Thermal treatment to form a void free aluminum metal layer for a semiconductor device

A method of forming a void free, reduced stress aluminum layer and an overlying nitride layer on a substrate, comprising:

• a) forming an aluminum alloy layer over a substrate surface;
• b) forming a silicon nitride layer over said aluminum alloy layer by ramping said substrate from room temperature up to between about 345.degree. and 355.degree. C.;
• the ramping from room temperature is performed at a pressure between about 2200 and 2500 mtorr and in a N.sub.2 ambient, for a time between about 3 and 8 minutes and ramping the temperature down to a temperature between 315.degree. and 325.degree. C. and depositing silicon nitride over said aluminum alloy layer at a temperature of between about 315.degree. and 325.degree. C. and the depositing of silicon nitride is performed using a PECVD process at a pressure in a range between 2200 and 2500 mtorr.

A method of forming a void free, reduced stress aluminum layer and an overlying nitride layer on a substrate, comprising:

• (a) forming an aluminum alloy layer over a substrate surface;
• (b) forming a silicon nitride layer over said aluminum alloy layer, at a pressure between about 2200 and 2500 m torr, in a N.sub.2 ambient, by ramping said substrate from room temperature up to between about 345.degree. and 355.degree. C.;
• and ramping the temperature down to a temperature between 315.degree. and 325.degree. C. and depositing silicon nitride over said aluminum alloy layer at a temperature of between about 315.degree. and 325.degree. C.

A method of forming a void free, reduced stress aluminum layer and an overlying nitride layer on a substrate, comprising:

• (a) forming an aluminum alloy layer over a substrate surface;
• (b) forming a silicon nitride layer over said aluminum alloy layer by ramping said substrate from room temperature up to between about 345.degree. and 355.degree. C.;
• and ramping the temperature down to a temperature between 315.degree. and 325.degree. C. and depositing silicon nitride over said aluminum alloy layer at a temperature of between about 315.degree. and 325.degree. C.