Method of inflating elastic membrane of polishing head, and polishing head system

A polishing-head system for polishing a workpiece, comprising:

• a polishing head having an elastic membrane forming a first pressure chamber and a second pressure chamber;
• a first gas delivery line and a second gas delivery line that communicate with the first pressure chamber and the second pressure chamber, respectively;
• a first flow-rate control valve and a second flow-rate control valve coupled to the first gas delivery line and the second gas delivery line, respectively;
• and
• a system controller configured to instruct the first flow-rate control valve and the second flow-rate control valve to supply a gas into the first pressure chamber and the second pressure chamber at a first flow rate and a second flow rate when a polished workpiece is released from the polishing head, or when a workpiece to be polished is held on the polishing head.