Patent ID: 11880141
Assignee: KLA CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC G  H | IPC G

Claim 14:
15. A system for measuring misregistration in the manufacture of semiconductor device wafers, the system comprising:
an imager configured to image at least a first layer and a second layer of a multilayered semiconductor device wafer comprising at least one misregistration measurement target comprising a first periodic structure formed together with said first layer having a first pitch and a second periodic structure formed together with said second layer having a second pitch, said imager operating at a depth of focus and using light having at least one first wavelength that causes images of both said first layer and said second layer to appear in at least one plane within said depth of focus, wherein said first layer and said second layer are mutually separated by a perpendicular distance which is greater than said depth of focus, and wherein the light is infrared radiation; and
an offset quantifier configured to measure offsets in said at least one plane between said images of said first layer and said second layer, thereby to calculate misregistration.