DEVICE FOR MEASURING PARTICLE ON WAFER

摘要

PURPOSE: A device for measuring particle on wafer is provided to enhance the reliability when measuring the particle. CONSTITUTION: A device for measuring particle on wafer comprises a laser(25), a beam split(26), a detector(28), a control unit(24) and a stage driver(24). The laser(25) irradiates laser beam on a surface of a wafer(20). The beam split(26) reflects the laser beam reflected from the surface of the wafer. The detector detects the laser beam reflected by the beam split. The control unit receives the detect signal of the detector and generates the correcting signal for correcting it. The stage driver receives the correcting signal of the control unit and drives the stage to control the focus of the stage.