Adjusting resistance of non-volatile memory using dummy memory cells

1. A method for operating non-volatile storage, comprising:

determining information indicative of a resistance characteristic for a set of non-volatile storage elements, said set of non-volatile storage elements includes data non-volatile storage elements and dummy non-volatile storage elements;

programming said data non-volatile storage elements; and

setting one or more dummy non-volatile storage elements based on said determined information indicative of a resistance characteristic, said setting one or more dummy non-volatile storage elements includes setting a first dummy non-volatile storage element and a second dummy non-volatile storage element after completing programming of all data non-volatile storage elements.

2. A method according to claim 1 , wherein:

said information indicative of a resistance characteristic can include information absolute resistance, relative resistance, change in resistance, threshold voltage data that can be used to determine information about resistance, or stored data that can be used to determine information about resistance; and

said information indicative of a resistance characteristic can pertain to all of said data non-volatile storage elements or a subset of said data non-volatile storage elements.

3. A method according to claim 1 , wherein:

said setting one or more dummy non-volatile storage elements changes said resistance characteristic.

4. A method according to claim 1 , wherein:

said setting one or more dummy non-volatile storage elements changes a group resistance for said set of non-volatile storage elements.

5. A method according to claim 1 , wherein:

said determining information indicative of a resistance characteristic includes determining a deviation of programmed data from a predefined distribution of data.

6. A method according to claim 1 , wherein:

said setting one or more dummy non-volatile storage elements includes adjusting a threshold voltage for the first dummy non-volatile storage element to a threshold voltage range associated with a data state.

7. A method according to claim 1 , wherein:

said setting one or more dummy non-volatile storage elements includes adjusting a threshold voltage for the first dummy non-volatile storage element to an analog value.

8. A method according to claim 1 , wherein said determining information indicative of a resistance characteristic comprises:

determining deviation of change in resistance for at least a subset of said data non-volatile storage elements with respect to a predefined change, for a given data non-volatile storage element said change in resistance is based on pre and post programming of other data non-volatile storage elements;

identifying a minimum deviation based on said determining deviation;

identifying a maximum deviation based on said determining deviation; and

determining a condition for one or more of said dummy non-volatile storage elements that alter said minimum deviation and said maximum deviation in accordance with an error reduction criteria.

9. A method according to claim 8 , wherein:

said setting one or more dummy non-volatile storage elements includes adjusting resistance for said set of non-volatile storage elements by setting said one or more of said dummy non-volatile storage elements to said condition.

10. A method according to claim 8 , wherein:

said predefined change pertains to an even distribution of data.

11. A method according to claim 1 , wherein:

said programming includes verify operations, said verify operations uses a first overdrive voltage for unselected data non-volatile storage elements and a second overdrive voltage for dummy data non-volatile storage elements, said first overdrive voltage is higher than said second overdrive voltage;

said setting one or more dummy non-volatile storage elements includes adjusting threshold voltages for said setting one or more dummy non-volatile storage elements to be within a range of threshold voltages near charge-neutrality for said dummy non-volatile storage elements; and

said method includes reading said data non-volatile storage elements, said reading includes using said first overdrive voltage for unselected data non-volatile storage elements and said second overdrive voltage for dummy data non-volatile storage elements.

12. A method according to claim 1 , wherein:

said determining information indicative of a resistance characteristic includes physically measuring resistance information.

13. A method according to claim 1 , wherein:

said data non-volatile storage elements are multi-state flash memory devices.

14. A method according to claim 1 , wherein:

said set of non-volatile storage elements are part of a NAND string; and

said determining information indicative of resistance includes determining a deviation of programmed data from a predefined set of data.

15. A method for operating non-volatile storage, comprising:

determining information indicative of a resistance characteristic for a set of non-volatile storage elements, said set of non-volatile storage elements includes data non-volatile storage elements and dummy non-volatile storage elements;

programming said data non-volatile storage elements; and

setting one or more dummy non-volatile storage elements based on said determined information indicative of a resistance characteristic, said setting one or more dummy non-volatile storage elements includes setting a first dummy non-volatile storage element after completing programming of a first subset of data non-volatile storage elements and prior to completing programming of all data non-volatile storage elements, said setting one or more dummy non-volatile storage elements further includes setting a second dummy non-volatile storage element after completing programming of all data non-volatile storage elements.

16. A method according to claim 15 , wherein:

said setting one or more dummy non-volatile storage elements includes adjusting a threshold voltage for at least one of said dummy non-volatile storage elements.

17. A method for operating non-volatile storage, comprising:

determining information indicative of a resistance characteristic for a set of non-volatile storage elements, said set of non-volatile storage elements includes data non-volatile storage elements and dummy non-volatile storage elements;

programming said data non-volatile storage elements; and

setting one or more dummy non-volatile storage elements based on said determined information indicative of a resistance characteristic, said setting one or more dummy non-volatile storage elements includes setting a first dummy non-volatile storage element after completing programming of a first subset of data non-volatile storage elements and prior to completing programming of all data non-volatile storage elements, said setting one or more dummy non-volatile storage elements further includes setting a second dummy non-volatile storage element after completing programming of a second subset of data non-volatile storage elements and prior to completing programming of all data non-volatile storage elements.

18. A method according to claim 17 , wherein:

said determining information indicative of a resistance characteristic includes determining a deviation of programmed data from a predefined distribution of data.

19. A method according to claim 17 , wherein:

said setting one or more dummy non-volatile storage elements changes resistance for NAND strings that include said dummy non-volatile storage elements.

20. A method for operating non-volatile storage, comprising:

determining deviation of change in resistance for at least a subset of a set of data non-volatile storage elements with respect to a predefined change, said set of non-volatile storage elements includes data non-volatile storage elements and one or more dummy non-volatile storage elements, for a given data non-volatile storage element said change in resistance is based on pre and post programming of other data non-volatile storage elements;

identifying a minimum deviation based on said determining deviation;

identifying a maximum deviation based on said determining deviation; and

determining a condition for one or more of said dummy non-volatile storage elements that alter said minimum deviation and said maximum deviation in accordance with an error reduction criteria; and

altering resistance for said set of non-volatile storage elements by setting said one or more of said dummy non-volatile storage elements to said condition.

21. A method according to claim 20 , wherein:

said set of non-volatile storage elements are part of a NAND string; and

said altering resistance for said set of non-volatile storage elements includes altering resistance for said NAND string by changing threshold voltages for one or more of said dummy non-volatile storage elements.

22. A method for operating non-volatile storage, comprising:

determining information indicative of a resistance characteristic for a set of non-volatile storage elements, said set of non-volatile storage elements includes data non-volatile storage elements and dummy non-volatile storage elements;

programming said data non-volatile storage elements, said programming includes verify operations, said verify operations uses a first overdrive voltage for unselected data non-volatile storage elements and a second overdrive voltage for dummy data non-volatile storage elements, said first overdrive voltage is higher than said second overdrive voltage; and

setting one or more dummy non-volatile storage elements to a range of threshold voltages near charge-neutrality for said dummy non-volatile storage elements based on said determined resistance information.

23. A method according to claim 22 , wherein said method further comprises:

reading said data non-volatile storage elements, said reading includes using said first overdrive voltage for unselected data non-volatile storage elements and said second overdrive voltage for dummy data non-volatile storage elements.