Substrate processing apparatus

A substrate processing apparatus for polishing a substrate by pressing the substrate against a polishing pad, the substrate processing apparatus comprising:

• a polishing head comprising an elastic film defining a plurality of pressure chambers for pressing the substrate;
• a retainer ring;
• a computer configured to perform pressure feedback control by individually controlling pressures in the plurality of pressure chambers;
• the computer in communication with a sensor configured to measure a film thickness distribution of the substrate being polished;
• a non-transitory storage medium configured to store multiple pieces of information on a plurality of preset pressures of the plurality of pressure chambers;
• and
• the computer in communication with a plurality of valves and in communication with the sensor, the computer further configured, during polishing a single substrate, to change the pressure of at least one pressure chamber to one of the plurality of preset pressures for at least one of the plurality of pressure chambers defined by the elastic film to press a portion of the substrate corresponding to the at least one of the plurality of pressure chambers each time one of a plurality of predetermined conditions is satisfied during polishing of the substrate by controlling at least one of the plurality of valves, to measure a polishing rate applied to the substrate, to acquire a response characteristic of the polishing of the substrate, and to store in the non-transitory storage medium the acquired response characteristic corresponding to each of the preset pressures of the plurality of pressure chambers, wherein the response characteristic indicates responsiveness of the polishing of the substrate to the pressure feedback in the plurality of pressure chambers,
• wherein one of the plurality of predetermined conditions is that a certain period of time has elapsed or an amount of the polishing of the substrate has reached a predetermined amount;
• and wherein the plurality of preset pressures for the at least one pressure chamber are predefined.