Optical metrology using targets with field enhancement elements

US8879073B2 · kind B2 · utility

Assignee

• KLA-TENCOR CORPORATION · US

Inventors

• Jonathan M. Madsen · Los Altos, US
• Andrei V. Shchegrov · Campbell, US
• Michael S. Bakeman · San Jose, US
• Thaddeus Gerard Dziura · San Jose, US
• Alexander Kuznetsov · Austin, US
• Bin-Ming Benjamin Tsai · Saratoga, US

Key dates

• Filing date: Feb 19, 2013
• Grant date: Nov 4, 2014
• Expiry date: Apr 29, 2033

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L22/30
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

Methods and systems for enhancing metrology sensitivity to particular parameters of interest are presented. Field enhancement elements (FEEs) are constructed as part of a specimen to enhance the measurement sensitivity of structures of interest present on the specimen. The design of the FEEs takes into account measurement goals and manufacturing design rules to make target fabrication compatible with the overall device fabrication process. Measurement of opaque materials, high-aspect ratio structures, structures with low-sensitivity, or mutually correlated parameters is enhanced by the addition of FEEs. Exemplary measurements include critical dimension, film thickness, film composition, and optical scatterometry overlay. In some examples, a target element includes different FEEs to improve the measurement of different structures of interest. In other examples, different target elements include different FEEs. In some other examples, field enhancement elements are shaped to concentrate an electric field in a thin film deposited over the FEE.