Highly polar cleans for removal of residues from semiconductor structures

• US 20040097388A1
• Filed: 06/04/2003
• Published: 05/20/2004
• Est. Priority Date: 11/15/2002
• Status: Active Grant

• Current Assignee: Justin K. Brask, Robert B. Turkot Jr, Vijayakumar S. Ramachandrarao
• Original Assignee: Justin K. Brask, Robert B. Turkot Jr, Vijayakumar S. Ramachandrarao
• Inventors: Brask, Justin K., Ramachandrarao, Vijayakumar S., Turkot, Robert B. Jr.
• Granted Patent: US 7,022,655 B2
• Time in Patent Office: Days
• US Class Current: 510/175
• CPC Class Codes: C11D 2111/22 Electronic devices, e.g. PCBs or semiconductors
• CPC Class Codes: C11D 7/3281 Heterocyclic compounds
• CPC Class Codes: C11D 7/36 containing phosphorus

Abstract

Supercritical carbon dioxide may be utilized to remove resistant residues such as those residues left when etching dielectrics in fluorine-based plasma gases. The supercritical carbon dioxide may include an ionic liquid in one embodiment.

Claims

1. A method of cleaning etch residues comprising:

exposing said etch residue to flowing supercritical carbon dioxide and an ionic liquid.

2. The method of claim 1 including exposing said etch residue to an ionic liquid including a fully, or a partially, miscible imidazolium compound.

3. The method of claim 2 including exposing said etch residue to 1-butyl-3-methylimidazolium hexafluorophosphate in supercritical carbon dioxide.

4. The method of claim 1 including providing a solvent with said carbon dioxide and ionic liquid.

5. The method of claim 4 wherein said solvent includes fluorine substituents.

6. The method of claim 1 including providing an ionic liquid which is only partially miscible in supercritical carbon dioxide and combining said ionic liquid and said flowing supercritical carbon dioxide.

7. The method of claim 1 including providing an ionic liquid which is fully miscible in supercritical carbon dioxide and combining said ionic liquid and said flowing supercritical carbon dioxide.

8. A cleaning material comprising:

supercritical carbon dioxide; and

an ionic liquid.

9. The material of claim 8 wherein said ionic liquid is only partially miscible in supercritical carbon dioxide.

10. The material of claim 8 wherein said ionic liquid is fully miscible in supercritical carbon dioxide.

11. The material of claims 9 or 10 wherein said ionic liquid includes an imidazolium compound.

12. The material of claim 11 wherein said compound is 1-butyl-3-methylimidazolium hexafluorophosphate.

13. The material of claims 9 or 10 including a co-solvent.

14. The material of claim 13 wherein said co-solvent includes fluorine substituents.

15. A method of removing etch residues comprising:

forming a mixture of 1-butyl-3-methylimidazolium hexafluorophosphate and supercritical carbon dioxide; and

flowing said mixture over said etch residue.

16. The method of claim 15 including forming a mixture in which the 1-butyl-3-methylimidazolium hexafluorophosphate is only partially miscible in supercritical carbon dioxide.

17. The method of claim 15 including forming the mixture with a solvent including a fluorine-based solvent.