Deposition of TiN films in a batch reactor

• US 20070077775A1
• Filed: 12/04/2006
• Published: 04/05/2007
• Est. Priority Date: 09/22/2004
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM International NV
• Inventors: Vandezande, Lieve, Snijders, Gert-Jan, Hasper, Albert, De Blank, Marinus, Bankras, Radko
• Granted Patent: US 7,732,350 B2
• Time in Patent Office: Days
• US Class Current: 438/758
• CPC Class Codes: C23C 16/34 Nitrides C23C16/303 takes precedence
• CPC Class Codes: C23C 16/45527 characterized by the ALD cycle, e.g. different flows or temperatures during half-reactions, unusual pulsing sequence, use of precursor mixtures or auxiliary reactants or activations
• CPC Class Codes: C23C 16/45546 specially adapted for a substrate stack in the ALD reactor
• 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

Abstract

Titanium nitride (TiN) films are formed in a batch reactor using titanium chloride (TiCl₄) and ammonia (NH₃) as precursors. The TiCl₄ is flowed into the reactor in temporally separated pulses. The NH₃ can also be flowed into the reactor in temporally spaced pulses which alternate with the TiCl₄ pulses, or the NH₃ can be flowed continuously into the reactor while the TiCl₄ is introduced in pulses. The resulting TiN films exhibit low resistivity and good uniformity.

Claims

1. A method of forming a titanium nitride film, comprising:

providing a vertical furnace having a reaction chamber, the reaction chamber configured to accommodate 25 or more substrates;

providing a plurality of semiconductor substrates in the reaction chamber;

flowing a titanium precursor into the reaction chamber in temporally separated pulses; and

flowing a nitrogen precursor into the reaction chamber.

2. The method of claim 1, wherein flowing the nitrogen precursor into the reaction chamber comprises flowing the nitrogen precursor into the reaction chamber in temporally separated nitrogen precursor pulses alternating with the temporally separated pulses of the titanium precursor.

3. The method of claim 2, wherein sequentially flowing one pulse of the titanium precursor and flowing one nitrogen precursor pulse constitute performing one cycle, wherein performing one cycle forms a titanium nitride film less than 0.1 nm thick.

4. The method of claim 2, wherein flowing the titanium precursor and flowing the nitrogen precursor forms a titanium nitride layer on each of the plurality of substrates, the titanium nitride layers each having a thickness, wherein the thickness of the titanium nitride layers varies by less than about 3 nm among the plurality of substrates.

5. The method of claim 2, wherein flowing the titanium precursor and flowing the nitrogen precursor forms a titanium nitride layer on each of the plurality of substrates, each titanium nitride layer having a resistivity, wherein the resitivity varies by less than about 5 μ

Ohm·

cm among the plurality of substrates.

6. The method of claim 2, further comprising removing the nitrogen precursor from the reaction chamber after each pulse of the nitrogen precursor before flowing the titanium precursor into the reaction chamber.

7. The method of claim 4, wherein the substrates are 200 mm wafers.

8. The method of claim 4, wherein the substrates are 300 mm wafers.

9. The method of claim 1, further comprising removing the titanium precursor from the reaction chamber after each pulse of the titanium precursor before flowing the nitrogen precursor into the reaction chamber, wherein removing the titanium precursor comprises purging the reaction chamber with inert gas or evacuating the reaction chamber.

10. The method of claim 1, wherein flowing the titanium precursor comprises depositing more than one monolayer of titanium nitride over each of the substrates.

11. The method of claim 10, wherein flowing the nitrogen precursor comprises continuously flowing the nitrogen precursor into the reaction chamber between and during the pulses of the titanium precursor.

12. The method of claim 1, wherein flowing the nitrogen precursor comprises introducing the nitrogen precursor from a plurality of vertically distributed points substantially along a height of the 25 or more substrates.

13. The method of claim 12, wherein the plurality of vertically distributed points are holes of a gas injector.

14. The method of claim 12, wherein flowing the titanium precursor comprises introducing the titanium precursor proximate only one end of the reaction chamber and flowing the titanium precursor toward an other end of the reaction chamber.

