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Heat Treatment of Aluminum to Reduce Electromigration

IP.com Disclosure Number: IPCOM000092325D
Original Publication Date: 1967-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Herdzik, RJ: AUTHOR [+3]

Abstract

This method materially increases the resistance to electromigration of thin-film aluminum conductor stripes in interconnection metallurgy systems for semiconductor devices.

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Heat Treatment of Aluminum to Reduce Electromigration

This method materially increases the resistance to electromigration of thin- film aluminum conductor stripes in interconnection metallurgy systems for semiconductor devices.

For integrated circuitry, fine, closely spaced conductors are necessary to realize the benefits of such structures. Consequently, conductor current densities and temperatures increase with increased microminiaturization. Vacuum-deposited aluminum film conductors under electrical stress degrade and become electrically discontinuous with time by a process of current induced mass transport known as electromigration. Since aluminum has many desirable properties in a metallization system, techniques to increase its resistance to electromigration and thus overcome this inherent weakness is highly desirable.

In the fabrication of semiconductor devices, the aluminum film structure is vacuum-deposited by conventional techniques at temperatures normally below 300 degrees C. In order to sinter in an ohmic contact, the film structure is normally reheated to a temperature above the deposition temperature.

When reheating to temperatures of 450 degrees C and below, the time to failure of the aluminum conductor stripes is materially affected. However, stripes subjected to 500 degrees C to 565 degrees C fail at a much faster rate.

In this method, the sputtering operation is done at relatively low temperatures. These are sufficiently high to achieve the int...