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Proceedings Paper

In-line lithography cluster monitoring and control using integrated scatterometry
Author(s): Ivan Pollentier; Shaunee Y. Cheng; Bart Baudemprez; David Laidler; Youri van Dommelen; Rene Carpaij; Jackie Yu; Junichi Uchida; Anita Viswanathan; Doris Chin; Kelly Barry; Nickhil Jakatdar
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Paper Abstract

In the continuous drive for smaller feature sizes, process monitoring becomes increasingly important to compensate for the smaller lithography process window and to assure that Critical Dimensions (CD) remain within the required specifications. Moreover, the higher level of automation in manufacturing enables almost real-time correction of lithography cluster machine parameters, resulting in a more efficient and controlled use of the tools. Therefore, fast and precise in-line lithography metrology using Advanced Process Control (APC) rules are becoming crucial, in order to guarantee that critical dimensions stay correctly targeted. In this paper, the feasibility of improving the CD control of a 193nm lithography cluster has been investigated by using integrated scatterometry. The target of the work was to identify if a dose correction on field and wafer level, based on precise in-line measurements, could improve the overall CD control. Firstly, the integrated metrology has been evaluated extensively towards precision and sensitivity in order to prove its benefits for this kind of control. Having a long-term repeatability of significantly better than 0.75nm 3σ, this was very promising towards the requirements for sub-nanometer CD correction. Moreover, based on an extensive evaluation of the process window on the lithography cluster, it has been shown that the focus variation is minimal and that CD control can be improved using dose correction only. In addition, systematic variations in across-wafer uniformity and across-lot uniformity have been determined during this monitoring period, in order to identify correctable fingerprints. Finally, the dose correction model has been applied to compensate for these systematic CD variations and improved CD control was demonstrated. Using a simple dose correction rule, a forty percent improvement in CD control was obtained.

Paper Details

Date Published: 29 April 2004
PDF: 11 pages
Proc. SPIE 5378, Data Analysis and Modeling for Process Control, (29 April 2004); doi: 10.1117/12.537384
Show Author Affiliations
Ivan Pollentier, IMEC (Belgium)
Shaunee Y. Cheng, IMEC (Belgium)
Bart Baudemprez, IMEC (Belgium)
David Laidler, IMEC (Belgium)
Youri van Dommelen, ASML (Netherlands)
Rene Carpaij, ASML (Netherlands)
Jackie Yu, Tokyo Electron Ltd. (Japan)
Junichi Uchida, Tokyo Electron Ltd. (Japan)
Anita Viswanathan, Tokyo Electron Ltd. (Japan)
Doris Chin, Tokyo Electron Ltd. (Japan)
Kelly Barry, Tokyo Electron Ltd. (Japan)
Nickhil Jakatdar, Tokyo Electron Ltd. (Japan)

Published in SPIE Proceedings Vol. 5378:
Data Analysis and Modeling for Process Control
Kenneth W. Tobin Jr., Editor(s)

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