PLASMA TREATMENT METHOD FOR PREVENTING DEFECTS IN DOPED SILICON OXIDE SURFACES DURING EXPOSURE TO ATMOSPHERE

• US 20090269934A1
• Filed: 07/15/2008
• Published: 10/29/2009
• Est. Priority Date: 04/25/2008
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Yang, Haichun, Kao, Chien-Teh, Lu, Xinliang, Chang, Mei
• Granted Patent: US 8,318,605 B2
• Time in Patent Office: Days
• US Class Current: 438/710
• CPC Class Codes: H01L 21/02063 the processing being the formation of vias or contact holes
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76828 thermal treatment

Abstract

Formation of BPSG surface defects upon exposure to atmosphere is prevented by a plasma treatment method for converting boron and/or phosphorus materials separated from silicon near the surface of the doped glass layer to gas phase compounds. The treatment plasma is generated from a treatment process gas containing one of (a) a fluorine compound or (b) a hydrogen compound.

Claims

1. A method of fabricating an integrated circuit on a semiconductor wafer, comprising:

forming a thin film device structure on the wafer including semiconductor elements;

covering said thin film device structure with a doped glass layer comprising silicon, oxygen and at least one of boron or phosphorus;

forming openings through said doped glass layer to expose a surface of each of said semiconductor elements;

performing an etch step by generating a plasma from a process gas comprising fluorine species and hydrogen species and exposing said wafer to by-products of said plasma;

converting boron and/or phosphorus materials separated from silicon near the surface of said doped glass layer to gas phase compounds.

2. The method of claim 1 wherein said converting comprises:

generating a treatment plasma from a treatment process gas containing one of (a) a fluorine compound or (b) a hydrogen compound so as to produce plasma treatment by-products from said plasma;

exposing said wafer to said plasma treatment by-products.

3. The method of claim 2 wherein said generating comprises holding said wafer in a process chamber while generating said treatment plasma in a remote plasma chamber and transporting plasma by-products from said remote plasma chamber to said process chamber.

4. The method of claim 2 wherein said generating comprises holding said wafer in a process chamber and generating said treatment plasma in said process chamber.

5. The method of claim 3 wherein:

said treatment process gas contains a fluorine compound;

said generating comprises flowing NF₃ gas into the remote plasma chamber at a first flow rate while flowing He gas into said remote plasma chamber at a second flow rate.

6. The method of claim 5 wherein said first flow rate is about one sixth of said second flow rate.

7. The method of claim 6 further comprising holding said wafer at a temperature in a range of about 90°

C.-200°

C.

8. The method of claim 7 wherein said first flow rate is in a range of about 25-150 sccm and said second flow rate is in a range of about 100-1000 sccm.

9. The method of claim 3 wherein:

said treatment process gas contains a hydrogen compound;

said generating comprises flowing NH₃ gas into the remote plasma chamber at a first flow rate while flowing H₂ gas into said remote plasma chamber at a second flow rate.

10. The method of claim 9 wherein said first flow rate is about one tenth of said second flow rate.

11. The method of claim 10 further comprising holding said wafer at a temperature is in a range of about 20°

C. to 70°

C.

12. The method of claim 11 wherein said first flow rate is in a range of about 50-300 sccm and said second flow rate is in a range of about 100-2000 sccm.

18. The method of claim 3 wherein:

said treatment process gas contains a hydrogen compound;

said generating comprises flowing NH₃ gas into a plasma chamber at a first flow rate while flowing H₂ gas into said plasma chamber at a second flow rate, said plasma chamber being one of a remote plasma chamber or an in situ plasma chamber.

19. The method of claim 18 wherein:

said first flow rate is about one tenth of said second flow rate, said method further comprising holding said wafer at a temperature is in a range of about 20°

C. to 70°

C. during exposure to said treatment plasma.

20. The method of claim 19 wherein said first flow rate is in a range of about 50-300 sccm and said second flow rate is in a range of about 100-2000 sccm.

13. A method of fabricating an integrated circuit on a semiconductor wafer, comprising:

forming a thin film device structure on the wafer including semiconductor elements;

covering said thin film device structure with a doped glass layer comprising silicon, oxygen and at least one of boron or phosphorus;

forming openings through said doped glass layer to expose a surface of each of said semiconductor elements;

performing an etch step by generating a plasma from a process gas comprising fluorine species and hydrogen species and exposing said wafer to by-products of said plasma;

generating a treatment plasma from a treatment process gas containing one of (a) a fluorine compound or (b) a hydrogen compound so as to produce plasma treatment by-products from said plasma;

exposing said wafer to said plasma treatment by-products.

14. The method of claim 13 wherein said generating comprises one of:

(a) holding said wafer in a process chamber while generating said treatment plasma in a remote plasma chamber and transporting plasma by-products from said remote plasma chamber to said process chamber;

(b) holding said wafer in an in situ process chamber and generating said treatment plasma in said process chamber.

15. The method of claim 13 wherein:

said treatment process gas contains a fluorine compound;

said generating comprises flowing NF₃ gas into a plasma chamber at a first flow rate while flowing He gas into said plasma chamber at a second flow rate, said plasma chamber being one of a remote plasma chamber or an in situ plasma chamber.

16. The method of claim 15 wherein:

said first flow rate is about one sixth of said second flow rate, said method further comprising holding said wafer at a temperature in a range of about 90°

C. to 200°

C. during exposure to said treatment plasma.

17. The method of claim 16 wherein said first flow rate is in a range of about 25-150 sccm and said second flow rate is in a range of about 100-1000 sccm.