Patent ID: 8728942

Claim:
A method of producing an epitaxial silicon wafer, the method comprising: simultaneously mirror-polishing a front surface and a rear surface of a silicon wafer using polishing liquid comprising an abrasive grain-free alkaline solution in which water-soluble polymers are added; and vapor-depositing after the mirror-polishing an epitaxial film on the mirror-polished front surface of the silicon wafer, wherein the method of producing the epitaxial silicon wafer further comprises: performing primary polishing prior to the mirror-polishing, the primary polishing using primary polishing liquid mainly comprising the alkaline solution and intervening abrasive grains to remove an oxide film formed on the front surface of the silicon wafer, wherein the mirror-polishing is secondary polishing using the polishing liquid as secondary polishing liquid, after the mirror-polishing, the front surface of the silicon wafer is cleaned by using a SC1 cleaning liquid consisting of NH 4 OH, H 2 O 2 , and H 2 O, after the cleaning, the epitaxial film is vapor-deposited on the mirror-polished front surface of the silicon wafer, the alkaline solution is an amine solution having a pH of 8 to 14, the water-soluble polymers are hydroxyethyl cellulose and concentration of the water-soluble polymers is 0.01 ppm to 1,000 ppm, and measuring a surface roughness in both a 1 μm×1 μm measurement area and a 10 μm×10 μm measurement area using an atomic force microscope, wherein the front surface of the mirror-polished silicon wafer has a surface roughness of less than 0.3 nm in RMS in measurement of the 1 μm×1 μm measurement area using the atomic force microscope and a surface roughness of 0.3 nm or less in RMS in measurement of the 10 μm×10 μm measurement area of using the atomic force microscope.