Granted Patent B2

US 11,476,091 · App. 17/111,743 · Granted Oct 18, 2022

Inventor: Imran Ahmed Bhutta (Moorestown, NJ)

H01J37/32183H01L21/02274H01L21/28556H01L21/31116H01L21/31138H01L21/32136H01L21/67069H03H7/38H03H7/40H01J2237/332H01J2237/334

Abstract

Claims (75)

1. An impedance matching network comprising:

a radio frequency (RF) input configured to operably couple to an RF source;

an RF output configured to operably couple to a plasma chamber;

a variable reactance element (VRE), the VRE having different positions for providing different reactances; and

a control circuit configured to carry out the operations of:

receiving or determining a valid range of values for a parameter related to the matching network;

determining a current value for the parameter related to the matching network based on a signal received from a sensor associated with the matching network;

determining a characteristic of the plasma chamber based on a determination that the current value is outside the valid range of values; and

providing a visual or audible indication of the determined characteristic of the plasma chamber, or causing an action to address the determined characteristic.

2. The matching network of claim 1 wherein the valid range of values for the parameter is based on values determined over a prior period of time of operation for:

an amount of current drawn by each of switches of the VRE, the VRE being electronically variable;

an amount of current drawn by at least one fan of the matching network;

a number of switching operations by each switch of the VRE, the VRE being electronically variable;

a number of motor reversals and a duration of each motor operation for a motor of the matching network, the VRE being mechanically variable using the motor;

an amount of DC or AC current drawn from an input power supply; or

an AC or DC voltage at a point inside the matching network.

3. A semiconductor processing tool comprising:

a plasma chamber configured to deposit a material onto a substrate or etch a material from the substrate; and

an impedance matching network comprising:

a radio frequency (RF) input configured to operably couple to an RF source;

an RF output configured to operably couple to the plasma chamber;

a variable reactance element (VRE), the VRE having different positions for providing different reactances; and

a control circuit configured to carry out the operations of:

receiving or determining a valid range of values for a parameter related to the matching network;

determining a current value for the parameter related to the matching network based on a signal received from a sensor associated with the matching network;

determining a characteristic of the plasma chamber based on a determination that the current value is outside the valid range of values; and

providing a visual or audible indication of the determined characteristic of the plasma chamber, or causing an action to address the determined characteristic.

4. A method of manufacturing a semiconductor:

operably coupling an impedance matching network between a radio frequency (RF) source and a plasma chamber, the matching network comprising:

an RF input configured to operably couple to the RF source;

an RF output configured to operably couple to the plasma chamber; and

a variable reactance element (VRE), the VRE having different positions for providing different reactances;

receiving or determining a valid range of values for a parameter related to the matching network;

placing a substrate in the plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate;

determining a current value for the parameter related to the matching network based on a signal received from a sensor associated with the matching network;

determining a characteristic of the plasma chamber based on a determination that the current value is outside the valid range of values; and

providing a visual or audible indication of the determined characteristic of the plasma chamber, or causing an action to address the determined characteristic.

5. A method of using an impedance matching network to determine a plasma chamber characteristic, the method comprising:

operably coupling an impedance matching network between a radio frequency (RF) source and a plasma chamber, the matching network comprising:

an RF input configured to operably couple to the RF source;

an RF output configured to operably couple to the plasma chamber; and

a variable reactance element (VRE), the VRE having different positions for providing different reactances; and

receiving or determining a valid range of values for a parameter related to the matching network;

determining a current value for the parameter related to the matching network based on a signal received from a sensor associated with the matching network;

determining a characteristic of the plasma chamber based on a determination that the current value is outside the valid range of values; and

providing a visual or audible indication of the determined characteristic of the plasma chamber, or causing an action to address the determined characteristic.

6. The method of claim 5 wherein the sensor is positioned at the RF input of the matching network, and the sensor is a voltage, current, and phase detector, a directional coupler, or a phase and magnitude detector.

7. The method of claim 5 wherein the sensor is positioned at the RF output of the matching network, and the sensor is a voltage, current, and phase detector, a directional coupler, or a phase and magnitude detector, an RF peak voltage sensor, an RF current sensor, a DC voltage sensor, or a DC current sensor.

8. The method of claim 5 wherein the sensor is positioned within the matching network, the sensor being a voltage sensor across the VRE, or a current sensor measuring current through a component of the matching network.

9. The method of claim 5 wherein the parameter related to the matching network is at least one of:

a current position of the VRE from among the possible positions of the VRE;

a load impedance at the RF output of the matching network or at a node internal to the matching network;

a matching tune time;

a reflected RF power or a reflection coefficient at the RF input of the matching network;

a peak-to-peak voltage at the RF output of the matching network;

a DC voltage at the RF output of the matching network;

a DC current at the RF output of the matching network; or

a phase angle of the load impedance at the RF output of the matching network.

10. The method of claim 5 wherein the valid range of values for the parameter is based on values determined over a prior period of time of operation for:

an amount of current drawn by each of switches of the VRE, the VRE being electronically variable;

an amount of current drawn by at least one fan of the matching network;

a number of switching operations by each switch of the VRE, the VRE being electronically variable;

a number of motor reversals and a duration of each motor operation for a motor of the matching network, the VRE being mechanically variable using the motor;

an amount of DC or AC current drawn from an input power supply; or

an AC or DC voltage at a point inside the matching network.

11. The method of claim 5 wherein the valid range of values is learned by the matching network during a learning period using machine learning.

12. The method of claim 5 wherein the determination of the characteristic of the plasma chamber is a determination that the plasma chamber has reached a particular stage in processing a silicon wafer.

13. The method of claim 12 wherein the determination of the particular stage in processing the silicon wafer is a determination that etching has reached certain layer of the silicon wafer, or a determination that depositing of a layer on the silicon wafer has reached a predetermined thickness.

14. The method of claim 5 wherein the determined characteristic is that the plasma chamber needs to be cleaned.

15. The method of claim 5 wherein the determination of the characteristic of the plasma chamber is further based on a Fourier transform of the current value of the parameter.

16. The method of claim 5 wherein the indication of the determined characteristic is an alarm indicating a problem associated with the plasma chamber.

17. The method of claim 5 further comprising

prior to determining the current value of the parameter, injecting a signal in the matching network, the signal having a frequency different from an operating frequency of the matching network;

wherein the injected signal alters the current value.

18. The method of claim 17 wherein the injected signal comprises multiple frequencies.

Assignments (3)

Continuity (23)