CAD-assisted TEM prep recipe creation
First Claim
1. A method for automatically preparing a semiconductor sample in a dual-beam charged particle system, the method comprising:
- positioning the dual-beam charged particle system with respect to a semiconductor die sample region of interest to be examined in a sample chamber;
with focused ion beam (FIB) deposition, forming a first precision fiducial marker and one or more additional fiducial markers at desired locations with respect to the region of interest;
acquiring a first scanning electronic microscope (SEM) image of the region of interest;
retrieving computer aided design (CAD) data describing the region of interest;
synthesizing a second SEM image from CAD data describing the region of interest;
masking the one or more additional fiducial markers in the first SEM image and comparing the masked first SEM image and the second SEM image to determine a final correction offset for an actual position of the precision fiducial marker;
applying the final correction offset to the location of the precision fiducial marker;
based on the corrected location of the precision fiducial marker, adjusting the position of the FIB relative to the sample, and milling with the FIB to create a sample lamellae for examination.
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Accused Products
Abstract
An improved process workflow and apparatus for S/TEM sample preparation and analysis is provided. Preferred embodiments provide improved methods for an automated recipe TEM sample creation, especially for small geometry TEM lamellae, employing CAD data to automatically align various stages of sample preparation. The process automatically verifies and aligns the position of FIB-created fiducials by masking off portions of acquired images, and then comparing them to synthesized images from CAD data. SEM beam positions are verified by comparison to images synthesized from CAD data. FIB beam position is also verified by comparison to already-aligned SEM images, or by synthesizing an FIB image from CAD using techniques for simulating FIB images. The automatic alignment techniques herein allow creation of sample lamellas at specified locations without operator intervention.
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Citations
15 Claims
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1. A method for automatically preparing a semiconductor sample in a dual-beam charged particle system, the method comprising:
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positioning the dual-beam charged particle system with respect to a semiconductor die sample region of interest to be examined in a sample chamber; with focused ion beam (FIB) deposition, forming a first precision fiducial marker and one or more additional fiducial markers at desired locations with respect to the region of interest; acquiring a first scanning electronic microscope (SEM) image of the region of interest; retrieving computer aided design (CAD) data describing the region of interest; synthesizing a second SEM image from CAD data describing the region of interest; masking the one or more additional fiducial markers in the first SEM image and comparing the masked first SEM image and the second SEM image to determine a final correction offset for an actual position of the precision fiducial marker; applying the final correction offset to the location of the precision fiducial marker; based on the corrected location of the precision fiducial marker, adjusting the position of the FIB relative to the sample, and milling with the FIB to create a sample lamellae for examination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for automatically preparing a semiconductor sample in a dual-beam charged particle system, the method comprising:
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aligning a scanning electron microscope (SEM) beam the dual-beam charged particle system with a desired feature of interest on a sample in a sample chamber by comparing computer aided design (CAD) data to an acquired SEM image and applying a resulting SEM correction offset; then, with beam-induced deposition, depositing a protective layer over at least part of the region of interest; then, with a focused ion beam (FIB), creating a first precision fiducial marker and one or more additional fiducial markers at desired locations with respect to the region of interest; acquiring a scanning electronic microscope (SEM) image of the region of interest; retrieving CAD data describing the region of interest; synthesizing a second SEM image from CAD data describing the region of interest; masking the one or more additional fiducial markers and the protective layer in the first SEM image and comparing the masked first SEM image and the second SEM image to determine a final correction offset for an actual position of the precision fiducial marker; applying the final correction offset to the FIB position and then FIB milling with reference to the corrected position to create a sample lamellae for examination. - View Dependent Claims (11)
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12. An automated sample preparation system comprising:
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a dual-beam scanning and milling system including a scanning electron microscope (SEM), a focused ion beam (FIB) both pointing at a sample chamber, a system controller operatively connected to the SEM and FIB and including at least one processor and tangible non-transitory computer media storing program instructions executable by the at least one processor for; aligning a scanning electron microscope (SEM) beam the dual-beam charged particle system with a desired feature of interest on a sample in the sample chamber by comparing computer aided design (CAD) data to an acquired SEM image and applying a resulting SEM correction offset; then, with beam-induced deposition, depositing a protective layer over at least part of the region of interest; then, with a focused ion beam (FIB), creating a first precision fiducial marker and one or more additional fiducial markers at desired locations with respect to the region of interest; acquiring a scanning electronic microscope (SEM) image of the region of interest; retrieving CAD data describing the region of interest; synthesizing a second SEM image from CAD data describing the region of interest; masking the one or more additional fiducial markers and the protective layer in the first SEM image and comparing the masked first SEM image and the second SEM image to determine a final correction offset for an actual position of the precision fiducial marker; applying the final correction offset to the FIB position and then FIB milling with reference to the corrected position to create a sample lamellae for examination. - View Dependent Claims (13, 14, 15)
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Specification