Method for forming a holder surface, and grinding apparatus

Abstract

A method for forming a holder surface of a chuck table by rotating a spindle, to which an annular grinding stone is attached, and grinding an upper surface of the chuck table with the grinding stone rotated along with the spindle. The chuck table includes a porous member and a frame having a dense body in an annular shape. The method includes a first grinding process including tilting an axis of the chuck table with respect to an axis of the spindle relatively at a predetermined first angle and grinding an entire upper surface of the frame with the grinding stone, and a second grinding process including tilting the axis of the chuck table with respect to the axis of the spindle relatively at a second angle, which is smaller than the first angle, and grinding an entire upper surface of the porous member with the grinding stone.

What is claimed is: 
     
         1 . A method for forming a holder surface of a chuck table to suction and hold a wafer thereon by rotating a spindle, to which an annular grinding stone is attached, and grinding an upper surface of the chuck table with the grinding stone rotated along with the spindle, the chuck table being composed of a porous member and a frame having a dense body in an annular shape surrounding an outer circumference of the porous member, the method comprising:
 a first grinding process including tilting an axis of the chuck table with respect to an axis of the spindle relatively at a predetermined first angle and grinding an entire upper surface of the frame with the grinding stone; and   a second grinding process including tilting the axis of the chuck table with respect to the axis of the spindle relatively at a second angle, the second angle being smaller than the first angle, and grinding an entire upper surface of the porous member with the grinding stone.   
     
     
         2 . The method according to  claim 1 , wherein a grain diameter of the grinding stone to be used in the second grinding process is smaller than a grain diameter of the grinding stone used in the first grinding process. 
     
     
         3 . A grinding apparatus configured to form the holder surface of the chuck table in the method according to  claim 1 , comprising:
 the chuck table configured to hold the wafer;   a table spindle configured to rotate the chuck table;   a grinding unit configured to grind the wafer held on the chuck table with the grinding stone attached to the spindle;   a tilt-adjusting assembly configured to adjust relative inclination between the table spindle and the spindle to one of the first angle or the second angle; and   a controller configured to control the tilt-adjusting assembly to form the first angle for grinding the frame with the grinding stone and to form the second angle for grinding the porous member with the grinding stone.   
     
     
         4 . A grinding apparatus configured to form the holder surface of the chuck table by rotating the spindle, the spindle including a first spindle and a second spindle, and by grinding the upper surface of the chuck table with the grinding stone, the grinding stone including a first grinding stone and a second griding stone, in the method according to  claim 2 , the grinding apparatus comprising:
 the chuck table configured to hold the wafer;   a table spindle configured to rotate the chuck table;   a first grinding unit configured to grind the wafer held on the chuck table with the first grinding stone attached to the first spindle;   a second grinding unit configured to grind the wafer held on the chuck table with the second grinding stone, of which grain diameter is smaller than a grain diameter of the first grinding stone, the second grinding stone being attached to the second spindle;   a tilt-adjusting assembly configured to adjust relative inclination between the table spindle and the first spindle to the first angle and relative inclination between the table spindle and the second spindle to the second angle; and   a controller configured to control the tilt-adjusting assembly to form the first angle for grinding the frame with the first grinding stone and to form the second angle for grinding the porous member with the second grinding stone.