Patent ID: 6838216

Claim:
A photolithographic mask for exposing a radiation-sensitive resist layer on a semiconductor substrate, comprising: a transparent carrier material; and a layer opaque to radiation disposed on said transparent carrier material; said layer opaque to radiation having a number of openings each with a square structure formed therein and forming a first pattern, said openings configured to be transferred into a resist layer during an exposure; and said layer opaque to radiation further having a further number of auxiliary openings formed therein and forming a second pattern, each of said auxiliary openings being assigned to a respective one of said openings and: having a cross section with a width below a limiting dimension to prevent said second pattern from being transferred to the resist layer during the exposure, being disposed at a distance from the respective one of said openings, said distance: being greater than a resolution limit of a projection apparatus used for the exposure based on a wafer scale, being less than a coherence length of light used in the projection apparatus, and producing a phase difference between 160 degrees and 200 degrees with respect to radiation passing through the respective one of said openings; said first pattern and said second pattern being a regular pattern; and said auxiliary openings having a length exceeding the resolution limit, a width exceeding the limiting dimension for the structure formation on the wafer, and an identical longitudinal alignment.