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Eliminating Formation of Hillocks during Annealing of Aluminum Copper Films

IP.com Disclosure Number: IPCOM000075850D
Original Publication Date: 1971-Nov-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

d'Heurle, FM: AUTHOR [+3]

Abstract

Very thin films of AlCu, of the order of microns in thickness, are vapor deposited onto a substrate in the normal manufacture of electronic components, units, devices, and the like. It is well known by those who grow such thin films, that hillocks (growths or protuberances) form on such thin metallic films when the latter are subjected to wide temperature changes. Such hillocks are detrimental to the operation and life of planar devices where the hillocks cause discontinuities in protective overlays on such planar devices, and become particularly aggravating when multiple layers of metallization are laid down and hillocks interfere with the operation of layers above and below them.

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Eliminating Formation of Hillocks during Annealing of Aluminum Copper Films

Very thin films of AlCu, of the order of microns in thickness, are vapor deposited onto a substrate in the normal manufacture of electronic components, units, devices, and the like. It is well known by those who grow such thin films, that hillocks (growths or protuberances) form on such thin metallic films when the latter are subjected to wide temperature changes. Such hillocks are detrimental to the operation and life of planar devices where the hillocks cause discontinuities in protective overlays on such planar devices, and become particularly aggravating when multiple layers of metallization are laid down and hillocks interfere with the operation of layers above and below them.

By the judicious use of manganese during the vapor deposition of Al-Cu alloy films, the tendency toward hillock growth has been virtually eliminated. If, during the deposition of Al-Cu alloy on a suitable substrate wherein the copper is about 1 to 15% by weight of the aluminum, manganese is simultaneously evaporated upon the substrate, future hillock formation is retarded. For example, manganese was added to a series of Al-Cu films to a concentration of 1/8 of the weight percentage of copper. Upon annealing at 480 degrees C and cooling to room temperature, these films were found to be hillock free.

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