Shielded vertically stacked data line architecture for memory

• US 10,242,746 B2
• Filed: 08/14/2017
• Issued: 03/26/2019
• Est. Priority Date: 06/17/2013
• Status: Active Grant

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Sakui, Koji
• Primary Examiner(s): Luu, Pho M
• Application Number:
  US15/676,659
• Publication Number:
  US 20180122482A1
• Time in Patent Office: 589 Days
• CPC Class Codes: G11C 16/0483 comprising cells having several storage transistors connected in series
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/24 Bit-line control circuits
• CPC Class Codes: G11C 16/3427 Circuits or methods to prevent or reduce disturbance of the state of a memory cell when neighbouring cells are read or written
• CPC Class Codes: G11C 7/12 Bit line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, equalising circuits, for bit lines
• CPC Class Codes: G11C 7/18 Bit line organisation; Bit line lay-out

Abstract

Apparatuses and methods are disclosed, including an apparatus that includes first and second strings of vertically stacked memory cells, and first and second pluralities of vertically stacked data lines. A data line of the first plurality of data lines is coupled to the first string through a first select device. A data line of the second plurality of data lines is coupled to the second string through a second select device and is adjacent to the data line coupled to the first string. Such an apparatus can he configured to couple the data line coupled to the first string to a shield potential during at least a portion of a memory operation involving a memory cell of the second string.

Claims

1. A memory array, comprising:

multiple strings of vertically arranged memory cells, each memory cell including a respective charge storage device, each memory cell string extending between a source and a respective bit line of multiple bit lines, wherein each bit line extends in a first direction;

a first group of memory cell strings each selectively coupled to a first bit line through a respective select device in each memory cell string;

a second group of memory cell strings each selectively coupled to a second bit line through a respective select device in each memory cell string, wherein the second bit line is stacked above the first bit line, and wherein the first and second groups of memory cell strings are interleaved with one another in a second direction orthogonal to the first direction in which the first and second bit lines extend;

access lines coupled to respective memory cells in each of the first and second groups of memory cell strings, each access line configured to allow access to a respective memory cell in each of the first and second groups of memory cell strings to perform a memory operation involving such memory cell;

a memory controller configured to couple the first bit line to a shield potential during at least a portion of a memory operation involving a memory cell in a memory cell string coupled to the second bit line.

2. The memory array of claim 1, wherein memory cell strings of the first and second groups of memory cell strings alternate with one another in the second direction.

3. The memory array of claim 1, further comprising:

a third group of memory cell strings each selectively coupled to a third bit line through a respective select device in each memory cell string of the third group, wherein the third bit line is stacked above the second bit line; and

a fourth group of memory cell strings each selectively coupled to a fourth bit line through a respective select device in each memory cell string of the fourth group, wherein the fourth bit line is stacked above the third bit line; and

wherein the memory controller is further configured to couple the first and third bit lines to a shield potential during at least a portion of the memory operation involving a memory cell in a memory cell string coupled to the second bit line.

4. The memory array of claim 3, wherein the memory controller is further configured to apply a read voltage to the second bit line during a first interval in the performing of the memory operation, and to couple the first and third bit lines to a shield potential during at least a portion of the first interval.

5. The memory array of claim 3, wherein the controller is configured to couple the third data line coupled to the third string of memory cells to the shield potential during at least a portion of a second memory operation involving a memory cell of the fourth group of memory cell strings.

6. The memory array of claim 5, wherein the unselected bit lines are coupled to a ground potential.

7. The memory array of claim 3, wherein the second and fourth bit lines are selected during the memory operation, and wherein the first and third bit lines are unselected during the memory operation.

8. The memory array of claim 1, wherein the first bit line and the second bit line are selectively coupled to a common page buffer through first and second bit line transfer devices, respectively.

9. The memory array of claim 1, wherein the memory operation comprises sensing the memory cell of the second string.

10. The memory array of claim 1, wherein the memory operation comprises programming the memory cell of the second string.

11. A method of operating a memory array having multiple strings of memory cells, each string having multiple charge storage devices and extending between a source and a bit line, comprising:

applying a pass voltage to unselected access lines of multiple access lines coupled to respective memory cells in multiple strings of memory cells;

applying an operational voltage to a selected access line of the multiple access lines to enable particular memory cells in multiple strings of memory cells;

coupling a first bit line of multiple bit stacked bit lines to a shield voltage line during at least a portion of a memory operation, wherein a second bit line extends in a tier above the first bit line;

wherein strings of memory cells comprising the enabled memory cells are operably coupled to the second bit line during the memory operation, and wherein strings of memory cells that do not contain the enabled memory cells are operably coupled to the first bit line during at least a portion of the memory operation.

12. The method of claim 11, wherein the operational voltage is a sense voltage.

13. The method of claim 11, wherein the shield voltage line is at ground potential.

14. The method of claim 13, further comprising enabling select gate drain and select gate source transistors that are coupled to strings of memory cells comprising the enabled memory cells.

15. The method of claim 14, further comprising enabling storing data from selected memory cells in page buffers.

16. The method of claim 11, further comprising disabling select gate drain and select gate source transistors that are coupled to strings of memory cells that do not include the enabled memory cells.

17. The method of claim 11, wherein the operational voltage is a program voltage.

18. The method of claim 11, further comprising applying a ground voltage to the shield voltage line when the operational voltage is a sense voltage.

19. The method of claim 11, further comprising applying a positive voltage to the shield voltage line when the operational voltage is a program voltage.

20. A method of operating a memory array having multiple strings of memory cells, wherein each memory cell string includes multiple charge storage devices and extends between a source and a bit line, and wherein each memory cell string is coupled to a different bit line than each adjacent memory cell string, the method comprising:

applying a read voltage to a selected access line of multiple access lines, each access line coupled to a respective memory cell in each string of a first group of strings of memory cells;

applying a read pass voltage to unselected access lines of the multiple access lines;

applying a pre-charge voltage to a first group of bit lines during a memory operation;

applying a shield voltage to a second group of bit lines during at least a portion of the memory operation; and

applying an enable voltage to select gate drain transistors of a second group of memory cell strings comprising the enabled memory cells to couple the second group of memory cell strings to respective bit lines of the second group of bit lines during the memory operation.

21. The method of claim 20, wherein the first group of bit lines are coupled to respective first bit line shield transistors, and wherein the method further comprises applying a disable voltage to control gates of the first data line shield transistors such that the first group of data lines are not operably coupled to the shield voltage line.

22. The method of claim 21, wherein the second group of data lines are coupled to respective second bit line shield transistors, and wherein applying a shield voltage to the second group of bit lines comprises applying an enable voltage to control gates of the second data line shield transistors such that the second group of data lines are coupled to the shield voltage line.

23. The method of claim 21, further comprising applying an enable voltage to sense transistors that are coupled to the first group of data lines.