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

Claim 20:
21. A system for measuring misregistration in the manufacture of semiconductor device wafers having a multilayered semiconductor device wafer comprising at least a first layer and a second layer 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 at least first layer and second layer being mutually separated by a perpendicular distance of greater than 2 μm, the system comprising;
at least one imager configured to image said first layer and said second layer at at least one 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.