Three-dimensional memory device containing dummy stack edge seal structure and methods for forming the same

A semiconductor structure comprising a memory die, wherein the memory die comprises:

• first and second memory-region alternating stacks of memory-region insulating layers and electrically conductive layers that are laterally spaced apart from each other by a respective first portion of a retro-stepped dielectric structure overlying first stepped surfaces of the first and second memory-region alternating stacks;
• memory openings vertically-extending through the first and second memory-region alternating stacks;
• memory opening fill structures located in the memory openings and comprising a respective vertical semiconductor channel and a respective vertical stack of memory elements;
• a peripheral alternating stack of peripheral insulating layers and spacer material layers having a different composition from the electrically conductive layers, the peripheral alternating stack is laterally spaced from the second memory-region alternating stack by a second portion of the retro-stepped dielectric structure overlying second stepped surfaces of the second memory-region alternating stack;
• interconnect-level dielectric material layers embedding metal interconnect structures and overlying the first and second memory-region alternating stacks and the peripheral alternating stack;
• and
• at least one edge seal wall structure comprising a respective set of at least one metal wall structure and a respective subset of the metal interconnect structures, and which continuously extends from a bottommost layer within the peripheral alternating stack to a horizontal plane including a top surface of the interconnect-level dielectric material layers
• wherein:
• bottom surfaces of the first and second memory-region alternating stacks are spaced apart by a first lateral spacing distance;
• and
• bottom surfaces of the second memory alternating stack and the peripheral alternating stack are spaced apart by the first lateral spacing distance.