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Salvaging Wafers After Apparatus Malfunction in Silicon Metal Overlay Formation

IP.com Disclosure Number: IPCOM000086878D
Original Publication Date: 1976-Nov-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

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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Salvaging Wafers After Apparatus Malfunction in Silicon Metal Overlay Formation

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.

With such evaporation apparatus, malfunctions tend to occur where the silicon fails to be evaporated on schedule due to cycle interruptions. In such a case, a metal oxide tends to occur readily. This is, of course, undesirable since this oxide will separate the metal from any subsequently deposited silicon.

In order to salvage the wafers after such an apparatus malfunction, the upper 1000 Angstroms of the aluminum layer is removed by conventional RF sputter- etching. This will serve to remove any undesirable oxide deposited on the surface. Then, 1000 Angstroms of the aluminum film is redeposited by the standard evaporation techniques, after which the silicon layer is deposited in the same evaporation in the conventional manner.

The conditions for the previously described RF sputter-etching are:

- RF sputter apparatus pressure - 3 x 10/6/ torr.

- Backfill with argon gas to 3 microns, and

1 kilowatt power for 10 minutes, after which

the system is vented.

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