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Proceedings Paper

Physical matching of CD-SEM: noise analysis and verification in FAB environment
Author(s): Uwe Kramer; Alessandra Navarra; Goeran Fleischer; Jan Kaiser; Frank Voss; Galit Zuckerman; Roman Kris; Igal Ben-Dayan; Elad Sommer; Amir Len; Shalev Dror; Dirk Schöne; Stefano Ventola
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Paper Abstract

CD-SEMs fleet matching is a widely discussed subject and various approaches and procedures to determine it were described in the literature [1,2,4-6]. The different approaches for matching are all based on statistical treatment of CD measurements that are performed on dedicated test structures. The test structures are a limited finite set of features, thus the matching results should be treated as valid only for the specific defined set of test features. The credibility of the matching should be in question for different layers and specifically production layers. Since matching is crucial for reliable process monitoring by a fleet of CD-SEMs, the current matching approaches must be extended so that the matching will be only tool dependent and reproducible on all layers regardless their specific material or topographic characteristics. In our previous work [1] the new approach named "Physical Matching" was introduced and a new matching procedure based on the direct estimation of tool physical parameters was described. This approach extends the conventional matching methods to enable significant improvement of the matching between CD-SEM tools in production environment. In this work we present results of applying the physical matching method in FAB environment by using the physical parameters of the brightness and SNR, extend it to noise frequency domain characteristics monitoring, and enhanced collection uniformity. Improving the collection uniformity is also demonstrated and proved to be a significant factor. The advantage of the physical matching with noise spectra analysis approach for a case study is demonstrated. This method will enable detection of specific reasons for mismatching between the tools, based on analysis of specific frequencies that are resulted from known mechanical/electrical noise. The proposed procedure allows tool problems fixing before CD measurements are affected. In order to get a reliable visualization of the difference between two systems, new automatic and manual tool finger print methods were developed. The application of the proposed approach to vendor to vendor matching problem is considered.

Paper Details

Date Published: 4 April 2008
PDF: 11 pages
Proc. SPIE 6922, Metrology, Inspection, and Process Control for Microlithography XXII, 69221R (4 April 2008); doi: 10.1117/12.776865
Show Author Affiliations
Uwe Kramer, Qimonda Dresden GmbH and Co. OHG (Germany)
Alessandra Navarra, Qimonda Dresden GmbH and Co. OHG (Germany)
Goeran Fleischer, Qimonda Dresden GmbH and Co. OHG (Germany)
Jan Kaiser, Qimonda Dresden GmbH and Co. OHG (Germany)
Frank Voss, Qimonda Dresden GmbH and Co. OHG (Germany)
Galit Zuckerman, Applied Materials, Inc. (Israel)
Roman Kris, Applied Materials, Inc. (Israel)
Igal Ben-Dayan, Applied Materials, Inc. (Israel)
Elad Sommer, Applied Materials, Inc. (Israel)
Amir Len, Applied Materials, Inc. (Israel)
Shalev Dror, Applied Materials, Inc. (Israel)
Dirk Schöne, Applied Materials, Inc. (Germany)
Stefano Ventola, Applied Materials, Inc. (Germany)

Published in SPIE Proceedings Vol. 6922:
Metrology, Inspection, and Process Control for Microlithography XXII
John A. Allgair; Christopher J. Raymond, Editor(s)

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