DEPOSITION OF SMOOTH METAL NITRIDE FILMS

• US 20140273452A1
• Filed: 03/13/2013
• Published: 09/18/2014
• Est. Priority Date: 03/13/2013
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Blomberg, Tom E., Anttila, Jaakko
• Granted Patent: US 9,412,602 B2
• Time in Patent Office: Days
• US Class Current: 438/680
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/45529 specially adapted for making a layer stack of alternating different compositions or gradient compositions
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: C23C 16/45553 characterized by the use of precursors specially adapted for ALD
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/28556 by chemical means, e.g. CVD, LPCVD, PECVD, laser CVD H01L21/28518 - H01L21/28537 and H01L21/28568 take precedence
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers

Abstract

In one aspect, methods of forming smooth ternary metal nitride films, such as Ti_xW_yN_z films, are provided. In some embodiments, the films are formed by an ALD process comprising multiple super-cycles, each super-cycle comprising two deposition sub-cycles. In one sub-cycle a metal nitride, such as TiN is deposited, for example from TiCl₄ and NH₃, and in the other sub-cycle an elemental metal, such as W, is deposited, for example from WF₆ and Si₂H₆. The ratio of the numbers of each sub-cycle carried out within each super-cycle can be selected to achieve a film of the desired composition and having desired properties.

Claims

1. An atomic layer deposition (ALD) process for depositing a ternary metal nitride film on a substrate, the process comprising a plurality of super-cycles, each super-cycle comprising a TiN sub-cycle and a W sub-cycle,

wherein the TiN sub-cycle comprises alternately and sequentially contacting the substrate with a titanium precursor and a nitrogen reactant;

wherein the W sub-cycle comprises alternately and sequentially contacting the substrate with a tungsten precursor and a second precursor, wherein the second precursor is a silane or borane; and

wherein the film does not have a columnar grain structure.

2. The process of claim 1, wherein the titanium precursor is a titanium halide or metal-organic titanium compound and the tungsten precursor is a tungsten halide or metal-organic tungsten compound.

3. The process of claim 2, wherein the titanium precursor is TiCl₄ and the tungsten precursor is WF₆.

4. The process of claim 1, wherein the nitrogen reactant is selected from the group consisting of ammonia, N₂H₄, nitrogen atoms, nitrogen containing plasma and nitrogen radicals.

5. The process of claim 1, wherein the second precursor comprises disilane or trisilane.

6. The process of claim 1, wherein the TiN sub-cycle and the W sub-cycle are carried out at a ratio of at least about 3 in at least one of the plurality of super-cycles.

7. The method of claim 1, wherein the film forms a continuous layer.

8. The method of claim 1, wherein the film is not a nanolaminate.

9. A method for forming a metal nitride film on a substrate in a reaction chamber, the method comprising:

conducting an atomic layer deposition super-cycle comprising a metal nitride sub-cycle and an elemental metal sub-cycle,

wherein the first metal nitride sub-cycle comprises;

pulsing a first vapor-phase metal precursor comprising a first metal (M¹) into the reaction chamber to form at most a molecular monolayer of the metal precursor on the substrate; and

pulsing a vapor phase nitrogen reactant into the reaction chamber, where the nitrogen reactant reacts with the metal precursor on the substrate to form a metal nitride; and

wherein the second elemental metal sub-cycle comprises;

pulsing a second vapor phase metal precursor comprising a second different metal (M²) into the reaction chamber to form at most a molecular monolayer of second metal precursor on the substrate; and

pulsing a vapor phase second reactant into the reaction chamber that reacts with the second metal precursor to form elemental metal; and

repeating the atomic layer deposition super-cycle to form a metal nitride film of the desired thickness

10. The method of claim 9, wherein M¹ is selected from Ti, Ta, Nb, Mo and W and M² is selected from Mo and W.

11. The method of claim 9, wherein the first metal precursor comprises a metal halide or metal-organic compound.

12. The method of claim 9, wherein the second metal precursor comprises a metal halide or metal-organic compound.

13. The method of claim 9, wherein the second reactant comprises a silane or borane.

14. The method of claim 9, wherein the nitrogen reactant comprises ammonia, N₂H₄, nitrogen atoms, nitrogen containing plasma or nitrogen radicals.

15. The method of claim 9, wherein the metal nitride film does not have a columnar grain structure.

16. A method for forming a ternary metal nitride film on a substrate in a reaction chamber, the method comprising:

a first metal nitride sub-cycle comprising;

contacting the substrate with a first vapor-phase metal precursor comprising a first metal to form at most a molecular monolayer of the metal precursor on the substrate; and

contacting the substrate with a vapor phase nitrogen reactant, such that the nitrogen reactant reacts with the metal precursor on the substrate to form a metal nitride; and

a second elemental metal sub-cycle comprising;

contacting the substrate with a second vapor phase metal precursor comprising a second metal different from the first metal to form at most a molecular monolayer of second metal precursor on the substrate; and

contacting the substrate with a vapor phase second reactant that reacts with the second metal precursor to form elemental metal; and

repeating the first and second sub-cycles to form a ternary metal nitride film of a desired thickness

17. The method of claim 16, wherein the second elemental metal sub-cycle is performed before the first metal nitride sub-cycle.

18. The method of claim 16, wherein the first metal is selected from Ti, Ta, Nb, Mo and W and the second metal is selected from Mo and W.

19. The method of claim 16, wherein the second reactant comprises a silane or borane.

20. The method of claim 16, wherein the first sub-cycle and second sub-cycle are repeated at a selected ratio in a plurality of super-cycles.

21. The method of claim 20, wherein the first sub-cycle is repeated no more than about 40 times consecutively and the second sub-cycle is repeated no more than about 10 times consecutively in each of the plurality of super-cycles.

22. The method of claim 16, wherein the ternary metal nitride film has a roughness of less than about 2 nm at a thickness of about 20 to about 50 nm as measured by x-ray reflectivity.