Electronically variable capacitor and RF matching network incorporating same
First Claim
1. An RF impedance matching network comprising:
- an RF input coupled to an RF source having a fixed impedance;
an RF output coupled to a plasma chamber having a variable impedance;
a series electronically variable capacitor having a first variable capacitance, the series electronically variable capacitor electrically coupled in series between the RF input and the RF output;
a shunt electronically variable capacitor having a second variable capacitance, the shunt electronically variable capacitor electrically coupled in parallel between a ground and one of the RF input and the RF output; and
a control circuit operatively coupled to the series electronically variable capacitor and to the shunt electronically variable capacitor to control the first variable capacitance and the second variable capacitance, wherein the control circuit is configured to;
determine the variable impedance of the plasma chamber,determine a first capacitance value for the first variable capacitance and a second capacitance value for the second variable capacitance, andgenerate a control signal to alter at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively,wherein an elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 μ
sec.
3 Assignments
1 Petition
Accused Products
Abstract
An RF impedance matching network includes an RF input coupled to an RF source having a fixed impedance and an RF output coupled to a plasma chamber having a variable impedance. A series electronically variable capacitor (EVC) is coupled in series between the RF input and the RF output. A shunt EVC is coupled in parallel between a ground and one of the RF input and the RF output. A control circuit is operatively coupled to the series and shunt EVCs to control first and second variable capacitances, wherein the control circuit is configured to: determine the variable impedance; determine first and second capacitance values for the first and second variable capacitances; and alter at least one of the first and second variable capacitances, wherein an elapsed time between determining the variable impedance and when RF power reflected back to the RF source decreases is less than about 150 μsec.
230 Citations
20 Claims
-
1. An RF impedance matching network comprising:
-
an RF input coupled to an RF source having a fixed impedance; an RF output coupled to a plasma chamber having a variable impedance; a series electronically variable capacitor having a first variable capacitance, the series electronically variable capacitor electrically coupled in series between the RF input and the RF output; a shunt electronically variable capacitor having a second variable capacitance, the shunt electronically variable capacitor electrically coupled in parallel between a ground and one of the RF input and the RF output; and a control circuit operatively coupled to the series electronically variable capacitor and to the shunt electronically variable capacitor to control the first variable capacitance and the second variable capacitance, wherein the control circuit is configured to; determine the variable impedance of the plasma chamber, determine a first capacitance value for the first variable capacitance and a second capacitance value for the second variable capacitance, and generate a control signal to alter at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively, wherein an elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 μ
sec. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A method of matching an impedance, the method comprising:
-
determining a variable impedance of a plasma chamber, with an impedance matching network electrically coupled between the plasma chamber and an RF source, wherein the RF source has a fixed impedance, and the impedance matching network includes a series electronically variable capacitor having a first variable capacitance and, coupled in series between the plasma chamber and the RF source, and a shunt electronically variable capacitor having a second variable capacitance and, coupled in parallel between a ground and one of the plasma chamber and the RF source; determining a first variable capacitance value and a second variable capacitance value for, respectively, the series electronically variable capacitor and the shunt electronically variable capacitor, for purposes of creating an impedance match at an RF input of the impedance matching network; and altering at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively, wherein an elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 μ
sec. - View Dependent Claims (7, 8, 9)
-
-
10. A method of manufacturing a semiconductor comprising:
- placing a substrate in a plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate; and
energizing plasma within the plasma chamber by coupling RF power from an RF source into the plasma chamber to perform a deposition or etching, and while energizing the plasma;
determining a variable impedance of the plasma within the plasma chamber, with an impedance matching network electrically coupled between the plasma chamber and the RF source, wherein the RF source has a fixed impedance, and the impedance matching network includes a series electronically variable capacitor having a first variable capacitance and coupled in series between the plasma chamber and the RF source, and a shunt electronically variable capacitor having a second variable capacitance and coupled in parallel between a ground and one of the plasma chamber and the RF source, determining a first variable capacitance value and a second variable capacitance value for, respectively, the series electronically variable capacitor and the shunt electronically variable capacitor, for purposes of creating an impedance match at an RF input of the impedance matching network; and
altering at least one of the first variable capacitance and the second variable capacitance to the first capacitance value and the second capacitance value, respectively, wherein an elapsed time between determining the variable impedance of the plasma chamber to when RF power reflected back to the RF source decreases is less than about 150 μ
sec. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- placing a substrate in a plasma chamber configured to deposit a material layer onto the substrate or etch a material layer from the substrate; and
Specification