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US 2026/0277117 A1Published application
Focus Metrology Method Using Overlay Measurement Tool
AssigneeKLA Corporation
InventorsBoris Johan Louis HABETS, Gaetan DE LIEDEKERKE BEAUFORT, Roel GRONHEID, Chufan ZHANG, Nadav GUTMAN
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Abstract
A workpiece, such as a semiconductor wafer, is imaged with one or more focus and dose offsets. The workpiece includes overlay targets that have different best focus positions and/or different through focus. A measurement recipe for an optical system is determined for each of the overlay targets such that a focus response is maximized. A neural network can be trained with the measurement recipes for the overlay targets.
Claims17
A method comprising:
- imaging a workpiece with one or more focus and dose offsets, wherein the workpiece includes a plurality of overlay targets that have different best focus positions and/or different through focus;
- determining a measurement recipe for an optical system for each of the overlay targets such that a focus response is maximized;
- and
- training a neural network with the measurement recipes for the overlay targets.
1 more element
An optical system comprising:
- a light source that generates a beam of light;
- a stage configured to hold a workpiece in a path of the beam of light;
- a detector configured to receive the light reflected from the workpiece;
- at least one optical element disposed in the path of the beam of light between the light source and the stage or between the stage and the detector;
- and
- a processor in electronic communication with the detector and the light source, wherein the processor is configured to operate a neural network, and wherein the processor is configured to determine a measurement recipe for each of the overlay targets on the workpiece such that a focus response is maximized.
3 more elements
Dependencies are inferred from the claim text.