Film forming method and tungsten film
There is provided a film forming method for forming a tungsten film, comprising: preparing a substrate; and forming a tungsten film on the substrate. A chlorine-containing tungsten film whose film stress is adjusted by chlorine concentration in the film is formed as at least a part of the tungsten film.
1. A film forming method for forming a tungsten film, comprising:
preparing a substrate; and
forming a tungsten film on the substrate,
wherein a chlorine-containing tungsten film whose film stress is adjusted by chlorine concentration in the film is formed as at least a part of the tungsten film, and
wherein the chlorine-containing tungsten film has a chlorine concentration of 4 at % or more.
2. The film forming method of claim 1 , wherein the chlorine-containing tungsten film has a tensile stress of 500 MPa or less or a compressive stress.
3. The film forming method of claim 1 , wherein in said forming the tungsten film, an initial tungsten film with a chlorine concentration lower than a chlorine concentration of the chlorine-containing tungsten film is formed on the substrate and, then, the chlorine-containing tungsten film is formed on the initial tungsten film.
4. The film forming method of claim 3 , wherein the initial tungsten film has a film thickness of 0.5 nm or more.
5. The film forming method of claim 4 , wherein the substrate has a base and a TiN film formed on the base, and the initial tungsten film is formed on the TiN film.
6. A film forming method for forming a tungsten film, comprising:
preparing a substrate; and
forming a tungsten film on the substrate,
wherein in said forming the tungsten film, the tungsten film is formed by a CVD method or an ALD method using tungsten chloride as a raw material gas and a reducing gas,
a chlorine-containing tungsten film whose film stress is adjusted by a chlorine concentration in the film is formed as at least a part of the tungsten film, and
wherein the chlorine-containing tungsten film has a chlorine concentration of 4 at % or more.
7. The film forming method of claim 6 , wherein said forming the tungsten film is performed by the ALD method, and H 2 gas is used as the reducing gas.
8. The film forming method of claim 7 , wherein when forming the chlorine-containing tungsten film, a partial pressure of H 2 gas is set to 404 Pa or less.
9. The film forming method of claim 8 , wherein when forming the chlorine-containing tungsten film, the partial pressure of H 2 gas is set to 259 Pa or less and/or a substrate temperature is set to 380° C. or less.
10. The film forming method of claim 6 , wherein the chlorine-containing tungsten film has a tensile stress of 500 MPa or less or a compressive stress.
11. The film forming method of claim 6 , wherein in said forming the tungsten film, an initial tungsten film with a chlorine concentration lower than a chlorine concentration of the chlorine-containing tungsten film is formed on the substrate and, then, the chlorine-containing tungsten film is formed on the initial tungsten film.
12. The film forming method of claim 11 , wherein the initial tungsten film is formed by the ALD method at a substrate temperature of 400° C. or higher and an H 2 gas partial pressure of 184 to 915 Pa.
13. The film forming method of claim 12 , wherein the initial tungsten film has a film thickness of 0.5 nm or more.
14. The film forming method of claim 11 , wherein the substrate has a base and a TiN film formed on the base, and the initial tungsten film is formed on the TiN film.
15. A tungsten film formed on a substrate, wherein at least a part of the tungsten film is a chlorine-containing tungsten film with a chlorine concentration of 4 at % or more, and
wherein the chlorine-containing tungsten film has a tensile stress of 500 MPa or less or a compressive stress.
16. The tungsten film of claim 15 , wherein the tungsten film includes an initial tungsten film formed on the substrate and having a chlorine concentration lower than a chlorine concentration of the chlorine-containing tungsten film, and the chlorine-containing tungsten film is formed on the initial tungsten film.
17. The tungsten film of claim 16 , wherein the initial tungsten film has a film thickness of 0.5 nm or more.