An overlay mark for determining the relative shift between two or more
successive layers of a substrate via scanning is disclosed. 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.