Patent ID: 8063545

Claim:
A wafer polishing apparatus for polishing two head and tail faces of a wafer while supplying a polishing solution to adjust a thickness of the wafer to a predetermined thickness, wherein the wafer is in a shape of a plate substantially in an angular shape used as a raw material of a piezoelectric vibrator; wherein all of corner portions of the substantially angular shape are formed in a shape of a curved face by chamfering providing curvatures, and the corner portions substantially in the shape of the curved face includes at least a first curved face portion and a second curved face portion chamfered by the curvatures different from each other or the same curvature; and wherein a reference face of a crystal orientation of the raw material is specified by the first curved face portion or the second curved face portion, the wafer polishing apparatus comprising: a carrier in a shape of a circular plate an outer peripheral edge of which is made to constitute a gear portion and which is formed with a holding hole of containing the wafer; a planetary gear mechanism brought in mesh with the carrier by way of the gear portion and revolving the carrier around an axis line while rotating the carrier; an upper surface plate and a lower surface plate formed in a shape of a circular plate a center of which is hollowed and arranged on upper and lower sides of the carrier for squeezing both faces of the wafer while applying a predetermined load to the wafer contained in the holding hole; and polishing solution supplying means for supplying the polishing solution to between the upper surface plate and the lower surface plate; wherein the holding hole of the carrier includes an opening in a circular shape, and a curvature of the circular shape of the opening is the same as or smaller than the smallest curvature of the curvatures of the corner portions of the wafer.