Systems and methods for compensating for RF power loss

Patent metadata

Field	Value
Publication number	US-12505985-B2
Application number	US-202418658329-A
Country	US
Kind code	B2
Filing date	May 8, 2024
Priority date	Jun 20, 2019
Publication date	Dec 23, 2025
Grant date	Dec 23, 2025

Abstract

Systems and methods for compensating for radio frequency (RF) power loss are described. One of the methods includes conducting a no plasma test to determine a resistance associated with an output of an impedance matching circuit. After conducting the no plasma test, a substrate is processed in a plasma chamber. During processing of the substrate, power loss associated with the output of the impedance matching circuit is determined. The power loss is used to determine an amount of power to be delivered by an RF generator. The amount of power delivered is adjusted until the power loss is stabilized. The stabilization of the power loss facilitates uniform process of the substrate and additional substrates in the plasma chamber.

First claim

The invention claimed is:

1 . A method for compensating for loss of radio frequency (RF) power, comprising:
obtaining a first value of a parameter associated with a component of a plasma system; determining a first amount of loss of RF power associated with the component of the plasma system from a resistance and the first value of the parameter; adjusting a set point of operation of an RF generator based on the first amount of loss of RF power to operate the RF generator at a second set point; obtaining a second value of the parameter associated with the component of the plasma system; determining a second amount of loss of RF power from the resistance and the second value of the parameter; and adjusting the set point of operation of the RF generator based on the second amount of loss of RF power to operate the RF generator at a third set point, wherein the set point of operation is adjusted based on the first and second amounts of loss of RF power to compensate for loss of RF power.

2 . The method of claim 1 , wherein the parameter is a current, wherein the component includes an impedance matching circuit, wherein said obtaining the first value of the parameter includes obtaining the first value of the current measured between the impedance matching circuit and a chuck of a plasma chamber of the plasma system, wherein said obtaining the second value of the parameter includes obtaining the second value of the current measured between the impedance matching circuit and the chuck.

3 . The method of claim 2 , wherein the current is a root mean square current, wherein the first value of the current is measured at an output of the impedance matching circuit and the second value of the current is measured at the output of the impedance matching circuit.

4 . The method of claim 2 , wherein the current is a root mean square current, wherein the first value of the current is measured on an RF transmission line coupled between the impedance matching circuit and the chuck and the second value of the current is measured on the RF transmission line.

5 . The method of claim 2 , wherein the current is a root mean square current, wherein the first value of the current is measured at an input of the chuck and the second value of the current is measured at the input of the chuck.

6 . The method of claim 1 , further comprising:
computing a square of the first value of the parameter, wherein said determining the first amount of loss of RF power includes multiplying the square of the first value of the parameter with the resistance; and computing a square of the second value of the parameter, wherein said determining the second amount of loss of RF power includes multiplying the square of the second value of the parameter with the resistance.

7 . The method of claim 1 , wherein said adjusting the set point of operation of the RF generator based on the first amount of loss of RF power includes adding the first amount of loss of RF power to the set point of operation to determine the second set point, wherein said adjusting the set point of operation of the RF generator based on the second amount of loss of RF power includes adding the second amount of loss of RF power to the set point of operation to determine the third set point.

8 . A controller for compensation for loss of radio frequency (RF) power, comprising:
a processor configured to:
obtain a first value of a parameter associated with a component of a plasma system;
determine a first amount of loss of RF power associated with the component of the plasma system from a resistance and the first value of the parameter;
adjust a set point of operation of an RF generator based on the first amount of loss of RF power to operate the RF generator at a second set point;
obtain a second value of the parameter associated with the component of the plasma system;
determine a second amount of loss of RF power from the resistance and the second value of the parameter; and
adjust the set point of operation of the RF generator based on the second amount of loss of RF power to operate the RF generator at a third set point,
wherein the set point of operation is adjusted based on the first and second amounts of loss of RF power to compensate for loss of RF power; and
a memory device coupled to the processor.

9 . The controller of claim 8 , wherein the parameter is a current, wherein the component includes an impedance matching circuit, wherein to obtain the first value of the parameter, the processor is configured to obtain the first value of the current measured between the impedance matching circuit and a chuck of a plasma chamber of the plasma system, wherein to obtain the second value of the parameter, the processor is configured to obtain the second value of the current measured between the impedance matching circuit and the chuck.

10 . The controller of claim 9 , wherein the current is a root mean square current, wherein the first value of the current is measured at an output of the impedance matching circuit and the second value of the current is measured at the output of the impedance matching circuit.

11 . The controller of claim 9 , wherein the current is a root mean square current, wherein the first value of the current is measured on an RF transmission line coupled between the impedance matching circuit and the chuck and the second value of the current is measured on the RF transmission line.

12 . The controller of claim 9 , wherein the current is a root mean square current, wherein the first value of the current is measured at an input of the chuck and the second value of the current is measured at the input of the chuck.

13 . The controller of claim 8 , wherein the processor is configured to:
compute a square of the first value of the parameter, wherein to determine the first amount of loss of RF power, the processor is configured to multiply the square of the first value of the parameter with the resistance; and compute a square of the second value of the parameter, wherein to determine the second amount of loss of RF power, the processor is configured to multiply the square of the second value of the parameter with the resistance.

14 . The controller of claim 8 , wherein to adjust the set point of operation of the RF generator based on the first amount of loss of RF power, the processor is configured to add the first amount of loss of RF power to the set point of operation, wherein to adjust the set point of operation of the RF generator based on the second amount of loss of RF power, the processor is configured to add the second amount of loss of RF power to the set point of operation.

15 . A plasma system for compensation for loss of radio frequency (RF) power, comprising:
a radio frequency (RF) generator configured to generate an RF signal; an impedance matching circuit coupled to the RF generator to receive the RF signal; and a computer coupled to the RF generator, wherein the computer is configured to:
obtain a first value of a parameter associated with a component of the plasma system;
determine a first amount of loss of RF power associated with the component of the plasma system from a resistance and the first value of the parameter;
adjust a set point of operation of the RF generator based on the first amount of loss of RF power to operate the RF generator at a second set point;
obtain a second value of the parameter associated with the component of the plasma system;
determine a second amount of loss of RF power from the resistance and the second value of the parameter; and
adjust the set point of operation of the RF

Assignees

• Lam Res Corp

Inventors

• Evans Mathew Dennis
• Flowers Cristofer Addison
• Drewery John

Classifications

• H01J37/32935 Primary

  Monitoring and controlling tubes by information coming from the object and/or discharge · CPC title

• H01J37/32926

  Software, data control or modelling · CPC title

• H01J37/3299

  Feedback systems · CPC title

• H01J37/32174 Primary

  Circuits specially adapted for controlling the RF discharge · CPC title

• H10P72/0604

  Process monitoring, e.g. flow or thickness monitoring · CPC title