METHOD FOR DEPOSITING THIN FILMS BY MIXED PULSED CVD AND ALD

• US 20080317972A1
• Filed: 06/21/2007
• Published: 12/25/2008
• Est. Priority Date: 06/21/2007
• Status: Active Grant

• Current Assignee: ASM International NV
• Original Assignee: ASM International NV
• Inventors: Haukka, Suvi, Knapp, Martin, Hendriks, Menso
• Granted Patent: US 8,017,182 B2
• Time in Patent Office: Days
• US Class Current: 427/569
• CPC Class Codes: C23C 16/18 from metallo-organic compounds
• CPC Class Codes: C23C 16/30 Deposition of compounds, mixtures or solid solutions, e.g. borides, carbides, nitrides
• CPC Class Codes: C23C 16/308 Oxynitrides
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/401 containing silicon
• CPC Class Codes: C23C 16/405 of refractory metals or yttrium
• CPC Class Codes: C23C 16/45523 Pulsed gas flow or change of composition over time

Abstract

Films are deposited on a substrate by a process in which atomic layer deposition (ALD) is used to deposit one layer of the film and pulsed chemical vapor deposition (CVD) is used to deposit another layer of the film. During the ALD part of the process, a layer is formed by flowing sequential and alternating pulses of mutually reactive reactants that deposit self-limitingly on a substrate. During the pulsed CVD part of the process, another layer is deposited by flowing two CVD reactants into a reaction chamber, with at least a first of the CVD reactants flowed into the reaction chamber in pulses, with those pulses overlapping at least partially with the flow of a second of the CVD reactants. The ALD and CVD parts of the process ca be used to deposit layers with different compositions, thereby forming, e.g., nanolaminate films. Preferably, high quality layers are formed by flowing the second CVD reactant into the reaction chamber for a longer total duration than the first CVD reactant. In some embodiments, the pulses of the third reactant at separated by a duration at least about 1.75 times the length of the pulse. Preferably, less than about 8 monolayers of material are deposited per pulse of the first CVD reactant.

Claims

1. A method for depositing a multi-component thin film on a substrate in a reaction chamber, the method comprising:

depositing a first component of the film on the substrate by flowing a first and second reactant into the reaction chamber in sequential and alternating pulses during a period A, the first and second reactants depositing self-limitedly on the substrate; and

depositing a second component of the film by flowing a third reactant into the reaction chamber while simultaneously flowing a fourth reactant into the reaction chamber during a period B, wherein the third and fourth reactants are mutually reactive, wherein a total exposure time of the substrate to the fourth reactant during the period B is longer than a total exposure time of the substrate to the third reactant during the period B.

2. The method of claim 1, wherein depositing the second component of the film comprises pulsing the third and fourth reactants into the reaction chamber during the period B.

3. The method of claim 2, wherein a total number of pulses of the fourth reactant is higher than a total number of pulses of the third reactant.

4. The method of claim 2, wherein a duration of each pulse of the fourth reactant is higher than a duration of each pulse of the third reactant so that each pulse of the third reactant is temporally entirely overlapped by a pulse of the fourth reactant.

5. The method of claim 1, wherein depositing the first component of the film comprises flowing a plurality of pulses of each of the first and the second reactants.

6. The method of claim 1, further comprising sequentially repeating depositing the first component of the film and depositing the second component of the film.

7. The method of claim 1, wherein the second reactant is an oxidant.

8. The method of claim 7, wherein the oxidant is selected from the group consisting of O₂, O₃ and H₂O.

9. The method of claim 8, wherein the fourth reactant is a nitrogen source or an oxidant.

10. The method of claim 9, wherein the nitrogen source is NH₃.

11. The method of claim 9, wherein the oxidant is O₃ or O₂.

12. The method of claim 9, wherein the first and third reactants comprise a metal.

13. The method of claim 12, wherein the first and third reactants comprise different metals.

14. The method of claim 12, wherein the first and third reactants comprise a same metal.

15. The method of claim 12, wherein the first and third reactants are a metal halide.

16. The method of claim 9, wherein the first and third reactants are the same.

17. The method of claim 1, wherein depositing the first component of the film comprises forming a nucleation layer.

18. The method of claim 17, wherein depositing the second component of the film comprises depositing a same material as a material forming the nucleation layer.

