Using bias RF pulsing to effectively clean electrostatic chuck (ESC)

• US 10,410,845 B2
• Filed: 11/22/2017
• Issued: 09/10/2019
• Est. Priority Date: 11/22/2017
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Doan, Kenny Linh, Dadu, Usama, Lee, Wonseok, Shimizu, Daisuke, Ling, Li, Choi, Kevin
• Primary Examiner(s): Roman, Angel
• Application Number:
  US15/821,661
• Publication Number:
  US 20190157052A1
• Time in Patent Office: 657 Days
• Field of Search: None
• CPC Class Codes: B08B 5/00 Cleaning by methods involving the use of air flow or gas flow B08B6/00 takes precedence
• CPC Class Codes: B08B 7/0071 by heating B08B7/0035 takes precedence
• CPC Class Codes: H01J 37/32146 Amplitude modulation, includes pulsing
• CPC Class Codes: H01J 37/32724 Temperature
• CPC Class Codes: H01J 37/32816 Pressure
• CPC Class Codes: H01J 37/32862 In situ cleaning of vessels and/or internal parts
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H02N 13/00 Clutches or holding devices using electrostatic attraction, e.g. using Johnson-Rahbek effect

Abstract

Embodiments include a plasma processing method for cleaning polymer byproducts from interior surfaces of the plasma chamber. In an embodiment the plasma process may include processing a workpiece in a plasma processing chamber. Thereafter, the method may include removing the workpiece from the processing chamber. After the workpiece is removed, embodiments may include cleaning the plasma processing chamber with a cleaning process that includes a high pressure cleaning process, a first low pressure cleaning process, and a second low pressure cleaning process, wherein the second low pressure cleaning process includes applying a pulsed bias.

Claims

1. A plasma processing method, comprising:

processing a workpiece in a plasma processing chamber;

removing the workpiece from the processing chamber;

cleaning the plasma processing chamber with a cleaning process that comprises a high pressure cleaning process, a first low pressure cleaning process, and a second low pressure cleaning process, wherein the second low pressure cleaning process includes applying a pulsed bias.

2. The plasma processing method of claim 1, wherein the second low pressure cleaning process utilizes a processing gas comprising an oxidizing source gas.

3. The plasma processing method of claim 2, wherein the oxidizing source gas includes one or more of O₂, NO, CO, COS.

4. The plasma processing method of claim 2, wherein the process pressure of the second low pressure cleaning process incudes a process pressure that is approximately 50 mT or less.

5. The plasma processing method of claim 4, wherein the process pressure of the second low pressure cleaning process includes a process pressure that is less than approximately 30 mT.

6. The plasma processing method of claim 4, wherein the second low pressure cleaning process includes a process pressure that is less than a processing pressure of the first low pressure cleaning process.

7. The plasma processing method of claim 4, wherein the flow rate of the oxidizing source is at least 2,000 sccm.

8. The plasma processing method of claim 6, wherein the flow rate of the oxidizing source is between approximately 5,000 sccm and 7,000 sccm.

9. The plasma processing method of claim 1, wherein the second low pressure cleaning process further comprises increasing a temperature of an electrostatic chuck in the processing chamber to a temperature that is greater than a temperature of the electrostatic chuck utilized during the processing of the workpiece.

10. The plasma processing method of claim 9, wherein the temperature of the electrostatic chuck is increased to greater than approximately 70°

C.

11. The plasma processing method of claim 1, wherein the bias is a 2 MHz bias.

12. The plasma processing method of claim 1, wherein the pulsed bias is a DC bias with the bias being applied between 1% and 99% of the duration of the second low pressure cleaning process.

13. The plasma processing method of claim 7, wherein the bias is applied for approximately 50% of the duration of the cleaning process.

14. The plasma processing operation of claim 1, wherein processing a workpiece in a plasma processing chamber comprises processing a plurality of workpieces, wherein the plurality of workpieces are processed in the plasma processing chamber sequentially until a variation between processed workpieces exceeds a predetermined threshold.

15. A cleaning process for a plasma chamber, comprising:

removing a workpiece from the processing chamber; and

implementing a high pressure cleaning process and then a low pressure cleaning process, the low pressure cleaning process at a processing pressure that is less than 50 mT with an oxidizing source gas, wherein the low pressure cleaning process includes applying a pulsed bias.

16. The processing method of claim 15, wherein the flow rate of the oxidizing source gas is greater than approximately 2,000 sccm.

17. The processing method of claim 15, further comprising increasing a temperature of an electrostatic chuck in the plasma chamber.

18. The method of claim 15, wherein the bias is a 2 MHz bias.

19. A plasma processing method, comprising:

processing a workpiece in a plasma processing chamber, wherein processing the workpiece results in a coating of polymer byproducts being deposited on surfaces of the plasma processing chamber;

removing the workpiece from the processing chamber;

cleaning the plasma processing chamber with a cleaning process that comprises a high pressure cleaning process optimized to clean polymer byproducts deposited on a showerhead of the plasma processing chamber, a first low pressure cleaning process optimized to clean polymer byproducts deposited along sidewall surfaces of the plasma processing chamber, and a second low pressure cleaning process, wherein the second low pressure cleaning process includes applying a pulsed bias, wherein the second low pressure cleaning process is optimized to clean polymer byproducts formed along sidewalls of an electrostatic chuck, and wherein a processing gas utilized for the second low pressure cleaning process is an oxidizing source.

20. The processing method of claim 19, wherein the oxidizing source gas is O₂, and wherein the flow rate of the oxidizing source gas is greater than approximately 2,000 sccm.