APPARATUS AND METHOD FOR MEASURING DIAMETER OF WAFER

摘要

An apparatus and a method for measuring a diameter of a wafer are provided to prevent defect and damage in processing due to an error of wafer diameter by using an optical unit having a light irradiating member and a light detecting member. A supporting unit(110) mounts a wafer(W) to support it. A driving unit(120) rotates and operates the supporting unit. An optical unit(130) has a first member(130a) and a second member(130b). The first member irradiates a light to an end of the rotating wafer supported on the supporting unit and the other end of the wafer opposite to the end thereof. The second member detects the light irradiated from the first member. The first member and the second member are separated from each other upwardly and downwardly centering the wafer. The optical unit includes an image sensor.