Example features relate to a method of polishing a chamfered wafer surface, the method including beveling a wafer to generate the chamfered wafer surface, the chamfered wafer surface being inclined with respect to a main wafer surface by an angle θ; and polishing the chamfered wafer surface with a polishing pad, a polishing surface of the polishing pad being inclined with respect to the chamfered wafer surface by an angle α; wherein the angle α is equal to or smaller than the angle θ. Example features relate to a system for polishing the chamfered surface, the system including a polishing pad mounting jig configured to polish the chamfered surface, an angle θ being defined between the chamfered surface and the main surface; and a polishing pad in contact with the chamfered surface at an angle α during polishing; wherein the angle α is smaller than the angle θ.

A glass blank is cut out from a glass plate by forming a crack starting portion inside the glass plate by moving a first laser beam relative to the glass plate such that a focal position of the laser beam is located in an inner portion of the glass plate in its thickness direction and the focal position forms a circle when viewed from a surface of the glass plate, then causing cracks to develop from the crack starting portion toward main surfaces of the glass plate, and splitting the glass plate to separate, from the glass plate, a glass blank that includes a separation surface having an arithmetic average surface roughness Ra smaller than 0.01 m and a roundness not larger than 15 m. Thereafter, main surfaces of the glass blank are ground or polished.

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 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.

Provided are a double-side polishing apparatus and a double-side polishing method which can terminate double-side polishing of a workpiece so that the workpiece will have a desired shape even when double-side polishing of the workpiece is performed repeatedly. The control means determines, from a reference time point determined based on the amplitude of the change of the temperature of the carrier plate, an offset time for the next batch during which additional double-side polishing is performed; and terminates double-side polishing after a lapse of the determined offset time from the reference time point. The offset time is determined based on a predicted value of the shape index of the workpiece in the next batch, predicted from the actual value of the shape index of the workpiece having been double-side polished in one or more previous batches and from difference of the offset time between batches.

Provided are a double-side polishing apparatus and a double-side polishing method which can terminate double-side polishing of a workpiece so that the workpiece will have a desired shape even when double-side polishing of the workpiece is performed repeatedly. The control means determines, from a reference time point determined based on the amplitude of the change of the temperature of the carrier plate, an offset time for the next batch during which additional double-side polishing is performed; and terminates double-side polishing after a lapse of the determined offset time from the reference time point. The offset time is determined based on a predicted value of the shape index of the workpiece in the next batch, predicted from the actual value of the shape index of the workpiece having been double-side polished in one or more previous batches and from difference of the offset time between batches.

A double-head grinding machine includes a disc-shaped carrier ring having a support hole for supporting a silicon wafer, a rotation mechanism rotating the carrier ring around a center of the carrier ring, and a grinding wheel including a grinding stone for grinding the silicon wafer. The support hole is circular and has a center eccentric to the center of the carrier ring.

A double-head grinding machine includes a disc-shaped carrier ring having a support hole for supporting a silicon wafer, a rotation mechanism rotating the carrier ring around a center of the carrier ring, and a grinding wheel including a grinding stone for grinding the silicon wafer. The support hole is circular and has a center eccentric to the center of the carrier ring.

Provided is a method of double-side polishing a wafer by which variations of the GBIR values of polished wafers between batches can be reduced. In the method of double-side polishing a wafer, a current batch includes measuring the center thickness of the wafer before polishing (S100); setting a target GBIR value within a predetermined range (S110); calculating a polishing time of the current batch based on Formula (1) (S120); and polishing both surfaces of the wafer for the calculated polishing time (S130).

Polishing time of current batch=polishing time of previous batch+A.sub.1(center thickness of wafer before polishing in previous batchcenter thickness of wafer before polishing in current batch)+A.sub.2(GBIR value of wafer after polishing in previous batchtarget GBIR value)+A.sub.3(1), where A.sub.1, A.sub.2, and A.sub.3 are predetermined coefficients.

Provided is a method of double-side polishing a wafer by which variations of the GBIR values of polished wafers between batches can be reduced. In the method of double-side polishing a wafer, a current batch includes measuring the center thickness of the wafer before polishing (S100); setting a target GBIR value within a predetermined range (S110); calculating a polishing time of the current batch based on Formula (1) (S120); and polishing both surfaces of the wafer for the calculated polishing time (S130).

Polishing time of current batch=polishing time of previous batch+A.sub.1(center thickness of wafer before polishing in previous batchcenter thickness of wafer before polishing in current batch)+A.sub.2(GBIR value of wafer after polishing in previous batchtarget GBIR value)+A.sub.3(1), where A.sub.1, A.sub.2, and A.sub.3 are predetermined coefficients.