Patent ID: 7247083

Claim:
A polishing apparatus, comprising: a polishing plate having an upper face, on which a polishing cloth is adhered; a holding head having a lower face, on which a workpiece is held so as to press the workpiece onto the polishing cloth; and a driving mechanism for relatively moving said polishing plate with respect to said holding head so as to polish a lower face of the workpiece, wherein said holding head comprises: a head base; a main head section being attached on the lower side of the head base with a first diaphragm and capable of moving toward said polishing plate, said main head section having a press ring, which is provided on the lower side thereof and capable of pressing the polishing cloth; a press plate being provided in the main head section with a second diaphragm and capable of moving toward said polishing plate; the press plate including a lower plate portion; an elastic sheet member being attached to an outer radial surface of the lower plate portion of the press plate; a first fluid chamber being formed between the head base and the main head section and closed by the first diaphragm; a second fluid chamber being formed between the main head section and the press plate and closed by the second diaphragm; a third fluid chamber being formed between the lower face of the press plate and the elastic sheet member; first pressing means for introducing a pressurized fluid into the first fluid chamber and pressing the main head section downward; second pressing means for introducing a pressurized fluid into the second fluid chamber and pressing the press plate downward; and third pressing means for introducing a pressurized fluid into the third fluid chamber and pressing the workpiece downward, and whereby the workpiece is held on the lower side of the elastic sheet member, and the lower face of the workpiece can be polished.