Process for removal of photoresist mask used for making vias in low K carbon-doped silicon oxide dielectric material, and for removal of etch residues from formation of vias and removal of photoresist mask

• US 20040072440A1
• Filed: 07/14/2003
• Published: 04/15/2004
• Est. Priority Date: 07/02/2001
• Status: Active Grant

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: Philippe Schoenborn, Yong-Bae Kim
• Inventors: Schoenborn, Philippe, Kim, Yong-Bae
• Granted Patent: US 7,071,113 B2
• Time in Patent Office: Days
• US Class Current: 438/709
• 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 21/76802 by forming openings in dielectrics
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: Y10S 438/963 Removing process residues from vertical substrate surfaces

Abstract

A process for removal of a photoresist mask used to etch openings in low k carbon-doped silicon oxide dielectric material of an integrated circuit structure, and for removing etch residues remaining from either the etching of the openings or removal of the resist mask, while inhibiting damage to the low k dielectric material comprises. The structure is exposed to a reducing plasma to remove a portion of the photoresist mask, and to remove a portion of the residues remaining from formation of the openings in the layer of low k dielectric material. The structure is then exposed to an oxidizing plasma to remove any remaining etch residues from the openings in the layer of low k dielectric material or removal of the resist mask.

Claims

1. A process for removing etch residues from vias and for removing a photoresist mask used to form said vias in low k carbon-doped silicon oxide dielectric material while inhibiting damage to said low k silicon oxide dielectric material which comprises:

a) exposing said photoresist mask and said vias to a plasma formed from one or more reducing agents to remove at least a portion of said resist mask and at least at least a portion of said etch residues in said vias; and

b) then exposing said vias and any remaining portions of said resist mask to a plasma formed from one or more oxidizing agents to remove the remainder of said etch residues in said vias and any remaining portions of said photoresist mask.

2. The process of claim 1 wherein said one or more reducing agents are selected from the group consisting of ammonia, hydrogen, a mixture of ammonia and hydrogen, a mixture of ammonia and nitrogen, a mixture of hydrogen and nitrogen, and a mixture of ammonia, hydrogen, and nitrogen.

3. The process of claim 1 wherein said one or more reducing agents includes a source of hydrogen and a source of nitrogen.

4. The process of claim 1 wherein said plasma formed from said one or more reducing agents contains radicals and charged particles.

5. The process of claim 1 wherein said one or more oxidizing agents used to form said plasma includes oxygen.

6. The process of claim 1 wherein said one or more oxidizing agents used to form said plasma comprises a combination of oxygen and at least one further gas.

7. The process of claim 1 wherein said one or more oxidizing agents used to form said plasma comprises a combination of oxygen and at least one further gas selected from the group consisting of nitrogen and argon.

8. The process of claim 1 wherein said one or more oxidizing agents used to form aid plasma consists essentially of a combination of oxygen and argon.

9. The process of claim 1 wherein said step of exposing said vias and any remaining portions of said resist mask to a plasma formed from one or more oxidizing agents further comprises exposing said remainder of said etch residues in said vias and any remaining portions of said photoresist mask to a directional beam of charged particles from said plasma formed from one or more oxidizing agents.

10. The process of claim 9 wherein said directional beam of charged particles is further characterized by the substantial absence of radicals.

11. The process of claim 1 wherein said step of exposing said photoresist mask and said vias to a plasma formed from one or more reducing agents further includes forming a coating on the sidewalls of said vias.

12. The process of claim 11 wherein said step of exposing said vias and any remaining portions of said resist mask to a plasma formed from one or more oxidizing agents further includes removing said coating formed on said sidewalls of said vias.

13. The process of claim 1 wherein said step of exposing said photoresist mask and said vias to a plasma formed from one or more reducing agents further includes forming said plasma from one or more reducing agents which includes hydrogen and nitrogen, and an organo nitrogen coating forms on the sidewalls of sid vias.

14. The process of claim 13 wherein said step of exposing said vias and any remaining portions of said resist mask to a plasma formed from one or more oxidizing agents further includes removing said organo nitrogen coating formed on said sidewalls of said vias.

15. The process of claim 1 which includes the further step of exposing said etch residues from formation of said vias and removal of said photoresist mask to a wet solvent to remove further residues.

16. A process for removal of a photoresist mask used to etch openings in a layer of carbon-doped low k carbon-doped silicon oxide dielectric material, and for removing etch residues remaining from either said etching of said openings or said removal of the photoresist mask, while inhibiting damage to said low k dielectric material, which comprises:

a) providing an integrated circuit structure comprising a layer of low k carbon-doped silicon oxide dielectric material having openings etched therein and a photoresist mask formed over said low k dielectric layer;

b) exposing the integrated circuit structure to a plasma formed from one or more reducing agents to remove at least a portion of said resist mask, and to remove at least a portion of;

i) said residues remaining from formation of said openings in said layer of low k carbon-doped silicon oxide dielectric material;

or

ii) said residues remaining from removal of said resist mask;

or

iii) residues remaining from both said formation of said openings in said layer of low k carbon-doped silicon oxide dielectric material and said removal of said resist mask;

c) then exposing said integrated circuit structure to an anisotropic etch comprising a plasma formed from one or more oxidizing agents to remove any remaining residues from both said formation of said openings in said layer of low k carbon-doped silicon oxide dielectric material and said removal of said resist mask.

17. The process of claim 16 wherein said one or more reducing agents includes a source of hydrogen and a source of nitrogen.

18. The process of claim 16 wherein said one or more oxidizing agents used to form said plasma comprises a combination of oxygen and at least one further gas selected from the group consisting of nitrogen and argon.

19. The process of claim 16 wherein said step of exposing said vias and any remaining portions of said resist mask to a plasma formed from one or more oxidizing agents further comprises exposing said remainder of said etch residues in said vias and any remaining portions of said photoresist mask to a directional beam of charged particles from a plasma of said one or more oxidizing agents, and further characterized by the substantial absence of uncharged radicals.

20. A process for removing etch residues from vias and for removing a photoresist mask used to form said vias in low k carbon-doped silicon oxide dielectric material while inhibiting damage to said low k silicon oxide dielectric material using a reducing plasma followed by an oxidizing plasma by which comprises:

a) exposing said photoresist mask and said vias to a plasma formed from one or more reducing agents selected from the group consisting of ammonia, hydrogen, a mixture of ammonia and hydrogen, a mixture of ammonia and nitrogen, a mixture of hydrogen and nitrogen, and a mixture of ammonia, hydrogen, and nitrogen, to remove at least a portion of said resist mask and at least at least a portion of said etch residues in said vias; and

b) then exposing said vias and any remaining portions of said resist mask to a directional beam of charged particles from a plasma of said one or more oxidizing agents, and further characterized by the substantial absence of uncharged radicals, said one or more oxidizing agents further comprising a combination of oxygen and at least one further gas selected from the group consisting of nitrogen and argon, to remove the remainder of said etch residues in said vias and any remaining portions of said photoresist mask.