Improved process for selective deposition of tungsten on semiconductor wafer

Claim 2

The process of claim 1, wherein said transferring step further comprises transferring said cleaned wafer (100) from said cleaning chamber (10) to said vacuum deposition chamber (40) through an air-tight passageway (70) maintained at a vacuum of from about 10⁻² to about 10⁻⁵ milliTorr.

Claim 3

The process of claim 1 or 2, wherein said transferring step further comprises transferring said cleaned wafer (100) from said cleaning chamber (10) to said vacuum deposition chamber (40) through an air-tight passageway (70) between said respective chambers (10, 40) while flowing through said passageway (70) at a rate of at least about 20 sccm one or more non-oxidizing gases, preferably argon, helium, nitrogen, hydrogen, or mixtures of same.

Claim 4

The process for the selective deposition of any of claims 1 to 3, wherein during cleaning the surfaces of the wafer (100) the cleaning chamber (10) is maintained at a pressure within a range of from about 1 milliTorr to about 760 Torr and at least one cleaning gas, preferably hydrogen or a halogen-containing gas is flowed into said chamber (10), while maintaining said wafer (100) at a temperature within a range of from about 20 to about 100°C, preferably to about 80°C.

Claim 5

The process of any of claims 1 to 4, wherein after transferring the cleaned wafer (100) from the cleaning chamber (10) to the vacuum deposition chamber (40) through the air-tight passageway (70) a vacuum deposition layer of tungsten is selectively deposited on the unmasked surfaces of the wafer (100) by flowing a tungsten-containing gas and a reducing gas through said vacuum deposition chamber (40).

Claim 6

The process of any of claims 1 to 5, wherein said cleaning step further comprises maintaining a plasma within said cleaning chamber (10) within a range of from about 1 to about 1000 watts, preferably 20 to 100 watts, during said cleaning step and maintaining the pressure in said cleaning chamber (10) within a range of from about 1 milliTorr to about 500 milliTorr during said cleaning step.

Claim 7

The process of claim 5 or 6, wherein said tungsten-containing gas is WF₆ and said reducing gas is H₂ or SiH₄ .

Claim 8

The process of any of claims 1 to 7, including the additional step of flowing, preferably while maintaining said plasma, a non-reactive gas through said cleaning chamber (10) after said cleaning step for a period of at least about 5 seconds after shutoff of the flow of said cleaning gas into said cleaning chamber (10) to remove any residues remaining from said cleaning step.

Claim 9

The process of any of claims 1 to 8, wherein a gas mixture comprising a cleaning gas, preferably H₂, BCl₃ , SF₆, and/or NF₃ is flown into said cleaning chamber (10) for from about 20 to about 300 seconds.

Claim 10

Apparatus for the selective deposition of tungsten or similar materials on a masked semiconductor wafer (100) comprising: a) means for cleaning the surfaces of the wafer (100) in a cleaning chamber (10) maintained at a pressure preferably within a range of from about 1 milliTorr to about 760 Torr, comprising means (20, 22) for flowing at least one cleaning gas into said cleaning chamber (10), and means (15) for maintaining said wafer (100) at a temperature within a range of preferably from about 20 to about 100°C; b) means for transferring the cleaned wafer (100) from the cleaning chamber (10) to a vacuum deposition chamber (40) comprising an air-tight passageway (70) between said respective chambers (10, 40) to exclude moisture or oxidizing gases to thereby permit subsequent selective tungsten deposition on the clean surfaces on the wafer (100) without exposing the cleaned wafer (100) to conditions which would recontaminate the cleaned wafer (100) prior to said selective deposition; and c) means (50, 52) for selectively depositing a layer of tungsten on the unmasked surfaces of the wafer (100) comprising a tungsten-containing gas and a reducing gas flowing through said vacuum deposition chamber (40).