Method of making conformal lining layers for damascene metallization

• US 6,727,169 B1
• Filed: 08/23/2000
• Issued: 04/27/2004
• Est. Priority Date: 10/15/1999
• Status: Expired due to Term

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Soininen, Pekka J., Raaijmakers, Ivo, Elers, Kai-Erik, Haukka, Suvi P., Granneman, Ernst H. A., Saanila, Ville A.
• Primary Examiner(s): Loke, Steven
• Assistant Examiner(s): Owens, Douglas W.
• Application Number:
  US09/644,416
• Time in Patent Office: 1,343 Days
• Field of Search: 438/622, 438/625, 438/627, 438/628, 438/641, 438/643, 438/644, 438/658, 438/677, 438/680, 438/681, 438/762, 438/763, 438/775, 438/774, 438/674
• US Class Current: 438/622
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/08 from metal halides
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/32 Carbides
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/44 characterised by the method of coating C23C16/04 takes precedence
• CPC Class Codes: C23C 16/45525 Atomic layer deposition [ALD]
• CPC Class Codes: C23C 16/45534 Use of auxiliary reactants other than used for contributing to the composition of the main film, e.g. catalysts, activators or scavengers
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: C30B 25/02 Epitaxial-layer growth
• CPC Class Codes: C30B 29/02 Elements
• CPC Class Codes: C30B 29/36 Carbides
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/7681 involving one or more buried masks
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76846 Layer combinations
• CPC Class Codes: H01L 21/76873 for electroplating
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53223 : Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53238 : Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53242 : the principal metal being a noble metal, e.g. gold
• CPC Class Codes: H01L 23/53252 : Additional layers associated with noble-metal layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/5329 : Insulating materials
• CPC Class Codes: H01L 23/53295 : Stacked insulating layers
• CPC Class Codes: H01L 2924/00 : Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 : Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

Method and structures are provided for conformal lining of dual damascene structures in integrated circuits. Trenches and contact vias are formed in insulating layers. The trenches and vias are exposed to alternating chemistries to form monolayers of a desired lining material. Exemplary process flows include alternately pulsed metal halide and ammonia gases injected into a constant carrier flow. Self-terminated metal layers are thus reacted with nitrogen. Near perfect step coverage allows minimal thickness for a diffusion barrier function, thereby maximizing the volume of a subsequent filling metal for any given trench and via dimensions.

Claims

1. A damascene metallization process, comprising:

forming a trench in a desired wiring pattern in an insulating layer above a semiconductor substrate;

forming a contact via extending downwardly from a floor of the trench to expose at least part of an underlying conductive element;

lining surfaces of the trench and contact via with no more than about one monolayer by exposure to a first reactant species;

removing the first reactant species from a reaction chamber containing the substrate;

reacting the monolayer with a non-radical reducing species;

reacting a second reactant species with the monolayer after removing the first reactant and reacting the monolayer; and

removing the second reactant species from the reaction chamber after reacting the second reactant species and before introducing any other reactants into the reaction chamber.

2. The method of claim 1, wherein lining comprises supplying a first chemistry excluding the second reactant species and reacting comprises supplying a second chemistry excluding the first reactant species.

3. The method of claim 2, further comprising repeatedly sequentially supplying the first chemistry, removing the first reactant species, reacting the monolayer, supplying the second chemistry and removing the second reactant species until a layer forms having a thickness between about 20 Å

and 200 Å

.

4. The method of claim 2, further comprising supplying a carrier gas while repeatedly sequentially supplying the first chemistry, removing the first reactant species, reacting the monolayer, supplying the second chemistry and removing the second reactant species.

5. The method of claim 4, wherein removing the first reactant species comprises purging the first reactant species with the carrier gas.

6. The method of claim 5, wherein supplying the first chemistry is stopped and the reaction chamber is purged with more than about two chamber volumes of purge gas before supplying the second chemistry.

7. The method of claim 1, wherein lining comprises forming a film in a self-limiting reaction.

8. The method of claim 7, wherein the film formed in the self-limiting reaction is halogen-terminated.

9. The method of claim 1, wherein reacting the monolayer with the reducing species comprises removing a halogen termination after lining and prior to reacting the second reactant species.

10. The method of claim 8, wherein the reducing species comprises triethyl boron.

11. The method of claim 1, wherein the first reactant species comprises a metal alkylamine.

12. The method of claim 1, wherein the first reactant species is a volatile metal organic compound, and the lining comprises forming a metal-containing film including an organic surface termination.

13. The method of claim 1, wherein the first reactant species comprises a volatile metal halide.

14. The method of claim 13 wherein the first reactant species comprises titanium tetrachloride.

15. The method of claim 13, wherein the first reactant species comprises tungsten hexafluoride.

16. The method of claim 13 wherein the second reactant species comprises a volatile nitrogen source.

17. The method of claim 16, wherein the nitrogen source comprises ammonia.

18. The method of claim 17, wherein reacting the monolayer comprises scavenging halide tails from the monolayer.

19. The method of claim 18, wherein scavenging comprises exposing the monolayer to triethyl boron.

20. The method of claim 1, further comprising preparing surfaces of the trench and contact via for reacting with the first reactant species prior to lining.

