Lithographic apparatus, substrate and device manufacturing method

摘要

A method uses a lithographic apparatus to form an inspection target structure upon a substrate. The method comprises forming the periphery of the inspection target structure so as to provide a progressive optical contrast transition between the inspection target structure and its surrounding environment. This may be achieved by providing a progressive change in the optical index at the periphery of the target structure.

主权项

1. A method comprising:
illuminating a target structure using a spot size that is larger than the target structure, wherein the target structure includes a progressive optical contrast transition at peripheral edges of the target structure; and measuring a diffraction pattern of the target structure, wherein a diffraction effect at the peripheral edges of the target structure is substantially reduced by the progressive optical contrast transition.