Component temperature control by coolant flow control and heater duty cycle control

• US 9,639,097 B2
• Filed: 09/25/2014
• Issued: 05/02/2017
• Est. Priority Date: 05/27/2010
• Status: Active Grant

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Mahadeswaraswamy, Chetan, Ramaswamy, Kartik, Liao, Bryan, Shoji, Sergio, Nguyen, Duy D., Noorbakhsh, Hamid, Palagashvili, David
• Primary Examiner(s): Bahta, Kidest
• Application Number:
  US14/497,253
• Publication Number:
  US 20150134128A1
• Time in Patent Office: 950 Days
• Field of Search: 700282, 216 59
• CPC Class Codes: G05B 15/02 electric
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: H01J 37/32522 Temperature
• CPC Class Codes: H01J 37/32724 Temperature
• CPC Class Codes: H01J 37/32908 Utilities
• CPC Class Codes: H01J 37/3299 Feedback systems
• CPC Class Codes: H01L 21/67248 Temperature monitoring

Abstract

Methods and systems for controlling temperatures in plasma processing chamber for a wide range of setpoint temperatures and reduced energy consumption. Temperature control is coordinated between a coolant liquid loop and a heat source by a control algorithm implemented by the plasma processing module controller. The control algorithm may completely stop the flow of coolant liquid to a temperature-controlled component in response to a feedback signal indicating an actual temperature is below the setpoint temperature. The control algorithm may further be based at least in part on a feedforward control signal derived from a plasma power or change in plasma power input into the processing chamber during process recipe execution.

Claims

1. A temperature controller, comprising:

a feedforward input to receive an indication of a plasma power to be input to a plasma processing chamber during execution of a process recipe;

a feedback input to receive an indication of an actual temperature of a component to be controlled to a setpoint temperature by the temperature controller;

a processor to execute a temperature control algorithm having a feedback portion that generates a control effort based on a difference between the actual temperature feedback input and the setpoint temperature; and

an actuator output to provide an actuator signal generated by the processor from the temperature control algorithm, the actuator signal to completely stop a coolant liquid flow to the temperature-controlled component when the temperature falls below the setpoint temperature.

2. The temperature controller as in claim 1, wherein the control algorithm further includes a feedforward portion that generates a control effort based on the plasma power feedforward input to reduce an effect of the plasma power on a temperature of the component.

3. The temperature controller as in claim 2, wherein the processor is to further generate the feedforward control effort based on a first group of gain values associated with a key value pairing of a change in the plasma input power and a change in the setpoint temperature between the executing step and a preceding or subsequent plasma process recipe step.

4. The temperature controller as in claim 3, wherein the processor is to further generate the feedforward control effort based on a group of transient gain values associated with a key value pairing of a change in the plasma input power and a change in the setpoint temperature between the executing step and a preceding or subsequent plasma process recipe step.

5. The temperature controller as in claim 4, wherein the group of transient gain values are applied for a duration dependent on the temperature of the component to be controlled and the change in the setpoint temperature.

6. The temperature controller as in claim 3, wherein the actuator signal is to modulate a pulse width modulation duty cycle to fully open and fully close a valve through which the coolant liquid flows, the pulse width modulation based at least in part on the first group of gain values.

7. The temperature controller as in claim 2, wherein the processor is to further modify the liquid coolant flow rate based on a lookup table value in response to the component temperature crossing a threshold level when the chamber is in an idle state.

8. The temperature controller as in claim 2, wherein the plasma power comprises a first bias power input to a chuck configured to support a workpiece and wherein the plasma power feedforward input comprises a transfer function between the first bias power input and the temperature of the temperature-controlled component.

9. The temperature controller as in claim 8, wherein the temperature-controlled component is a process gas showerhead and wherein the coolant liquid flow to the temperature-controlled component passes through a coolant channel embedded in the showerhead.

10. The temperature controller as in claim 9, wherein m independently controlled heating elements are embedded within the showerhead, wherein the coolant loop is one of n coolant loops embedded in the showerhead, and m is not equal to n.

11. A temperature controller, comprising:

a feedforward input to receive an indication of a plasma power to be input to a plasma processing chamber during execution of a process recipe;

a feedback input to receive an indication of an actual temperature of a component to be controlled to a setpoint temperature by the temperature controller, wherein the temperature-controlled component is a process gas showerhead;

a processor to execute a temperature control algorithm having a feedback portion that generates a control effort based on a difference between the actual temperature feedback input and the setpoint temperature, wherein the control algorithm further includes a feedforward portion that generates a control effort based on the plasma power feedforward input to reduce an effect of the plasma power on a temperature of the component, and wherein the processor is to further generate the feedforward control effort based on a first group of gain values associated with a key value pairing of a change in the plasma input power and a change in the setpoint temperature between the executing step and a preceding or subsequent plasma process recipe step; and

an actuator output to provide an actuator signal generated by the processor from the temperature control algorithm, the actuator signal to completely stop a coolant liquid flow to the temperature-controlled component when the temperature falls below the setpoint temperature.

12. The temperature controller as in claim 11, wherein the processor is to further generate the feedforward control effort based on a first group of gain values associated with a key value pairing of a change in the plasma input power and a change in the setpoint temperature between the executing step and a preceding or subsequent plasma process recipe step.

13. The temperature controller as in claim 12, wherein the processor is to further generate the feedforward control effort based on a group of transient gain values associated with a key value pairing of a change in the plasma input power and a change in the setpoint temperature between the executing step and a preceding or subsequent plasma process recipe step.

14. The temperature controller as in claim 11, wherein the processor is to further modify the liquid coolant flow rate based on a lookup table value in response to the component temperature crossing a threshold level when the chamber is in an idle state.

15. The temperature controller as in claim 11, wherein the coolant liquid flow to the temperature-controlled component passes through a coolant channel embedded in the showerhead.