| 摘要 |
PROBLEM TO BE SOLVED: To measure the thickness of a wafer and observe the double sides of the wafer by providing the wafer with a specific diameter to the diameters of upper and lower surface plates, holding the wafer between the upper and lower surface plates in grinding, and mounting a wafer rotating mechanism on a peripheral edge of the wafer outside of the upper and lower surface plates. SOLUTION: The diameters of upper and lower surface plates are approximately same as one another and a diameter of a wafer is preferably 5/8 through 7/8 of those of the upper and lower surface plates. When the double sides of the wafer is grinded by a double side grinder 1, the wafer (w) is placed on an abrasive cloth 5 of the lower surface plate, the drive rollers 15, 15, 15 are pressed to an end face of the wafer, then an air cylinder of an elevator mechanism is lowered to contact an abrasive cloth 2b of the upper surface plate with the wafer. The upper surface plate 2, the lower surface plate 5 and the wafer (w) are rotated while supplying the abrasive fluid to grind both surfaces of the wafer. During the grinding of the wafer, a thickness of the wafer is measured by a thickness measuring device 17, the obtained value is communicated to RAM of CPU by a signal to be collated with the thickness of the wafer input to ROM and the final thickness by a computing device, a ground amount, a remained grinding amount and a grinding time are calculate to send their signals to the double side grinder to execute the grinding for the remained amount. |
