Patent ID: 6916234

Claim:
A polishing machine, comprising: a rotary shaft; a rotatable polishing plate on which polishing cloth is adhered; a top ring connected to said rotary shaft, said top ring including a holding plate for holding and pressing a wafer onto a predetermined position of the polishing cloth of said polishing plate so to polish a surface of the wafer; a retainer ring independently rotatable with respect to said top ring, said retainer ring being separated from said rotary shaft and not integrated with said rotary shaft, said retainer ring including a pressing member which encloses an outer edge of the wafer when the surface of the wafer held by the holding plate of said top ring is pressed onto the polishing cloth, said retainer ring pressing the polishing cloth so as to locate a surface of the polishing cloth pressed by the pressing member and another surface of the polishing cloth pressed by the wafer in a common plane, said top ring being freely insertable into and removable from said retainer ring without contacting said retainer ring; and a positioning member for correctly positioning said retainer ring on the polishing cloth of said polishing plate while said retainer ring is rotated about a rotationally axis of said top ring with rotation of said polishing plate, said positioning member contacting at least a part of an outer circumferential face of said retainer ring on the polishing cloth so as to correctly position said retainer ring.