US 12,134,165 B2
Grinding method of workpiece
Satoru Fujimura, Tokyo (JP)
Assigned to DISCO CORPORATION, Tokyo (JP)
Filed by DISCO CORPORATION, Tokyo (JP)
Filed on Nov. 18, 2021, as Appl. No. 17/455,492.
Claims priority of application No. 2020-205662 (JP), filed on Dec. 11, 2020.
Prior Publication US 2022/0184774 A1, Jun. 16, 2022
Int. Cl. B24B 51/00 (2006.01); B24B 7/07 (2006.01); B24B 49/04 (2006.01)
CPC B24B 51/00 (2013.01) [B24B 49/04 (2013.01); B24B 7/075 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A grinding method of a workpiece that is a grinding method for grinding the workpiece, the grinding method comprising:
a holding step of placing the workpiece over a holding surface of a holding table that has the holding surface with a conical surface shape as an upper surface and that is rotatable around a table rotation axis that passes through a center of the holding surface and holding the workpiece by the holding table;
a first grinding step of grinding the workpiece in such a manner that an outer circumferential part of the workpiece becomes thinner than a central part of the workpiece by rotating a first spindle having a lower end to which a first grinding wheel having first grinding abrasive stones on a bottom surface is fixed to rotate the first grinding abrasive stones on a first annular track and by bringing the holding table and the first grinding wheel close to each other to cause the first grinding abrasive stones to get contact with the workpiece in a state in which a generatrix closest to the first grinding abrasive stones in the holding surface with the conical surface shape is set non-parallel to the first annular track;
a measurement step of measuring a thickness of the workpiece at the outer circumferential part or a height of an upper surface of the workpiece at the outer circumferential part after the first grinding step; and
after the first grinding step, a second grinding step of grinding the workpiece by rotating a second spindle having a lower end to which a second grinding wheel having second grinding abrasive stones on a bottom surface is fixed to rotate the second grinding abrasive stones on a second annular track and by bringing the holding table and the second grinding wheel close to each other to cause the second grinding abrasive stones to get contact with the workpiece in a state in which a generatrix closest to the second grinding abrasive stones in the holding surface with the conical surface shape is set parallel to the second annular track, wherein the holding surface with the conical surface shape is set parallel to the second annular track prior to the initiation of grinding the workpiece with the second grinding abrasive stones, wherein,
in the second grinding step, the grinding is started from the central part of the workpiece and the grinding is ended when the workpiece reaches a finished thickness of the workpiece at the outer circumferential part or the height of the upper surface of the workpiece at the outer circumferential part, wherein the finished thickness is set based on a result obtained during the measuring step at the end of the first grinding step and before the workpiece has been ground by the second grinding abrasive stones of the second grinding wheel.