Browse Prior Art Database

Process for Overlay Silicon Diffusion During Metallization

IP.com Disclosure Number: IPCOM000086238D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

DiAngelo, DW: AUTHOR [+3]

Abstract

With aluminum or aluminum alloy metallization, a layer of silicon may be applied on the aluminum metallurgy to prevent penetration of aluminum from metallurgy into the silicon substrate in integrated circuit fabrication. In the fabrication of such structures, it is customary for the silicon layer to be evaporated onto the aluminum metallurgy in evaporation apparatus after the formation of the aluminum layer by evaporation.

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Process for Overlay Silicon Diffusion During Metallization

With aluminum or aluminum alloy metallization, a layer of silicon may be applied on the aluminum metallurgy to prevent penetration of aluminum from metallurgy into the silicon substrate in integrated circuit fabrication. In the fabrication of such structures, it is customary for the silicon layer to be evaporated onto the aluminum metallurgy in evaporation apparatus after the formation of the aluminum layer by evaporation.

A processing expedient has been found for obtaining the maximum effectiveness of the deposited silicon on aluminum metallurgy, and particularly on aluminum-copper alloy metallurgy. (Such copper-doped aluminum metallurgy has a standard copper content in the order of five per cent.)

In the deposition of the silicon layer by evaporation, it is critical that the temperature of the structure being deposited upon be maintained above 260 degrees C, and preferably between 260 degrees and 300 degrees C during the deposition of the silicon overlay. At these higher temperatures, virtually all of the deposited silicon becomes dispersed in the underlying aluminum metallurgy, and at most, a very thin silicon layer is formed over the metallurgy which is discontinuous.

In standard operations and equipment, this is accomplished by the simple expedient of permitting the substrate heaters which have been on during the evaporation of the aluminum metallurgy, to remain on during the deposition of the silico...