Plasma process for removing excess molding material from a substrate

• US 20060131790A1
• Filed: 12/22/2004
• Published: 06/22/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Nordson Corporation
• Original Assignee: Nordson Corporation
• Inventors: Getty, James D., Zhao, Jiangang
• Granted Patent: US 7,842,223 B2
• Time in Patent Office: Days
• US Class Current: 264/400
• CPC Class Codes: B29C 59/14 by plasma treatment plasma tubes per se H01J
• CPC Class Codes: H01L 21/56 Encapsulations, e.g. encapsulation layers, coatings
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05K 3/288 Removal of non-metallic coatings, e.g. for repairing

Abstract

A method for removing thin layers of a two-component molding material from areas on a substrate. The method includes using a plasma formed using a first gas mixture for removing one component of the molding material and a plasma formed using a different second gas mixture for removing the other component of the molding material. For filled epoxies commonly used as molding materials, the first gas mixture may be an oxygen-rich mixture of an oxygen-containing gas species and a fluorine-containing gas species, and the second gas mixture may be a fluorine-rich mixture of the same gases.

Claims

1. A method for removing amounts of a two-component molding material from an area on a substrate, comprising:

exposing the substrate to a first plasma effective to remove a first component of the molding material from the area with a higher etch rate than a second component of the molding material; and

exposing the substrate to a second plasma effective to remove the second component of the molding material from the area with a higher etch rate than the first component of the molding material.

2. The method of claim 1 wherein exposing the substrate to the first plasma comprises:

forming the first plasma from a first gas mixture effective to provide the higher etch rate for the first component of the molding material.

3. The method of claim 2 wherein exposing the substrate to the second plasma comprises:

forming the second plasma from a second gas mixture that differs from the first gas mixture and that is effective to provide the higher etch rate for the second component of the molding material.

4. The method of claim 3 wherein the first gas mixture and the second gas mixture each include a fluorine-containing gas species and an oxygen-containing gas species.

5. The method of claim 4 wherein the first gas mixture includes less than 50 percent by volume of the fluorine-containing gas species.

6. The method of claim 5 wherein the second gas mixture includes more than 50 percent by volume of the fluorine-containing gas species.

7. The method of claim 4 wherein the second gas mixture includes more than 50 percent by volume of the fluorine-containing gas species.

8. The method of claim 4 wherein the fluorine-containing gas species is selected from the group consisting of carbon tetrafluoride, nitrogen trifluoride, and sulfur hexafluoride.

9. The method of claim 4 wherein the oxygen-containing gas species is molecular oxygen.

10. The method of claim 1 wherein the first component includes an organic matrix and the second component includes an inorganic filler dispersed in the organic matrix.

11. The method of claim 10 wherein the organic matrix is an epoxy and the inorganic filler comprises silica particles dispersed in the epoxy.

12. The method of claim 1 further comprising:

placing the substrate at a fixed treatment position inside a treatment chamber while exposing the substrate to the first and second plasmas in the treatment chamber.

13. The method of claim 12 wherein the first and second plasmas are generated inside the treatment chamber.

14. The method of claim 12 wherein an operating pressure in the treatment chamber while the substrate is exposed to the first and second plasmas is in the range of about 800 mTorr to about 2500 mTorr.

15. The method of claim 1 wherein exposing the substrate to the second plasma further comprises:

exposing the substrate to the second plasma without extinguishing the first plasma.

16. A method for removing amounts of a two-component molding material from an area on a substrate, comprising:

generating a first plasma formed from a first gas mixture including a lower concentration by volume of a fluorine-containing gas species than an oxygen-containing gas species;

exposing the substrate to the first plasma to remove a first component of the molding material from the area at a higher etch rate than a second component of the molding material;

generating a second plasma formed from a second gas mixture including a higher concentration by volume of the fluorine-containing gas species than the oxygen-containing gas species; and

exposing the substrate to the second plasma to remove the second component of the molding material from the area at a higher etch rate than the first component of the molding material.

17. The method of claim 16 wherein the fluorine-containing gas species is selected from the group consisting of carbon tetrafluoride and sulfur hexafluoride.

18. The method of claim 16 wherein the oxygen-containing gas species is molecular oxygen.

19. The method of claim 16 wherein the first component includes an organic matrix and the second component includes an inorganic filler dispersed in the organic matrix.

20. The method of claim 19 wherein the organic matrix is an epoxy and the inorganic filler comprises silica particles dispersed in the epoxy.

21. The method of claim 16 wherein exposing the substrate to the second plasma further comprises:

exposing the substrate to the second plasma without extinguishing the first plasma.

22. The method of claim 16 wherein the first and second plasmas are generated inside the treatment chamber.

23. The method of claim 16 further comprising:

placing the substrate at a treatment position inside a treatment chamber and exposing the substrate to the first and second plasmas without removing the substrate from the treatment chamber.

24. The method of claim 23 wherein an operating pressure in the treatment chamber while the substrate is exposed to the first and second plasmas is in the range of about 800 mTorr to about 2500 mTorr.

25. The method of claim 16 wherein the first gas mixture includes less than 50 percent by volume of the fluorine-containing gas species and more than 50 percent by volume of the oxygen-containing gas species.

26. The method of claim 16 wherein the second gas mixture includes more than 50 percent by volume of the fluorine-containing gas species and less than 50 percent by volume of the oxygen-containing gas species.