| 摘要 |
The invention includes a method for inspecting a wafer (2) for electronics, optics or optoelectronics, wherein said method includes: rotating the wafer (2) about an axis of symmetry perpendicular to a main surface (S) of said wafer; emitting, from at least one light source (20), at least two pairs of incident coherent light beams, in order to form two measurement spaces containing interference fringes having different fringe spacings; collecting a light beam diffused by the surface of the wafer; acquiring the collected light and emitting an electric signal representing the temporal variation of the light intensity of the collected light; detecting a frequency component in said signal, said frequency being the time signature of the passage of a defect through a respective measurement space; determining a parameter, referred to as defect visibility, for each detected signature, using the visibility determined for each measurement space; obtaining respective information on the size of said defect; and cross-checking information obtained for each measurement space in order to determine the size of the defect. |
