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Proceedings Paper

Multiple layer CD control treatment
Author(s): Anka Birnstein; Christoph Röpke; Martin Sczyrba; Rainer Pforr; Mario Hennig; Guy Ben-Zvi; Erez Graitzer; Avi Cohen
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Paper Abstract

Tight control of intra-field CD variations becomes more and more important as the pattern sizes on wafer shrink. For intra-field CD uniformity improvement several techniques have been developed. A very effective method is changing the local mask blank transmittance according to measured Intra Field (IF) CD variations using Pixer's CDCTM technique. This process is irreversible. For various practical reasons it would be helpful to have the opportunity for a second or more mask blank treatments. A first application could be to improve an unsatisfying CDU post first treatment. A second application can be the switch of the mask usage to another tool group. Furthermore, the opportunity to use multiple CDC treatments would allow the splitting of the correction process for the mask and the tool separately, whereas in a first correction only the mask CDU errors will be corrected and after the mask is supplied to the customer another correction may be required to reduce the exposure tool contributions to the CDU budget. Therefore the intention of the paper is to evaluate the opportunities of a Multiple CDC (MCDC) correction process, to determine its accuracy and the corresponding limits. To do this two CDC tool projection lenses have been characterized, which have been developed for different focus positions. We will characterize their transmittance transfer performance, stability and sensitivities. The required multiple layer distances will be determined. The linearity of the multiple CDC treatment will be analyzed using AIMSTM measurements and wafer prints. We will present results of successful multiple CDC corrections for production masks.

Paper Details

Date Published: 16 March 2009
PDF: 12 pages
Proc. SPIE 7274, Optical Microlithography XXII, 727422 (16 March 2009); doi: 10.1117/12.814123
Show Author Affiliations
Anka Birnstein, AMTC GmbH & Co. KG (Germany)
Christoph Röpke, AMTC GmbH & Co. KG (Germany)
Martin Sczyrba, AMTC GmbH & Co. KG (Germany)
Rainer Pforr, Qimonda Dresden GmbH & Co. OHG (Germany)
Mario Hennig, Qimonda Dresden GmbH & Co. OHG (Germany)
Guy Ben-Zvi, Pixer Technology, Ltd. (Israel)
Erez Graitzer, Pixer Technology, Ltd. (Israel)
Avi Cohen, Pixer Technology, Ltd. (Israel)

Published in SPIE Proceedings Vol. 7274:
Optical Microlithography XXII
Harry J. Levinson; Mircea V. Dusa, Editor(s)

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