SUBSTRATE PROCESSING SYSTEM, SWITCHING TIMING CREATION SUPPORT DEVICE,SWITCHING TIMING CREATION SUPPORT METHOD, AND SUBSTRATE PROCESSING APPARATUS

A substrate processing system includes a substrate processing apparatus and a switching timing creation support device, wherein the switching timing creation support device includes: an acquisition part configured to acquire, for each of a plurality of properties of particles contained in a gas in the substrate processing apparatus during a processing for a substrate, a measured value of an amount of the particles from a measuring device; a selection part configured to select properties of a predetermined number of the particles in descending order of temporal variations in the amount of the particles; a determination part configured to determine an operation expression and a switching condition for determining a switching timing based on a temporal change in the amount of the particles for each of the selected properties of the particles; and an output part configured to output the operation expression and the switching condition to the substrate processing apparatus