Workpiece grinding method

Abstract

A method of grinding a back side of a workpiece having a device region and a peripheral surplus region on a front side thereof includes covering the front side of the workpiece with a protective member, holding a protective member side of the workpiece by a holding surface of a chuck table that is rotated around a rotational axis inclined at an angle of 45 to 180 degrees relative to a vertical direction, and grinding the back side of the workpiece corresponding to the device region by a grindstone rotated around a rotational axis orthogonal to the holding surface while supplying grinding water, to form a circular recess and an annular reinforcement section surrounding the circular recess. When grinding, discharge of the grinding water containing abrasive grains dropped from the grindstone is promoted by the inclination of the workpiece.

What is claimed is: 
     
         1 . A workpiece grinding method of grinding by a grindstone a back side of a workpiece having on a front side thereof a device region in which a plurality of devices are formed and a peripheral surplus region surrounding the device region, the workpiece grinding method comprising:
 a front side protecting step of covering the front side of the workpiece with a protective member;   a holding step of holding a protective member side of the workpiece by a holding surface of a chuck table that is rotated around a rotational axis inclined at an angle of 45 to 180 degrees relative to a vertical direction, after the front side protecting step is performed; and   a grinding step of grinding the back side of the workpiece corresponding to the device region by the grindstone rotated around a rotational axis orthogonal to the holding surface while supplying grinding water, to form a circular recess and an annular reinforcement section that corresponds to the peripheral surplus region and that surrounds the circular recess,   wherein in the grinding step, discharge of the grinding water containing abrasive grains dropped from the grindstone is promoted by the inclination of the workpiece.   
     
     
         2 . The workpiece grinding method according to  claim 1 , wherein the protective member is an adhesive tape. 
     
     
         3 . The workpiece grinding method according to  claim 1 , wherein in the grinding step, the grindstone is positioned in such a manner that a rotational trajectory of the grindstone and a discharge position of the grinding water containing the abrasive grains dropped from the grindstone do not overlap each other since the discharge position is located at a lowermost point of the chuck table whose rotational axis is inclined.