Metal via processing schemes with via critical dimension (cd) control for back end of line (beol) interconnects and the resulting structures

Abstract

Via CD control for BEOL interconnects is described. For example, a method of fabricating an interconnect structure includes forming a lower metallization layer comprising alternating metal lines and dielectric lines above a substrate. The method also includes forming an inter-layer dielectric layer above the metallization layer. The method also includes forming a first grating pattern above the inter-layer dielectric layer, orthogonal to the alternating metal lines and dielectric lines of the lower metallization layer. The method also includes forming a second grating pattern above the first grating pattern. The method also includes patterning the inter-layer dielectric layer using the first grating pattern and the second grating pattern to form via locations and line regions in the inter-layer dielectric layer. The method also includes forming metal vias and metal lines in the via locations and line regions, respectively, of the inter-layer dielectric layer.