Three-dimensional memory devices with lateral block isolation structures and methods of forming the same

Abstract

A three-dimensional memory device includes alternating stacks of insulating strips and electrically conductive strips, backside trenches located between neighboring pairs of alternating stacks, memory openings vertically extending through the alternating stacks, and memory opening fill structures located within the memory openings. In some embodiments, dielectric etch stop structures may be located within or outside the backside trenches such that each of the dielectric etch stop structures includes a respective pair of dielectric sidewalls that are located within a pair of lengthwise sidewalls of the respective one of the backside trenches. In some other embodiments, a dielectric isolation structure can laterally contact each of the insulating strips within the alternating stacks. Laterally insulated contact via structures can be provided to provide electrical contact to a respective one of the electrically conductive strips.