Leak checking method, and computer-readable storage medium for performing the leak checking method
A leak checking method which is capable of detecting a leak of compressed gas supplied to a polishing head without removing the polishing head from a polishing apparatus is disclosed. The leak checking method includes: supplying a compressed gas into a pressure chamber, which is formed by a membrane of a polishing head, with the membrane placed in contact with a stationary surface; measuring a flow rate of the compressed gas during supplying of the compressed gas into the pressure chamber, while regulating a pressure of the compressed gas by use of a pressure regulator; deciding whether or not the flow rate measured when a variation in the pressure of the compressed gas is within an allowable range of variation, is within a reference range; and generating a leak-detection signal when the flow rate is outside of the reference range.
1. A leak checking method comprising:
supplying a compressed gas into a pressure chamber, which is forming by a membrane of a polishing head, with the membrane placed in contact with a stationary surface;
measuring flow rate of the compressed gas during supplying of the compressed gas into the pressure chamber, while regulating pressure of the compressed gas in the pressure chamber by use of a pressure regulator;
measuring the pressure of the compressed gas in the pressure chamber;
deciding whether or not the flow rate of the compressed gas measured when a variation in the pressure of the compressed gas is within an allowable range of variation, is within a reference range; and
generating a leak-detection signal when the flow rate is outside of the reference range.
2. The leak checking method according to claim 1 , wherein deciding whether or not the flow rate of the compressed gas is within the reference range includes:
deciding a point of time when the variation in the pressure of the compressed gas is within the allowable range of variation; and
deciding whether or not the flow rate of compressed gas, which has been measured before reaching the point of time and measured in a predetermined time interval, is within the reference range.
3. The leak checking method according to claim 1 , wherein deciding whether or not the flow rate of the compressed gas is within the reference range includes:
deciding a point of time when the variation in the pressure of the compressed gas is within the allowable range of variation; and
deciding whether or not the flow rate of compressed gas, which is measured after reaching the point of time and measured in a predetermined time interval, is within the reference range.
4. The leak checking method according to claim 1 , wherein during performing of a calibration of the pressure regulator, it is determined whether or not the measured value of the flow rate is within the reference range.
5. A non-transitory computer-readable storage medium storing therein a program for causing the computer to perform operations of:
obtaining a measured value of flow rate of a compressed gas supplied into a pressure chamber, which is formed by a membrane of a polishing head, with the membrane placed in contact with the stationary surface;
commanding a pressure regulator to cause the pressure regulator to perform an action for regulating a pressure of the compressed gas in the pressure chamber;
obtaining a measured value of the pressure of the compressed gas in the pressure chamber;
deciding whether or not the flow rate of the compressed gas measured when a variation in the pressure of the compressed gas is within an allowable range of variation, is within a reference range; and
generating a leak-detection signal when the flow rate is outside of the reference range.