Patent ID: 8932952
Filing Date: 2015-01-13
Classification: B24B,H01L

Abstract:
1. A method for polishing silicon wafers comprising the steps of: eliminating a native oxide film formed on a silicon wafer by using an alkaline aqueous solution containing free abrasive grains as a primary polishing liquid; simultaneously rough polishing a surface and a rear surface of the silicon wafer with a double-sided polisher having a carrier plate in which the silicon wafer is housed, an upper surface plate in which a hard abrasive cloth is pasted on a lower surface, and a lower surface plate in which the hard abrasive cloth is pasted on a top surface, wherein the upper surface plate and the lower surface plate hold the carrier plate respectively from above and below therebetween, so as to relatively rotate the silicon wafer and the hard abrasive cloth while supplying a secondary polishing liquid in which hydroxyethyl cellulose is added to an alkaline aqueous solution with no free abrasive grains, to the hard abrasive cloth; and applying final polishing on at least the rough polished surface of the silicon wafer, wherein: the hard abrasive cloth has Shore-D hardness of 70 to 90 and a compressibility of 1 to 5%, a polishing rate of the silicon wafer in the rough polishing is 0.05 to 1 μm per minute, and the final polishing is carried out with a soft abrasive cloth and is performed with a third polishing liquid containing free abrasive grains.