High-density CD measurement technology with high throughput and high precision on the entire surface of a process wafer, capable of capturing randomly occurring CD defects

Kazuhiko Fukazawa; Shigeru Hirukawa; Yosuke Miyazaki; Yoshihiko Fujimori; Tomohiro Iwaki; Tomonori Okada

doi:10.1117/12.2657873

27 April 2023 High-density CD measurement technology with high throughput and high precision on the entire surface of a process wafer, capable of capturing randomly occurring CD defects

Kazuhiko Fukazawa, Shigeru Hirukawa, Yosuke Miyazaki, Yoshihiko Fujimori, Tomohiro Iwaki, Tomonori Okada

Author Affiliations +

Proceedings Volume 12496, Metrology, Inspection, and Process Control XXXVII; 1249611 (2023) https://doi.org/10.1117/12.2657873
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Abstract

In recent years, the number of manufacturing processes is increasing in pursuit of device pattern miniaturization. Complicated processes such as SAQP have been introduced, increasing the number of control parameters. Nevertheless, the demand for production yield enhancement is as high as ever. To detect CD changes, fixed-point measurement by using CD-SEM or scatterometry tools is typically performed, but these time-consuming measurement methods are not suitable for high-density, across-a-wafer measurement or for detecting CD anomalies that randomly occur. To address these issues, we have developed a technology that enables high-precision CD measurement of more than 100,000 points per wafer within a few minutes. It enables monitoring various CD defects in various processes such as holes and L/S patterns after photolithography, L/S patterns after SAQP/SADP, and fine hole diameters after etching. It can also measure CD imbalances after SAQP processes. In addition, it enables precisely obtaining intra-shot CD distribution based on the distribution over the entire surface of a wafer. We evaluated this technology using actual device wafers. CD imbalances of SAQP on DRAM process wafers were measured, within a few minutes across a wafer, at an accuracy of |X|+3σ<0.5 nm. CD changes at the outermost area of the wafer were captured by CD measurement of 27 nm hole patterns on a DRAM process wafer. Random CD defects were captured by CD measurement of 38 nm hole patterns on a DRAM process wafer. These defects affect device yield but were not detectable by using conventional inspection tools.

Conference Presentation

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Kazuhiko Fukazawa, Shigeru Hirukawa, Yosuke Miyazaki, Yoshihiko Fujimori, Tomohiro Iwaki, and Tomonori Okada "High-density CD measurement technology with high throughput and high precision on the entire surface of a process wafer, capable of capturing randomly occurring CD defects", Proc. SPIE 12496, Metrology, Inspection, and Process Control XXXVII, 1249611 (27 April 2023); https://doi.org/10.1117/12.2657873

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