Three-dimensional memory device containing horizontal and vertical word line interconnections and methods of forming the same

Abstract

A method of forming a three-dimensional memory device includes forming a vertically alternating sequence of insulating layers and spacer material layers over a substrate, where the spacer material layers are formed as, or are subsequently replaced with, electrically conductive layers, forming multiple sets of stepped surfaces in terrace regions of the vertically alternating sequence, forming memory stack structures through memory array regions of the vertically alternating sequence, and forming a metal interconnect structure which electrically connects a portion of a topmost electrically conductive layer in the first memory array region and a portion of a topmost electrically conductive layer in the second memory array region, and which extends above a horizontal plane of the topmost electrically conductive layer in the first memory array region and a portion of a topmost electrically conductive layer in the second memory array region.