Multiheight contact via structures for a multilevel interconnect structure

摘要

A recessed region can be formed on a semiconductor substrate, and peripheral semiconductor devices can be formed on a recessed horizontal surface of the semiconductor substrate. An alternating stack of insulating layers and sacrificial material layers are formed over the semiconductor substrate, and memory stack structures are formed therethrough. Contact openings extending to sacrificial material layers located at different depths can be formed by sequentially exposing a greater number of openings in a mask layer by iterative alternation of trimming of a slimming layer over the mask layer and an anisotropic etch that recesses pre-existing contact openings by one level. Electrically conductive via structures extending to electrically conductive electrodes located at different level can be provided with self-aligned insulating liners.

主权项

1. A three-dimensional memory device comprising:
a first alternating stack of insulating layers and electrically conductive layers located over a substrate; memory stack structures extending through the alternating stack, each of the memory stack structures comprising a memory film and a vertical semiconductor channel extending substantially perpendicular to a top surface of the substrate and laterally surrounded by the memory film; an array of contact via structures located within the alternating stack and laterally spaced apart along a first horizontal direction and having different heights; and a peripheral semiconductor device located in a peripheral region on the substrate; wherein: each contact via structure within the array of contact via structures is laterally surrounded by a respective insulating liner; top surfaces of the plurality of contact via structures are located within a same horizontal plane; a bottom portion of each of the plurality of contact via structures is adjoined to a respective electrically conductive layer; and each contact via structure that passes through a topmost electrically conductive layer is laterally surrounded by each electrically conductive layer that overlies the respective electrically conductive layer to which the contact via structure is adjoined.