Copper oxide removal techniques

• US 8,758,638 B2
• Filed: 05/10/2011
• Issued: 06/24/2014
• Est. Priority Date: 05/10/2011
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Ye, Weifeng, Nguyen, Victor, Shek, Mei-Yee, Balseanu, Mihaela, Xia, Li-Qun, Witty, Derek R.
• Primary Examiner(s): OLSEN, ALLAN W
• Application Number:
  US13/104,314
• Publication Number:
  US 20120289049A1
• Time in Patent Office: 1,141 Days
• Field of Search: None
• US Class Current: 216/78
• CPC Class Codes: H01L 21/02074 the processing being a planarization of conductive layers
• CPC Class Codes: H01L 21/76883 Post-treatment or after-treatment of the conductive material

Abstract

A method for the removal of copper oxide from a copper and dielectric containing structure of a semiconductor chip is provided. The copper and dielectric containing structure may be planarized by chemical mechanical planarization (CMP) and treated by the method to remove copper oxide and CMP residues. Annealing in a hydrogen (H₂) gas and ultraviolet (UV) environment removes copper oxide, and a pulsed ammonia plasma removes CMP residues.

Claims

1. A method of removing copper oxide from a copper and dielectric containing structure, comprising:

positioning a substrate containing a copper and dielectric containing structure in a processing chamber;

heating the substrate to a temperature between about 200°

C. and about 400°

C.;

exposing the copper and dielectric containing structure to a hydrogen (H₂) gas in the processing chamber; and

exposing the copper and dielectric containing structure to at least one pulse of an ammonia plasma having a duration of 4 seconds or less in the processing chamber while maintaining the substrate at a temperature between about 200°

C. and about 400°

C.

2. The method of claim 1, further comprising

flowing the hydrogen gas into the processing chamber for an anneal treatment time;

and

removing CMP residue during an ammonia plasma treatment time.

3. The method of claim 1, wherein the exposing the copper and dielectric containing structure to the hydrogen gas is conducted using a chamber pressure between 2 Torr and 10 Torr, a substrate temperature of about 350°

C., a hydrogen gas flow rate between 1000 sccm and 10,000 sccm, and an annealing treatment time between 1 second and 60 seconds.

4. The method of claim 1, wherein the exposing the copper and dielectric containing structure to the ammonia plasma comprises:

flowing an ammonia gas into the processing chamber; and

forming the ammonia plasma from the ammonia gas.

5. The method of claim 4, wherein the ammonia plasma is formed by coupling RF power to the ammonia gas, and wherein the exposing the copper and dielectric containing structure to the ammonia plasma is conducted using a chamber pressure between 2 Torr and 4 Torr, a substrate temperature of about 350°

C., a RF power between 300 W and 1000 W, a RF power frequency between 300 kHz and 15 MHz, an ammonia gas flow rate between 1000 sccm and 3000 sccm, a pulse frequency between 1 Hz and 50 kHz.

6. The method of claim 4, wherein the ammonia gas is mixed with a nitrogen (N₂) carrier gas.

7. The method of claim 1, further comprising forming a diffusion barrier layer onto the copper and dielectric containing structure.

8. The method of claim 1, wherein exposing the copper and dielectric containing structure to the ammonia plasma occurs during a treatment time, and wherein the copper and dielectric containing structure is exposed to the ammonia plasma for a total time that is a percentage of the treatment time as defined by a duty cycle.

9. The method of claim 8, wherein the treatment time is between 10 seconds and 60 seconds, and wherein the duty cycle is between 5% and 50%.

10. The method of claim 8, wherein the total time is evenly divided into a number of divisions between 2 and 50000, and wherein the divisions are evenly distributed within the treatment time.

11. The method of claim 8, wherein the total time is unevenly divided into a number of divisions between 2 and 50000, and wherein the divisions are unevenly distributed within the treatment time.

12. The method of claim 1, wherein the copper and dielectric containing structure is exposed to the hydrogen gas prior to being exposed to the ammonia plasma.

13. The method of claim 1, wherein heating comprises radiantly heating the substrate using UV radiation.

14. The method of claim 13, the UV radiation has an UV irradiance power between 1000 W/m² and 2000 W/m² and UV wavelengths between 200 nm and 400 nm.

15. A method of removing copper oxide from a copper and dielectric containing structure, comprising:

removing the copper oxide from the copper and dielectric containing structure using a hydrogen (H₂) gas, comprising;

positioning a substrate containing the copper and dielectric containing structure in a processing volume of a processing chamber;

heating the substrate to a temperature between about 200°

C. and about 400°

C.;

flowing the hydrogen gas into the processing volume; and

exposing the copper and dielectric containing structure to a pulsed ammonia plasma having a duration of 4 seconds or less in the processing chamber to remove CMP residue, comprising;

maintaining the substrate at a temperature between about 200°

C. and about 400°

C.;

flowing an ammonia gas into the processing volume; and

forming the pulsed ammonia plasma from the ammonia gas.

16. The method of claim 15, wherein the exposing the copper and dielectric containing structure to the hydrogen gas is conducted at a chamber pressure between 2 Torr and 10 Torr, a substrate temperature of about 350°

C., a hydrogen gas flow rate between 1000 sccm and 10,000 sccm, and an annealing treatment time between 1 second and 60 seconds.

17. The method of claim 15, wherein the pulsed ammonia plasma is formed by coupling RF power to the ammonia gas, and wherein the exposing the copper and dielectric containing structure to the pulsed ammonia plasma in the processing volume is conducted using a chamber pressure between 2 Torr and 4 Torr, a substrate temperature of about 350°

C., a RF power between 300 W and 1000 W, a RF power frequency between 300 kHz and 15 MHz, an ammonia gas flow rate between 1000 sccm and 3000 sccm, a pulse frequency between 1 Hz and 50 kHz.

18. The method of claim 15, wherein exposing the copper and dielectric containing structure to the pulsed ammonia plasma occurs during a treatment time, and wherein the copper and dielectric containing structure is exposed to the pulsed ammonia plasma for a total time that is a percentage of the treatment time as defined by a duty cycle.

19. The method of claim 18, wherein the treatment time is between 10 seconds and 60 seconds, and wherein the duty cycle is between 5% and 50%.

20. The method of claim 19, wherein the total time is evenly divided into a number of divisions between 2 and 50000, and wherein the divisions are evenly distributed within the treatment time.

21. The method of claim 19, wherein the total time is unevenly divided into a number of divisions between 2 and 50000, and wherein the divisions are unevenly distributed within the treatment time.

22. The method of claim 15, wherein heating comprises radiantly heating the substrate using UV radiation.

23. The method of claim 22, the UV radiation has an UV irradiance power between 1000 W/m² and 2000 W/m² and UV wavelengths between 200 nm and 400 nm.

24. A method of removing copper oxide from a copper and dielectric containing structure, comprising:

positioning a substrate containing a copper and dielectric containing structure in a processing chamber;

radiantly heating the substrate with a UV source to a temperature between about 200°

C. and about 400°

C.;

removing copper oxide from the copper and dielectric containing structure using a hydrogen (H₂) gas in the processing chamber during an annealing treatment time; and

exposing the copper and dielectric containing structure to a pulsed ammonia plasma having a duration of 4 seconds or less during a plasma treatment time in the processing chamber while maintaining the substrate at a temperature between about 200°

C. and about 400°

C., wherein the copper and dielectric containing structure is exposed to the pulsed ammonia plasma for a total time that is a percentage of the treatment time as defined by a duty cycle, and wherein the total time is divided into divisions distributed within the plasma treatment time.