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Proceedings Paper

Scatterometry for contact hole lithography
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Paper Abstract

Scatterometry has been most commonly applied to CD metrology of line/space grating structures. However, for the process development and control of 3D structures for contact hole lithography applications, the current metrology methods of CD-SEM, electrical CD (ECD) and/or cross-sectional SEM (X-SEM) produce the desired information either (a) as an incomplete solution, (b) too late in process flow, or (c) in a destructive manner. In this paper, we will present use cases for the application of scatterometry to 3D structures, i.e., post-lithography hole/space patterns, where measurements of CD, profile, and film thickness can be made immediately following the lithography process, in a method nondestructive to the wafer. These use cases demonstrate the capability of 3D metrology integrated onto a TEL Clean Track platform, where a Therma-Wave reflectometer was used to generate spectra that were then processed via Timbre ODP, for a film stack of patterned photoresist (PR), anti-reflective coating (ARC), and oxide on top of a silicon (Si) substrate. Focus-Exposure Matrix (FEM) wafers have also been produced in order to characterize the contact hole profile and CD variation as a result of changing focus and exposure conditions. The results of the experiment show that ODP can be used successfully to monitor CD, film thickness, and profile variation, providing a valuable solution to contact hole lithography. Tool precision and matching results are also shown, which indicate the stability of the measurement process, and correlation to CD-SEM is also provided as a reference metrology. These results suggest that integrated 3D scatterometry is a viable production metrology solution, enabling the progression toward Advanced Process Control (APC).

Paper Details

Date Published: 24 May 2004
PDF: 6 pages
Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); doi: 10.1117/12.536057
Show Author Affiliations
Kelly A. Barry, Timbre Technologies, Inc. (United States)
Anita Viswanathan, Tokyo Electron America, Inc. (United States)
Xinhui Niu, Timbre Technologies, Inc. (United States)
Joerg Bischoff, Timbre Technologies, Inc. (United States)

Published in SPIE Proceedings Vol. 5375:
Metrology, Inspection, and Process Control for Microlithography XVIII
Richard M. Silver, Editor(s)

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