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Proceedings Paper

Advanced applications of scatterometry based optical metrology
Author(s): Dhairya Dixit; Nick Keller; Taher Kagalwala; Fiona Recchia; Yevgeny Lifshitz; Alexander Elia; Vinit Todi; Jody Fronheiser; Alok Vaid
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Paper Abstract

The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, and lower cost per transistor. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require continuous development of metrology tools used for characterization of these complex 3D device architectures. Optical scatterometry or optical critical dimension (OCD) is one of the most prevalent inline metrology techniques in semiconductor manufacturing because it is a quick, precise and non-destructive metrology technique. However, at present OCD is predominantly used to measure the feature dimensions such as line-width, height, side-wall angle, etc. of the patterned nano structures. Use of optical scatterometry for characterizing defects such as pitch-walking, overlay, line edge roughness, etc. is fairly limited. Inspection of process induced abnormalities is a fundamental part of process yield improvement. It provides process engineers with important information about process errors, and consequently helps optimize materials and process parameters. Scatterometry is an averaging technique and extending it to measure the position of local process induced defectivity and feature-to-feature variation is extremely challenging. This report is an overview of applications and benefits of using optical scatterometry for characterizing defects such as pitch-walking, overlay and fin bending for advanced technology nodes beyond 7nm. Currently, the optical scatterometry is based on conventional spectroscopic ellipsometry and spectroscopic reflectometry measurements, but generalized ellipsometry or Mueller matrix spectroscopic ellipsometry data provides important, additional information about complex structures that exhibit anisotropy and depolarization effects. In addition the symmetry-antisymmetry properties associated with Mueller matrix (MM) elements provide an excellent means of measuring asymmetry present in the structure. The useful additional information as well as symmetry-antisymmetry properties of MM elements is used to characterize fin bending, overlay defects and design improvements in the OCD test structures are used to boost OCDs’ sensitivity to pitch-walking. In addition, the validity of the OCD based results is established by comparing the results to the top down critical dimensionscanning electron microscope (CD-SEM) and cross-sectional transmission electron microscope (TEM) images.

Paper Details

Date Published: 28 March 2017
PDF: 10 pages
Proc. SPIE 10145, Metrology, Inspection, and Process Control for Microlithography XXXI, 101451H (28 March 2017); doi: 10.1117/12.2261430
Show Author Affiliations
Dhairya Dixit, GLOBALFOUNDRIES Inc. (United States)
Nick Keller, Nanometrics Inc. (United States)
Taher Kagalwala, GLOBALFOUNDRIES Inc. (United States)
Fiona Recchia, GLOBALFOUNDRIES Inc. (United States)
Yevgeny Lifshitz, Nanometrics Inc. (United States)
Alexander Elia, GLOBALFOUNDRIES Inc (United States)
Vinit Todi, GLOBALFOUNDRIES Inc. (United States)
Jody Fronheiser, GLOBALFOUNDRIES Inc. (United States)
Alok Vaid, GLOBALFOUNDRIES Inc. (United States)

Published in SPIE Proceedings Vol. 10145:
Metrology, Inspection, and Process Control for Microlithography XXXI
Martha I. Sanchez, Editor(s)

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