APPAREIL ET PROCEDE DE DETERMINATION D'UNE PROFONDEUR D'UNE REGION AYANT UN RAPPORT DE FORME ELEVE QUI S'AVANCE DANS UNE SURFACE D'UNE PLAQUETTE SEMI-CONDUCTRICE

An apparatus and method for determining a depth of a region having a high aspect ratio that protrudes into a surface of a semiconductor wafer are provided. The apparatus comprises a multi-wavelength light source, a semiconductor wafer holder for holding a semiconductor wafer, a head for directing the light source onto the semiconductor wafer, a spectrometer for collecting light comprising multiple wavelengths reflected from the semiconductor wafer and analysis means for determining a depth of the region from an interference pattern of light reflected from the semiconductor wafer by performing Fourier domain optical coherence tomography.