Optical alignment correction using convolutional neural network evaluation of a beam image
AssigneeFEI Company
InventorsGalen Gledhill, Mostafa Maazouz, Gavin Mitchson
Life of this patent
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Abstract
A focused ion beam (FIB) is used to mill beam spots into a substrate at a variety of ion beam column settings to form a set of training images that are used to train a convolutional neural network. After the neural network is trained, an ion beam can be adjusted by obtaining spot image which is processed with the neural network. The neural network can provide a magnitude and direction of defocus, aperture position, lens adjustments, or other ion beam or ion beam column settings. In some cases, adjustments are not made by the neural network, but serve to indicate that the ion beam and associated ion column continue to operate stably, and additional adjustment is not required.
Claims28
A method, comprising:
- exposing a substrate to a charged particle beam (CPB) to obtain a plurality of training images, each of the training images associated with at least one CPB column characteristic;
- defining a neural network based on the training images so that the neural network is configured to indicate the at least one CPB column characteristic.
A system, comprising:
- a charged particle beam source;
- a charged particle beam column;
- and
- a processor coupled to the charged particle beam column, the processor coupled to process a spot image obtained with the charged particle beam source and the charged particle beam column with a neural network to determine at least one adjustment of the charged particle beam source and the charged particle beam column.
A method, comprising:
- obtaining a plurality of images of a focused beam produced at a test substrate at corresponding focus settings;
- training a convolutional neural network with the plurality of images;
- and
- obtaining an operational image of the focused beam;
- and
- processing the operational image of the focused beam to determine a focus adjustment.
Dependencies are inferred from the claim text.