Method of forming metal wiring line

• US 20030049927A1
• Filed: 08/30/2002
• Published: 03/13/2003
• Est. Priority Date: 09/04/2001
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Corporation
• Inventors: Inoue, Tomoko, Tsuchiya, Yasuaki, Tonegawa, Takashi
• Granted Patent: US 7,091,123 B2
• Time in Patent Office: Days
• US Class Current: 438/622
• CPC Class Codes: H01L 21/31053 involving a dielectric removal step
• CPC Class Codes: H01L 21/3212 by chemical mechanical polishing [CMP]
• CPC Class Codes: H01L 21/7684 Smoothing; Planarisation

Abstract

In a method of forming a metal wiring line, a first insulating film is formed directly or indirectly on a semiconductor substrate. A second insulating film is formed on the first insulating film. A wiring line groove is formed to pass through the second insulating film to an inside of the first insulating film. A conductive film is formed to fill the wiring line groove and to cover the second insulating film. The conductive film and the second insulating film are removed by a first CMP polishing process, using the first insulating film as a stopper film, until the first insulating film is exposed.

Claims

1. A method of forming a metal wiring line, comprising the steps of:

(a) forming a first insulating film directly or indirectly on a semiconductor substrate;

(b) forming a second insulating film on said first insulating film;

(c) forming a wiring line groove to pass through said second insulating film to an inside of said first insulating film;

(d) forming a conductive film to fill said wiring line groove and to cover said second insulating film; and

(e) removing said conductive film and said second insulating film by a first CMP polishing process, using said first insulating film as a stopper film, until said first insulating film is exposed.

2. The method according to claim 1, wherein said (d) forming step comprises the steps of:

(f) forming a first conductive film to cover an inner wall surface of said wiring line groove and to cover said second insulating film; and

(g) forming a second conductive film to fill said wiring line groove and to cover said first conductive film, and

said (e) removing step comprises the steps of;

(h) removing said second conductive film until said first conductive film is exposed; and

(i) removing said first conductive film, said second conductive film and said second insulating film by said first CMP polishing process, using said first insulating film as a stopper film, until said first insulating film is exposed.

3. The method according to claim 2, wherein said (h) removing step is carried out using a second CMP polishing method.

4. The method according to claim 3, wherein first slurry used in said (h) removing step is different from second slurry used in said (i) removing step.

5. The method according to claim 4, wherein a polishing selection ratio of said second slurry of a polishing rate of said second insulating film to a polishing rate of said first insulating film is 5 or above.

6. The method according to claim 4, wherein said second slurry contains abrasive particles, and a diameter of each of said abrasive particles is in a range of 0.01 to 1 μ

m.

7. The method according to claim 4, wherein said second slurry contains colloidal silica.

8. The method according to claim 4, wherein said first insulating film functions as a stopper film in said (i) removing step.

9. The method according to claim 1, wherein said first insulating film has a dielectric constant lower than that of silicon dioxide.

10. The method according to claim 1, wherein said first insulating film comprises an organic insulating film.

11. The method according to claim 10, wherein a relative dielectric constant of said organic insulating film is in a range of 2.0 to 3.0.

12. The method according to claim 10, wherein said organic insulating film is formed of at least a material selected the group consisting of a hydrocarbon system polymer and aromatic polymer.

13. The method according to claim 10, wherein said organic insulating film is formed of at least a material selected the group consisting of polyphenylene, poly-allyl-ether, poly-allylene, and benzocyclobutene.

14. The method according to claim 10, wherein said organic insulating film is a porous film.

15. The method according to claim 1, wherein said conductive film and said second conductive film comprises copper.

16. A method of forming a metal wiring line, comprising the steps of:

(a) forming an organic insulating film with a dielectric constant lower than that of silicon dioxide directly or indirectly on a semiconductor substrate;

(b) forming an inorganic insulating film on said organic insulating film;

(c) forming a wiring line groove to pass through said second insulating film to an inside of said first insulating film;

(d) forming a first conductive film to cover an inner wall surface of said wiring line groove and to cover said second insulating film;

(e) forming a second conductive film to fill said wiring line groove and to cover said first conductive film; and

(f) removing said first and second conductive films and said inorganic insulating film by a first CMP polishing process using slurry containing abrasive particles, until said organic insulating film is exposed, and

wherein a polishing selection ratio of said abrasive particles of a polishing rate of said second insulating film to a polishing rate of said first insulating film is 5 or above.

17. The method according to claim 16, wherein said

said (f) removing step comprises the steps of:

(g) removing said second conductive film by a second CMP polishing process, until said first conductive film is exposed; and

(h) removing said first conductive film, said second conductive film and said inorganic insulating film by said first CMP polishing process, using said organic insulating film as a stopper film, until said organic insulating film is exposed.

18. The method according to claim 16, wherein a diameter of each of said abrasive particles is in a range of 0.01 to 1 μ

m.

19. The method according to claim 16, wherein said abrasive particles are formed of colloidal silica.

20. The method according to claim 16, wherein a relative dielectric constant of said organic insulating film is in a range of 2.0 to 3.0.

21. The method according to claim 16, wherein said organic insulating film is formed of at least a material selected the group consisting of a hydrocarbon system polymer and aromatic polymer.

22. The method according to claim 16, wherein said organic insulating film is formed of at least a material selected the group consisting of polyphenylene, poly-allyl-ether, poly-allylene, and benzocyclobutene.

23. The method according to claim 16, wherein diameters of said abrasive particles are within ±

50% of an average diameter of the diameters.