Polishing apparatus including thickness or flatness detector

A polishing apparatus comprising:

• a turntable having thereon a polishing surface;
• a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface;
• and
• a thickness detector operable to, during relative movement between said top ring and said turntable, detect a thickness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the thickness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising:
• a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots;
• and
• means for determining the thickness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.

A polishing apparatus comprising:

• a turntable having thereon a polishing surface;
• a top ring disposed above said turntable for supporting a workpiece to be polished and for pressing the workpiece against said polishing surface;
• and
• a thickness detector operable to, during relative movement between said top ring and said turntable, detect a flatness of a surface layer of the workpiece by performing a plurality of thickness detection operations over time and thereby to detect the flatness of the entire surface layer of the workpiece, each said thickness detection operation comprising detecting thickness of the surface layer at a plurality of spots spaced radially of said turntable at one time on a real-time basis, said thickness detector comprising:
• a sensor mounted in said turntable at a position within a path of relative movement between said top ring and said turntable and operable to perform said plurality of thickness detection operations over time, said sensor comprising a plurality light-emitting elements operable to emit respective light beams toward the surface layer of the workpiece and a plurality of light-detecting elements operable to detect respective of the light beams reflected from the surface layer of the workpiece, said plurality of said light-emitting elements and said plurality of said light-detecting elements being spaced radially of said turntable, and said light-detecting elements generating signals representative of detected thickness at said plurality of spots;
• and
• means for determining the flatness of the surface layer of the workpiece by processing together said signals from said light-detecting elements.