Method for detecting defects and associated device

A method for determining a size of a void-type defect in a top semiconductor layer of a semiconductor-on-insulator semiconductor substrate, comprising:

• introducing the semiconductor-on-insulator semiconductor substrate into a reflected darkfield microscopy device and generating, from a light ray scattered by the top semiconductor layer, a defect-related first signal and a roughness-related second signal;
• capturing, with pixels, the intensity of the roughness-related second signal;
• comparing the intensity captured by each of the pixels with the intensities captured by neighboring pixels and defining whether each pixel is contained in an abnormal zone;
• determining a standard deviation of the intensity values captured by each pixel contained in the abnormal zone;
• and
• determining the size of the void-type defect associated with the abnormal zone from the determined standard deviation.

A device for detecting a void-type defect in a top side of a structure comprising a top layer placed on a substrate, the defect being located in the top layer, the device comprising:

• a reflected darkfield microscopy apparatus configured to project an incident light ray in the direction of the top side of the structure and to collect a light ray scattered by the top side;
• a detecting unit configured to generate, from the scattered light ray, a defect-related first signal and a roughness-related second signal, and to capture, with a plurality of pixels, the intensity of the roughness-related second signal;
• a first processing unit that is connected to the detecting unit, and configured to compare the intensity captured by each pixel with the intensities captured by neighboring pixels, and to define whether the pixel is contained in an abnormal zone;
• a second processing unit that is configured to extract the standard deviation of the values of the intensities captured by the pixels of the abnormal zone;
• and
• a correlation curve for determining the size of the void-type defect associated with the abnormal zone, from the extracted standard deviation.