Grinding apparatus and evaluation method for processed modified layer in grinding apparatus

Abstract

This invention provides a novel evaluation method for processed modified layers using an eddy current detector. It also provides a grinding apparatus for grinding a workpiece having a processed modified layer. The grinding apparatus comprises: a first holder configured to hold and rotate the workpiece; a second holder configured to hold and rotate a grinding tool for grinding the workpiece relative to it; at least one eddy current detector disposed on either the first or second holder; and a control unit. During grinding, the control unit acquires the output signal of the eddy current detector, calculates the resistance value of the ground layer in the workpiece based on the output signal, and determines the thickness of the processed modified layer in the workpiece based on the deviation between the calculated resistance value and a specified reference.

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