Self-aligned metallurgy

Abstract

A method is provided for filling undesired sublithographic contact hole defects in a semiconductor structure caused by misalignment and undesirable overlap of metal line images over contact openings during photolithographic patterning. Unwanted contact between conductive metallization levels through these defects is thereby diminished. The method also provides self-alignment of the lines and contact holes for subsequent formation of stud via connections through which contact is desired to underlying metallization levels. Deposition of a conformal sacrificial material film fills the small, undesired sublithographic contact hole image formed and covers both mask surfaces through which the misaligned line image and contact opening were etched. Isotropic etching removes the conformal layer from all planar surfaces except those of the undesired sublithographic contact hole image. Translation into the underlying insulating layer results in the formation of only contact holes through which contact with underlying substrate metallization is desired. The method of the present invention may alternatively be practiced after the undesired sublithographic contact hole image is etched into the insulating layer to the underlying substrate metallization. Translation of sublithographic defects in a single mask layer overlying an insulating layer disposed over a substrate having metallization therein can also be avoided.