Atomic layer deposition of tungsten for enhanced fill and reduced substrate attack

1. A method for depositing tungsten, comprising:

arranging a substrate including a titanium nitride layer in a substrate processing chamber;

performing multi-stage atomic layer deposition of tungsten on the substrate using a precursor gas includes tungsten chloride (WCl x ) gas, wherein x is an integer and wherein the performing includes:

depositing the tungsten during a first ALD stage for M consecutive times using a first dose intensity of the precursor gas, the first dose intensity including at least one of a first dose concentration of the precursor gas ranging between 0.1% and 5% and a dose period ranging between 0.05 seconds and 2 seconds, wherein M is greater than 1;

depositing the tungsten during a second ALD stage for Y consecutive times using a second dose intensity of the precursor gas, wherein Y is greater than 1;

depositing the tungsten during a third ALD stage using a third dose intensity of the precursor gas;

wherein the first dose intensity is based on a first dose concentration and a first dose period,

wherein the second dose intensity is based on a second dose concentration and a second dose period,

wherein the second dose intensity is 1.5 to 10 times the first dose intensity, and

wherein the third ALD stage has a higher dose intensity than the second dose intensity.

2. The method of claim 1 , wherein the first ALD stage comprises:

a) exposing the substrate to the precursor gas for the first dose period at the first dose concentration;

b) purging the substrate processing chamber after the first dose period;

c) exposing the substrate to a reactant gas for a first reactant period; and

d) purging the substrate processing chamber after the first reactant period.

3. The method of claim 2 , wherein the second ALD stage comprises:

e) exposing the substrate to the precursor gas for the second dose period at the second dose concentration;

f) purging the substrate processing chamber after the second dose period;

g) exposing the substrate to the reactant gas for a second reactant period; and

h) purging the substrate processing chamber after the second reactant period.

4. The method of claim 1 , further comprising setting process temperature in the substrate processing chamber to a temperature range from 450° C. to 600° C.

5. The method of claim 1 , further comprising setting process pressure in the substrate processing chamber to a pressure range from 1 Torr to 10 Torr.

6. The method of claim 2 , wherein the reactant gas includes at least one gas selected from a group consisting of molecular hydrogen, diborane, silane and germane.

7. The method of claim 1 , wherein the second dose intensity is 2 to 5 times the first dose intensity.

8. The method of claim 1 , wherein a first thickness of the tungsten deposited during the first ALD stage is in a range from 20 Å to 100 Å.

9. The method of claim 1 , wherein a second thickness of the tungsten deposited during the second ALD stage is in a range from 10 Å to 500 Å.

10. A method for depositing tungsten, comprising:

arranging a substrate including a titanium nitride layer in a substrate processing chamber;

performing multi-stage atomic layer deposition of tungsten on the substrate using a precursor gas including tungsten chloride (WCl x ) gas where x is an integer and a reactant gas including at least one gas selected from a group consisting of molecular hydrogen, diborane, silane and germane,

wherein the performing includes:

depositing the tungsten during a first ALD stage for M consecutive times using a first dose intensity of the precursor gas, the first dose intensity including at least one of a first dose concentration of the precursor gas ranging between 0.1% and 5% and a dose period ranging between 0.05 seconds and 2 seconds, wherein M is greater than 1;

depositing the tungsten during a second ALD stage for Y consecutive times using a second dose intensity of the precursor gas, wherein Y is greater than 1;

after the second ALD stage, performing a third ALD stage;

wherein the first dose intensity is based on a first dose concentration and a first dose period,

wherein the second dose intensity is based on a second dose concentration and a second dose period,

wherein the second dose intensity is 1.5 to 10 times the first dose intensity, and

wherein the third ALD stage has a higher dose intensity than the second dose intensity.

11. The method of claim 10 , wherein:

the first ALD stage comprises:

a) exposing the substrate to the precursor gas for the first dose period at the first dose concentration;

b) purging the substrate processing chamber after the first dose period;

c) exposing the substrate to the reactant gas for a first reactant period; and

d) purging the substrate processing chamber after the first reactant period; and

the second ALD stage comprises:

e) exposing the substrate to the precursor gas for the second dose period at the second dose concentration;

f) purging the substrate processing chamber after the second dose period;

g) exposing the substrate to the reactant gas for a second reactant period; and

h) purging the substrate processing chamber after the second reactant period.

12. The method of claim 10 , further comprising:

setting process temperature in the substrate processing chamber to temperature range from 450° C. to 600° C.; and

setting process pressure in the substrate processing chamber to pressure range from 1 Torr to 10 Torr.

13. The method of claim 10 , wherein the second dose intensity is 2 to 5 times the first dose intensity.

14. The method of claim 10 , wherein:

a first thickness of the tungsten deposited during the first ALD stage is in a range from 20 Å to 100 Å; and

a second thickness of the tungsten deposited during the second ALD stage is in a range from 10 Å to 500 Å.