A method for implementing alignment of a semiconductor device structure
includes forming first and second sets of alignment marks within a lower
level of the structure, the second set of alignment marks adjacent the
first set of alignment marks. An opaque layer is formed over the lower
level, including the first and second sets of alignment marks. A portion
of the opaque layer corresponding to the location of said first set of
alignment marks is opened so as to render the first set optically visible
while the second set of alignment marks initially remains covered by the
opaque layer. The opaque layer is patterned using the optically visible
first set of alignment marks, wherein the second set of alignment marks
remain available for subsequent alignment operations in the event the
first set becomes damaged during patterning of the opaque layer.