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US 12,640,337 B2Granted
Autofocus method for single beam and multi-beam systems
AssigneeKLA Corporation
InventorWeijie Huang
Life of this patent
Estimating the term…
Abstract
An electron beam is directed at a workpiece on a stage with a first astigmatism applied. The electron beam reflected off the workpiece is detected and an image of the workpiece with the first astigmatism applied is generated. An autofocus model is applied to the image to determine a focus offset for the image with the autofocus model.
Claims20
An electron beam system comprising:
- an electron beam source, wherein the electron beam source generates at least one electron beam;
- a stage configured to hold a workpiece in a path of the electron beam;
- at least one lens in the path of the electron beam that is configured to control astigmatism of the electron beam;
- a detector configured to image the workpiece using the electron beam;
- and
- a processor in electronic communication with the detector and the electron beam source, wherein the processor is configured to:
- generate an image of the workpiece with a first astigmatism applied;
- apply an autofocus model to the image, wherein the autofocus model is a deep learning neural network;
- and
- determine a focus offset for the image using the autofocus model.
7 more elements
A method comprising:
- directing an electron beam at a workpiece on a stage, wherein the electron beam has a first astigmatism applied;
- detecting the electron beam reflected off the workpiece using a detector;
- generating, using a processor, an image of the workpiece with the first astigmatism applied;
- applying, using the processor, an autofocus model to the image, wherein the autofocus model is a deep learning neural network;
- and
- determining, using the processor, a focus offset for the image with the autofocus model.
3 more elements
A non-transitory computer-readable storage medium, comprising one or more programs for executing the following steps on one or more computing devices:
- generating an image of a workpiece with a first astigmatism applied;
- applying an autofocus model to the image, wherein the autofocus model is a deep learning neural network;
- and
- determining a focus offset for the image using the autofocus model.
1 more element
Dependencies are inferred from the claim text.