Holographic microscope and manufacturing method of semiconductor device using the same
Provided is a holographic microscope including an input optical system configured to emit polarized input beam, a first beam splitter configured to emit an object beam by reflecting a portion of the polarized input beam, and emit a reference beam by transmitting a remaining portion of the polarized input beam, a reference optical system configured to separate the reference beam into a first reference beam and a second reference beam, a camera configured to receive the first reference beam and the second reference beam and the object beam that is reflected by an inspection object, the camera including a micro polarizer array, wherein a first polarization axis of the first reference beam is perpendicular to a second polarization axis of the second reference beam.
1. A manufacturing method of a semiconductor device, the manufacturing method comprising:
generating a first hologram image by interfering a first reference beam that is linearly polarized with an object beam that is reflected by a top surface of a wafer, and generating a second hologram image by interfering a second reference beam having a polarization direction substantially perpendicular to the first reference beam with the object beam;
generating the first hologram image in a wave number domain and the second hologram image in the wave number domain by applying Fourier transform to a first image and a second image, respectively; and
generating a differential image in the wave number domain based on the first hologram image in the wave number domain and the second hologram image in the wave number domain,
wherein the first hologram image and the second hologram image are generated by a camera, and
wherein the first reference beam and the second reference beam are obliquely incident on the camera, and the object beam is perpendicularly incident on the camera.
2. The manufacturing method of claim 1 , wherein a first polarization direction of the first reference beam is substantially perpendicular to a second polarization direction of the second reference beam.
3. The manufacturing method of claim 1 , wherein a magnitude of a polarization component of the object beam parallel with a first polarization direction of the first reference beam is identical to a magnitude of a polarization component of the object beam parallel with a second polarization direction of the second reference beam.
4. The manufacturing method of claim 1 , further comprising applying a filter comprising first pass bands centered at first local maximum points of the first hologram image in the wave number domain to the first hologram image and the second hologram image.
5. The manufacturing method of claim 4 , further comprising generating a differential image of a first pass band of the first hologram image in a first wave number domain and the first pass band of the second hologram image in a second wave number domain.
6. The manufacturing method of claim 5 , further comprising applying a parallel movement to the first pass band such that a local maximum included in the first pass band is located at an origin, with respect to the first pass band that is any one of pass bands of the differential image of the first pass band.
7. The manufacturing method of claim 6 , further comprising generating a real domain image by applying inverse Fourier transform to the first pass band to which the parallel movement has been applied.
8. A manufacturing method of a semiconductor device, the manufacturing method comprising:
coating a photoresist layer on a wafer;
removing a portion of the photoresist layer coated on a boundary of the wafer based on an edge bead removal operation; and
evaluating the edge bead removal operation,
wherein the evaluating the edge bead removal operation comprises:
generating a first hologram image by interfering a first reference beam that is linearly polarized with an object beam that is reflected by an edge portion of the wafer, and generating a second hologram image by interfering a second reference beam having a polarization direction perpendicular to the first reference beam with the object beam;
generating the first hologram image in a wave number domain and the second hologram image in the wave number domain by applying Fourier transform to a first image and a second image, respectively; and
generating a differential image in the wave number domain based on the first hologram image in the wave number domain and the second hologram image in the wave number domain,
wherein the first hologram image and the second hologram image are generated by a camera, and
wherein the first reference beam and the second reference beam are inclined at angles that are different from each other with respect to the camera, and the object beam is perpendicularly incident on the camera.
9. The manufacturing method of claim 8 , wherein a first polarization direction of the first reference beam is substantially perpendicular to a second polarization direction of the second reference beam.
10. The manufacturing method of claim 8 , wherein a magnitude of a polarization component of the object beam parallel with a first polarization direction of the first reference beam is identical to a magnitude of a polarization component of the object beam parallel with a second polarization direction of the second reference beam.
11. The manufacturing method of claim 8 , further comprising applying a filter comprising first pass bands centered at first local maximum points of the first hologram image in the wave number domain to the first hologram image and the second hologram image.
12. The manufacturing method of claim 11 , further comprising generating a differential image of a first pass band of the first hologram image in a first wave number domain and the first pass band of the second hologram image in a second wave number domain.
13. The manufacturing method of claim 12 , further comprising applying a parallel movement to the first pass band such that a local maximum included in the first pass band is located at an origin, with respect to the first pass band that is any one of pass bands of the differential image of the first pass band.
14. The manufacturing method of claim 13 , further comprising generating a real domain image by applying inverse Fourier transform to the first pass band to which the parallel movement has been applied.
15. The manufacturing method of claim 8 , further comprising performing laser cleaning on the photoresist layer based on the evaluation of the edge bead removal operation.
16. A manufacturing method of a semiconductor device, the manufacturing method comprising:
coating a photoresist layer on a wafer;
removing a portion of the photoresist layer coated on a boundary of the wafer based on an edge bead removal operation;
evaluating the edge bead removal operation; and
performing laser cleaning on the photoresist layer based on the evaluation of edge bead removal operation,
wherein the evaluating the edge bead removal operation comprises:
generating a first hologram image by interfering a first reference beam that is linearly polarized with an object beam that is reflected by an edge portion of the wafer, and generating a second hologram image by interfering a second reference beam having a polarization direction perpendicular to the first reference beam with the object beam;
generating the first hologram image in a wave number domain and the second hologram image in the wave number domain by applying Fourier transform to a first image and a second image, respectively; and
generating a differential image in the wave number domain based on the first hologram image in the wave number domain and the second hologram image in the wave number domain,
wherein the first hologram image and the second hologram image are generated by a camera, and
wherein a first polarization direction of the first reference beam is substantially perpendicular to a second polarization direction of the second reference beam.
17. The manufacturing method of claim 16 , wherein a magnitude of a polarization component of the object beam parallel with a first polarization direction of the first reference beam is identical to a magnitude of a polarization component of the object beam parallel with a second polarization direction of the second reference beam.
18. The manufacturing method of claim 16 , wherein the first reference beam and the second reference beam are inclined at angles that are different from each other with respect to the camera.
19. The manufacturing method of claim 16 , wherein the object beam is perpendicularly incident on the camera.
20. The manufacturing method of claim 16 , further comprising applying a filter comprising first pass bands centered at first local maximum points of the first hologram image in the wave number domain to the first hologram image and the second hologram image.