19. The method of claim 1, wherein depositing the first component of the film is performed before depositing the second component of the film.

40. The method of claim 1, wherein flowing the first and the second reactant into the reaction chamber in sequential and alternating pulses during the period A constitutes an atomic layer deposition, wherein flowing the third reactant into the reaction chamber while simultaneously flowing the fourth reactant into the reaction chamber during the period B constitutes a pulsed chemical vapor deposition, wherein the pulsed chemical vapor deposition occurs before the atomic layer deposition.

20. A method for depositing a film on a substrate, comprising:

exposing the substrate to temporally separated pulses of at least two mutually reactive reactants during a period A to deposit a compound comprising elements of the at least two mutually reactive reactants, wherein about a monolayer or less of material is deposited per pulse; and

exposing the substrate to one or more pulses of a third reactant while exposing the substrate to a fourth reactant during a period B, wherein the third and fourth reactants are mutually reactive, and wherein an interval between each of the pulses of the third reactant is at least about 1.75 times a duration of an immediately preceding pulse of the third reactant.

21. The method of claim 20, wherein the interval is at least about 2 times a duration of an immediately preceding pulse of the third reactant.

22. The method of claim 20, wherein exposing the substrate to temporally separated pulses of the at least two mutually reactive reactants comprises sequentially flowing each of the at least two mutually reactive reactants into a reaction chamber holding the substrate.

23. The method of claim 20, wherein a monolayer or more of material is deposited per pulse of the third reactant.

24. The method of claim 20, wherein the substrate is continuously exposed to the fourth reactant during the period B.

25. The method of claim 20, wherein exposing the substrate to one or more pulses of the third reactant while exposing the substrate to the fourth reactant comprises:

simultaneously exposing the substrate to the third and the fourth reactants;

subsequently removing reactant from a reaction chamber holding the substrate; and

subsequently exposing the substrate to the fourth reactant.

26. The method of claim 25, wherein simultaneously exposing, subsequently removing and subsequently exposing constitute one cycle, wherein exposing the substrate to one or more pulses of the third reactant while exposing the substrate to the fourth reactant comprises performing more than one cycle.

27. The method of claim 26, wherein the substrate is exposed to one pulse of the third reactant per cycle.

28. The method of claim 27, wherein subsequently exposing comprises elevating a flow rate of the fourth reactant relative to a flow rate of the fourth reactant during simultaneously exposing.

29. The method of claim 25, wherein subsequently removing comprises purging or evacuating reactant from the reaction chamber.

30. The method of claim 25, wherein subsequently removing comprises purging and evacuating reactant from the reaction chamber.

31. The method of claim 25, further comprising removing reactant from the reaction chamber after subsequently exposing and before simultaneously exposing.

32. A method for depositing a metal compound film on a substrate, comprising:

exposing the substrate to one or more pulses of a metal source reactant while exposing the substrate to a first reactant reactive with the metal source reactant, thereby forming a film comprising a metal compound during a period A, wherein less than about 8 monolayers of the metal compound are deposited per pulse of the metal source reactant; and

exposing the substrate to pulses of a second reactant reactive with the metal compound film during a period B, wherein the substrate is not exposed to a metal precursor during the period B.

33. The method of claim 32, wherein less than about 5 monolayers of the metal compound are deposited per pulse of the metal source reactant.

34. The method of claim 32, further comprising exposing the substrate to one or more pulses of an other metal source reactant during the period A.

35. The method of claim 32, wherein the metal source reactant is a metal halide.

36. The method of claim 35, wherein the first reactant is a nitrogen precursor.

37. The method of claim 36, wherein the nitrogen precursor is ammonia.

38. The method of claim 35, wherein the second reactant is an oxygen precursor.

39. The method of claim 38, wherein the oxygen precursor is ozone.