Complete Barrier Metal Coverage
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
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.