公开(公告)号：US11175592B2

公开(公告)日：2021-11-16

申请号：US16656094

申请日：2019-10-17

Applicant: ASML Netherlands B. V.

Inventor： Elie Badr ,  Shawn Shakahwat Millat ,  Giacomo Miceli ,  Alok Verma

IPC: G03F7/20

Abstract: A method for determining an overlay metric is disclosed including obtaining angle resolved distribution spectrum data relating to a measurement of a target structure including a symmetrical component. An overlay dependent contour of a feature of the target structure is determined from the angle resolved distribution spectrum data, from which an overlay metric is determined. The method includes exposing an exposed feature onto a masked layer including a mask which defines masked and unmasked areas of the layer, such that a first portion of the exposed feature is exposed on a masked area of the layer and a second portion of the exposed feature is exposed on a non-masked area of the layer, the size of the first portion with respect to the second portion being overlay dependent; and performing an etch step to define an etched feature, the etched feature corresponding to the second portion of the exposed feature.