Three-dimensional memory devices with lateral block isolation structures and methods of forming the same
AssigneeSanDisk Technologies LLC
InventorAkihiro TOBIOKA
Life of this patent
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Abstract
A memory device includes an alternating stack of insulating layers and composite layers that alternate along a vertical direction, where each of the composite layers includes a combination of a dielectric connection plate and a plurality of electrically conductive strips that are laterally spaced apart by backside trench isolation structures, arrays of memory openings vertically extending through the alternating stack, memory opening fill structures located in the memory openings, and dielectric isolation structures adjoined to an end portion of a respective one of the backside trench fill structures.
Claims20
A memory device, comprising:
- an alternating stack of insulating layers and composite layers that alternate along a vertical direction, wherein each of the composite layers comprises a combination of a dielectric connection plate and a plurality of electrically conductive strips that laterally extend along a first horizontal direction and are laterally spaced apart along a second horizontal direction by backside trench fill structures that laterally extend along the first horizontal direction;
- arrays of memory openings vertically extending through the alternating stack;
- memory opening fill structures located in the memory openings and comprising a respective vertical semiconductor channel and a respective vertical stack of memory elements located at levels of the electrically conductive strips in the alternating stack;
- and
- dielectric isolation structures that vertically extend through each of the insulating layers and the composite layers within the alternating stack and are adjoined to an end portion of a respective one of the backside trench fill structures.
A method of forming a semiconductor structure, comprising:
- forming an alternating stack of insulating layers and sacrificial material layers comprising a dielectric material over a substrate;
- forming dielectric isolation structures vertically extending through the alternating stack;
- forming backside trenches through the alternating stack, wherein each of the backside trenches laterally extends along a first horizontal direction and has a trench width along a second horizontal direction, and each of the dielectric isolation structures comprises a sidewall that is exposed to a respective one of the backside trenches;
- and
- replacing portions of the sacrificial material layers that are proximal to the backside trenches with electrically conductive strips and with vertical stacks of electrically conductive plates, wherein each of the vertical stacks of electrically conductive plates is exposed to an end portion of a respective one of the backside trenches, has a greater lateral extent along the second horizontal direction than the trench width, and is electrically isolated from each neighboring electrically conductive strip within the alternating stack by a respective subset of the dielectric isolation structures.
Dependencies are inferred from the claim text.