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Proceedings Paper

Co-optimization of RegC and TWINSCAN corrections to improve the intra-field on-product overlay performance
Author(s): Kujan Gorhad; Ofir Sharoni; Vladimir Dmitriev; Avi Cohen; Richard van Haren; Christian Roelofs; Hakki Ergun Cekli; Emily Gallagher; Philippe Leray; Dirk Beyer; Thomas Trautzsch; Steffen Steinert
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Paper Abstract

Improving wafer On Product Overlay (OPO) is becoming a major challenge in lithography, especially for multipatterning techniques like N-repetitive Litho-Etch steps (LEN, N ≥ 2). When using different scanner settings and litho processes between inter-layer overlays, intra-field overlay control becomes more complicated. In addition to the Image Placement Error (IPE) contribution, the TWINSCANTM lens fingerprint in combination with the exposure settings is playing a significant role as well. Furthermore the scanner needs to deal with dynamic fingerprints caused by for instance lens and/or reticle heating.

This paper will demonstrate the complementary RegC® and TWINSCANTM solution for improving the OPO by cooptimizing the correction capabilities of the individual tools, respectively. As a consequence, the systematic intra-field fingerprints can be decreased along with the overlay (OVL) error at wafer level. Furthermore, the application could be utilized for extending some of the scanner actuators ranges by inducing a pre-determined signatures. These solutions perfectly fit into the ASML Litho InSight (LIS) product in which feedforward and feedback corrections based on YieldStar overlay and other measurements are used to improve the OPO. While the TWINSCANTM scanner corrects for global distortions (up to third order) - scanner Correctable Errors ( CE), the RegC® application can correct for the None Correctable Errors (NCE) by making the high frequency NCE into a CE with low frequency nature. The RegC® induces predictable deformation elements inside the quartz (Qz) material of the reticle, and by doing so it can induce a desired pre-defined signature into the reticle. The deformation introduced by the RegC® is optimized for the actual wafer print taking into account the scale and ortho compensation by the scanner, to correct for the systematic fingerprints and the wafer overlay. These two applications might be very powerful and could contribute to achieve a better OPO performance.

Paper Details

Date Published: 8 March 2016
PDF: 21 pages
Proc. SPIE 9778, Metrology, Inspection, and Process Control for Microlithography XXX, 97783D (8 March 2016); doi: 10.1117/12.2219291
Show Author Affiliations
Kujan Gorhad, Carl Zeiss SMS Ltd. (Israel)
Ofir Sharoni, Carl Zeiss SMS Ltd. (Israel)
Vladimir Dmitriev, Carl Zeiss SMS Ltd. (Israel)
Avi Cohen, Carl Zeiss SMS Ltd. (Israel)
Richard van Haren, ASML (Netherlands)
Christian Roelofs, ASML (Netherlands)
Hakki Ergun Cekli, ASML (Netherlands)
Emily Gallagher, IMEC (Belgium)
Philippe Leray, IMEC (Belgium)
Dirk Beyer, Carl Zeiss SMS GmbH (Germany)
Thomas Trautzsch, Carl Zeiss SMS GmbH (Germany)
Steffen Steinert, Carl Zeiss SMS GmbH (Germany)

Published in SPIE Proceedings Vol. 9778:
Metrology, Inspection, and Process Control for Microlithography XXX
Martha I. Sanchez, Editor(s)

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