Tomographic imaging method
AssigneeFEI Company
InventorsRemco Schoenmakers, Pavel Poto{hacek over (c)}ek
Life of this patent
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Abstract
Methods of investigating a specimen using tomographic imaging include directing a beam of radiation through a specimen and onto a detector, thereby generating an image of the specimen. The directing is repeated for different specimen orientations relative to the beam, thereby generating a corresponding set of images. An iterative mathematical reconstruction technique is used to convert the images into a tomogram. The reconstruction is mathematically constrained to curtail a solution space using three-dimensional SEM imagery of at least a part of the specimen that overlaps the tomogram by requiring iterative results of the reconstruction to be consistent with pixel values derived from the SEM imagery.
Claims19
A method of investigating a specimen using tomographic imaging, comprising:
- directing a tomographic radiation beam through the specimen and onto a detector, thereby generating an image of the specimen;
- repeating said directing for a set of different specimen orientations relative to said tomographic radiation beam, thereby generating a corresponding set of images;
- using an iterative mathematical reconstruction technique to convert said set of images obtained with the tomographic radiation beam into a tomogram of at least a portion of the specimen;
- mathematically constraining said reconstruction into the tomogram to curtail a solution space resulting therefrom, characterized by:
- obtaining three-dimensional Scanning Electron Microscope (SEM) imagery of at least a part of the specimen that overlaps at least partially with said portion of the specimen associated with the tomogram, wherein the three-dimensional Scanning Electron Microscope (SEM) imagery is obtained by scanning an electron beam, and
- using said SEM imagery to perform said constraining by requiring iterative results of said reconstruction to be consistent with pixel values derived from said SEM imagery.
A tomographic imaging apparatus comprising:
- a tomographic imaging source, for producing a beam of radiation that can be directed through the specimen onto a detector to generate an image of at least part of the specimen;
- an adjustment mechanism for producing a set of different specimen orientations relative to the beam, allowing a corresponding set of images to be generated;
- a processing apparatus configured to:
- apply an iterative mathematical reconstruction technique to convert the set of images into a tomogram,
- mathematically constrain the reconstruction into the tomogram to curtail a solution space resulting therefrom, wherein the constraining comprises:
- accessing three-dimensional Scanning Electron Microscope (SEM) imagery of at least a portion of the specimen;
- and
- using the SEM imagery to perform the constraining by requiring iterative results of said reconstruction to be consistent with pixel values derived from the SEM imagery.
A method of investigating a specimen using tomographic imaging, comprising:
- repetitively directing a tomographic radiation beam through a specimen and onto a detector, thereby generating corresponding specimen images for a set of different specimen orientations relative to the tomographic radiation beam;
- iteratively reconstructing to convert the set of images into a tomogram of at least a portion of the specimen, wherein the reconstructing into the tomogram is constrained to curtail a solution space resulting therefrom, wherein the constraining includes:
- obtaining at least one three-dimensional Scanning Electron Microscope (SEM) image of at least a part of the specimen that overlaps at least partially with the portion of the specimen associated with the tomogram, and
- using the at least one three-dimensional SEM image to perform the constraining by requiring iterative results of the reconstruction to be consistent with pixel values derived from the at least one three dimensional SEM image.
Dependencies are inferred from the claim text.