Controlling showerhead heating via resistive thermal measurements

A system comprising:

• a resistive heater configured to receive power to heat a showerhead of a plasma chamber;
• a resistive element thermally bonded to the showerhead of the plasma chamber,
• wherein the resistive element changes resistance in response to a change in temperature of the showerhead,
• wherein the resistive element is encapsulated in an insulating material to electrically insulate the resistive element from the showerhead,
• wherein the insulating material is a good conductor of heat, and
• wherein the power to the resistive heater is received based on the resistance of the resistive element;
• and
• a controller configured to:
• supply the power to the resistive heater;
• supply a voltage to the resistive element;
• measure a current through the resistive element;
• determine the resistance of the resistive element based on the voltage supplied to the resistive element and the current measured through the resistive element;
• determine the temperature of the showerhead based on the resistance of the resistive element;
• compare the temperature to a setpoint temperature for the showerhead;
• and
• control the supply of the power to the resistive heater based on the comparison to control the heating of the showerhead,
• wherein the determination of the resistance of the resistive element is immune to a DC bias associated with the showerhead.