Imaging method using phase boundary masking with modified illumination

A method for imaging a linear feature extending along orthogonal first and second directions, said method comprising:

• providing a light source with decreased intensity portions at the center thereof and decreased along orthogonal axes arranged at about 45 degrees between the first and second orthogonal directions;
• providing a photomask with phase shift boundary patterns disposed closely spaced from each other for creating a dark region corresponding to the space between the closely spaced phase shift boundary regions.

An imaging system for producing fine lithographic features oriented along two orthogonal directions, comprising

• an illumination source having four separate localized areas having higher transmittance than portions of said illumination surrounding said areas and being arranged at locations corresponding to the two orientation axes of the lithographic features at a separation distance corresponding to the frequency of the fine pattern detail;
• a phase shifting mask comprising a transparent substrate with a plurality of relief boundaries closely spaced to each other on the transparent substrate, said relief boundaries spaced close enough so that individual relief boundaries are not imaged and a dark region corresponding to the space between closely paced relief boundaries is imaged.

A projection lithography system for forming finely spaced features on a sensitized surface of a comprising:

• means for generating pairs of illumination regions with each of a first pair disposed on opposite sides of a first axis and each of a second pair disposedon opposite sides of a second axis orthogonal to the first axis;
• and
• phase shift means disposed on a translucent substrate in the path of illumination from said illumination regions and closely spaced apart a distance to define a relatively dark line corresponding to the space between the phase shift means.

A projection lithography system comprising:

• a quadrupole illumination system with four poles placed on axial positions for off-axis illumination of X and Y oriented mask geometry for providing off-axis illumination angles in the same manner as a dipole and equivalent diffraction energy distribution results;
• and
• a phase shift boundary mask comprising two fine phase shift feature boundaries disposed in close proximity to each other for imaging a dark space on a photosensitized surface of a wafer, said dark space corresponding to the region between the phase shift masking boundaries.

A boundary phase shift photomask comprising;

• a transparent substrate for receiving radiation at a chosen wave length;
• a relief pattern defined on the transparent substrate and comprising one or more pairs of closely spaced phase shift boundaries wherein the boundaries are parallel to each other and the boundaries are spaced closely adjacent each other in accordance with the chosen wave length of the radiation for forming a relatively dark region in a focal plane corresponding to the space between the closely spaced phase shift boundary regions.