Apparatus and methods for detecting overlay errors using scatterometry

US7301634B2 · kind B2 · utility

Assignee

• KLA-Tencor Technologies Corp. · US

Inventors

• Walter D. Mieher · Los Gatos, US
• Ady Levy · Sunnyvale, US
• Boris Golovanesky · Haifa, IL
• Michael Friedmann · Nesher, IL
• Ian Smith · Los Gatos, US
• Michael Adel · Zichron Ya'akov, IL
• Christopher F. Bevis · Los Gatos, US
• John Fielden · Los Altos, US
• Noah Bareket · Saratoga, US
• Anatoly Fabrikant · Fremont, US
• Mark Ghinovker · Migdal HaEmek, IL
• Piotr Zalicki · Sunnyvale, US
• Dan Wack · Los Altos, US

Key dates

• Filing date: Feb 23, 2004
• Grant date: Nov 27, 2007
• Expiry date: Apr 24, 2025

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2021/213
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Disclosed is a method of determining an overlay error between two layers of a multiple layer sample. For a plurality of periodic targets that each have a first structure formed from a first layer and a second structure formed from a second layer of the sample, an interferometer is employed to modulate substantially a plurality of wavelengths of a broadband source and then acquiring one or more images of the periodic targets. There are predefined offsets between the first and second structures. An overlay error between the first and second structures is then determined by analyzing the one or more acquired images from the periodic targets using a scatterometry overlay technique based on the predefined offsets.