Method of fabricating a semiconductor device with amorphous carbon layer

• US 6,033,979 A
• Filed: 01/10/1997
• Issued: 03/07/2000
• Est. Priority Date: 09/12/1994
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Endo, Kazuhiko
• Primary Examiner(s): Bowers, Charles
• Assistant Examiner(s): WHIPPLE, MATTHEW LAVERNE
• Application Number:
  US08/782,573
• Time in Patent Office: 1,152 Days
• Field of Search: 438/778, 438/784, 438/786, 438/622, 438/628
• US Class Current: 438/622
• CPC Class Codes: H01L 21/02115 the material being carbon, e.g. alpha-C, diamond or hydrogen doped carbon
• CPC Class Codes: H01L 21/0212 the material being fluoro carbon compounds, e.g.(CFx) n, (CHxFy) n or polytetrafluoroethylene
• CPC Class Codes: H01L 21/02131 the material being halogen doped silicon oxides, e.g. FSG
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/3127 Layers comprising fluoro (hydro)carbon compounds, e.g. polytetrafluoroethylene
• CPC Class Codes: H01L 21/3146 Carbon layers, e.g. diamond-like layers
• CPC Class Codes: H01L 23/5329 Insulating materials
• 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

The invention provides a semiconductor device in which interlayer insulative layers are composed of amorphous carbon film. The amorphous carbon film may include fluorine (F) therein. The invention further provides a method of fabricating a semiconductor device including an interlayer insulative layer composed of amorphous carbon film including fluorine (F), the method having the step of carrying out plasma-enhanced chemical vapor deposition (PCVD) using a mixture gas including (a) at least one of CF₄, C₂ F₆, C₃ F₈, C₄ F₈ and CHF₃, and (b) at least one of N₂, NO, NO₂, NH₃ and NF₃. The method provides amorphous carbon film having superior heat resistance and etching characteristics. By composing interlayer insulative layers of a semiconductor device of the amorphous carbon film, the semiconductor device can operate at higher speed.

Claims

1. A method of fabricating a semiconductor device, comprising the step of forming an interlayer insulative layer composed of an amorphous carbon film including fluorine (F), where a concentration of fluorine in the amorphous carbon film varies in a depth-wise direction to enhance cohesion of the film with a substrate, by plasma-enhanced chemical vapor deposition (PCVD) using a mixture gas including (a) at least one of CF₄, C₂ F₆, C₃ F₈, and CHF₃, and (b) at least one of N₂, NO, NO₂, NH₃, and NF₃.

2. The method as recited in claim 1, wherein said mixture gas further including (c) at least one of H₂, CH₄, C₂ H₆, C₂ H₄, C₂ H₂, and C₃ H₈.

3. The method of fabricating a semiconductor device as recited in claim 1, wherein said interlayer insulative layer composed of amorphous carbon film including fluorine (F) is formed to have a content of said fluorine that decreases in said depth-wise direction of said amorphous carbon film.

4. The method as recited in claim 3, further comprising the step of forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

5. The method of fabricating a semiconductor device as recited in claim 4, further comprise the steps of:

providing a semiconductor substrate; and

forming a transistor on said semiconductor substrate over which said interlayer insulative layer of an amorphous carbon film is formed.

6. A method of fabricating a semiconductor device, comprising the step of forming an interlayer insulative layer composed of an amorphous carbon film including fluorine (F), where a concentration of fluorine in the amorphous carbon film varies in a depth-wise direction to enhance cohesion of the film with a substrate, by plasma-enhanced chemical vapor deposition (PCVD) using a mixture gas including (a) at least one of CF₄, C₂ F₆, C₃ F₈, and CHF₃, and (b) at least one of SiH₄, Si₂ H₆, and SiF₄.

7. The method as recited in claim 6, wherein said mixture gas further including (c) at least one of H₂, CH₄, C₂ H₆, C₂ H₄, C₂ H₂, and C₃ H₈.

8. The method of fabricating a semiconductor device as recited in claim 6, wherein said interlayer insulative layer composed of amorphous carbon film including fluorine (F) is formed to have a content of said fluorine that decreases in said depth-wise direction of said amorphous carbon film.

9. The method as recited in claim 8, further comprising the step of forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

10. The method of fabricating a semiconductor device as recited in claim 9, further comprising the steps of:

providing a semiconductor substrate; and

forming a transistor on said semiconductor substrate over which said interlayer insulative layer of an amorphous carbon film is formed.

