Browse Prior Art Database

Complete Barrier Metal Coverage

IP.com Disclosure Number: IPCOM000059666D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 74K

Publishing Venue

IBM

Related People

Cannone, CR: AUTHOR [+2]

Abstract

In the manufacture of semiconductor devices, the presence of silicon nitride ledges creates gaps which permit penetration of Al, thereby leading to faulty devices. This article proposes to form a continuous Cr barrier layer which will prevent Al from penetrating to the underlying layers. The basic structure is shown in Fig. 1 prior to first metal deposition. The presence of silicon nitride ledges 2 can lead to a ring of missing barrier metal around the contact holes. The basic structure shown in the figure includes Si3N4 1, SiO2 3, and PtSi 6. A "cavity" 5 may exist. Fig. 2 shows the barrier metal Cr/Cr2O3 7 with the missing ring (gap) 10 around contact holes. Such a gap will permit the Al conducting metal 9 to penetrate to, and alloy with, the underlying silicon 4. This can lead to faulty and shorted devices.

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Complete Barrier Metal Coverage

In the manufacture of semiconductor devices, the presence of silicon nitride ledges creates gaps which permit penetration of Al, thereby leading to faulty devices. This article proposes to form a continuous Cr barrier layer which will prevent Al from penetrating to the underlying layers. The basic structure is shown in Fig. 1 prior to first metal deposition. The presence of silicon nitride ledges 2 can lead to a ring of missing barrier metal around the contact holes. The basic structure shown in the figure includes Si3N4 1, SiO2 3, and PtSi 6. A "cavity" 5 may exist. Fig. 2 shows the barrier metal Cr/Cr2O3 7 with the missing ring (gap) 10 around contact holes. Such a gap will permit the Al conducting metal 9 to penetrate to, and alloy with, the underlying silicon 4. This can lead to faulty and shorted devices. Additionally, if the nitride ledges crack off, this can lead to parasitic rectifiers and failed chips. The cavity traps contaminants that induce charges in the peripheral oxide lead to unstable devices. While the removal of the nitride ledges prior to Pt contact metal deposition 6 would minimize most of the problems, the large variability of the overhang length can add more than 0.4 mm/side on contacts with thin (180 mm) underlying oxide and more than 0.6 mm/side on contacts with thicker (OE180 mm) underlying oxide. The resultant images are not suitable for high circuit density products. The article proposes to eliminate the...