15. The method of claim 1, wherein the titanium precursor and the nitrogen precursor are non-radical species.

16. The method of claim 1, wherein the titanium precursor is titanium tetrachloride.

17. The method of claim 16, wherein flowing the titanium precursor comprises flowing inert gas through a bubbler comprising titanium tetrachloride.

18. The method of claim 16, wherein flowing the titanium precursor comprises vaporizing titanium tetrachloride in a liquid vaporizer.

19. The method of claim 16, wherein the nitrogen precursor is ammonia.

20. The method of claim 1, wherein the substrates are maintained at a temperature of about 600°

C. or less during flowing the titanium precursor and flowing the nitrogen precursor.

21. The method of claim 20, wherein the substrates are maintained at a temperature of about 500°

C. or less during flowing the titanium precursor and flowing the nitrogen precursor.

22. The method of claim 1, wherein flowing the titanium precursor and flowing the nitrogen precursor comprise introducing the titanium precursor and the nitrogen precursor through an inlet proximate one vertical end of the reaction chamber and exhausting the titanium precursor and the nitrogen out of an opposing vertical end of the reaction chamber.

23. The method of claim 1, wherein the reaction chamber is configured to accommodate 50 or more substrates.

24. The method of claim 23, wherein the reaction chamber is configured to accommodate 100 or more substrates.

25. A process for depositing a titanium nitride film, comprising:

chemical vapor depositing titanium nitride on a substrate in a reaction chamber by exposing the substrate to a nitrogen precursor and to a titanium precursor,

wherein one of the nitrogen precursor and the titanium precursor is flowed into the reaction chamber in temporally spaced pulses while an other of the nitrogen precursor and the titanium precursor is flowed continuously into the reaction chamber during and between the temporally spaced pulses.

26. The process of claim 25, further comprising selecting a pulse duration based upon a desired titanium nitride film resistivity.

27. The process of claim 26, wherein the titanium nitride film resistivity is about 520 μ

Ohm·

cm or less.

28. The process of claim 26, wherein the titanium nitride film resistivity is about 220 μ

Ohm·

cm or less.

29. The process of claim 25, wherein each temporally spaced pulse is about 60 seconds or less.

30. The process of claim 29, wherein each temporally spaced pulse is about 30 seconds or less.

31. The process of claim 30, wherein each temporally spaced pulse is about 15 seconds or less.

32. The process of claim 25, wherein the nitrogen precursor is flowed continuously into the reaction chamber and the titanium precursor is flowed into the reaction chamber in the temporally spaced pulses.

33. The process of claim 25, wherein the reaction chamber is a batch reaction chamber accommodating a plurality of substrates, wherein chemical vapor depositing forms a titanium nitride film on each of the substrates.

34. The process of claim 33, wherein sequentially exposing the substrate to the titanium precursor and to the nitrogen precursor constitute one deposition cycle, wherein more than one monolayer of titanium nitride is deposited on each of the substrates per deposition cycle.

35. The process of claim 33, wherein exposing the substrate to the nitrogen precursor comprises flowing the nitrogen precursor out of a vertically extending injector, wherein the injector comprises a plurality of vertically spaced holes.

36. The process of claim 35, wherein exposing the substrate to the titanium precursor comprises flowing the titanium precursor out of an inlet opening proximate one end of the reaction chamber, wherein the titanium precursor enters the reaction chamber proximate only the one end of the reaction chamber.

37. The process of claim 35, wherein exposing the substrate to the titanium precursor comprises flowing the titanium precursor out of an other vertically extending injector, wherein the injector comprises a plurality of vertically spaced holes.

38. The process of claim 25, wherein the nitrogen precursor is NH₃.

39. The process of claim 25, wherein the titanium precursor is TiCl₄.

40. The process of claim 25, wherein chemical vapor depositing is performed at about 600°

C. or less.

41. The process of claim 40, wherein chemical vapor depositing is performed at about 500°

C. or less.

42. The process of claim 25, wherein each substrate is supported on a slot in a wafer boat in the reactor.

43. The process of claim 42, wherein the substrates are vertically separated and major faces of the substrate are oriented horizontally on the wafer boat.

44. The process of claim 43, wherein the substrates are each separated by a distance of about 4.76 mm.

45. The process of claim 43, wherein the substrates are each separated by a distance of about 9.54 mm.