SCANNING DIFFRACTION-BASED OVERLAY SCATTEROMETRY
Dossier Overview
Applicant
KLA Corporation
Inventor
Alon Alexander Volfman; Itay Gdor; Iftach Galon; David Koprivica; Yonatan Vaknin; Vladimir Levinski; Yaniv Weiss; Yuval Lubashevsky; Daria Negri; Mark Ghinovker
IPC Classification
CPC Classification
An overlay metrology system includes a controller communicatively coupled to a first photodetector and a second photodetector. The controller may be configured to receive one or more signals from the first and second photodetector as an overlay target is scanned. The overlay target may include a plurality of measurement cells, where each measurement cell includes a grating-over-grating structure including a first-layer grating feature on a first layer of a sample and a second-layer grating feature on a second layer of the sample in an overlapping region. The first-layer grating feature and the second-layer grating feature may have a common pitch. The controller may be further configured to determine one or more differential signals between the first photodetector and the second photodetector for each measurement cell of the plurality of measurement cells and determine an overlay measurement based on the determined one or more differential signals.
Original (Chinese)
An overlay metrology system includes a controller communicatively coupled to a first photodetector and a second photodetector. The controller may be configured to receive one or more signals from the first and second photodetector as an overlay target is scanned. The overlay target may include a plurality of measurement cells, where each measurement cell includes a grating-over-grating structure including a first-layer grating feature on a first layer of a sample and a second-layer grating feature on a second layer of the sample in an overlapping region. The first-layer grating feature and the second-layer grating feature may have a common pitch. The controller may be further configured to determine one or more differential signals between the first photodetector and the second photodetector for each measurement cell of the plurality of measurement cells and determine an overlay measurement based on the determined one or more differential signals.
External Resources