Method of reducing metal voidings in 0.25 .mu.m AL interconnect

A method of reducing formation of voidings in a stacked interconnect structure comprising a titanium layer adjacent a layer comprising aluminum, comprising:

• providing a substrate having the stacked interconnect structure;
• depositing the dielectric layer over the stacked interconnect structure and at least a part of the substrate under a condition selected from the following conditions
• under a pressure from about 2 Torr to about 2.8 Torr, an N.sub.2 flow rate from about 7 l to about 11.5 l, an N.sub.2 O flow rate from about 1 l to about 2 l and a silane flow rate from about 250 sccm to about 300 sccm at a power from about 900 W to about 1300 W at a temperature from about 300.degree. C. to about 350.degree. C., and
• under a pressure from about 2 Torr to about 2.8 Torr, an N.sub.2 flow rate from about 7 l to about 11.5 l, an N.sub.2 O flow rate from about 1 l to about 2 l and a silane flow rate from about 80 sccm to about 120 sccm at a power from about 900 W to about 1300 W at a temperature from about 390.degree. C. to about 410.degree. C.

A method of depositing a silicon dioxide interlayer dielectric layer over a stacked interconnect structure, comprising:

• providing a substrate having at least one stacked interconnect structure comprising a titanium layer adjacent at least one of an aluminum layer and an aluminum alloy layer;
• depositing the silicon dioxide interlayer dielectric layer over the stacked interconnect structure under a condition selected from the following conditions
• under a pressure from about 2 Torr to about 2.8 Torr, an N.sub.2 flow rate from about 8 l to about 11 l, an N.sub.2 O flow rate from about 1 l to about 2 l and a silane flow rate from about 260 sccm to about 290 sccm at a power from about 1000 W to about 1200 W at a temperature from about 310.degree. C. to about 340.degree. C., and
• under a pressure from about 2 Torr to about 2.8 Torr, an N.sub.2 flow rate from about 8 l to about 11 l, an N.sub.2 O flow rate from about 1 l to about 2 l and a silane flow rate from about 90 sccm to about 110 sccm at a power from about 1000 W to about 1200 W at a temperature from about 390.degree. C. to about 410.degree. C.