Apparatus and methods for detecting overlay errors using scatterometry

US7876440B2 · 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
• Anatoly Fabrikant · Fremont, US

Key dates

• Filing date: Jul 17, 2009
• Grant date: Jan 25, 2011
• Expiry date: Jul 17, 2029

Classification

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

Abstract

Disclosed are apparatus and methods for determining overlay between a plurality of first structures in a first layer of a sample and a plurality of second structures in a second layer of the sample. Targets A, B, C and D that each include a portion of the first and second structures are provided. The target A is designed to have an offset Xa between its first and second structures portions; the target B is designed to have an offset Xb between its first and second structures portions; the target C is designed to have an offset Xc between its first and second structures portions; and the target D is designed to have an offset Xd between its first and second structures portions. Each of the offsets Xa, Xb, Xc and Xd is different from zero, and Xa is an opposite sign and differ from Xb.