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Proceedings Paper

Improving overlay manufacturing metrics through application of feedforward mask-bias
Author(s): Etienne Joubert; Joseph C. Pellegrini; Manish Misra; John L. Sturtevant; John M. Bernhard; Phu Ong; Nathan K. Crawshaw; Vern Puchalski
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Paper Abstract

Traditional run-to-run controllers that rely on highly correlated historical events to forecast process corrections have been shown to provide substantial benefit over manual control in the case of a fab that is primarily manufacturing high volume, frequent running parts (i.e., DRAM, MPU, and similar operations). However, a limitation of the traditional controller emerges when it is applied to a fab whose work in process (WIP) is composed of primarily short-running, high part count products (typical of foundries and ASIC fabs). This limitation exists because there is a strong likelihood that each reticle has a unique set of process corrections different from other reticles at the same process layer. Further limitations exist when it is realized that each reticle is loaded and aligned differently on multiple exposure tools.A structural change in how the run-to-run controller manages the frequent reticle changes associated with the high part count environment has allowed for breakthrough performance to be achieved. This breakthrough was mad possible by the realization that; 1. Reticle sourced errors were highly stable over long periods of time, thus allowing them to be deconvolved from the day to day tool and process drifts. 2. Reticle sourced errors can be modeled as a feedforward disturbance rather than as discriminates in defining and dividing process streams. In this paper, we show how to deconvolve the static (reticle) and dynamic (day to day tool and process) components from the overall error vector to better forecast feedback for existing products as well as how to compute or learn these values for new product introductions - or new tool startups. Manufacturing data will presented to support this discussion with some real world success stories.

Paper Details

Date Published: 1 July 2003
PDF: 12 pages
Proc. SPIE 5044, Advanced Process Control and Automation, (1 July 2003); doi: 10.1117/12.485314
Show Author Affiliations
Etienne Joubert, INFICON (United States)
Joseph C. Pellegrini, INFICON (United States)
Manish Misra, INFICON (United States)
John L. Sturtevant, Integrated Device Technology, Inc. (United States)
John M. Bernhard, Integrated Device Technology, Inc. (United States)
Phu Ong, Integrated Device Technology, Inc. (United States)
Nathan K. Crawshaw, Integrated Device Technology, Inc. (United States)
Vern Puchalski, Integrated Device Technology, Inc. (United States)

Published in SPIE Proceedings Vol. 5044:
Advanced Process Control and Automation
Matt Hankinson; Christopher P. Ausschnitt, Editor(s)

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