Patent ID: 7951716

Claim:
A method of producing a wafer which comprises a step of polishing a predetermined face of a wafer to flatten the predetermined face while supplying a polishing liquid onto a bonded abrasive cloth, wherein the bonded abrasive cloth comprises a urethane bonding material consisting of a soft segment having a polyfunctional isocyanate and a hard segment having a polyfunctional polyol and having an expansion ratio of 1.1-4 times and silica having an average particle size of 0.2-10 μm and a hydroxy group, and a ratio of the hard segment occupied in the urethane bonding material is 40-55% as a molecular weight ratio, and a volume ratio of silica in the whole of the bonded abrasive cloth is within a range of 20-60%, and a Shore D hardness of the bonded abrasive cloth is 40-80; wherein the polishing is carried out with a sheet-feed polishing machine; wherein the polishing machine is provided with a controlling function which removes only a micro-projection existing on a rear surface of the wafer.