Plasma health determination in semiconductor substrate processing reactors

A method of forming a local plasma, the method comprising:

• flowing a precursor into a substrate processing region housing a semiconductor substrate, wherein the substrate processing region is within a substrate processing chamber;
• turning on a local RF power from an RF power supply disposed outside the substrate processing chamber;
• analyzing the local RF power in a V/I probe disposed between the RF power supply and the substrate processing region, wherein analyzing the local RF power in the V/I probe determines a voltage amplitude, a current amplitude and a voltage-current phase difference;
• delivering the local RF power to the substrate processing region to excite a local RF plasma within the substrate processing region from the precursor;
• calculating a power delivered to the local RF plasma by multiplying the voltage amplitude by the current amplitude and further by a cosine of the voltage-current phase difference;
• calculating a power difference between the local RF power and the power delivered to the local RF plasma and then calculating a dimensionless ratio of the power difference to the local RF power;
• terminating the local RF power from the RF power supply if the dimensionless ratio is greater than 0.30.