公开(公告)号：US11092644B2

公开(公告)日：2021-08-17

申请号：US16087056

申请日：2017-03-14

Applicant: UNITY SEMICONDUCTOR

Inventor： Philippe Gastaldo ,  Mayeul Durand De Gevigney ,  Tristan Combier

IPC: G01R31/308 ,  G01R31/28

Abstract: A method for inspecting a wafer including: rotating the wafer about an axis of symmetry (X) perpendicular to a main wafer surface (S); emitting, from a light source coupled with an interferometric device, two incident light beams, to form, at the intersection between the two beams, a measurement volume (V) containing interference fringes so that a region of the main surface (S) of the wafer passes through a fringe, the dimension (Dy) of the measurement volume in a radial direction of the wafer being between 5 and 100 μm; collecting a portion of the light scattered by the wafer region; acquiring the collected light and emitting a signal representing the variation in the collected light intensity as a function of time; and detecting, a frequency component in the collected light, the frequency being the time signature of a defect passage through the measurement volume.