Patent ID: 7892903

Claim:
A device manufacturing method comprising: providing a substrate; providing a first layer of electromagnetic radiation sensitive material on said substrate; providing a second layer of electromagnetic radiation sensitive material on said first layer of radiation sensitive material, the first and second layers of electromagnetic radiation sensitive material having a same tonality, said second layer of radiation sensitive material being of a different material than said first layer of radiation sensitive material, said first layer of radiation sensitive material having a dose size of at least approximately 1.5 times the magnitude of a dose size of said second layer of radiation sensitive material; providing a beam of electromagnetic radiation using an illumination system; imparting said beam of radiation with a desired pattern in its cross-section by employing a patterning device; projecting said patterned beam of radiation onto a target portion of said substrate to expose both said first and second layers of radiation sensitive material; and developing said first and second layers of radiation sensitive material to remove portions which have been exposed, wherein said second layer overhangs said first layer after developing.