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Evaluation of Copper Oxide to Copper Selectivity of Chemical Systems for BEOL Cleaning Through Electrochemical Investigations

Published online by Cambridge University Press:  01 February 2011

Nandini Venkataraman ,
Ashok Kumar Muthukumaran  and
Srini Raghavan
Nandini Venkataraman
Affiliation:
[email protected], The University of Arizona, Materials Science and Engineering, 4715 E Ft Lowell Rd, Tucson, AZ, 85712, United States
Ashok Kumar Muthukumaran
Affiliation:
[email protected], The University of Arizona, Materials Science and Engineering, 4715 E Ft Lowell Rd, Tucson, AZ, 85712, United States
Srini Raghavan
Affiliation:
[email protected], The University of Arizona, Materials Science and Engineering, 4715 E Ft Lowell Rd, Tucson, AZ, 85712, United States
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Abstract

Back End of Line (BEOL) cleaning of copper based structures requires chemical formulations that can remove copper oxide selectively without corroding copper and etching the dielectric. Many commercially available semi-aqueous and all aqueous formulations claim to meet these criteria. These include semi-aqueous fluoride strippers (SAF) and all- aqueous ammonium phosphate based chemical systems.

This paper will report the results from a fundamental study undertaken to evaluate the performance of a semi-aqueous fluoride formulation in removing copper oxide films of controlled thickness grown on copper. The thickness and composition of the oxide films were determined electrochemically using cathodic reduction technique. Electrochemical impedance spectra of samples immersed in the formulation have been measured as a function of time to follow copper oxide dissolution and the data have been analyzed to detect the transition of copper oxide to copper.

Keywords

Cucorrosionchemical composition
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 990: Symposium B – Materials, Processes, Integration and Reliability in Advanced Interconnects for Micro- and Nanoelectronics , 2007 , 0990-B08-25
Copyright
Copyright © Materials Research Society 2007

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References

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