Chucking status detection with chucking sensor normalized figure of merit and active chucking voltage control

A method for monitoring a chucking status of a substrate, comprising:

• supplying a chucking voltage to an electrostatic chuck disposed in a substrate pedestal, wherein a substrate is supported by the substrate pedestal;
• applying a signal having a frequency range to an electrode of the electrostatic chuck;
• measuring an impedance of the signal;
• normalizing the impedance over the frequency range;
• determining a chucking status value, wherein determining the chucking status value comprises comparing the normalized impedance to a baseline impedance value, and wherein the baseline impedance value is indicative of the substrate pedestal not supporting the substrate;
• and
• determining a chucking status of the substrate based on the chucking status value.

A method for actively controlling chucking voltage to chuck a substrate, comprising:

• supplying a chucking voltage to an electrostatic chuck disposed in a substrate pedestal, wherein a substrate is supported by the substrate pedestal;
• applying a signal having a frequency range to an electrode of the electrostatic chuck;
• measuring an impedance of the signal;
• determining a chucking status value, wherein determining the chucking status value comprises comparing the measured impedance to a baseline impedance value, and wherein the baseline impedance value is indicative of the substrate pedestal not supporting the substrate;
• determining a chucking status of the substrate based on the chucking status value;
• and
• modifying the chucking voltage based on the chucking status value.