Catalyzed deposition of metal films
Methods of depositing a metal film with high purity are discussed. Some embodiments utilize a thermal ALD process comprising an alkyl halide and a metal precursor. Some embodiments selectively deposit a metal film with high purity on a metal surface over a dielectric surface. Some embodiments selectively deposit a metal film with high purity on a dielectric surface over a metal surface. Some embodiments deposit a metal film with greater than 99% metal atoms on an atomic basis.
1. A ruthenium deposition method comprising: maintaining a substrate having a dielectric surface and a metal surface at a deposition temperature while sequentially exposing the substrate to an alkyl halide, the alkyl halide adsorbing to a surface of the substrate to form an activated substrate surface, then exposing the activated substrate surface to a ruthenium precursor to selectively form a ruthenium film on the metal surface over the dielectric surface, the ruthenium precursor having a decomposition temperature above the deposition temperature, and the alkyl halide comprising bromine or iodine, wherein the method is performed without the use of an oxygen-containing reactive gas.
2. The method of claim 1 , wherein the ruthenium precursor comprises a ruthenium atom bonded to one or more of an optionally alkyl substituted benzene ring and an open or closed diene.
3. The method of claim 1 , wherein the alkyl halide consists essentially of iodoethane or diiodomethane.
4. The method of claim 1 , wherein exposing the substrate to the ruthenium precursor and the alkyl halide comprises a cycle, and the ruthenium film is deposited at a rate of greater than or equal to about 0.2 Å/cycle.
5. The method of claim 1 , wherein the ruthenium film has a surface roughness of less than or equal to about 10% of a thickness of the ruthenium film.
6. The method of claim 1 , wherein the ruthenium film has a carbon content less than or equal to about 2% carbon on an atomic basis.
7. The method of claim 1 , wherein the ruthenium film has a purity of greater than or equal to about 97% ruthenium.
8. The method of claim 1 , wherein the halogen of the alkyl halide is insoluble in the ruthenium film.
9. The method of claim 1 , wherein exposing the substrate to the ruthenium precursor and the alkyl halide comprises a cycle, and the ruthenium film is deposited at a rate of greater than or equal to about 0.5 Å/cycle.
10. A ruthenium deposition method comprising:
exposing a substrate at a deposition temperature to an alkyl halide (R—X) to adsorb R and X on the substrate;
desorbing R in the form of R—R or R;
exposing the substrate to a ruthenium precursor (M—L);
reacting M—L with the adsorbed X to form M—X; and
reacting M—X with M—X to form M—M,
wherein M—L is thermally stable at the deposition temperature, X is insoluble within M, the bond strength of M—L is less than M—X is less than M—M, and the deposited ruthenium has a purity of greater than or equal to about 97% ruthenium on an atomic basis.
11. The method of claim 10 , wherein R—X is thermally stable at the deposition temperature.
12. A method of selectively depositing a ruthenium film, the method comprising:
sequentially exposing a substrate having a first dielectric surface and a second metal surface to a ruthenium precursor and an alkyl halide while the substrate is maintained at a deposition temperature, the alkyl halide comprising bromine or iodine, and both the ruthenium precursor and the alkyl halide having a decomposition temperature above the deposition temperature, wherein a ruthenium film is selectively deposited on the second metal surface over the first dielectric surface.
13. The method of claim 12 , wherein the ruthenium precursor comprises a ruthenium atom bonded to one or more of an optionally alkyl substituted benzene ring and an open or closed diene.
14. The method of claim 12 , wherein the halogen of the alkyl halide is insoluble in the ruthenium film.
15. The method of claim 12 , wherein the alkyl halide consists essentially of iodoethane.
16. The method of claim 12 , wherein exposing the substrate to the ruthenium precursor and the alkyl halide comprises a cycle, and the ruthenium film is deposited at a rate of greater than or equal to about 0.2 Å/cycle.
17. The method of claim 12 , wherein the ruthenium film has a surface roughness of less than or equal to about 10% of thickness.
18. The method of claim 12 , wherein the ruthenium film has a carbon content less than 2% carbon on an atomic basis.
19. The method of claim 12 , wherein the ruthenium film has a purity of greater than or equal to about 97% ruthenium.
20. The method of claim 12 , wherein maintaining the substrate at a deposition temperature below the decomposition temperature of the ruthenium precursor and alkyl halide provides selective deposition of the ruthenium film on the second metal surface without a blocking layer.