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US 11,112,369 B2Granted
Hybrid overlay target design for imaging-based overlay and scatterometry-based overlay
AssigneeKLA-Tencor Corporation
InventorDavid Gready
Life of this patent
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Abstract
Designs for a hybrid overlay target design that includes a target area with both an imaging-based target and a scatterometry-based target are disclosed. The imaging-based overlay target design can include side-by-side grating structure. A scatterometry-based overlay target design at a different location in the target area can include grating-over-grating structure. A method of measuring the hybrid overlay target design and a system with both an imaging optical system and a scatterometry system for measuring the hybrid overlay target design are also disclosed.
Claims10
A method comprising:
- acquiring a region of a wafer on a chuck with an overlay target on a surface of the wafer in the region using an imaging optical system thereby forming an acquired image, wherein the overlay target includes gratings in an imaging-based overlay target design and gratings in a scatterometry-based overlay target design, wherein the gratings in the imaging-based overlay target design are in a side-by-side configuration, and wherein the gratings in the scatterometry-based overlay target design are in a grating-over-grating configuration;
- measuring the overlay target with a first illumination beam from the imaging optical system using the acquired image;
- and
- measuring the overlay target with a second illumination beam from the scatterometry system,
- wherein the imaging-based overlay target design and the scatterometry-based overlay target design are in a same field of view during the measuring with the first illumination beam and the second illumination beam.
2 more elements
A system comprising:
- a chuck configured to hold a wafer having an overlay target on a surface of the wafer, wherein the overlay target includes gratings in an imaging-based overlay target design and gratings in a scatterometry-based overlay target design, wherein the gratings in the imaging-based overlay target design are in a side-by-side configuration, and wherein the gratings in the scatterometry-based overlay target design are in a grating-over-grating configuration;
- an imaging optical system with a first illumination source configured to measure the overlay target on the chuck;
- a scatterometry system with a second illumination source configured to measure the overlay target on the chuck;
- and
- a processor in electronic communication with the imaging optical system and the scatterometry system, wherein the imaging optical system and the scatterometry system are configured to measure the same overlay target, wherein the imaging-based overlay target design and the scatterometry-based overlay target design are in a same field of view of the imaging optical system and the scatterometry system.
2 more elements
Dependencies are inferred from the claim text.