Real time monitoring with closed loop chucking force control

Patent metadata

Field	Value
Publication number	US-10460916-B2
Application number	US-201815979787-A
Country	US
Kind code	B2
Filing date	May 15, 2018
Priority date	May 15, 2017
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

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.

First claim

What is claimed is:

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.

Assignees

• Applied Materials Inc

Inventors

• Boyd Jr Wendell Glenn
• Parkhe Vijay D
• Busche Matthew James
• Makhratchev Konstantin
• Ono Masanori
• Thach Senh

Classifications

• H10P72/7612

  characterised by lifting arrangements, e.g. lift pins · CPC title

• H10P72/0421

  for drying etching · CPC title

• H10P74/23

  characterised by multiple measurements, corrections, marking or sorting processes · CPC title

• H10P72/722

  Details of electrostatic chucks · CPC title

• H10P72/0606

  Position monitoring, e.g. misposition detection or presence detection · CPC title