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Aluminum Copper Silicon Semiconductor Metallurgy

IP.com Disclosure Number: IPCOM000074531D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Conrad, EE: AUTHOR

Abstract

The fabrication of semiconductor interconnections of aluminum with small percentages of silicon to prevent penetration of the aluminum into the silicon wafer during subsequent high temperature processes is well known. The use of copper in aluminum to prevent early wearout failures has been recently published. Where both of these additives to aluminum are desired, the uniform distribution of copper throughout the film in a concentration below the eutectic composition becomes critical.

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Aluminum Copper Silicon Semiconductor Metallurgy

The fabrication of semiconductor interconnections of aluminum with small percentages of silicon to prevent penetration of the aluminum into the silicon wafer during subsequent high temperature processes is well known. The use of copper in aluminum to prevent early wearout failures has been recently published. Where both of these additives to aluminum are desired, the uniform distribution of copper throughout the film in a concentration below the eutectic composition becomes critical.

One solution to this problem is to prepare many small charges with the proper composition of aluminum, copper and silicon and then evaporate these charges one at a time from a high temperature flash evaporation filament. The flash evaporation of Al-Cu-Si from small charges with uniform composition results in a film where the copper is evenly distributed throughout the film, even though there are local concentrations of pure silicon. Because the temperature needed to evaporate aluminum and copper under high vacuum conditions is very close, the result is a very nearly simultaneous evaporation of aluminum and copper under flash evaporation conditions. The silicon, however, requires a somewhat higher temperature and therefore arrives at the substrate, in most part, after the aluminum and copper. Since there are many layers of the Al-Cu and Si, the silicon is still effectively distributed throughout the film. Under the subsequent high tempe...