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Proceedings Paper

Intra-field alignment for overlay feed-forward simulation with sampling optimization
Author(s): Cheng Hao Yang; Chun Chi Yu; Patrick Lomtscher; Martin Freitag; Steven Tottewitz; Boris Habets; Hsiao Lin Hsu; Rex H. Liu
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Paper Abstract

It was proven that higher order intra-field alignment data modeling and correction has the potential to improve overlay performance by correcting reticle heating and lens heating effects intra-wafer and wafer- to-wafer.1 But there were also challenges shown that needed further investigation. As the alignment measurement is done on a coordinate system with absolute positions, the modeled iHOPC values might be high. A suitable method needs to be developed to distinguish between tool-to-tool offsets, process influence and layer-to-layer tool stack effect. In this paper we will take the next step and evaluate the overlay improvement potential by using intra-field alignment data in an overlay feed-forward simulation. An overlay run-to-run simulation is afterwards performed to estimate the optimization potential. To simulate higher order intra-field overlay, dense alignment data is needed. Facing the challenge of optimizing the number of measured marks but not losing relevant information, an intra-field alignment mark sampling optimization is done to find the best compromise between throughput and overlay accuracy.

Paper Details

Date Published: 26 March 2019
PDF: 11 pages
Proc. SPIE 10959, Metrology, Inspection, and Process Control for Microlithography XXXIII, 109592T (26 March 2019); doi: 10.1117/12.2514984
Show Author Affiliations
Cheng Hao Yang, United Microelectronics Corp. (Taiwan)
Chun Chi Yu, United Microelectronics Corp. (Taiwan)
Patrick Lomtscher, Qoniac GmbH (Germany)
Martin Freitag, Qoniac GmbH (Germany)
Steven Tottewitz, Qoniac GmbH (Germany)
Boris Habets, Qoniac GmbH (Germany)
Hsiao Lin Hsu, Qoniac Taiwan Ltd. (Taiwan)
Rex H. Liu, Qoniac Taiwan Ltd. (Taiwan)

Published in SPIE Proceedings Vol. 10959:
Metrology, Inspection, and Process Control for Microlithography XXXIII
Vladimir A. Ukraintsev; Ofer Adan, Editor(s)

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