US Patent 7848844 Substrate grinding method and device

A grinding method wherein the correlation between the amount of inertial grinding occurring in performing spark-out by a grinding unit and the maximum load current in a motor of the grinding unit is grasped, and a correction value for the amount of inertial grinding corresponding to the maximum load current is preliminarily obtained. When the wafer thickness measured by a thickness measuring gauge has reached the sum of a desired value and the correction value (=the amount of inertial grinding) corresponding to the maximum load current, the spark-out is started. Accordingly, the wafer thickness becomes the desired value after the inertial grinding in performing the spark-out.