Advanced cross-layer overlay simulation with exposure grid re-calculation

Yueh-Feng Lu; Chao-Jen Tsou; Onur Demirer; Holger Bald; Siegfried Hille; Meng-Syun Li; Martin Freitag; Clemens Utzny; Scott Eitapence; Boris Habets; Cheng-Shuai Li; Kao-Tsai Tsai

doi:10.1117/12.3009745

9 April 2024 Advanced cross-layer overlay simulation with exposure grid re-calculation

Yueh-Feng Lu, Chao-Jen Tsou, Onur Demirer, Holger Bald, Siegfried Hille, Meng-Syun Li, Martin Freitag, Clemens Utzny, Scott Eitapence, Boris Habets, Cheng-Shuai Li, Kao-Tsai Tsai

Author Affiliations +

Proceedings Volume 12955, Metrology, Inspection, and Process Control XXXVIII; 1295524 (2024) https://doi.org/10.1117/12.3009745
Event: SPIE Advanced Lithography + Patterning, 2024, San Jose, California, United States

Conference Poster

Abstract

In today’s advanced semiconductor industry with the multitude of new products and device requirements, lithography process changes are inevitable and expected due to tighter overlay specifications and the increasing influence of process effects. To minimize the overlay impact from the wafer-to-wafer and lot-to-lot variation, lithography engineers often need to adjust wafer alignment and overlay strategies to optimize product yield. Overlay simulation methods are often used to estimate if new alignment and/or overlay strategies can help achieve better overlay performance. By removing the old corrections from the original alignment and overlay data, and then applying new corrections, the overlay performance can be readily predicted, saving significant time. However, available software suites only simulate the current layer overlay. Overlay risks would therefore remain on subsequent layers without an effective simulation method to predict the impact resulting from changes to the alignment and/or overlay strategies on the current layer. In our study, we demonstrate a new method to simulate the overlay performance on the subsequent layers by re-calculating the current layer exposure grid. Our dataset has 3 layers: L0, L1, and L2. On L1 (current layer), we apply a new alignment model and overlay control strategy with a feedforward solution. Then, we re-calculate the exposure grid to generate a new (virtual) alignment and overlay dataset for L2 (following layer). Finally, we estimate the overlay impact on L2 with the new alignment and overlay dataset and summarize the benefits of this new cross-layer overlay simulation method.

(2024) Published by SPIE. Downloading of the abstract is permitted for personal use only.

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Yueh-Feng Lu, Chao-Jen Tsou, Onur Demirer, Holger Bald, Siegfried Hille, Meng-Syun Li, Martin Freitag, Clemens Utzny, Scott Eitapence, Boris Habets, Cheng-Shuai Li, and Kao-Tsai Tsai "Advanced cross-layer overlay simulation with exposure grid re-calculation", Proc. SPIE 12955, Metrology, Inspection, and Process Control XXXVIII, 1295524 (9 April 2024); https://doi.org/10.1117/12.3009745

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