Patent ID: 7525671

Claim:
A method for determining a relative position of a third mark provided on a workpiece, the method comprising: detecting a first mark on said workpiece; detecting a first set of marks on said workpiece; detecting a second mark on said workpiece; detecting a second set of marks on said workpiece; measuring a first list of relative distance(s) between said first mark and mark(s) in said first set of marks; measuring a second list of relative distance(s) between said second mark and mark(s) in said second set of marks, said second set of marks including at least said first mark; determining the relative position of the third mark, said third mark being included in both said first set of marks and said second set of marks; wherein said determining of the relative position of said third mark is performed by using information from said first list of relative distance(s) measured between said first mark and mark(s) in said first set of marks and information from at least said second list of relative distance(s) measured between said second mark and mark(s) in said second set of marks.