Patent ID: 8898028
Filing Date: 2014-11-25
Classification: G01N

Abstract:
1. A device to inspect a non-pattern wafer comprising: a light source emitting light; a detection unit detecting the light that is emitted from the light source and is reflected from a wafer; a judgment unit to convert the light detected by the detection unit into a quantitative measured value and to determine whether the wafer is faulty based on the measured value; and a support unit to support one surface of the wafer and being movable in a vertical direction; wherein the wafer comprises a first region and a second region; the detection unit sequentially detects lights reflected from the first and second regions of the wafer; and the judgment unit converts the lights reflected from the first and second regions of the wafer that are sequentially detected by the detection unit into first and second quantitative measured values, respectively, and determines whether the second region of the wafer is faulty by comparing the second measured value with a first reference value; wherein the first reference value is calculated using an average value based on the first and second measured values and a characteristic value stored in the judgment unit that indicates a distribution of the first and second measured values; and wherein when at least one of the first and second measured values escapes from a predetermined range, the judgment unit moves the support unit in the vertical direction so that the at least one of the first or second measured value is within the predetermined range.