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Al Diffusion in Polycrystalline Cu

Published online by Cambridge University Press:  01 February 2011

Florian Gstrein
Affiliation:
florian.gstrein@intel.com, Intel Corporation, Components Research, 2501 NW 229th Avenue, RA3-252, .Hillsboro, OR, .97124, United States, 971-214-1605
Harold Kennel
Affiliation:
harold.kennel@intel.com, Intel Corporation, Hillsboro, OR, 97214, United States
Andre Budrevich
Affiliation:
andrew.budrevich@intel.com, Intel Corporation, Hillsboro, OR, 97214, United States
Barbara Miner
Affiliation:
barbara.miner@intel.com, Intel Corporation, Hillsboro, OR, 97214, United States
John Plombon
Affiliation:
john.p.plombon@intel.com, Intel Corporation, Hillsboro, OR, 97214, United States
Ebrahim Andideh
Affiliation:
ebandideh@comcast.com, Intel Corporation, Hillsboro, OR, 97214, United States
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Abstract

The diffusion of aluminum (Al) from a source sandwiched between polycrystalline copper (Cu) thin films was investigated as a function of time and temperature through secondary ion mass spectroscopy (SIMS) and continuum simulations. Extracted diffusion coefficients for the bulk were in line with literature values. In order to simulate the experimentally derived diffusion profiles at temperatures where bulk diffusion is not the dominant diffusion mechanism (room temperature to 350 °C), it was necessary to explicitly include the re-distribution of Al as a result of Cu grain growth during anneal. Aluminum has the tendency to segregate to the Cu/liner and Cu/etch stop (ES) interface. The tendency of Al to segregate to the liner is ten times stronger for ruthenium (Ru) than for tantalum (Ta). In 100 nm wide dual damascene structures lined with Ru, this segregation behavior was responsible for the Al depletion in bulk Cu and for the Al depletion at the Cu/ES interface.

Keywords

Type
Research Article
Copyright
Copyright © Materials Research Society 2008

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References

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