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USE OF A DELAYED ENTRY WATER PROCESS IN Cr/CrxOy DIFFUSION BARRIER METALLURGY

IP.com Disclosure Number: IPCOM000042765D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Giddings, JJ: AUTHOR [+4]

Abstract

Existing fabrication processes utilize a first level interconnection metallurgy of aluminum-copper and chromium. A Cr/CrxOy diffusion barrier is required in these devices to prevent aluminum penetration into the silicon and also to enhance electromigration resistance. A persistent defect resulting from the use of this Cr,Al-Cu metallurgy is metal blistering. This defect, characterized by an erruption and deadherence of the aluminum-copper film from the chromium film, can have a major impact upon yields and possibly upon reliability. Severe blistering, larger than 5-micron diameter, can cause defective lands and interlevel shorts. The decreased current-carrying area is predicted to be an electromigration concern. Despite significant investigation, no cause of this blistering has been pinpointed.

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USE OF A DELAYED ENTRY WATER PROCESS IN Cr/CrxOy DIFFUSION BARRIER METALLURGY

Existing fabrication processes utilize a first level interconnection metallurgy of aluminum-copper and chromium. A Cr/CrxOy diffusion barrier is required in these devices to prevent aluminum penetration into the silicon and also to enhance electromigration resistance. A persistent defect resulting from the use of this Cr,Al-Cu metallurgy is metal blistering. This defect, characterized by an erruption and deadherence of the aluminum-copper film from the chromium film, can have a major impact upon yields and possibly upon reliability. Severe blistering, larger than 5-micron diameter, can cause defective lands and interlevel shorts. The decreased current-carrying area is predicted to be an electromigration concern. Despite significant investigation, no cause of this blistering has been pinpointed. It is believed that the water introduced into the system to form the CrxOy at grain boundaries plays a key role. Under normal process conditions, this water is bled into the system prior to chromium deposition and disassociates immediately upon the start of chromium evaporation. A simple, positive process has been formulated and practiced that reduces the metal blistering. The process, termed delayed entry water (DEW), does not bleed the water in until chromium deposition has begun. This delay greatly reduces the exposure of the wafers to water vapor, as the water disassociates immediately upon e...