Method for forming an interlayer insulating film, and semiconductor device

• US 6,413,879 B1
• Filed: 02/10/2000
• Issued: 07/02/2002
• Est. Priority Date: 03/17/1999
• Status: Expired due to Fees

• Current Assignee: Canon Sales Co., Inc. (Canon Inc.), Semiconductor Process Laboratory Co., Ltd.
• Original Assignee: Canon Sales Co., Inc. (Canon Inc.), Semiconductor Process Laboratory Co., Ltd.
• Inventors: Maeda, Kazuo
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): BERRY, RENEE R
• Application Number:
  US09/499,519
• Time in Patent Office: 873 Days
• Field of Search: 438/758, 438/760, 438/759
• US Class Current: 438/758
• CPC Class Codes: H01L 21/02126 the material containing Si, O, and at least one of H, N, C, F, or other non-metal elements, e.g. SiOC, SiOC:H or SiONC
• CPC Class Codes: H01L 21/02129 the material being boron or phosphorus doped silicon oxides, e.g. BPSG, BSG or PSG
• CPC Class Codes: H01L 21/02131 the material being halogen doped silicon oxides, e.g. FSG
• CPC Class Codes: H01L 21/02167 the material being a silicon carbide not containing oxygen, e.g. SiC, SiC:H or silicon carbonitrides H01L21/02126 and H01L21/0214 take precedence
• 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 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02362 formation of intermediate layers, e.g. capping layers or diffusion barriers
• CPC Class Codes: H01L 21/31695 Deposition of porous oxides or porous glassy oxides or oxide based porous glass
• CPC Class Codes: H01L 21/76801 characterised by the formation and the after-treatment of the dielectrics, e.g. smoothing
• CPC Class Codes: H01L 21/7682 the dielectric comprising air gaps
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 2221/1047 the air gaps being formed by pores in the dielectric

Abstract

A method for forming an interlayer insulating film is disclosed. This method comprises the steps of: forming an Si—C film or an Si—C—H film on an underlying insulating film by performing plasma polymerization for an Si and C containing compound; forming a porous SiO₂ film by performing O (oxygen) plasma oxidation for the Si—C film or the Si—C—H film; and forming a cover insulating film on the porous SiO₂ film by performing H (hydrogen) plasma treatment for the porous SiO₂ film.

Claims

1. A method for forming a porous SiO₂ interlayer insulating film comprising the steps of:

applying RF power to a source gas that contains a first compound containing silicon and at least one element selected from the group consisting of carbon and hydrogen, to form a film on a substrate, said film containing silicon and at least one element selected from the group consisting of carbon and hydrogen; and

oxidizing said film to oxidize and discharge from said film at least one element selected from the group consisting of said carbon and said hydrogen contained in said film, said discharge forming voids in said film and converting said film to the porous SiO₂ insulating film.

2. The method according to claim 1, wherein said source gas further contains O₂.

3. The method according to claim 1, wherein said source gas further contains H₂O.

4. The method according to claim 1, wherein said source gas further contains a second compound containing boron and hydrogen and said porous SiO₂ film contains boron.

5. The method according to claim 4, wherein said source gas further contains O₂.

6. The method according to claim 4, wherein said source gas further contains H₂O.

7. The method according to claim 1, wherein said source gas further contains a second compound containing fluorine and said porous SiO₂ film contains fluorine.

8. The method according to claim 7, wherein said source gas further contains O₂.

9. The method according to claim 7, wherein said source gas further contains H₂O.

10. The method according to claim 1, wherein said first compound is a compound selected from the group consisting of TEOS, SiH₄, methylsilane(Si(CH₃)₃H₃) and trimethyl-siliruborate ({(CH₃)₃SiO}₃B).

11. The method according to claim 4, wherein said second compound is a compound selected from the group consisting of B₂H₆, TMB(B(OCH₃)₃) and TEB(B(OC₂H₅)₃).

12. The method according to claim 7, wherein said second compound is C₂F₆.

13. The method according to claim 1, wherein an inert gas is added to said source gas.

14. The method according to claim 1, wherein said oxidizing is performed by oxygen plasma.

15. The method according to claim 1, further comprising the step of:

bringing a hydrogen plasma into contact with said porous SiO₂ film.

16. The method according to claim 1, wherein an underlying insulating film is formed on said substrate, and said porous SiQ₂ film is formed on said underlying insulating film.

17. The method according to claim 1, further comprising the steps of:

forming a damascene trench in said porous SiO₂ film;

forming a side-wall insulating film on a side portion of said damascene trench;

burying a metallic film in said damascene trench; and

forming a barrier metal film on said metallic film.

18. The method according to claim 17, wherein said side-wall insulating film is formed by forming a first insulating film on said porous SiO₂ film and on side and bottom portions of said damascene trench, and etching said first insulating film anisotropically to leave said first insulating film on said side portion of said damascene trench and to remove said first insulating film from said bottom portion of said damascene trench.

19. The method according to claim 1, further comprising the step of:

forming a cover insulating film on said porous SiO₂ film.