Patent ID: 9429856
Filing Date: 2016-08-30
CPC Classification: G01B,G03F,G06K,G06T,H01L

Claim Text:
1. A semiconductor device, the semiconductor device including an overlay measurement target, the overlay measurement target comprising: a first ring target located on a first measured layer of the semiconductor device, the first ring target including a plurality of detectable features arranged in a circular manner having a first circumference; and a second ring target located on a second measured layer of the semiconductor device, the second ring target including a plurality of detectable features arranged in a circular manner having a second circumference different from the first circumference, wherein a center of the first ring target is detectable by: wherein a center of the second ring target is detectable by: wherein a displacement between the center of the first ring target and the center of the second ring target indicates an overlay error between the first measured layer and the second measured layer.