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Aluminum Copper Thin Film Conductors Resistant to Electromigration

IP.com Disclosure Number: IPCOM000075187D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

d'Heurle, F: AUTHOR [+2]

Abstract

Aluminum thin-film conductors are known to fail after prolonged exposure to the passage of direct current as a result of mass transport caused by momentum transfer from the electrons to the aluminum atoms. It has been previously demonstrated that the addition of copper to aluminum substantially increases the lifetime of thin-film conductors.

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Aluminum Copper Thin Film Conductors Resistant to Electromigration

Aluminum thin-film conductors are known to fail after prolonged exposure to the passage of direct current as a result of mass transport caused by momentum transfer from the electrons to the aluminum atoms. It has been previously demonstrated that the addition of copper to aluminum substantially increases the lifetime of thin-film conductors.

Films were deposited by vacuum evaporation onto substrates at a temperature of 200 degrees C. The deposition was carried out in the following five successive steps without breaking vacuum: Al, Cu, Al, Mg, Al. The additions to aluminum were approximately 2 wt. % Cu, and 2 wt. % Mg. Annealing at 340 degrees C, for fifteen minutes in a nitrogen atmosphere is considered to have provided for the diffusion of both additive elements through the aluminum. The result of accelerated current stress testing, at 175 degrees C and 4 x 10/6/ amp/cm/2/, indicates a mean lifetime for eleven stripes of 2000 hours.

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