inspection, and Process Control XXXVII; 124963A (2023) https://doi.org/10.1117/12.2659163
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Conference Poster

Abstract

A diffraction-based measurement of overlay requires a target composed of two cells per direction of measurement, with induced shifts of opposite signs designed into each of the cells. We present a method for a measurement which only requires a single cell per direction. This is achieved by resolving the image in the pupil plane and using the angle of incidence inlieu of the induced shift. The use of single-celled targets reduces the target size by half and enables the placement of the target in-die, as well as reducing the measurement time. This single-cell measurement requires the calibration of the target’s optical stack height, which is done on a small number of two-cell targets. This calibration also produces a stable map of the aligned layers’ height profile across the wafer.

Citation Download Citation

Mordecai Kot, Yuval Lamhot, Alon Yagil, Tal Yaziv, Nadav Gutman, and Renan Milo "Parallax method for diffraction-based single-cell overlay and film thickness measurement", Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 124963A (27 April 2023); https://doi.org/10.1117/12.2659163

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