Real time monitoring with closed loop chucking force control

• US 10,460,916 B2
• Filed: 05/15/2018
• Issued: 10/29/2019
• Est. Priority Date: 05/15/2017
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Boyd, Jr., Wendell Glenn, Parkhe, Vijay D., Busche, Matthew James, Makhratchev, Konstantin, Ono, Masanori, Thach, Senh
• Primary Examiner(s): King, Monica C
• Application Number:
  US15/979,787
• Publication Number:
  US 20180330926A1
• Time in Patent Office: 532 Days
• CPC Class Codes: H01J 2237/002 Cooling arrangements
• CPC Class Codes: H01J 2237/2007 Holding mechanisms
• CPC Class Codes: H01J 2237/24585 Other variables, e.g. energy, mass, velocity, time, temperature
• CPC Class Codes: H01J 2237/332 Coating
• CPC Class Codes: H01J 2237/334 Etching
• CPC Class Codes: H01J 37/32697 Electrostatic control
• CPC Class Codes: H01J 37/32715 Workpiece holder
• CPC Class Codes: H01J 37/32724 Temperature
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: H01L 21/67248 Temperature monitoring
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 21/67259 Position monitoring, e.g. misposition detection or presence detection
• CPC Class Codes: H01L 21/6831 using electrostatic chucks
• CPC Class Codes: H01L 21/6833 Details of electrostatic chucks
• CPC Class Codes: H01L 21/68742 characterised by a lifting arrangement, e.g. lift pins
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

Embodiments disclosed herein include a method for minimizing chucking forces on a workpiece disposed on a electrostatic chuck within a plasma processing chamber. The method begins by placing a workpiece on an electrostatic chuck in a processing chamber. A plasma is struck within the processing chamber. A deflection force is monitored on the workpiece. A chucking voltage is applied at a minimum value. A backside gas pressure is applied at a minimum pressure. The chucking voltage and or backside gas pressure is adjusted such that the deflection force is less than a threshold value. And the chucking voltage and the backside gas pressure are simultaneously ramped up.

Claims

1. A method for minimizing chucking forces on a workpiece disposed on a electrostatic chuck within a plasma processing chamber, the method comprising:

placing a workpiece on an electrostatic chuck in a processing chamber;

striking a plasma within the processing chamber;

monitoring a deflection force on the workpiece;

applying a chucking voltage at a minimum value;

applying a backside gas pressure at a minimum pressure;

adjusting the chucking voltage and or backside gas pressure such that the deflection force is less than a threshold value; and

simultaneously ramping up the chucking voltage and the backside gas pressure.

2. The method of claim 1, further comprising:

reversing the process for de-chucking.

3. The method of claim 1, wherein a minimum value of the chucking voltage force is less than a minimum value of the backside gas pressure.

4. The method of claim 1, wherein the value of the backside gas pressure is less than the value of the chucking voltage force when the workpiece is chucked.

5. The method of claim 1, wherein the deflection force is between about 50 mTorr and about 50 Torr.

6. The method of claim 5, wherein the deflection force is about 1 Torr or less.

7. The method of claim 1, further comprising:

Introducing a small time delay between the striking of the plasma and the chucking the workpiece.

8. The method of claim 7, wherein the small time delay is between about 200 milliseconds and about 10 seconds.

9. The method of claim 1, further comprising:

providing a closed loop control of the chucking force and backside gas pressure; and

minimizing the chucking force in response to the closed loop control.

10. The method of claim 1, further comprising:

adjusting the clamping voltage to the ESC so that the clamping force reaches and maintains a target total clamping force.

11. The method of claim 1, wherein applying the chucking voltage at the minimum value, further comprises:

selecting the chucking voltage to achieve a minimum force.