Multi-radiofrequency impedance control for plasma uniformity tuning

A wafer processing apparatus including a top electrode and a bottom electrode of a processing chamber, the wafer processing apparatus comprising:

• a first radio frequency (RF) power source coupled between the bottom electrode and electrical ground, the first RF power source controlled by a first power controller;
• a second RF power source coupled between the bottom electrode and ground, the second RF power source controlled by a second power controller;
• a third RF power source coupled between the bottom electrode and electrical ground, the third RF power source controlled by a third power controller, wherein the first, second and third RF power sources are coupled in parallel;
• a low frequency RF power source coupled to the top electrode;
• a first resonant circuit coupled between electrical ground and a first switch and the top electrode coupled in series, wherein a frequency-dependent impedance of the first resonant circuit is defined to present a maximum value at a frequency of the first RF power source, wherein the first switch operates to couple or uncouple the first resonant circuit to the top electrode;
• a second resonant circuit coupled between electrical ground and a second switch and the top electrode coupled in series, wherein a frequency-dependent impedance of the second resonant circuit is defined to present a maximum value at a frequency of the second RF power source, wherein the second switch operates to couple or uncouple the second resonant circuit to the top electrode;
• and
• a third resonant circuit coupled between electrical ground and a third switch and the top electrode coupled in series, wherein a frequency-dependent impedance of the third resonant circuit is defined to present a maximum value at a frequency of the third RF power source, wherein the third switch operates to couple or uncouple the third resonant circuit to the top electrode.