21. The method of claim 20, wherein preparing comprises depositing an adhesion layer.

22. The method of claim 21, wherein the adhesion layer comprises a metal layer.

23. The method of claim 21, wherein preparing further comprises forming a surface termination on the adhesion layer, the first reactant species conducting a ligand-exchange reaction with the surface termination.

24. The method of claim 20, wherein preparing comprises forming a surface termination on at least some surfaces of the trench and contact via, the first reactant species conducting a ligand-exchange reaction with the surface termination.

25. The method of claim 24, wherein the surface termination comprises an NH_x termination on at least exposed metal surfaces of the trench and contact via.

26. A process for forming metal structures in an integrated circuit, comprising:

forming a dual damascene trench and contact structure in a partially fabricated integrated circuit;

supplying a first chemistry to surfaces of the trench and contact structure;

removing the first chemistry from the trench and contact structure, wherein removing the first chemistry comprises removing a reactant containing the first chemistry from a reaction chamber containing the partially fabricated integrated circuit;

exposing the trench and contact structure to a non-radical reducer;

supplying a second chemistry to the trench and contact structure after removing the first chemistry;

removing the second chemistry from the trench and contact structure, wherein removing the second chemistry comprises removing a reactant containing the second chemistry from the reaction chamber before introducing other reactants into the reaction chamber; and

repeating supplying and removing the first chemistry and supplying and removing the second chemistry at least about 10 times.

27. The process of claim 26 wherein removing the first chemistry comprises flowing an inert gas after supplying the first chemistry and before supplying the second chemistry.

28. The process of claim 26, further comprising flowing the inert gas while supplying the first chemistry and while supplying the second chemistry.

29. A method of forming a metal nitride barrier layer in a dual damascene structure having a trench and a contact via formed through an insulating layer in an integrated circuit, comprising:

forming no more than about one monolayer of a metal-containing species in a self-limited reaction;

removing the metal-containing species from the trench and the contact via;

reacting the monolayer with a non-radical reducer after removing the metal-containing species;

reacting a nitrogen-containing species with the monolayer after reacting the monolayer; and

removing the nitrogen-containing species from the trench and the contact via.

30. The method of claim 29 wherein the self-limited reaction comprises forming a halogen-terminated metal film.

31. The method of claim 30, wherein reacting the nitrogen-containing species comprises adsorbing ammonia upon the film.

32. The method of claim 31, wherein reacting the monolayer comprises removing a halogen termination from the halogen-terminated metal film.

33. The method of claim 29 further comprising forming a second monolayer of the metal-containing species after reacting the nitrogen-containing species with the monolayer;

and reacting the nitrogen-containing species with the second monolayer.

34. A metallization process, comprising:

forming an opening in an insulating layer above a semiconductor substrate to expose at least part of an underlying conductive element;

lining surfaces of the opening with no more than about one monolayer of a halide-terminated metal species in a first phase;

removing halogen tails from the halide-terminated metal with a reducer including triethyl boron (TEB) in a second phase distinct from the first phase;

adsorbing no more than about one monolayer of a reactive species upon the metal species in a third phase; and

repeating the first, second and third phases in at least about 10 cycles, wherein the metal species is removed from a reaction chamber containing the substrate after the first phase, the reducer and the halogen tails are removed from the chamber after the second phase and before the third phase, and the reactive species is removed from the chamber after the third phase.

35. The process of claim 34, wherein the opening is a trench formed as part of a single damascene process.

36. The process of claim 34, wherein the opening is a via extending from a floor of a damascene trench formed as part of a dual damascene process.

37. The process of claim 34, wherein the reactive species of the third phase comprises a nitrogen-containing species.

38. The process of claim 37, wherein the first phase comprises flowing tungsten hexafluoride, the second phase comprises flowing triethyl boron, and the third phase comprises flowing ammonia.

39. The process of claim 34 wherein the third phase of each cycle comprises the first phase of an immediately subsequent cycle.

40. The process of claim 39, wherein the first and third phase comprise flowing a metal halide and the second phase comprises flowing a reducing agent.

42. The process of claim 34 wherein the metal species comprises copper chloride.

41. A method of forming a metal nitride liner in a damascene structure including a trench during metallization of an integrated circuit, the method comprising:

chemisorbing no more than about one monolayer of a metal halide species upon surfaces of the trench;

removing halogen atoms from the metal halide species with triethyl boron;

reacting a nitrogen-containing species with the monolayer after removing halogen atoms; and

repeatedly chemisorbing, removing and reacting until a thickness of metal nitride forms over surfaces of the trench sufficient to prevent copper diffusion therethrough.