Process for CVD deposition of tungsten layer on semiconductor wafer

An improved process for the deposition of a layer of tungsten over a layer of silicon dioxide previously formed on a semiconductor wafer in a vacuum chamber wherein the improvement comprises:

• (a) forming an intermediate layer selected from the group consisting of a tungsten, a titanium tungsten, and a titanium nitride layer over said silicon dioxide layer;
• and
• (b) depositing tungsten over said intermediate layer on said semiconductor wafer in the presence of a mixture of gases comprising:
• (i) from about 20 to about 200 sccm WF.sub.6 ;
• (ii) from about 100 to about 5000 sccm Ar;
• (iii) from about 10 to about 300 sccm N.sub.2, and
• (iv) from about 300 to about 3000 sccm H.sub.2 ;
• while maintaining the pressure in said vacuum chamber at from about 20 to about 760 Torr and the susceptor temperature at from about 350.degree. C. to about 525.degree. C. during said tungsten deposition step.

An improved process for the deposition of a layer of tungsten on an intermediate layer formed over a silicon dioxide layer on a semiconductor wafer in a vacuum chamber wherein the improvement comprises depositing tungsten on said intermediate layer on said semiconductor wafer by contacting said wafer with a mixture of gases flowing through said vacuum chamber comprising:

• (a) from about 20 to about 200 sccm WF.sub.6 ;
• (b) from about 100 to about 5000 sccm Ar;
• (c) from about 10 to about 300 sccm N.sub.2, and
• (d) from about 300 to about 3000 sccm H.sub.2 ;
• while maintaining the pressure in said vacuum chamber at from about 20 Torr to about 760 Torr and the susceptor temperature at from about 350.degree. C. to about 525.degree. during said tungsten deposition step.

An improved process for the deposition of a layer of tungsten on an intermediate layer formed over a silicon dioxide layer on a semiconductor wafer in a vacuum chamber wherein the improvement comprises depositing tungsten on said intermediate layer on said semiconductor wafer by contacting said wafer with a mixture of gases flowing through said vacuum chamber comprising:

• (a) from about 20 to about 200 sccm WF.sub.6 ;
• (b) from about 100 to about 5000 sccm Ar;
• (c) from about 10 to about 300 sccm N.sub.2, and (d) from about 300 to about 3000 sccm H.sub.2 ;
• while maintaining the pressure in said vacuum chamber at from about 75 Torr to about 85 Torr and the susceptor temperature at from about 450.degree. C. to about 475.degree. C. during said tungsten deposition step.

An improved process for the deposition of a layer of tungsten on a semiconductor wafer in a vacuum chamber wherein the improvement comprises:

• (a) forming a nucleation layer on a semiconductor wafer prior to the step of depositing tungsten on the semiconductor wafer by contacting said wafer with a mixture of gases flowing through said vacuum chamber to form said nucleation layer comprising:
• (i) from about 5 to about 50 sccm WF.sub.6 ;
• (ii) from about 500 to about 3000 sccm Ar;
• (iii) from about 20 to about 300 sccm N.sub.2, and
• (iv) from about 5 to about 50 sccm SiH.sub.4 ;
• and
• (b) then depositing tungsten on said semiconductor wafer over said nucleation layer by contacting said wafer with a mixture of gases flowing through said vacuum chamber comprising:
• (i) from about 20 to about 200 sccm WF.sub.6 ;
• (ii) from about 100 to about 5000 sccm Ar;
• (iii) from about 10 to about 300 sccm N.sub.2, and
• (iv) from bout 300 to about 3000 sccm H.sub.2 ;
• while maintaining the pressure in said vacuum chamber at from about 75 Torr to about 85 Torr and the susceptor temperature at from about 450.degree. C. to about 475.degree. C. during said tungsten deposition step.