Stairless three-dimensional memory device and method of making the same by forming replacement word lines

Abstract

An alternating stack of insulating layers and sacrificial material layers is formed over a substrate, memory openings are formed through the alternating stack, and memory opening fill structures including a respective vertical stack of memory elements are formed in the memory openings. The sacrificial material layers are replaced with electrically conductive layers. Electrical contacts to the electrically conductive layers may be provided by forming integrated layer-and-via structures that simultaneously forms metallic via portions as an integral portion of a continuous electrically conductive structure that includes a respective electrically conductive layer. Alternatively, electrical contacts to the electrically conductive layers may be provided by forming integrated line-and-via structures that includes a metallic plate portion contacting a respective electrically conductive layer and a metallic via portion.