Nonvolatile semiconductor memory device
A nonvolatile semiconductor memory device comprises a cell unit including a first and a second selection gate transistor and a memory string provided between the first and second selection gate transistors and composed of a plurality of serially connected electrically erasable programmable memory cells operative to store effective data; and a data write circuit operative to write data into the memory cell, wherein the number of program stages for at least one of memory cells on both ends of the memory string is lower than the number of program stages for other memory cells, and the data write circuit executes the first stage program to the memory cell having the number of program stages lower than the number of program stages for the other memory cells after the first stage program to the other memory cells.
1. A memory system comprising:
a nonvolatile semiconductor memory device; and
a controller device configured to control the nonvolatile semiconductor memory device,
the nonvolatile semiconductor memory device comprising:
a memory cell array including:
a first selection gate transistor,
a second selection gate transistor, and
a plurality of serially-connected memory cells provided between the first selection gate transistor and the second selection gate transistor,
the memory cells including:
a first memory cell connected with a first word line and capable of being programmed in one stage and storing data of one bit,
a second memory cell connected with a second word line and capable of being programmed in multi stages and storing data of three bits, the second memory cell being closer to the first selection gate transistor as compared with the first memory cell,
a third memory cell connected with a third word line and capable of being programmed in the multi stages and storing data of three bits, the third memory cell being closer to the first selection gate transistor as compared with the second memory cell, and
a fourth memory cell connected with a fourth word line and capable of being programmed in the multi stages and storing data of three bits, the fourth memory cell being closer to the first selection gate transistor as compared with the third memory cell,
the controller device causing the nonvolatile semiconductor memory device to:
perform a first program on the third memory cell as a non-final stage of the multi stages;
perform a second program on the fourth memory cell as a final stage of the multi stages, after the first program is performed;
perform a third program on the second memory cell as the non-final stage of the multi stages, after the second program is performed;
perform a fourth program on the third memory cell as the final stage of the multi stages, after the third program is performed;
perform a fifth program on the first memory cell as the one stage, after the fourth program is performed; and
perform a sixth program on the second memory cell as the final stage of the multi stages, after the fifth program is performed.
2. The system according to claim 1 , wherein
the memory cells further include:
a fifth memory cell connected with a fifth word line and capable of being programmed in the multi stages and storing data of three bits, the fifth memory cell being closer to the first selection gate transistor as compared with the fourth memory cell, and
the controller device further causes the nonvolatile semiconductor memory device to:
perform a seventh program on the fifth memory cell as the final stage of the multi stages, before the first program is performed; and
perform an eighth program on the fourth memory cell as the non-final stage of the multi stages, before the seventh program is performed.
3. The system according to claim 2 , wherein
the multi stages includes a first stage, a second stage, and a third stage, and
the non-final stage is the second stage, and the final stage is the third stage.
4. The system according to claim 3 , wherein:
the controller device further causes the nonvolatile semiconductor memory device to:
perform a ninth program on the third memory cell as the first stage of the multi stages, before the eighth program is performed; and
perform a tenth program on the second memory cell as the first stage of the multi stages, after the seventh program is performed and before the first program is performed.
5. The system according to claim 1 , wherein
the memory cell array further includes:
a first dummy cell having a structure same as one of the memory cells between the second selection gate transistor and the first memory cell, and
a second dummy cell having a structure same as one of the memory cells between the first selection gate transistor and the fourth memory cell.
6. The system according to claim 1 , wherein
the nonvolatile semiconductor memory device further includes:
a source line connected to a source of the first selection gate transistor, and
a bit line connected to a drain of the second selection gate transistor.
