A double-sided polishing apparatus includes: a lower surface plate; an upper surface plate; and a carrier disposed between the lower surface plate and the upper surface plate and holding a disk-shaped workpiece, wherein the carrier is configured to rotate about a center of the lower surface plate and the upper surface plate and to rotate about a center of the carrier, the double-sided polishing apparatus includes a thickness measuring sensor at a fixed position above the upper surface plate or below the lower surface plate or at a movable position in an upper portion of the upper surface plate or a lower portion of the lower surface plate, the carrier includes circular perforations each holding the workpiece at a position eccentric to the center of the carrier, when a central position of any of the perforations preset by a user is defined as a first reference position, with a distance between a center of the upper surface plate or the lower surface plate and a center of any of the perforations preset by the user being shortest or longest, and a position apart from the first reference position by half of a first distance in a direction of the center of the carrier is defined as a second reference position, with the first distance being a predetermined length within 30% of a radius of the perforation, then the thickness measuring sensor is provided in a range of the first distance about the second reference position in a plan view, and the thickness measuring sensor is configured to measure a thickness of the workpiece in a state in which the workpiece is held in the perforation, through a measuring hole provided on the upper surface plate or the lower surface plate closer to a side on which the thickness measuring sensor is disposed.

A control method of a grinding water flow rate during a double side grinding process. A double side grinder used includes a grinding wheel, a feed unit and a water supply device, wherein a water inlet is disposed on the feed unit. The control method includes: prepare for grinding and complete the installation of a workpiece according to an operation procedure of the double side grinder; during a process of double side grinding, the flow rate of the water inlet is set to decrease with the shortening of the teeth length of the grinding wheel, with the flow rate of the water inlet being set to have a linear relationship with the teeth length of the grinding wheel.

A control method of a grinding water flow rate during a double side grinding process. A double side grinder used includes a grinding wheel, a feed unit and a water supply device, wherein a water inlet is disposed on the feed unit. The control method includes: prepare for grinding and complete the installation of a workpiece according to an operation procedure of the double side grinder; during a process of double side grinding, the flow rate of the water inlet is set to decrease with the shortening of the teeth length of the grinding wheel, with the flow rate of the water inlet being set to have a linear relationship with the teeth length of the grinding wheel.

Provided is a method capable of efficiently polishing the front and back sides of a carrier plate unused after manufacture, which is used in a double-sided polishing process for semiconductor wafers. The method comprises: sandwiching a carrier plate unused after manufacture and to be polished between an upper surface plate and a lower surface plate in the double-sided polishing apparatus, and supplying a polishing liquid while relatively rotating the carrier plate to be polished, the upper surface plate, and the lower surface plate to polish both sides of the carrier plate to be polished, wherein a polishing pad including, on its surface, an abrasive grain-containing layer in which abrasive grains of 2 m or more in grain size are embedded is used as a polishing pad in a double-sided polishing apparatus.

Provided are a method of polishing a silicon wafer and a method of producing a silicon wafer which can reduce the formation of step-forming microdefects on a silicon wafer. The method includes: a double-side polishing step of performing polishing on front and back surfaces of a silicon wafer; a notch portion polishing step of performing polishing on a beveled portion of a notch portion of the silicon wafer after the double-side polishing step; a peripheral beveled portion polishing step of performing polishing on the beveled portion on the periphery of the silicon wafer other than the beveled portion of the notch portion after the notch portion polishing step; and a finish polishing step of performing finish polishing on the front surface of the silicon wafer after the peripheral beveled portion polishing step. The notch portion polishing step is performed in a state where the front surface is wet with water.

Provided are a method of polishing a silicon wafer and a method of producing a silicon wafer which can reduce the formation of step-forming microdefects on a silicon wafer. The method includes: a double-side polishing step of performing polishing on front and back surfaces of a silicon wafer; a notch portion polishing step of performing polishing on a beveled portion of a notch portion of the silicon wafer after the double-side polishing step; a peripheral beveled portion polishing step of performing polishing on the beveled portion on the periphery of the silicon wafer other than the beveled portion of the notch portion after the notch portion polishing step; and a finish polishing step of performing finish polishing on the front surface of the silicon wafer after the peripheral beveled portion polishing step. The notch portion polishing step is performed in a state where the front surface is wet with water.

An indium phosphide substrate, a method of inspecting thereof and a method of producing thereof are provided, by which an epitaxial film grown on the substrate is rendered excellently uniform, thereby allowing improvement in PL characteristics and electrical characteristics of an epitaxial wafer formed using this epitaxial film. The indium phosphide substrate has a first main surface and a second main surface, a surface roughness Ra1 at a center position on the first main surface, and surface roughnesses Ra2, Ra3, Ra4, and Ra5 at four positions arranged equidistantly along an outer edge of the first main surface and located at a distance of 5 mm inwardly from the outer edge. An average value m1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.5 nm or less, and a standard deviation 1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.2 nm or less.

An indium phosphide substrate, a method of inspecting thereof and a method of producing thereof are provided, by which an epitaxial film grown on the substrate is rendered excellently uniform, thereby allowing improvement in PL characteristics and electrical characteristics of an epitaxial wafer formed using this epitaxial film. The indium phosphide substrate has a first main surface and a second main surface, a surface roughness Ra1 at a center position on the first main surface, and surface roughnesses Ra2, Ra3, Ra4, and Ra5 at four positions arranged equidistantly along an outer edge of the first main surface and located at a distance of 5 mm inwardly from the outer edge. An average value m1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.5 nm or less, and a standard deviation 1 of the surface roughnesses Ra1, Ra2, Ra3, Ra4, and Ra5 is 0.2 nm or less.

A method of producing a glass article includes holding a carrier having a circular shape, in which a glass substrate having a circular shape is retained, with an upper surface plate and a lower surface plate; and polishing the glass substrate by rotating the carrier with respect to the upper surface plate and the lower surface plate, to obtain the glass article. The glass substrate is disposed in the carrier such that, in a top plan view, a center of the carrier is included in a region of the glass substrate, and a center of the glass substrate is shifted from the center of the carrier.

A method of producing a glass article includes holding a carrier having a circular shape, in which a glass substrate having a circular shape is retained, with an upper surface plate and a lower surface plate; and polishing the glass substrate by rotating the carrier with respect to the upper surface plate and the lower surface plate, to obtain the glass article. The glass substrate is disposed in the carrier such that, in a top plan view, a center of the carrier is included in a region of the glass substrate, and a center of the glass substrate is shifted from the center of the carrier.