Flash memory devices and programming methods for the same

• US 7,539,063 B2
• Filed: 01/10/2007
• Issued: 05/26/2009
• Est. Priority Date: 09/15/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lim, Young-Ho, Kang, Sang-Gu
• Primary Examiner(s): Dinh; Son
• Assistant Examiner(s): NGUYEN, NAM THANH
• Application Number:
  US11/651,521
• Publication Number:
  US 20080068883A1
• Time in Patent Office: 867 Days
• Field of Search: 365/185.22, 365/185.33, 365/189.011, 365/189.04
• US Class Current: 365/185.22
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits

Abstract

Flash memory devices and methods of programming the same are provided. The flash memory devices include a plurality of memory cells storing multi-bit data representing at least one of first through fourth states and including most significant bits and least significant bits. The method includes programming the plural memory cells into a provisional state according to the least significant bit, and programming the plurality of memory cells into the second through fourth states from the first and provisional states according to the most significant bit. Programming the plurality of memory cells into the second through fourth states includes simultaneously programming the plurality of memory cells at least partially into at least two states during one programming operation period.

Claims

1. A method of programming a flash memory device, comprising:

programming a plurality of memory cells into a provisional state, in accordance with a first page data; and

programming the plurality of memory cells into second through fourth states from a first state or the provisional state, in accordance with a second page data,

wherein programming the plurality of memory cells into the second through fourth states includes an operation of simultaneously programming the plurality of memory cells partially or entirely into at least two states, during one programming operation period.

2. The method as set forth in claim 1, wherein a verify-read voltage for programming the plurality of memory cells into the provisional state is higher than a verify-read voltage corresponding to the second state and lower than a verify-read voltage corresponding to the third state.

3. The method as set forth in claim 2, wherein programming the plurality of memory cells into the second through fourth states is carried out with comprising:

a first programming stage programming the memory cells into one of the second through fourth states from the first or provisional state; and

a second programming stage simultaneously programming the memory cells from the first or provisional state into the rest two states that are excluded from the first programming stage, during said one programming operation period.

4. The method as set forth in claim 3, wherein the first programming stage is provided to program the memory cells which have been programmed into the provisional state, into the fourth state in accordance with the second page data.

5. The method as set forth in claim 4, wherein during the second programming stage, the memory cells excluded from the first programming stage are simultaneously programmed into the second state from the first state, in accordance with the second page data, and into the third state from the provisional state.

6. The method as set forth in claim 5, wherein the first, second, third, and fourth states correspond to ‘

11’

, ‘

01’

, ‘

10’

, and ‘

00’

, respectively, and the provisional state correspond to a provisional ′

10″

higher than the second state but lower than the third state.

7. The method as set forth in claim 6, wherein the second programming state is carried out with including a program loop conducting two times of verify-read operations for verifying whether the memory cells have been programmed into the second and third states.

8. The method as set forth in claim 1, wherein said one programming operation period is a program cycle for which 1-bit data is written in an incremental step pulse programming (ISPP) mode.

9. A method of programming a flash memory device, comprising:

programming a plurality of memory cells into a provisional state, in accordance with a first page data; and

programming the plurality of memory cells into second through fourth states from a first or provisional state, in accordance with one of different programming modes, in response to information of option for selecting a mode of programming a second page data.

10. The method as set forth in claim 9, wherein programming the plurality of memory cells into the second through fourth states comprises, when a first program mode is selected from the different programming modes in accordance with the information of option, a step of programming the plurality of memory cells from the first or provisional state into the second, third, or fourth state in accordance with the second page data, the plurality of memory cells being simultaneously programmed into at least two states during one programming operation period.

11. The method as set forth in claim 10, wherein the first programming mode comprises:

a first programming stage programming the memory cells into one of the second through fourth states from the first or provisional state; and

a second programming stage programming the memory cells from the first or provisional state into the rest two states that are excluded from the first programming stage, during the same programming operation period.

12. The method as set forth in claim 11, wherein the memory cells, which have been programmed into the provisional state with the first page data, are partially or entirely programmed into the fourth state in accordance with the second page data during the first programming stage.

13. The method as set forth in claim 12, wherein during the second programming stage, the memory cells excluded from the first programming stage are simultaneously programmed into the first state from the second state, in accordance with the second page data, and into the third state from the provisional state.

14. The method as set forth in claim 13, wherein the first, second, third, and fourth states correspond to ‘

11’

, ‘

01’

, ‘

10’

, and ‘

00’

, respectively, and the provisional state correspond to a provisional ‘

10’

higher than the second state but lower than the third state.

