Polishing apparatus and polishing method

A polishing apparatus comprising:

• a first surface plate for supporting a polishing object;
• a second surface plate arranged so as to oppose to said first surface plate and having cavities therein to amplify vibrations in said second surface plate;
• an abrasive cloth stuck to said second surface plate;
• a vibration detector attached to said first surface plate or said second surface plate, for outputting vibration signals caused in polishing;
• and
• a controlling portion, receiving the output of said vibration detector, for controlling polishing operation of at least one of said first surface plate and said second surface plate as a function of said vibrating signals output by said vibration detector.

A polishing apparatus comprising:

• a first surface plate for supporting an object to be polished;
• a second surface plate arranged to oppose to said first surface plate;
• an abrasive cloth stuck to said second surface plate;
• a vibration detector attached to said first surface plate or said second surface plate;
• a driving mechanism for driving at least one of said first surface plate and said second surface plate;
• a transmitting portion attached to said first surface plate or said second surface plate to which said vibration detector is attached, for transmitting vibration information detected by said vibration detector by radio;
• a receiving portion for receiving radio signal output from said transmitting portion;
• a signal analyzing portion connected to said receiving portion, for analyzing said radio signal received;
• a controlling portion for outputting a signal indicating a stopping of polishing or a change of polishing conditions to at least said driving mechanism based on a signal from said signal analyzing portion;
• an annular transmitting antenna formed around a rotating axis of said first surface plate or said second surface plate to which said vibration detector is attached, and connected to said transmitting portion;
• and
• a receiving antenna provided on a prolonged line of said rotating axis and connected to said receiving portion.

A polishing apparatus comprising:

• a first surface plate for supporting an object to be polished;
• a second surface plate arranged to oppose to said first surface plate;
• an abrasive cloth stuck to said second surface plate;
• driving means for shifting said first surface plate periodically in a predetermined area on said abrasive cloth;
• and
• polishing end-point detecting means for dividing vibration intensity of said first surface plate or driving torque of said driving means by a function of location information of said first surface plate so as to set a resultant value as a polishing state signal, differentiating change of said polishing state signal by time, and detecting end-point of polishing based on a differential value.