Patent ID: 10692699

Abstract:
In one embodiment, an RF impedance matching network for a plasma chamber is disclosed. It includes a variable capacitor comprising a plurality of capacitors comprising first coarse capacitors each having a substantially similar first coarse capacitance, second coarse capacitors each having a substantially similar second coarse capacitance, and fine capacitors having different capacitances that increase in value. At least one of the fine capacitors has a capacitance greater than the first coarse capacitance. A control circuit is configured cause a gradual increase in the total capacitance of the variable capacitor by switching in, in a predetermined order, each of the first coarse capacitors, followed by each of the second coarse capacitors, only switching in the fine capacitors whose capacitance is less than a capacitance of a next coarse capacitor of the coarse capacitors predetermined to be switched in next.