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Proceedings Paper

Improvement in total measurement uncertainty for gate CD control
Author(s): Benjamin D. Bunday; Osman Sorkhabi; Youxian Wen; Ajit Paranjpe; Paul Terbeek; John Allgair; Amy Peterson
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Paper Abstract

With shrinkage of device size, metrology requirements for Critical Dimension (CD), as defined as the ratio of precision of metrology to process tolerance (P/T), must meet the 0.1 (10%) or 0.2 (20%) criterion.[1][2][14] The precision requirement for gate CD at the 90nm node is thus ~ 0.3nm or less with P/T of 10%, which is far beyond what traditional CD metrology can achieve today. At future nodes, this requirement becomes even tougher, even with P/T of 20%. For years, scatterometry has demonstrated its capability to determine CD and cross sectional profile over periodically aligned line and space (i.e. grating) structures with superior precision. However, to gauge the true capability of scatterometry for process monitoring, the concept of Total Measurement Uncertainty (TMU)[11] of scatterometry in reference to CD-SEM and CD-AFM should be implemented since TMU comprehends both precision and accuracy relative to a reference measurement system. The methodology of implementation of TMU has been discussed in a separate article.[1][12][14][15][17] This paper presents a systematic study on TMU of scatterometry for Final Inspect (FI, post-etch) gate CD and profile, and includes a discussion on how the TMU may be further reduced. One potential option is to feed forward film stack information into the profile modeling, which reduces the number of parameters that have to be calculated during the real-time regression of the scatterometry data.

Paper Details

Date Published: 18 August 2005
PDF: 12 pages
Proc. SPIE 5878, Advanced Characterization Techniques for Optics, Semiconductors, and Nanotechnologies II, 58780M (18 August 2005); doi: 10.1117/12.616344
Show Author Affiliations
Benjamin D. Bunday, ISMI (United States)
Osman Sorkhabi, Therma-Wave, Inc. (United States)
Youxian Wen, Therma-Wave, Inc. (United States)
Ajit Paranjpe, Therma-Wave, Inc. (United States)
Paul Terbeek, Therma-Wave, Inc. (United States)
John Allgair, ISMI (United States)
Amy Peterson, ISMI (United States)

Published in SPIE Proceedings Vol. 5878:
Advanced Characterization Techniques for Optics, Semiconductors, and Nanotechnologies II
Angela Duparre; Bhanwar Singh; Zu-Han Gu, Editor(s)

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