Supercritical carbon dioxide/chemical formulation for removal of photoresists

• US 20040087457A1
• Filed: 10/31/2002
• Published: 05/06/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Original Assignee: Advanced Technology Materials, Inc. (Entegris Incorporated)
• Inventors: Ghenciu, Eliodor G., Xu, Chongying, Korzenski, Michael B., Baum, Thomas H.
• Granted Patent: US 6,989,358 B2
• Time in Patent Office: Days
• US Class Current: 510/177
• CPC Class Codes: C11D 7/02 Inorganic compounds
• CPC Class Codes: C11D 7/10 Salts
• CPC Class Codes: C11D 7/3209 Amines or imines with one to four nitrogen atoms; Quaternized amines
• CPC Class Codes: C11D 7/3281 Heterocyclic compounds
• CPC Class Codes: C11D 7/5022 containing oxygen
• CPC Class Codes: G03F 7/423 containing mineral acids or salts thereof, containing mineral oxidizing substances, e.g. peroxy compounds

Abstract

A photoresist cleaning composition for removing photoresist and ion implanted photoresist from semiconductor substrates. The cleaning composition contains supercritical CO₂ (SCCO2) and alcohol for use in removing photoresist that is not ion-implanted. When the photoresist has been subjected to ion implantation, the cleaning composition additionally contains a fluorine ion source. Such cleaning composition overcomes the intrinsic deficiency of SCCO2 as a cleaning reagent, viz., the non-polar character of SCCO2 and its associated inability to solubilize species such as inorganic salts and polar organic compounds that are present in the photoresist and that must be removed from the semiconductor substrate for efficient cleaning. The cleaning composition enables damage-free, residue-free cleaning of substrates having photoresist or ion implanted photoresist thereon.

Claims

1. A photoresist cleaning composition, comprising SCCO2 and alcohol.

2. The composition of claim 1, wherein the alcohol comprises at least one C₁-C₄ alcohol.

3. The composition of claim 1, wherein the alcohol comprises ethanol.

4. The composition of claim 1, wherein the alcohol comprises methanol.

5. The composition of claim 1, wherein the alcohol comprises isopropanol.

6. The composition of claim 1, wherein the alcohol comprises butanol.

7. The composition of claim 1, wherein the concentration of alcohol is from about 5 wt. % to about 20 wt. %, based on the total weight of the composition.

8. The composition of claim 1, further comprising a fluorine ion source.

9. The composition of claim 8, wherein said fluorine ion source includes at least one fluorine source reagent selected from the group consisting of hydrogen fluoride (HF), amine trihydrogen fluoride compounds of the formula NR₃(HF)₃ wherein each R is independently selected from hydrogen and lower alkyl, hydrogen fluoride-pyridine (pyr-HF), ammonium fluorides of the formula R₄NF, wherein each R is independently selected from hydrogen and lower alkyl, other quaternary fluorides, xenon difluoride, and fluoromethane.

10. The composition of claim 8, wherein the fluorine ion source has a concentration of from about 0.01 wt. % to about 5 wt. %, based on the total weight of the composition.

11. The composition of claim 8, wherein the fluorine ion source has a concentration of from about 0.1 wt. % to about 1 wt. %, based on the total weight of the composition.

12. The composition of claim 8, wherein the fluorine ion source includes a compound of the formula NR₄F wherein each R is independently selected from hydrogen and lower alkyl.

13. The composition of claim 8, wherein the fluorine ion source includes ammonium fluoride.

14. The composition of claim 1, further comprising an oxidation inhibitor.

15. The composition of claim 14, wherein the oxidation inhibitor comprises boric acid.

16. A photoresist cleaning composition, comprising SCCO2 and alcohol, wherein the alcohol is selected from the group consisting of methanol, ethanol and isopropanol, wherein the alcohol is present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the cleaning composition, and wherein SCCO2 is present at a concentration of from about 80 to about 95 wt. %, based on the total weight of the cleaning composition.

17. A photoresist cleaning composition, comprising SCCO2, alcohol and a fluorine ion source, wherein the alcohol is selected from the group consisting of methanol and isopropanol, wherein the fluorine ion source is present at a concentration of from about 0.1 to about 1 wt. %, based on the total weight of the composition, wherein the alcohol is present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the cleaning composition, and wherein SCCO2 is present at a concentration of from about 79 to about 94.9 wt. %, based on the total weight of the cleaning composition.

