Patent ID: 8216939

Claim:
A method of forming openings to a plurality of conductive structures, comprising: forming a material over a plurality of electrically conductive structures that are elongated along a first direction, the first direction being parallel to a first axis; forming a first patterned mask over the material, the first patterned mask comprising a plurality of rings that are elongated along a second direction; individual rings comprising a pair of long sides extending primarily along the second direction, and a pair of short sides that join the long sides to one another; the second direction being parallel to a second axis which intersects the first axis; forming a second patterned mask over the first patterned mask; the second patterned mask covering a first region of the first patterned mask, and leaving a second region of the first patterned mask exposed; the first and second patterned masks together defining a plurality of openings over the material; and transferring said openings into the material to form openings to the electrically conductive structures.