COMPENSATING FOR COUPLING DURING PROGRAMMING

• US 20100067296A1
• Filed: 11/17/2009
• Published: 03/18/2010
• Est. Priority Date: 07/20/2006
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Li, Yan
• Granted Patent: US 8,284,606 B2
• Time in Patent Office: Days
• US Class Current: 365/185.30
• CPC Class Codes: G11C 16/3418 Disturbance prevention or evaluation; Refreshing of disturbed memory data
• CPC Class Codes: G11C 8/10 Decoders

Abstract

Shifts in the apparent charge stored on a floating gate (or other charge storing element) of a non-volatile memory cell can occur because of the coupling of an electric field based on the charge stored in adjacent floating gates (or other adjacent charge storing elements). To compensate for this coupling, the read or programming process for a given memory cell can take into account the programmed state of an adjacent memory cell. To determine whether compensation is needed, a process can be performed that includes sensing information about the programmed state of an adjacent memory cell (e.g., on an adjacent bit line or other location).

Claims

1. A method of programming non-volatile storage, comprising:

programming a first non-volatile storage element to store first data; and

programming a second non-volatile storage element to store second data, the programming of the first non-volatile storage element to store first data is configured in response to the second data.

2. The method of claim 1, wherein:

the programming of the first non-volatile storage element to store first data is configured by setting a verify level used during the programming of the first non-volatile storage element.

3. The method of claim 1, wherein:

the programming of the first non-volatile storage element to store first data is configured by setting a target of the programming of the first non-volatile storage element.

4. The method of claim 1, further comprising:

determining whether to compensate for the second non-volatile storage element when programming the first non-volatile storage element to store first data; and

configuring the programming of the first non-volatile storage element to store first data based on the determining.

5. The method of claim 1, wherein:

the second non-volatile storage element is adjacent to the first non-volatile storage element.

6. The method of claim 1, wherein:

the second non-volatile storage element is connected to the first non-volatile storage element.

7. The method of claim 1, wherein:

the programming of the first non-volatile storage element to store first data and the programming of the second non-volatile storage element to store second data are performed by applying a common programming signal to the first non-volatile storage element and the second non-volatile storage element.

8. The method of claim 1, further comprising:

programming a third non-volatile storage element to store third data, the programming of the first non-volatile storage element to store first data is configured in response to the second data and the third data.

9. The method of claim 8, wherein:

the first data corresponds to a lowest data state other than an erased data state; and

the second data and the third data correspond to a highest data state.

10. The method of claim 8, wherein:

the first non-volatile storage element is connected to the second non-volatile storage element and the third non-volatile storage element.

11. The method of claim 8, wherein:

the programming of the first non-volatile storage element to store first data, the programming of the second non-volatile storage element to store second data and the programming of the third non-volatile storage element to store third data are performed by applying a common programming signal to the first non-volatile storage element, the second non-volatile storage element, and the third non-volatile storage element.

12. The method of claim 8, wherein:

the first non-volatile storage element is adjacent to the second non-volatile storage element and the third non-volatile storage element.

13. The method of claim 8, wherein:

the programming of the first non-volatile storage element to store first data is configured by setting a first target of the programming of the first non-volatile storage element if neither the second non-volatile storage element nor the third non-volatile storage element need to be compensated for due to coupling, setting a second target of the programming of the first non-volatile storage element if both the second non-volatile storage element and the third non-volatile storage element need to be compensated for due to coupling, setting a third target of the programming of the first non-volatile storage element if only one of the second non-volatile storage element and the third non-volatile storage element need to be compensated for due to coupling.

14. A non-volatile storage system, comprising:

a plurality of non-volatile storage elements, the plurality of non-volatile storage elements include a first non-volatile storage element and a second non-volatile storage element; and

one or more circuits that program the non-volatile storage elements, the one or more circuits program the first non-volatile storage element to store first data and program the second non-volatile storage element to store second data, the programming of the first non-volatile storage element to store first data is based on the first data and the second data.

15. The non-volatile storage system of claim 14, wherein:

a target for the programming of the first non-volatile storage element is based on the first data and the second data.

16. The non-volatile storage system of claim 14, wherein:

the second non-volatile storage element is adjacent to the first non-volatile storage element.

17. The non-volatile storage system of claim 14, wherein:

the second non-volatile storage element is connected to the first non-volatile storage element.

18. The non-volatile storage system of claim 14, wherein:

the plurality of non-volatile storage elements include a third non-volatile storage element;

the one or more circuits program the third non-volatile storage element to store third data; and

the programming of the first non-volatile storage element to store first data is based on the first data, the second data and the third data.

19. A method of programming non-volatile storage, comprising:

accessing first data to be stored into a first non-volatile storage element;

determining whether to adjust programming of the first data into the first non-volatile storage element based on second data to be programmed into a different non-volatile storage element; and

programming the first data into the first non-volatile storage element, the programming of the first data into the first non-volatile storage element includes an adjustment if the determining concluded that the programming of the first data into the first non-volatile storage element should be adjusted.

20. The method of claim 19, wherein:

the different non-volatile storage element is adjacent to and connected to the first non-volatile storage element.

21. The method of claim 20, further comprising:

programming the second data into the different non-volatile storage element, the programming the second data into the different non-volatile storage element overlaps in time with the programming of the first data into the first non-volatile storage element.

22. A non-volatile storage system, comprising:

a plurality of non-volatile storage elements, the plurality of non-volatile storage elements include a first non-volatile storage element and a second non-volatile storage element; and

one or more circuits that program the non-volatile storage elements including programming the first non-volatile storage element to store first data and programming the second non-volatile storage element to store second data, wherein the first non-volatile memory element is programmed with an adjustment calculated from the second data.

23. The non-volatile storage system of claim 22, wherein:

the adjustment is a change to the target of the programming of the first non-volatile storage element.

24. The non-volatile storage system of claim 22, wherein:

the second non-volatile storage element is adjacent to the first non-volatile storage element.

25. The non-volatile storage system of claim 22, wherein:

the second non-volatile storage element is connected to the first non-volatile storage element.

26. The non-volatile storage system of claim 22, wherein:

the plurality of non-volatile storage elements include a third non-volatile storage element;

the one or more circuits program the third non-volatile storage element to store third data; and

the first non-volatile memory element is programmed with the adjustment calculated from the second data and the third data.

27. A method of programming non-volatile storage, comprising:

(a) applying a predetermined dose of programming voltage to a group of non-volatile memory cells in parallel to increase a threshold voltage of each non-volatile memory cell under programming;

(b) sensing each non-volatile memory cell of the group in parallel to verify its memory state relative to a respective target state, the sensing determines the threshold voltage of each non-volatile memory cell relative to a predetermined verify level, the predetermined verify level being a function of the respective target state and the target states of one or more neighboring non-volatile memory cells; and

(c) inhibiting from further programming each non-volatile memory cell in the group that has been verified; and

repeating (a)-(c) until more non-volatile memory cells of the group have been verified to the respective target memory states.

28. The method of claim 27, wherein:

the predetermined verify level is function of the respective target state and the target states of two neighboring non-volatile memory cells.