Abstract: Provided is a cleaning method in a plasma processing apparatus for substrates. This cleaning method comprises: (a) forming a plasma in a chamber of the plasma processing apparatus while a substrate is not being held in place by an electrostatic chuck in the chamber; and (b) supplying voltage to the electrostatic chuck to reduce the charge on the surface of the electrostatic chuck while plasma is being formed in (a).

Abstract: A method of determining cleaning conditions includes: processing a substrate under a substrate processing condition in a chamber, acquiring light emission intensity data by performing cleaning of an interior of the chamber based on cleaning conditions which are different from each other; and performing a step of evaluating the cleaning conditions based on the light emission intensity data, and a step of selecting the cleaning conditions based on the evaluation of the cleaning conditions.