Three-dimensional memory device including self-aligned dielectric isolation regions for connection via structures and method of making the same

Abstract

A vertically alternating sequence of continuous insulating layers and continuous sacrificial material layers is formed over a substrate. Memory stack structures are formed through the vertically alternating sequence. The vertically alternating sequence is divided into alternating stacks of insulating layers and sacrificial material layers by forming backside trenches therethrough. Each neighboring pair of alternating stacks is laterally spaced apart from each other by a respective backside trench. The sacrificial material layers are replaced with multipart layers. Each multipart layer includes a respective electrically conductive layer that laterally extends continuously between a respective neighboring pair of backside trenches and at least one dielectric material plate that is a remaining portion of a sacrificial material layer, is laterally enclosed by the respective electrically conductive layer, and is laterally spaced from a most proximal one of the backside trenches by a uniform lateral offset distance.