Method for determining amount of wear of edge ring, plasma processing apparatus, and substrate processing system

A plasma processing apparatus, comprising:

• a chamber;
• a substrate support in the chamber, the substrate support including a first portion to support a substrate placed on the substrate support and a second portion to support an edge ring placed on the substrate support, the first portion being a central portion of the substrate support and including a first electrode therein, the second portion being an annular portion of the substrate support, surrounding the first portion, and including a second electrode therein;
• a gas supply configured to supply a gas into the chamber;
• a plasma generator configured to generate plasma from the gas in the chamber;
• a pulse generator configured to cyclically apply a pulse of a direct current voltage to the first electrode and the second electrode;
• a sensor configured to measure a voltage value of the first electrode and a voltage value of the second electrode;
• and
• a controller configured to
• (a) control the gas supply and the plasma generator to generate plasma in the chamber,
• (b) control the pulse generator to cyclically apply, during generation of the plasma in (a), the pulse of the direct current voltage to the first electrode and the second electrode to draw ions from the plasma to the substrate support, and
• (c) determine an amount of wear of the edge ring based on a first voltage value of the first electrode and a second voltage value of the second electrode measured when the pulse is applied to the first electrode and the second electrode in (b).