Patent ID: 8485864

Claim:
A method of polishing both sides of a wafer in a double-side polishing apparatus comprising: a lower polishing plate having an upper face, on which a first polishing cloth is adhered; an upper polishing plate being provided above said lower polishing plate and capable of being moved upward and downward, said upper polishing plate having a lower face, on which a second polishing cloth is adhered; a carrier being provided between said lower polishing plate and said upper polishing plate, said carrier having a main body part, in which at least one through-hole for holding a wafer is formed; a plate driving unit for rotating said lower polishing plate and said upper polishing plate about their axial lines; a carrier driving unit for rotating said carrier; and a slurry supply source, wherein said lower polishing plate, said upper polishing plate and said carrier are rotated, with supplying slurry onto said lower polishing plate, so as to polish both sides of the wafer which is sandwiched between said lower polishing plate and said upper polishing plate; edges of the at least one through-hole in an upper face and a lower face of said carrier are coated with diamond-like carbon (DLC) coating layers, which have a prescribed width and a prescribed thickness; a resin cushion ring, which has a prescribed width and whose thickness is equal to that of the main body part of said carrier, is provided to an inner circumferential face of the at least one thorough-hole, and the wafer is held in said resin cushion ring, said method comprising: stopping a polishing operation when the thickness of the wafer reaches a prescribed thickness range, which is from a thickness equal to that of the main body part of said carrier to a thickness equal to a distance between the coating layer in the upper face of the main body part and the coating layer in the lower face thereof.