Optical illumination optimization for patterned defect inspection

Published

April 20, 2011

Author(s)

Bryan M. Barnes, Richard Quintanilha, Martin Y. Sohn, Hui Zhou, Richard M. Silver

Abstract

Rapidly decreasing critical dimensions (CD) for semiconductor devices drive the study of improved methods for the detection of defects within patterned areas. As reduced CDs are being achieved through directional patterning, additional constraints and opportunities present themselves in defect metrology. This simulation and experimental study assesses potential improvements in patterned defect inspection that may be achieved by engineering the light incident to the sample within a high-magnification imaging platform. Simulation variables include the incident angle, polarization, and wavelength for defect types common to directional device layouts. Detectability is determined through differential images between no-defect- and defect-containing images. Alternative metrologies such as interference microscopy are also investigated through modeling. The measurement of a sub-20 nm defects is demonstrated experimentally using 193 nm light. The complex interplay of unidirectional patterning and highly directional defects is explored using structured off-axis illumination and polarization.

Proceedings Title

SPIE Advanced Lithography

Volume

7971

Conference Dates

February 27-March 3, 2011

Conference Location

Gaithersburg, MD

Conference Title

Metrology, Inspection, and Process Control for Microlithography XXV

Pub Type

Conferences

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Keywords

Defect detection, Scatterfield optical microscopy, illumination optimization, bright-field microscopy, dark-field microscopy

Citation

Barnes, B. , Quintanilha, R. , Sohn, M. , Zhou, H. and Silver, R. (2011), Optical illumination optimization for patterned defect inspection, SPIE Advanced Lithography, Gaithersburg, MD, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=908276 (Accessed October 14, 2025)