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US 2026/0100325 A1Published application
Dark correction for long term acquisition
AssigneeFEI Company
InventorsBart Jozef Janssen, Erik Franken
Life of this patent
Estimating the term…
Abstract
A charged particle beam (CPB) imaging apparatus intermittently acquires dark frames while the CPB is blanked and updates a dark reference with the intermittently acquired dark frames. The dark reference is used to compensate additive noise components in acquired sample frames, especially additive noise that increases during multiple image acquisitions over extended time periods.
Claims22
A method comprising:
- acquiring a first set of one or more sample frames associated with a sample;
- compensating the first set of one or more sample frames based on a first dark reference to produce a first set of one or more compensated sample frames;
- acquiring a second set of one or more sample frames;
- after acquiring the first set of one or more frames, acquiring one or more dark frames, wherein the one or more dark frames are acquired before, after, or both before and after the acquisition of the second set of one or more sample frames;
- updating the first dark reference based on the one or more acquired dark frames to create a second dark reference;
- and
- compensating the second set of one or more frames based on the second dark reference to produce a second set of one or more compensated sample frames.
4 more elements
A charged particle beam (CPB) imaging apparatus, comprising:
- a CPB source operable to irradiate a sample with a CPB;
- a beam blanker operable to selectively direct the CPB to the sample;
- and
- a detection system operable to acquire a sequence of frames that includes a first set of sample frames, a second set of sample frames, a first set of dark frames, and a second set of dark frames respectively, wherein the first set of sample frames and the second set of sample frames are associated with operation of the beam blanker to irradiate the sample with the CPB and the first set of dark frames and the second set of dark frames are associated with operation of the beam blanker to divert at least a portion of the CPB from the sample.
1 more element
A charged particle beam (CPB) imaging method, comprising:
- intermittently interrupting acquisition of sample frames based on radiation received from a sample responsive to a CPB to acquire one or more dark frames during each intermittent interruption;
- and
- establishing a sample image based on the sample frames and on one or more of the dark frames acquired during each of the intermittent interruptions.
Dependencies are inferred from the claim text.