15. The method as set forth in claim 13, wherein said one programming operation period is a program cycle for which 1-bit data is written in an incremental step pulse programming (ISPP) mode.

16. The method as set forth in claim 15, wherein the second programming state is carried out with including a program loop conducting two times of verify-read operations for verifying whether the memory cells have been programmed into the second and third states.

17. The method as set forth in claim 9, wherein programming the plurality of memory cells into the second through fourth states comprises, when a second program mode is selected from the different programming modes in accordance with the information of option, steps of programming the plurality of memory cells from the first or provisional state into one of the second through fourth states in accordance with the second page data, each step programming the plurality of memory cells into one state during said one programming operation period.

18. The method as set forth in claim 17, wherein the second programming mode comprises:

a first programming stage programming selected memory cells into the fourth state from the provisional state in response to the second page data;

a second programming stage programming selected memory cells into the third state from the provisional state in response to the second page data; and

a third programming stage programming selected memory cells into the second state from the first state in response to the second page data.

19. The method as set forth in claim 18, wherein the first, second, third, and fourth states correspond to ‘

11’

, ‘

01’

, ‘

10’

, and ‘

00’

, respectively, and the provisional state correspond to a provisional ‘

10’

higher than the second state but lower than the third state.

20. A flash memory device comprising:

a cell array having a plurality of memory cells storing multi-bit data that represents at least one of first through fourth states and includes a most and a least significant bits;

a voltage generator configured to generate and provide a program voltage and verify-read voltages to a word line of memory cells selected from the plurality of memory cells;

a page buffer coupled to bit lines respective to the plurality of memory cells, writing the multi-bit data into the selected memory cells and conducting verify-read and read operations;

a program controller regulating the page buffer and the voltage controller to program the most significant bits into the plurality of memory cells in response to information of option; and

an option selector configured to select one of first and second options in a programming mode with the most significant bit, generating the information of option.

21. The flash memory device as set forth in claim 20, wherein the program controller, when the information of option is generated in correspondence with the first option, regulates the page buffer and the voltage generator to program the plurality of memory cells into two states during one programming cycle, while programming the most significant bit.

22. The flash memory device as set forth in claim 21, wherein the program controller regulates the page buffer and the voltage generator to program the plurality of memory cells into the second through fourth states from the first or provisional state in response to the most significant bit, the plurality of memory cells being programmed into at least two states during said one programming cycle.

23. The flash memory device as set forth in claim 22, wherein the program controller conducts a first programming state to program the memory cells from the first or provisional state into one of the second through fourth stages and during said one program cycle, a second programming stage to program the memory cells from the first or provisional state into the rest two states excluded from the first programming stage.

24. The flash memory device as set forth in claim 23, wherein the program controller operates to program the memory cells, which have been programmed into the provisional state during the first programming stage, into the fourth state in response to the most significant bit.

25. The flash memory device as set forth in claim 24, wherein during the second programming stage, the program controller operates to simultaneously program the memory cells, which are excluded from the first programming stage, into the second state from the first state, in response to the most significant bit, and into the third state from the provisional state.

26. The flash memory device as set forth in claim 25, wherein the first, second, third, and fourth states correspond to ‘

11’

, ‘

01’

, ‘

10’

, and ‘

00’

, respectively, and the provisional state correspond to a provisional ‘

10’

higher than the second state but lower than the third state.

27. The flash memory device as set forth in claim 25, wherein the program controller regulates the voltage generator and the page buffer to conduct two times of verilty-read operations for verifying whether the memory cells have been programmed into the second and third states in one program loop during the second programming stage.

28. The flash memory device as set forth in claim 20, wherein the program controller, when the information of option is generated in correspondence with the second option, regulates the page buffer and the voltage generator to program the plurality of memory cells into one state during one programming cycle while programming the most significant bit.

29. The flash memory device as set forth in claim 28, wherein the program controller operates to program selected memory cells:

into the fourth state from the provisional state in response to the most significant bit;

into the third state from the provisional state in response to the most significant bit; and

into the second state from the first state in response to the most significant bit.

30. The flash memory device as set forth in claim 29, wherein the first, second, third, and fourth states correspond to ‘

11’

, ‘

01’

, ‘

10’

, and ‘

00’

, respectively, and the provisional state correspond to a provisional ‘

10’

higher than the second state but lower than the third state.

31. The flash memory device as set forth in claim 20, wherein the page buffer comprises:

a first latch storing data of programmed result for the least significant bit; and

a second latch storing the most significant bit to be programmed.