Patent attributes
An overlay mark for determining the relative shift between two or more successive layers of a substrate and methods for using such overlay mark are disclosed. In one embodiment, the overlay mark includes at least one test pattern for determining the relative shift between a first and a second layer of the substrate in a first direction. The test pattern includes a first set of working zones and a second set of working zones. The first set of working zones are disposed on a first layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The second set of working zones are disposed on a second layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The first set of working zones are generally angled relative to the second set of working zones thus forming an “X” shaped test pattern.
