Patent ID: 11967506
Assignee: DISCO CORPORATION
Field: Machine tools (Mechanical engineering)
Classification: CPC H  B | IPC B  H

Claim 16:
17. A method for grinding a wafer using a grinding apparatus that includes at least four chuck tables for holding respective wafers on holding surfaces thereof, a first grinding mechanism for grinding the wafer held on the holding surface of one of the chuck tables by keeping lower surfaces of first grindstones arranged in an annular array on a first grinding wheel in contact with a radial area of the wafer, a second grinding mechanism for grinding the wafer held on the holding surface of one of the chuck tables by keeping lower surfaces of second grindstones arranged in an annular array on a second grinding wheel in contact with a radial area of the wafer, a third grinding mechanism for grinding the wafer held on the holding surface of one of the chuck tables by keeping lower surfaces of third grindstones arranged in an annular array on a third grinding wheel in contact with a radial area of the wafer, a first grinding feed mechanism for grinding-feeding the first grinding mechanism in a grinding feed direction perpendicular to the holding surface of one of the chuck tables, a second grinding feed mechanism for grinding-feeding the second grinding mechanism in a grinding feed direction perpendicular to the holding surface of one of the chuck tables, a third grinding feed mechanism for grinding-feeding the third grinding mechanism in a grinding feed direction perpendicular to the holding surface of one of the chuck tables, and a turntable with the chuck tables mounted thereon, the turntable being rotatable about a central axis of the turntable for positioning the chuck tables respectively with respect to the first grindstones, the second grindstones, and the third grindstones, wherein the method comprises: producing a first ground mark on the wafer by grinding the wafer with the first grindstones; producing a second ground mark on the wafer by grinding the wafer with the second grindstones such that the second ground mark extends across the first ground mark, wherein the first ground mark is developed radially inwardly on the wafer by rotating the first grinding wheel in a first direction while simultaneously rotating an associated one of the chuck tables in a first direction and wherein the second ground mark is developed radially inwardly on the wafer by rotating the second grinding wheel in a second direction that is opposite of the first direction while simultaneously rotating an associated one of the chuck tables in the second direction, and producing a third ground mark on the wafer by grinding the wafer with the third grindstones such that the third ground mark extends across the second ground mark produced on the wafer by the second grindstones, wherein the third ground mark is developed radially inwardly on the wafer by rotating the third grinding wheel in the first direction while simultaneously rotating an associated one of the chuck tables in the first direction.