WHITE LIGHT SCANNING TYPE WAFER THICKNESS MEASURING METHOD USING A FOCAL DISTANCE DIFFERENCE ACCORDING TO THE OVERLAPPING LIGHT PATHS OF WHITE LIGHT

摘要

PURPOSE: A white light scanning type wafer thickness measuring method is provided to reduce an error caused by light refraction according to the position of a wafer by optimizing the amount of scattering or reflected lights according to the state of the wafer.;CONSTITUTION: A white light scanning type wafer thickness measuring method is as follows. A wafer(10) is set on a turntable jig. The turntable jig is rotated at regular angle intervals and white light is irradiated to the wafer through a light source unit(20). The light reflected off the wafer is received through a camera(30), wherein the center and four exterior sides of the wafer are alternately measured. A thickness calculation unit measures the thickness of the wafer by taking signals of specific wave lengths from image signals transmitted from the camera.;COPYRIGHT KIPO 2012