Three-dimensional memory devices with architecture of increased number of bit lines
Embodiments of a three-dimensional (3D) memory device are disclosed. The 3D memory device has an architecture with an increased number of bit lines. In an example, the 3D memory device includes a substrate, a plurality of memory strings each extending vertically above the substrate in a memory region, and a plurality of bit lines over the plurality of memory strings. At least one of the plurality of bit lines is electrically connected to a single one of the plurality of memory strings.
1. A three-dimensional (3D) memory device, comprising:
a substrate;
a plurality of memory strings each extending vertically above the substrate in a memory region; and
a plurality of bit lines over the plurality of memory strings, wherein at least one of the plurality of bit lines is electrically connected to a single one of the plurality of memory strings, wherein the plurality of memory strings are arranged in an array extending along a first lateral direction and a second lateral direction in the memory region, the first lateral direction being perpendicular to the second lateral direction, wherein the plurality of bit lines are arranged along the first direction and extend along the second lateral direction, being parallel with one another, and in a plan view, a number of bit lines arranged in a channel pitch along the first lateral direction is at least six.
2. The 3D memory device of claim 1 , wherein each one of the plurality of memory strings is electrically connected to a single different one of the plurality of bit lines.
3. The 3D memory device of claim 2 , further comprising at least one slit structure extending laterally along a boundary of the memory region.
4. The 3D memory device of claim 1 , wherein
in the plan view, the number of bit lines arranged in the channel pitch along the first lateral direction is equal to a number of memory strings electrically connected to the bit lines along the second lateral direction.
5. The 3D memory device of claim 1 , wherein
the array is arranged between two slit structures each laterally extending along the first direction; and
in the plan view, the number of bit lines arranged in the channel pitch is equal to the number of memory strings in the channel pitch and between the two slit structures.
6. The 3D memory device of claim 5 , wherein in the plan view, the bit lines in the channel pitch are evenly spaced, a bit line pitch along the first lateral direction being nominally equal to 1/N of the channel pitch, N being equal to the number of bit lines in the channel pitch.
7. The 3D memory device of claim 1 , wherein N is a positive even integer.
8. The 3D memory device of claim 1 , wherein the plurality of memory strings each comprises a channel structure and a drain over the channel structure, the drain being electrically connected to a respective bit line.
9. The 3D memory device of claim 1 , further comprising a plurality of interleaved conductor layers and insulating layers extending laterally and intersecting with the plurality of memory strings, wherein
in the plan view, no cut structure overlaps with the plurality of memory strings in the memory region, the memory region being a finger; and
a first conductor layer extends continuously along a direction it extends in the memory region.
10. A three-dimensional (3D) memory device, comprising:
a substrate;
a plurality of memory strings extending along a first lateral direction and a second lateral direction in a plan view, each of the plurality of memory strings extending vertically above the substrate in a memory region;
a plurality of bit lines extending along the second lateral direction over the plurality of memory strings, the plurality of bit lines being nominally parallel to one another; and
a cut structure overlapping with at least one of the plurality of memory strings in the plan view and dividing the plurality of memory strings into a first portion and a second portion along the second lateral direction, wherein a number of bit lines above each of the plurality of memory strings is three, wherein each of the plurality of memory strings is contacted by a corresponding bit line of the plurality of bit lines above the corresponding memory string.
11. The 3D memory device of claim 10 , wherein
the first portion and the second portion of the plurality of memory strings comprises a same number of string rows along the second lateral direction and a same number of string columns along the first lateral direction; and
each one of the plurality of bit lines is electrically connected to one memory string in the first portion and another memory string in the second portion.
12. The 3D memory device of claim 11 , wherein
the plurality of memory strings are arranged in an array extending along the first lateral direction and the second lateral direction; and
each of the first portion and the second portion of the plurality of memory strings comprises an even number of string rows along the second lateral direction.
13. The 3D memory device of claim 12 , wherein in the plan view,
each of the first portion and the second portion includes N string rows along the second lateral direction;
a channel pitch includes N bit lines arranged along the first lateral direction; and
a bit line pitch is nominally 1/N of the channel pitch along the first lateral direction, N being equal to at least 6.
14. The 3D memory device of claim 13 , wherein N is a positive even integer.
15. The 3D memory device of claim 10 , wherein each memory string of the plurality of memory strings comprises a channel structure and a drain over the channel structure, the drain being electrically connected to the corresponding bit line.
16. A three-dimensional (3D) memory system, comprising:
a memory stack comprising a plurality of interleaved conductor layers and insulating layers in an insulating structure over a substrate;
a plurality of memory strings extending in the memory stack along a first lateral direction and a second lateral direction of a memory region in a plan view, each of the plurality of memory strings extending vertically into the substrate;
a plurality of bit lines over and electrically connected to the plurality of memory strings, wherein at least one of the plurality of bit lines is electrically connected to a single one of the plurality of memory strings; and
a plurality of peripheral devices electrically connected to the plurality of memory strings, wherein the plurality of memory strings are arranged in an array extending along a first lateral direction and a second lateral direction in the memory region, the first lateral direction being perpendicular to the second lateral direction, wherein the plurality of bit lines are arranged along the first direction and extend along the second lateral direction, being parallel with one another, and in a plan view, a number of bit lines arranged in a channel pitch along the first lateral direction is at least six.
17. The 3D memory system of claim 16 , wherein each one of the plurality of memory strings is electrically connected to a single different one of the plurality of bit lines.
18. The 3D memory system of claim 17 , further comprising at least one slit structure laterally extending along a boundary of the memory region.
19. The 3D memory system of claim 18 , wherein
in the plan view, no cut structure overlaps with the plurality of memory strings in the memory region, the memory region being a finger; and
a first conductor layer extends continuously along a direction it extends in the memory region.
20. The 3D memory device of claim 16 , wherein the plurality of memory strings each comprises a channel structure and a drain over the channel structure, the drain being electrically connected to a respective bit line.