Off-axis illumination overlay measurement using two-diffracted orders imaging

US11281111B2 · kind B2 · utility

Assignee

• KLA-TENCOR CORPORATION · US

Inventors

• Yoni Shalibo · Or Akiva, IL
• Yuri Paskover · Or Akiva, IL
• Vladimir Levinski · Milpitas, US
• Amnon Manassen · Haifa, IL
• Shlomo Eisenbach · Milpitas, US
• Gilad Laredo · Migdal HaEmek, IL
• Ariel Hildesheim · Kiryat Tivon, IL

Key dates

• Filing date: Dec 14, 2018
• Grant date: Mar 22, 2022
• Expiry date: Jun 28, 2040

Classification

• Technology area (CPC G): Physics
• CPC primary: G03F7/70616
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Metrology methods and tools are provided, which enhance the accuracy of the measurements and enable simplification of the measurement process as well as improving the correspondence between the metrology targets and the semiconductor devices. Methods comprise illuminating the target in a Littrow configuration to yield a first measurement signal comprising a −1st diffraction order and a 0th diffraction order and a second measurement signal comprising a +1st distraction order and a 0th diffraction order, wherein the −1st diffraction order of the first measurement signal and the +1st diffraction order of the second measurement signal are diffracted at 180° to a direction of the illumination, performing a first measurement of the first measurement signal and a second measurement of the second measurement signal, and deriving metrology metric(s) therefrom. Optionally, a reflected 0th diffraction order may be split to yield components which interact with the −1st and +1st diffraction orders.