Defect reviewing method and device
To review minute defects that were buried in roughness scattered light with an observation device provided with a dark-field microscope, a scanning electron microscope (SEM), and a control unit, the present invention configures the dark-field microscope by installing a filter for blocking a portion of the scattered light, an imaging lens for focusing the scattered light that has passed through the filter, and a detector for dividing the image of the scattered light focused by the imaging lens into the polarization directions converted by a wavelength plate and detecting the resulting images, and the control has a calculation unit for determining the position of a defect candidate detected by another inspection device using the plurality of images separated into polarization directions and detected by the detector.
1. A defect reviewing device comprising:
a dark-field microscope that includes:
an illumination light source that illuminates a sample with illumination light,
an objective lens that collects scattered light generated from the sample illuminated with the illumination light from the illumination light source,
a wavelength plate that converts polarization directions of the scattered light from the sample, the scattered light being collected by the objective lens,
a filter that selectively blocks part of the scattered light transmitted through the wavelength plate and transmits a remaining portion of the scattered light,
an imaging lens that forms an image of the scattered light transmitted through the filter, and
a detector that captures the image of the scattered light formed by the imaging lens;
a scanning electron microscope (SEM);
a table that carries the sample between the dark-field microscope and the SEM; and
a control unit that is communicatively coupled to the dark-field microscope, the SEM, and the table, wherein a processor of the control unit:
causes the table to move the sample to the dark-field microscope,
removes the filter to allow radially polarized light and azimuthally polarized light to be transmitted,
captures, using the detector, first images formed by the radially polarized light and the azimuthally polarized light with the filter removed,
replaces the filter,
captures, using the detector, second images formed by the radially polarized light and the azimuthally polarized light with the filter replaced,
determines a position of the defect on the sample by comparing the first images and the second images,
causes the table to move to the sample to the SEM, and
captures, using the SEM, SEM images of the defect based on the position of the defect determined.
2. The defect reviewing device according to claim 1 , wherein the detector includes two-dimensionally arrayed pixels; and wherein neighboring pixels of the two-dimensionally arrayed pixels detect light beams polarized in different directions.
3. The defect reviewing device according to claim 1 , wherein the wavelength plate further:
converts the radially polarized light and the azimuthally polarized light to different beams of linearly polarized light.
4. The defect reviewing device according to claim 1 , wherein the processor further:
calculates a defect candidate by performing a threshold value process on a brightness values of images in different polarization directions.