Method and apparatus for impedance matching in a power delivery system for remote plasma generation

A plasma-generating system comprising:

• a variable-frequency microwave generator configured to generate microwave power;
• a plasma applicator configured to use the microwave power from the microwave generator to (i) ignite a process gas therein for initiating a plasma in a plasma ignition process and (ii) maintain the plasma in a steady state process, wherein a load impedance of the plasma generated during the plasma ignition process and the steady state process is adapted to vary over an impedance range;
• and
• a coarse tuner connected between the microwave generator and the plasma applicator, wherein at least one physical parameter of the coarse tuner is adapted to be set to achieve coarse impedance matching between the microwave generator and the plasma generated during both the plasma ignition process and the steady state process;
• wherein the microwave generator is configured to tune an operating frequency at the at least one set physical parameter of the coarse tuner, without altering the at least one set physical parameter of the coarse tuner during both the plasma ignition process and the steady state process, to achieve (i) ignition of the process gas during the plasma ignition process and (ii) optimization of the microwave power delivered to the plasma in the steady state process.