Defect inspection apparatus and defect inspection method

A defect inspection apparatus comprising:

• an illumination optical system configured to irradiate a sample surface with a linear illumination spot of light having a wavelength of any one of 240 nm to 293 nm;
• an illumination spot scanning unit configured to move the sample surface and scan the linear illumination spot in a lateral direction of the illumination spot;
• a light condensing unit configured to condense reflected light of the illumination spot from the sample surface;
• a polarization control unit comprising a first wavelength plate that rotates to control a polarization direction of incident light, a polarization beam splitter that splits the light whose polarization direction is determined by the first wavelength plate, and a second wavelength plate that rotates to control a specific polarization direction of the split light emitted from the polarization beam splitter;
• an imaging unit configured to form an optical image by the light split by the polarization control unit and having the specific polarization direction;
• and
• a sensor unit configured to output the optical image as an electrical signal, the sensor unit including a receiving portion and an antireflection film at a position conjugate with the illumination spot with which the sample surface is irradiated,
• wherein
• a first angle, α, formed by an optical axis of the light condensing unit and a longitudinal direction of the linear illumination spot irradiated on the sample is 10 degrees or more and less than 80 degrees,
• a second angle, β, formed by an arrangement direction of the light receiving portion of the sensor unit and an optical axis of the light condensing unit is 10 degrees or more and less than 80 degrees,
• the second angle, β, satisfies a condition that an inner product of a vector of the optical axis of the light condensing unit and a pixel arrangement vector of the sensor unit is equal to cos α multiplied by an imaging magnification M,
• the sensor unit includes a first sensor unit and a second sensor unit,
• the polarization beam splitter splits light whose polarization direction is controlled by the first wavelength plate to have a polarization component of S-polarized light and a polarization component of P-polarized light, and guides the polarized light to a first optical path and a second optical path, respectively, and
• the defect inspection apparatus further comprises:
• a first polarization direction conversion unit that guides the S-polarized light guided to the first optical path to the first sensor unit;
• and
• a second polarization direction conversion unit that converts the P-polarized light guided to the second optical path to a direction of the S-polarized light and guides the converted light to the second sensor unit.