Apparatus and methods for detecting overlay errors using scatterometry

US7379183B2 · 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
• Paola deCecco · Redwood City, US
• John Fielden · Los Altos, US
• Noah Bareket · Saratoga, US
• Kenneth P. Gross · Redwood City, US
• Mark Ghinovker · Migdal HaEmek, IL

Key dates

• Filing date: Feb 23, 2004
• Grant date: May 27, 2008
• Expiry date: Dec 24, 2024

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 optical system is employed to thereby measure an optical signal from each of the periodic targets. There are predefined offsets between the first and second structures. An overlay error is determined between the first and second structures by analyzing the measured optical signals from the periodic targets using a scatterometry overlay technique based on the predefined offsets.