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Proceedings Paper

Logic gate scanner focus control in high-volume manufacturing using scatterometry
Author(s): Richard J Dare; Bryan Swain; Michael Laughery
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Paper Abstract

Tool matching and optimal process control are critical requirements for success in semiconductor manufacturing. It is imperative that a tool’s operating conditions are understood and controlled in order to create a process that is repeatable and produces devices within specifications. Likewise, it is important where possible to match multiple systems using some methodology, so that regardless of which tool is used the process remains in control. Agere Systems is currently using Timbre Technologies’ Optical Digital Profilometry (ODP) scatterometry for controlling Nikon scanner focus at the most critical lithography layer; logic gate. By adjusting focus settings and verifying the resultant changes in resist profile shape using ODP, it becomes possible to actively control scanner focus to achieve a desired resist profile. Since many critical lithography processes are designed to produce slightly re-entrant resist profiles, this type of focus control is not possible via Critical Dimension Scanning Electron Microscopy (CDSEM) where reentrant profiles cannot be accurately determined. Additionally, the high throughput and non-destructive nature of this measurement technique saves both cycle time and wafer costs compared to cross-section SEM. By implementing an ODP daily process check and after any maintenance on a scanner, Agere successfully enabled focus drift control, i.e. making necessary focus or equipment changes in order to maintain a desired resist profile.

Paper Details

Date Published: 24 May 2004
PDF: 8 pages
Proc. SPIE 5375, Metrology, Inspection, and Process Control for Microlithography XVIII, (24 May 2004); doi: 10.1117/12.533835
Show Author Affiliations
Richard J Dare, Agere Systems (United States)
Bryan Swain, Timbre Technologies, Inc. (United States)
Michael Laughery, 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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