Apparatus and methods for detecting overlay errors using scatterometry

US7663753B2 · kind B2 · utility

Assignee

• KLA-Tencor Technologies Corp. · US

Inventors

• Walter D. Mieher · Los Gatos, US
• Ady Levy · Sunnyvale, US
• Boris Golovanevsky · Haifa, IL
• Michael Friedmann · Nesher, IL
• Ian Smith · Los Gatos, US
• Michael Adel · Zichron Ya'akov, IL
• Anatoly Fabrikant · Fremont, US
• Christopher F. Bevis · Los Gatos, US
• John Fielden · Los Altos, US
• Noah Bareket · Saratoga, US
• Ken Gross · Vancouver, US
• Piotr Zalicki · Sunnyvale, US
• Dan Wack · Los Altos, US
• Paola deCecco · Redwood City, US
• Thaddeus Gerard Dziura · San Jose, US
• Mark Ghinovker · Migdal HaEmek, IL

Key dates

• Filing date: Dec 21, 2007
• Grant date: Feb 16, 2010
• Expiry date: Dec 21, 2027

Classification

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

Abstract

Disclosed are techniques, apparatus, and targets for determining overlay error between two layers of a sample. Target A is designed to have an offset Xa between its first and second structures portions; target B is designed to have an offset Xb; target C is designed to have an offset Xc; and target D is designed to have an offset Xd. Each of the offsets Xa, Xb, Xc and Xd is preferably different from zero; Xa is an opposite sign and differ from Xb; and Xc is an opposite sign and differs from Xd. The targets A, B, C and D are illuminated with electromagnetic radiation to obtain spectra SA, SB, SC, and SD from targets A, B, C, and D, respectively. Any overlay error between the first structures and the second structures is then determined using a linear approximation based on the obtained spectra SA, SB, SC, and SD.