11. A method of fabricating a semiconductor device, comprising the step of forming an interlayer insulative layer composed of an amorphous carbon film including fluorine (F) having a content that decreases in a depth-wise direction of said amorphous carbon film, formed by carrying out plasma-enhanced chemical vapor deposition (PCVD) using CxFy gas, wherein x is an integer ranging from 1 to 4 both inclusive and y is an integer ranging from 4 to 8 both inclusive.

12. The method as recited in claim 11, wherein said plasma is generated by microwave discharge.

13. The method as recited in claim 11, wherein said plasma is generated by helicon wave discharge.

14. The method of fabricating a semiconductor device as recited in claim 11, further comprising the step of forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

15. The method of fabricating a semiconductor device as recited in claim 14, further comprising the steps of:

providing a semiconductor substrate; and

forming a transistor on said semiconductor substrate over which said interlayer insulative layer of an amorphous carbon film is formed.

16. The method of fabricating a semiconductor device as recited in claim 15, wherein said semiconductor substrate on which said amorphous carbon film to be deposited is disposed outside an area in which plasma is generated.

17. A method of fabricating a semiconductor device, comprising the step of forming an interlayer insulative layer composed of an amorphous carbon film including fluorine (F) having a content that decreases in a depth-wise direction of said amorphous carbon film, formed by carrying out plasma-enhanced chemical vapor deposition (PCVD) using CxFy gas, wherein x is an integer ranting from 1 to 4 both inclusive, and y is an integer ranting from 4 to 8 both inclusive, and providing a frequency of electric power with said substrate while PCVD is being carried out.

18. The method as recited in claim 17, wherein said plasma is generated by microwave discharge.

19. The method as recited in claim 17, wherein said plasma is generated by helicon wave discharge.

20. The method of fabricating a semiconductor device as recited in claim 17, further comprising the step of forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

21. The method of fabricating a semiconductor device as recited in claim 20, further comprising the steps of:

providing a semiconductor substrate; and

forming a transistor on said semiconductor substrate over which said interlayer insulative layer of an amorphous carbon film is formed.

22. The method of fabricating a semiconductor device as recited in claim 21, wherein said semiconductor substrate on which said amorphous carbon film is to be deposited is disposed outside an area in which plasma is generated.

23. A method of fabricating a semiconductor device, comprising the steps of:

forming an interlayer insulative layer composed of amorphous carbon film including fluorine (F) so that a content of said fluorine decreases in a depth-wise direction of said amorphous carbon film.

24. The method of fabricating a semiconductor device as recited in claim 23, further comprising the step of forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

25. The method of fabricating a semiconductor device as recited in claim 23, wherein said interlayer insulative layers further includes nitrogen (N).

26. The method of fabricating a semiconductor device as recited in claim 23, wherein said interlayer insulative layer further includes silicon (Si).

27. A method of fabricating a semiconductor device, comprising the steps of:

forming an interlayer insulative layer composed of amorphous carbon film;

forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film; and

forming a transition layer interposed between said amorphous carbon film and said buffer layer, said transition layer having a composition gradually varying from a composition of said amorphous carbon film to a composition of said buffer layer.

28. The method of fabricating a semiconductor device as recited in claim 27, wherein said interlayer insulating layer includes fluorine (F).

29. The method of fabricating a semiconductor device as recited in claim 28, wherein said fluorine (F) decreases in a depth-wise direction of said interlayer insulating layer.

30. The method of fabricating a semiconductor device as recited in claim 29, wherein none of said fluorine (F) is present at an interface between said interlayer insulating layer and an underlying layer disposed below said interlayer insulating layer.

31. The method of fabricating a semiconductor device as recited in claim 30, wherein said underlying layer is a semiconductor substrate.

32. A method of fabricating a semiconductor device, comprising the step of:

forming an interlayer insulative layer composed of an amorphous carbon film including fluorine (F), where a concentration of fluorine in the amorphous carbon film varies in a depth-wise direction to enhance cohesion of the film with a substrate; and

forming a buffer layer for suppressing gas discharge out of said amorphous carbon film, said buffer layer being disposed between said amorphous carbon film and elements of said semiconductor device disposed adjacent to said amorphous carbon film.

33. The method of fabricating a semiconductor device recited in claim 32, further comprising the step of forming a transition layer interposed between said amorphous carbon film and said buffer layer.

34. The method of fabricating a semiconductor device recited in claim 33, wherein said interlayer insulating layer of an amorphous carbon film includes fluorine (F).

35. The method of fabricating a semiconductor device as recited in claim 34, wherein said fluorine (F) decreases in said depth-wise direction of said interlayer insulating layer.

36. The method of fabricating a semiconductor device as recited in claim 35, wherein none of said fluorine (F) is present at an interface between said interlayer insulating layer and an underlying layer disposed below said interlayer insulating layer.