CHEMICAL OXIDE REMOVAL OF PLASMA DAMAGED SICOH LOW K DIELECTRICS

• US 20070246442A1
• Filed: 04/20/2006
• Published: 10/25/2007
• Est. Priority Date: 04/20/2006
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: International Business Machines Corporation
• Inventors: America, William, Messenger, Brian, Johnston, Steven
• Granted Patent: US 7,368,393 B2
• Time in Patent Office: Days
• US Class Current: 216/58
• 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;

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 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.

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

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 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.

22. 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.

18. A semiconductor device comprising a plasma etched dual damascene structure with an interlevel dielectric film whereby damage to a surface of the plasma etched dual damascene structure are removed by a method comprising:

depositing a controlled amount of gaseous hydrofluoric acid and ammonia gas onto the surface of the dual damascene structure;

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

removing the volatile reaction products.

19. The semiconductor device according to claim 18, wherein the interlevel dielectric film comprises low k material having a dielectric constant of 3.9 or less.

20. The semiconductor device according to claim 18, wherein the damage is removed by trimming a surface between 1 and 25 nm.