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Proceedings Paper

A study of reticle non-flatness induced image placement error contributions in EUV lithography
Author(s): Sudhar Raghunathan; Obert Wood; Pradeep Vukkadala; Roxann Engelstad; Brian Lee; Sander Bouten; Thomas Laursen; John Zimmerman; Jaewoong Sohn; John Hartley
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Paper Abstract

Image placement (IP) and overlay error specifications are serious concerns for lithography at each successive technology node. Some of the primary contributors to image placement error (IPE) in EUV lithography are reticle and chuck surface non-flatness and chucking flatness non- uniformity. Flatness compensation has been proposed as a method to relax flatness specification for EUV substrates. However, in order for flatness compensation to work effectively, the various components of IPE i.e., reticle flattening and as-chucked z-height variation needs to be estimated accurately. Flatness compensation models assume a completely flat, rigid chuck and conformal clamping of the reticle backside. In this paper we will describe experiments designed to verify the different assumptions that the flatness compensation models are based on. The experiments involve printing wafers using a set of reticles of different flatness specifications on the ASML EUV Alpha Demo Tool (ADT) in Albany, NY. We will discuss results from these experiments and use Finite Element Modeling to simulate reticle chucking to correlate these results to physical properties electrostatic chuck on the ADT.

Paper Details

Date Published: 20 March 2010
PDF: 10 pages
Proc. SPIE 7636, Extreme Ultraviolet (EUV) Lithography, 76360W (20 March 2010); doi: 10.1117/12.847107
Show Author Affiliations
Sudhar Raghunathan, Univ. at Albany (United States)
Obert Wood, GLOBALFOUNDRIES Inc. (United States)
Pradeep Vukkadala, Univ. of Wisconsin-Madison (United States)
Roxann Engelstad, Univ. of Wisconsin-Madison (United States)
Brian Lee, ASML US, Inc. (United States)
Sander Bouten, ASML US, Inc. (United States)
Thomas Laursen, ASML US, Inc. (United States)
John Zimmerman, ASML US, Inc. (United States)
Jaewoong Sohn, SEMATECH North (United States)
John Hartley, Univ. at Albany (United States)

Published in SPIE Proceedings Vol. 7636:
Extreme Ultraviolet (EUV) Lithography
Bruno M. La Fontaine, Editor(s)

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