Method for manufacturing a semiconductor device

• US 20060019491A1
• Filed: 07/19/2005
• Published: 01/26/2006
• Est. Priority Date: 07/23/2004
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Soda, Eiichi
• Granted Patent: US 7,799,693 B2
• Time in Patent Office: Days
• US Class Current: 438/638
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/31116 by dry-etching
• CPC Class Codes: H01L 21/31138 by dry-etching
• CPC Class Codes: H01L 21/31144 using masks
• CPC Class Codes: H01L 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76811 involving multiple stacked pre-patterned masks
• CPC Class Codes: H01L 21/76813 involving a partial via etch
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76831 in via holes or trenches, e.g. non-conductive sidewall liners
• CPC Class Codes: H01L 21/76835 Combinations of two or more different dielectric layers having a low dielectric constant H01L21/76832 takes precedence

Abstract

Method for manufacturing a semiconductor device including a semiconductor substrate, an element formed on the substrate, and an insulating film formed on the element, includes: (a) forming a first conductive layer (b) forming a first insulating film on the upper portion of the first conductive layer; (c) forming a second insulating film with a porous structure on the first insulating film; (d) forming a third insulating film different from the second insulating film on the second insulating film; (e) forming a via hole in the second and third insulating film by dry etching of the third insulating films; (f) removing a part of the first insulating film such that the surface of the first conductive layer is exposed at the bottom of the via hole and (g) forming a second conductive material film layer so as to fill the via hole.

Claims

1. A method for manufacturing a semiconductor device including a semiconductor substrate, an element formed on said semiconductor substrate, and an insulating film formed on said element, comprising:

(a) forming a first conductive layer composed of copper as a main component on said insulating film;

(b) forming a first insulating film composed of silicon carbide as a main component on the upper portion of said first conductive layer;

(c) forming a second insulating film with a porous structure on said first insulating film;

(d) forming a third insulating film different from said second insulating film on said second insulating film;

(e) forming a via hole or an interconnect trench in said second insulating film and said third insulating film by dry etching of said third insulating film and said second insulating film in this order;

(f) removing a part of said first insulating film by dry etching with said third insulating film used as an etching mask, and a mixed gas of fluorine compound gas and a nitrogen content gas used as an etching gas under the condition where the pressure of said mixed gas in an etching processing chamber is set within a range of 0.1 Pa to 6.0 Pa, such that the surface of said first conductive layer is exposed at the bottom of said via hole or said interconnect trench, said fluorine compound gas including at least one of the gases selected from a group including CF₄, CHF₃, CH₂F₂, CH₃F, and NF₃; and

(g) forming a second conductive material film layer so as to fill said via hole or said interconnect trench.

2. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (f) process, said fluorine compound gas including at least one of the gases selected from a group including CF₄, CHF₃, CH₂F₂, and CH₃F.

3. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (d) process, said insulating film is formed with a material containing carbon.

4. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (f) process, said dry etching is performed under plasma-excitation of said mixed gas while a side wall protective layer is formed on the side wall 5 of said via hole or said interconnect trench by adhering scatters or reaction products, generated by sputtering of said first insulating film and said third insulating film with ions generated by said plasma excitation, onto the side wall of said via hole or said interconnect trench.

5. The method for manufacturing a semiconductor device according to claim 4, wherein, in said (d) process, a fourth insulating film composed of silicon carbide as a main component is formed on said third insulating film;

in said (e) process, said via hole or said interconnect trench is formed in said second insulating film, said third insulating film, and said fourth insulating film by dry etching of said fourth insulating film, said third insulating film and said second insulating film in this order; and

in said (f) process, said fourth insulating film is sputtered with said first insulating film by said ions generated by said plasma excitation ions generated by plasma excitation of said mixed gas.

10. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (f) process, said nitrogen content gas includes at least one of the gases selected from a group including N₂, NH₃, and N₂H₄.

12. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (e) process, said dry etching of said second insulating film is executed, using at least one of the gases etching gas selected from a group including a fluorocarbon gas represented by a chemical formula of C_xH_yF_z (where x, y, and z are integers, x is equal to or larger than 4, y is equal to or larger than 0, and z is equal to or larger than 1).

14. The method for manufacturing a semiconductor device according to claim 12, wherein, in said (e) process, said fluorocarbon gas is C₄F₆, C₄F₈, or C₅F₈.

16. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (e) process or said (f) process, said etching gas of said dry etching includes an inert gas.

18. The method for manufacturing a semiconductor device according to claim 1, wherein, in said (b) process, said first insulating film includes at least one of the films selected from a group including an SiC film, an SiCN film, an SiOC film, and an SiCH film.

20. The method for manufacturing a semiconductor device according to claim 5, wherein said fourth insulating film includes at least one of the films selected from a group including an SiC film, an SiCN film, an SiOC film, and an SiCH film.

6. A method for manufacturing a semiconductor device including a semiconductor substrate, an element formed on said semiconductor substrate, and an insulating film formed on said element, comprising:

(a) forming a first conductive layer composed of copper as a main component on said insulating film;

(b) forming a first insulating film composed of silicon carbide as a main component on the upper portion of said first conductive layer;

(c) forming a second insulating film with a porous structure on said first insulating film;

(d) forming a third insulating film different from said second insulating film on said second insulating film;

(e) forming a via hole or an interconnect trench in said second insulating film and said third insulating film by dry etching of said third insulating film and said second insulating film in this order;

(f) removing a part of said first insulating film by dry etching under plasma-excitation of a mixed gas of fluorine compound gas and a nitrogen content gas with said third insulating film used as an etching mask, while forming a side wall protective layer on the side wall of said via hole or said interconnect trench by adhering scatters or reaction products, generated by sputtering of said first insulating film with ions generated by said plasma excitation, onto the side wall of said via hole or said interconnect trench, such that the surface of said first conductive layer is exposed at the bottom of said via hole or said interconnect trench, said fluorine compound gas including at least one of the gases selected from a group including CF₄, CHF₃, CH₂F₂, CH₃F, and NF₃; and

(g) forming a second conductive material film layer so as to fill said via hole or said interconnect trench.

7. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (f) process, said fluorine compound gas including at least one of the gases selected from a group including CF₄, CHF₃, CH₂F₂, and CH₃F.

8. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (d) process, a fourth insulating film composed of silicon carbide as a main component is formed on said third insulating film;

in said (e) process, said via hole or said interconnect trench is formed in said second insulating film, said third insulating film, and said fourth insulating film by dry etching of said fourth insulating film, said third insulating film and said second insulating film in this order; and

in said (f) process, said fourth insulating film is sputtered with said first insulating film by said ions generated by said plasma excitation ions generated by plasma excitation of said mixed gas.

9. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (d) process, said insulating film is formed with a material containing carbon.

11. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (f) process, said nitrogen content gas includes at least one of the gases selected from a group including N₂, NH₃, and N₂H₄.

13. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (e) process, said dry etching of said second insulating film is executed, using at least one of the gases etching gas selected from a group including a fluorocarbon gas represented by a chemical formula of C_xH_yF_z (where x, y, and z are integers, x is equal to or larger than 4, y is equal to or larger than 0, and z is equal to or larger than 1).

15. The method for manufacturing a semiconductor device according to claim 13, wherein, in said (e) process, said fluorocarbon gas is C₄F₆, C₄F₈, or C₅F₈.

17. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (e) process or said (f) process, said etching gas of said dry etching includes an inert gas.

19. The method for manufacturing a semiconductor device according to claim 6, wherein, in said (b) process, said first insulating film includes at least one of the films selected from a group including an SiC film, an SiCN film, an SiOC film, and an SiCH film.