Apparatus and methods for detecting overlay errors using scatterometry

US7280212B2 · 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
• Mark Ghinovker · Migdal HaEmek, IL
• John Fielden · Los Altos, US
• Noah Bareket · Saratoga, US

Key dates

• Filing date: Feb 23, 2004
• Grant date: Oct 9, 2007
• Expiry date: Jun 8, 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 each of 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, a first optical signal is measured using a first ellipsometer or a first reflectometer and a second optical signal is measured using a second ellipsometer or a second reflectometer. 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 first and second optical signals from the periodic targets using a scatterometry overlay technique based on the predefined offsets.