Semiconductor measurement apparatus
A semiconductor measurement apparatus includes an illumination unit including a light source and at least one illumination polarization element, a light receiving unit including at least one light-receiving polarization element disposed on a path of light reflected by a sample, and an image sensor positioned to receive light passing through the at least one light-receiving polarization element and configured to output an original image, and a control unit configured to determine, by processing the original image, a selected critical dimension among critical dimensions of a structure included in a region of the sample. The control unit is configured to obtain a plurality of sample images by selecting regions of the original image in which a peak due to interference appears, to determine a plurality of elements included in a Mueller matrix using the plurality of sample images, and to determine the selected critical dimension based on the plurality of elements.
1. A semiconductor measurement apparatus, comprising:
an illumination unit including a light source and at least one illumination polarization element disposed on a path of light emitted by the light source;
a light receiving unit including at least one light-receiving polarization element disposed on a path of light passing through the at least one illumination polarization element and reflected by a sample, and an image sensor positioned to receive light passing through the at least one light-receiving polarization element and configured to output an original image; and
a control unit configured to determine, by processing the original image, a selected critical dimension among critical dimensions of a structure included in a region of the sample to which light is incident,
wherein the control unit is configured to obtain a plurality of sample images by selecting regions of the original image in which a peak due to interference appears, to determine a plurality of elements included in a Mueller matrix using the plurality of sample images, and to determine the selected critical dimension based on the plurality of elements.
2. The semiconductor measurement apparatus of claim 1 ,
wherein the illumination unit includes a first illumination polarization element and a second illumination polarization element, and
wherein the light receiving unit includes a first light-receiving polarization element and a second light-receiving polarization element.
3. The semiconductor measurement apparatus of claim 1 ,
wherein the control unit is configured to transform the original image into a frequency domain and extract a plurality of peak images corresponding to regions in which peaks appear due to interference between polarization components passing through the at least one illumination polarization element and the at least one light-receiving polarization element, and
wherein the plurality of sample images are obtained by frequency-inverse transformation of each of the plurality of peak images.
4. The semiconductor measurement apparatus of claim 3 , wherein each of the plurality of sample images corresponds to each of the regions in which the peak appears, and a peak appearing in each of the regions is displayed in a center.
5. The semiconductor measurement apparatus of claim 1 ,
wherein the control unit is configured to calculate a measurement parameter for determining the selected critical dimension based on the plurality of elements, and
wherein the selected critical dimension is determined by comparing the measurement parameter with a reference parameter included in library data.
6. The semiconductor measurement apparatus of claim 5 , wherein the measurement parameter includes a difference in intensity between polarization components of light incident to the image sensor, a phase difference between the polarization components, and a degree of polarization (DOP).
7. The semiconductor measurement apparatus of claim 1 ,
wherein each of the plurality of elements includes data in an image format, and
wherein the control unit is configured to determine the selected critical dimension by comparing the plurality of elements with reference image data stored in library data.
8. The semiconductor measurement apparatus of claim 1 , further comprising:
an objective lens disposed in a path of light incident to the sample and a path of light reflected from the sample,
wherein a numerical aperture of the objective lens is 0.95 or more and less than 1.0.
9. The semiconductor measurement apparatus of claim 8 , wherein an incidence angle of light reflected by the sample and incident to the objective lens is 0 degrees or more and 85 degrees or less.
10. The semiconductor measurement apparatus of claim 8 , wherein a surface of the image sensor is disposed in a conjugate position with respect to a position of a back focal plane of the objective lens.
11. The semiconductor measurement apparatus of claim 1 , wherein the control unit is configured to determine the selected critical dimension by specifying an azimuth, an incidence angle, and a wavelength band of light reflected by the sample and incident to the image sensor and extracting data corresponding to the azimuth, the incidence angle, and the wavelength band from at least one of the plurality of elements.
12. The semiconductor measurement apparatus of claim 1 , wherein the control unit is configured to select at least one element having a highest sensitivity for the selected critical dimension among the plurality of elements, and to determine the selected critical dimension based on the at least one element.