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Proceedings Paper

Novel diffraction-based spectroscopic method for overlay metrology
Author(s): Weidong Yang; Roger Lowe-Webb; Silvio Rabello; Jiangtao Hu; Je-Yi Lin; John D. Heaton; Mircea V. Dusa; Arie J. den Boef; Maurits van der Schaar; Adolph Hunter
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Paper Abstract

A spectroscopic, diffraction based technique is proposed in this paper as an alternative solution for overlay metrology in technology nodes below 90 nanometers. This novel technique extracts alignment error from broadband diffraction efficiency of specially designed diffraction targets in real-time. Feasibility of the technique is studied for a front-end process flow by measuring grating targets printed on a series of wafers which were intentionally mis-processed to introduce inter-die (grid) level programmed overlay errors. Correlation to conventional imaging overlay measurements is demonstrated. Short term and long term data sets demonstrate sub-half-nanometer in 3-sigma statistical parameters that characterize the diffraction overlay system, repeatability, reproducibility, Tool-Induced-Shift and tool-to-tool matching. The resulting total measurement uncertainty for this technique is thus demonstrated to be in the sub-nanometer range.

Paper Details

Date Published: 2 June 2003
PDF: 8 pages
Proc. SPIE 5038, Metrology, Inspection, and Process Control for Microlithography XVII, (2 June 2003); doi: 10.1117/12.483476
Show Author Affiliations
Weidong Yang, Nanometrics Inc. (United States)
Roger Lowe-Webb, Nanometrics Inc. (United States)
Silvio Rabello, Nanometrics Inc. (United States)
Jiangtao Hu, Nanometrics, Inc. (United States)
Je-Yi Lin, Nanometrics Inc. (United States)
John D. Heaton, Nanometrics Inc. (United States)
Mircea V. Dusa, ASML (United States)
Arie J. den Boef, ASML (Netherlands)
Maurits van der Schaar, ASML (Netherlands)
Adolph Hunter, ASML (United States)

Published in SPIE Proceedings Vol. 5038:
Metrology, Inspection, and Process Control for Microlithography XVII
Daniel J. Herr, Editor(s)

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