Chemical oxide removal of plasma damaged SiCOH low k dielectrics

• US 7,368,393 B2
• Filed: 04/20/2006
• Issued: 05/06/2008
• Est. Priority Date: 04/20/2006
• Status: Expired due to Fees

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: International Business Machines Corporation
• Inventors: Johnston, Steven H., America, William G., Messenger, Brian W.
• Primary Examiner(s): Ahmed; Shamim
• Assistant Examiner(s): ANGADI, MAKI A
• Application Number:
  US11/308,672
• Publication Number:
  US 20070246442A1
• Time in Patent Office: 747 Days
• Field of Search: 438/706, 216/37
• US Class Current: 438/706
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• 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 21/312 Organic layers, e.g. photoresist H01L21/3105, H01L21/32 take precedence; photoresists per se G03C
• CPC Class Codes: H01L 21/31633 Deposition of carbon doped silicon oxide, e.g. SiOC
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors

Abstract

A method for removing damages of a dual damascene structure after plasma etching is disclosed. The method comprises the use of sublimation processes to deposit reactive material onto the damaged regions and conditions to achieve a controlled removal of the damaged region. Furthermore a semiconductor structure comprising a dual damascene structure that has been treated by the method is disclosed.

Claims

1. A method, comprising:

depositing a mixture of gaseous hydrofluoric acid and ammonia gas onto a plasma induced damaged layer formed in a trench sidewall;

forming volatile reaction products from a chemical reaction between the plasma induced damaged layer and the deposited mixture of ammonia gas and gaseous hydrofluoric acid; and

removing the volatile reaction products with vacuum or a non-reactive flushing gas.

2. The method according to claim 1, wherein a non-reactive diluent gas is used to dilute the mixture of gaseous hydrofluoric acid and ammonia gas.

3. The method according to claim 2, wherein the non-reactive gas belongs to a group of gases comprising nitrogen, helium, neon, argon.

4. The method according to claim 1, wherein the damaged layer is a low k dielectric material comprising organic siloxanes having a dielectric constant of less than 3.9.

5. The method according to claim 1, wherein the mixture of gaseous hydrofluoric acid and ammonia gas has a stochiometric ratio comprising a range from 4:

1 to 1;

4 (HF;

NH₃).

6. The method according to claim 2, wherein the mixture of gaseous hydrofluoric acid, ammonia gas and the non-reactive diluent gas has a combined partial pressure of 1 to 20 millitorr.

7. The method according to claim 2, wherein the non-reactive diluent gas is supplied at a flow between 0 and 400 cm³/min.

8. The method according to claim 1, wherein the forming of volatile reaction products is accelerated by adjusting the temperature between ambient and 200°

C.

9. The method according to claim 1, wherein the removing of the volatile reaction products includes flushing with nitrogen.

10. The method according to claim 1, wherein the removing of the volatile reaction products includes applying a vacuum.

18. The method according to claim 1, wherein the removing of the volatile reaction products is subsequent to the forming of volatile reaction products.

20. The method according to claim 1, further comprising etching the trench through a photoresist material.

22. The method according to claim 1, wherein the depositing occurs through a photoresist material.

24. The method according to claim 1, wherein the forming occurs while a photoresist material is arranged on a structure having the trench.

26. The method according to claim 1, further comprising forming the trench by etching into a dual damascene structure through a photoresist material.

27. The method according to claim 1, further comprising forming the trench by etching into an interlevel dielectric film (ILD) of a dual damascene structure.

11. A method for trimming a dual damascene, comprising

depositing a material generated from a dilute mixture of gaseous hydrofluoric acid and ammonia gas in a non-reactive diluent gas onto a trench of a dual damascene structure;

heating the dual damascene structure with the deposited material; and

flushing the dual damascene structure with a non-reactive flush gas to remove the material and chemically formed products.

12. The method according to claim 11, wherein the trimming has a thickness between 1 and 25 nm.

13. The method according to claim 11, wherein the dilute mixture of gaseous hydrofluoric acid and ammonia gas has a stochiometric ratio between 4:

1 and 1;

4 (HF;

NH₃), and the non-reactive diluent gas is from a group comprising nitrogen, helium, neon, and argon.

14. The method according to claim 13 wherein the dilute mixture of hydrofluoric acid and ammonia gas has a partial pressure between 1 and 20 millitorr, preferably between 10 and 14 millitorr and the non-reactive diluent gas has a flow rate of 0 to 400 cm³/min, preferably 0 to 225 cm³/min.

15. The method according to claim 11, wherein the heating of the dual damascene structure with the deposited material occurs between ambient and 200°

C., preferably 150°

C.

16. The method according to claim 11, wherein the non-reactive flush gas is one of nitrogen, helium, neon, and argon.

17. A method according to claim 11, wherein the flushing of the dual damascene structure is followed by applying a vacuum.

19. The method according to claim 11, wherein the flushing the dual damascene structure with a non-reactive flush gas to remove the material and chemically formed products is subsequent to the heating the dual damascene structure with the deposited material.

21. The method according to claim 11, further comprising etching the trench through a photoresist material.

23. The method according to claim 11, wherein the deposing occurs through a photoresist material.

25. The method according to claim 11, wherein the flushing occurs while a photoresist material is arranged on the dual damascene structure.