18. The composition of claim 17, wherein the fluorine ion source comprises NH₄F.

19. A method of removing photoresist from a substrate having same thereon, said method comprising contacting the photoresist with a cleaning composition comprising SCCO2 and alcohol, for sufficient time and under sufficient contacting conditions to remove the photoresist from the substrate.

20. The method of claim 19, wherein said contacting conditions comprise elevated pressure.

21. The method of claim 20, wherein said elevated pressure comprises pressure in a range of from about 1000 to about 7500 psi.

22. The method of claim 19, wherein said contacting conditions comprise elevated temperature.

23. The method of claim 22, wherein said elevated temperature comprises temperature in a range of from about 35°

C. to about 100°

C.

24. The method of claim 19, wherein said contacting time is in a range of from about 1 to about 30 minutes.

25. The method of claim 19, wherein said composition comprises methanol as said alcohol, present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the cleaning composition.

39. The method of claim 23, wherein said contacting time is in a range of from about 1 to about 15 minutes.

26. A method of removing photoresist from a substrate having same thereon, said method comprising contacting the photoresist with a cleaning composition comprising SCCO2 and alcohol, to remove the photoresist from the substrate, wherein said alcohol is selected from the group consisting of methanol, ethanol and isopropanol, and said alcohol is present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the composition, and said contacting is carried out under conditions including pressure in a range of from about 1000 to about 7500 psi, temperature in a range of from about 35°

C. to about 100°

C., for sufficient time to remove the photoresist from the substrate.

27. The method of claim 26, wherein the contacting time is in a range of from about 1 to about 30 minutes.

28. A method of removing ion implanted photoresist from a substrate having same thereon, said method comprising contacting the photoresist with a cleaning composition comprising SCCO2, alcohol and a fluorine ion source, for sufficient time and under sufficient contacting conditions to remove the ion implanted photoresist from the substrate.

29. The method of claim 28, wherein said fluorine ion source includes at least one fluorine source reagent selected from the group consisting of hydrogen fluoride (HF), amine trihydrogen fluoride compounds of the formula NR₃(HF)₃ wherein each R is independently selected from hydrogen and lower alkyl, hydrogen fluoride-pyridine (pyr-HF), ammonium fluorides of the formula R₄NF, wherein each R is independently selected from hydrogen and lower alkyl, other quaternary fluorides, xenon difluoride, and fluoromethane.

30. The method of claim 28, wherein the fluorine ion source has a concentration of from about 0.01 wt. % to about 5 wt. %, based on the total weight of the composition.

31. The method of claim 28, wherein the fluorine ion source has a concentration of from about 0.1 wt. % to about 1 wt. %, based on the total weight of the composition.

32. The method of claim 28, wherein the fluorine ion source comprises NH₄F.

33. The method of claim 28, wherein the alcohol is selected from the group consisting of methanol, ethanol and isopropanol, wherein the fluorine ion source is present at a concentration of from about 0.1 to about 1 wt. %, based on the total weight of the composition, wherein the alcohol is present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the cleaning composition, and wherein SCCO2 is present at a concentration of from about 79 to about 94.9 wt. %, based on the total weight of the cleaning composition.

34. The method of claim 33, wherein the fluorine ion source comprises NH₄F.

35. The method of claim 28, wherein said contacting conditions comprise elevated pressure.

36. The method of claim 35, wherein said elevated pressure comprises pressure in a range of from about 1000 to about 7500 psi.

37. The method of claim 28, wherein said contacting conditions comprise elevated temperature.

38. The method of claim 37, wherein said elevated temperature comprises temperature in a range of from about 45°

C. to about 100°

C.

40. A method of removing ion implanted photoresist from a substrate having same thereon, said method comprising contacting the ion implanted photoresist with a cleaning composition comprising SCCO2, alcohol and fluorine ion source, to remove the ion implanted photoresist from the substrate, wherein said alcohol is selected from the group consisting of methanol, ethanol and isopropanol, said alcohol is present at a concentration of from about 5 to about 20 wt. %, based on the total weight of the composition, said fluorine ion source is present at a concentration of from about 0.1 to about 1 wt. %, based on the total weight of the composition, and said contacting is carried out under conditions including pressure in a range of from about 2000 to about 4500 psi, temperature in a range of from about 45°

C. to about 75°

C., for sufficient time to remove the photoresist from the substrate.

41. The method of claim 40, wherein the contacting time is in a range of from about 5 to about 15 minutes.