| CPC B24B 37/08 (2013.01) [B24B 37/005 (2013.01)] | 8 Claims |
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1. A double-sided polishing apparatus comprising:
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 comprises 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.
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