KLA Corporation
METROLOGY METHODS AND OPTICAL SCHEMES FOR MEASUREMENT OF MISREGISTRATION BY USING HATCHED TARGET DESIGNS

Abstract:

A metrology system configured to measure overlay errors on a sample is disclosed. The metrology system measures overlay error on the sample in a first direction and/or a second direction simultaneously or sequentially. The metrology system comprises an illumination sub-system configured to illuminate a hatched overlay target on the sample with one or more illumination lobes. The metrology system further comprises an objective lens and a detector at an image plane configured to image the hatched overlay target. A controller is configured to direct illumination source to generate the illumination lobes, receive images of the hatched overlay target, and calculate the overlay errors between a first layer of the sample and a second layer of the sample.