Three-dimensional memory device having ring-shaped etch-stop patterns interposed between lower and upper layer stacks

A semiconductor device comprising:

• a first stack including a plurality of alternating layers of first interlayer insulating layers and first conductive patterns;
• a second stack including a plurality of alternating layers of second conductive patterns and second interlayer insulating layers, the second stack being positioned above the first stack;
• a plurality of pillar-structures each pillar structure passing through the first and second stacks;
• and
• a ring pattern layer disposed between the first and second stacks, the ring pattern layer comprising a plurality of ring patterns, each ring pattern surrounding each pillar-structure, wherein the ring patterns directly contact a lowermost second conductive pattern among the second conductive patterns and directly contact an uppermost first interlayer insulating layer among the first interlayer insulating layers.