A method for dynamic placement of overlay measurement area cursors using segmentation technique

Shinya Kyogoku; Minoru Harada; Mayuka Osaki; Takahiro Nishihata; Yasunori Goto

doi:10.1117/12.3008535

9 April 2024 A method for dynamic placement of overlay measurement area cursors using segmentation technique

Shinya Kyogoku, Minoru Harada, Mayuka Osaki, Takahiro Nishihata, Yasunori Goto

Proceedings Volume 12955, Metrology, Inspection, and Process Control XXXVIII; 1295521 (2024) https://doi.org/10.1117/12.3008535
Event: SPIE Advanced Lithography + Patterning, 2024, San Jose, California, United States

Conference Poster

Abstract

As the design rules for semiconductor devices continue to shrink, layer-to-layer overlay of actual circuit patterns needs to be measured by using a critical dimension scanning electron microscope (CD-SEM). In addition to the overlay, process variations are making not only local size variations but also local position errors in patterns on the same layer increasingly non-negligible compared to pattern size. In cases where upper and lower patterns partially overlap, these variations and errors cause variations to occur in the positions and visible area of the lower layer patterns in SEM images. As a result, the center position of each lower layer pattern has become difficult to accurately measure resulting in errors in the overlay measurement. In response to this problem, we have developed a method for dynamically placing measurement area cursors for overlay metrology using segmentation technique. This method determines a measurement area cursor by recognizing the position and size of each lower layer pattern through segmentation images generated from the target SEM images using unsupervised deep learning. The performance of this method is evaluated by creating imitated images having the programmed overlay, the local size variations, and the local position errors. We compared the measurement results for the imitated images obtained by the proposed method and a conventional method that uses fixed measurement area cursors and found that the proposed method maintains sensitivity and repeatability even for targets where sensitivity and repeatability degrade with the conventional method due to process variations.

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

Citation Download Citation

Shinya Kyogoku, Minoru Harada, Mayuka Osaki, Takahiro Nishihata, and Yasunori Goto "A method for dynamic placement of overlay measurement area cursors using segmentation technique", Proc. SPIE 12955, Metrology, Inspection, and Process Control XXXVIII, 1295521 (9 April 2024); https://doi.org/10.1117/12.3008535

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