METHOD TO PRINT CONTACT HOLES AT HIGH RESOLUTION

摘要

A two-dimensional dense array of contact holes can be printed on a negative photoresist employing a combination of a quadrupole illumination lens and a lithographic mask including a criss-cross pattern of opaque lines. The openings in the quadrupole illumination lens are aligned along the perpendicular directions of the opaque lines. Discrete contact holes can be printed on a negative photoresist employing a combination of a quadrupole illumination lens and a lithographic mask including a criss-cross pattern of opaque subresolution assist features and discrete opaque cross patterns. Alternately, a two-dimensional array of contact holes can be printed on a negative photoresist employing a quadrupole illumination lens and a checkerboard pattern of openings. The openings in the quadrupole illumination lens are in diagonal directions.

主权项

1. A method for printing a plurality of contact holes in a photoresist, said method comprising:
providing a reticle including a transparent substrate and a patterned opaque material layer thereupon, said patterned opaque material layer comprising a criss-cross grid of intersections of a set of first parallel opaque lines and a set of second parallel opaque lines; loading said reticle in a lithographic exposure tool; loading a substrate with a negative photoresist layer thereupon into said lithographic exposure tool; and lithographically exposing and developing said negative photoresist layer, wherein an array of holes is formed in areas of said lithographically exposed and developed negative photoresist layer that correspond to intersections of said set of first parallel opaque lines and said set of second parallel opaque lines.