7. A memory system comprising:
a nonvolatile semiconductor memory device; and
a controller device configured to control the nonvolatile semiconductor memory device,
the nonvolatile semiconductor memory device comprising:
a memory cell array including:
a first selection gate transistor,
a second selection gate transistor, and
a plurality of serially-connected memory cells provided between the first selection gate transistor and the second selection gate transistor,
the memory cells including:
a first memory cell connected with a first word line and capable of being storing data of two bits,
a second memory cell connected with a second word line and capable of storing data of three bits, the second memory cell being closer to the first selection gate transistor as compared with the first memory cell,
a third memory cell connected with a third word line and capable of storing data of three bits, the third memory cell being closer to the first selection gate transistor as compared with the second memory cell,
a fourth memory cell connected with a fourth word line and capable of storing data of three bits, the fourth memory cell being closer to the first selection gate transistor as compared with the third memory cell, and
a fifth memory cell connected with a fifth word line and capable of storing data of three bits, the fifth memory cell being closer to the first selection gate transistor as compared with the fourth memory cell,
the controller device causing the nonvolatile semiconductor memory device to:
perform a first program on the fourth memory cell as a non-final one of stages for writing three bits;
perform a second program on the fifth memory cell as a final one of stages for writing three bits, after the first program is performed;
perform a third program on the third memory cell as the non-final one of stages for writing three bits, after the second program is performed;
perform a fourth program on the fourth memory cell as the final one of stages for writing three bits, after the third program is performed;
perform a fifth program on the second memory cell as the non-final one of stages for writing three bits, after the fourth program is performed;
perform a sixth program on the first memory cell as a final one of stages for writing two bits, after the fifth program is performed; and
perform a seventh program on the second memory cell as the final one of stages for writing three bits, after the sixth program is performed.
8. The system according to claim 7 , wherein:
the controller device further causes the nonvolatile semiconductor memory device to:
perform an eighth program on the first memory cell as a non-final one of stages for writing two bits, after the fourth program is performed and before the fifth program is performed.
9. The system according to claim 8 , wherein
the three bits are written in first to third stages, among which the third stage corresponds to the final one of stages, and the second stage corresponds to the non-final one of stages, and
the two bits are written in first and second stages, among which the second stage corresponds to the final one of stages, and the first stage corresponds to the non-final one of stages.
10. The system according to claim 9 , wherein:
the controller device further causes the nonvolatile semiconductor memory device to:
perform a ninth program on the third memory cell as the first stage for writing three bits, before the first program is performed; and
perform a tenth program on the second memory cell as the first stage for writing three bits, after the second program is performed and before the third program is performed.
11. The system according to claim 7 , wherein
the memory cell array further includes:
a first dummy cell having a structure same as one of the memory cells between the second selection gate transistor and the first memory cell, and
a second dummy cell having a structure same as one of the memory cells between the first selection gate transistor and the fifth memory cell.
12. The system according to claim 7 , wherein
the nonvolatile semiconductor memory device further includes:
a source line connected to a source of the first selection gate transistor, and
a bit line connected to a drain of the second selection gate transistor.
13. A memory system comprising:
a nonvolatile semiconductor memory device; and
a controller device configured to control the nonvolatile semiconductor memory device,
the nonvolatile semiconductor memory device comprising:
a memory cell array including:
a first selection gate transistor,
a second selection gate transistor, and
a plurality of serially-connected memory cells provided between the first selection gate transistor and the second selection gate transistor,
the memory cells including:
a first memory cell connected with a first word line and capable of being programmable in D1 stages to thereby store data of D1 bits, D1 being an integer of 1 or more,
a second memory cell connected with a second word line and capable of being programmable in D2 stages to thereby store data of D2 bits, D2 being an integer of 3 or more and greater than D1, the second memory cell being closer to the first selection gate transistor than the first memory cell,
a third memory cell connected with a third word line and capable of being programmable in D3 stages to thereby store data of D3 bits, D3 being an integer of 3 or more and greater than D1, the third memory cell being closer to the first selection gate transistor than the second memory cell, and
a fourth memory cell connected with a fourth word line and capable of being programmable in D4 stages to thereby store data of D4 bits, D4 being an integer of 3 or more and greater than D1, the fourth memory cell being closer to the first selection gate transistor than the third memory cell,
the controller device causing the nonvolatile semiconductor memory device to:
perform a first program on the third memory cell as a first one of the D3 stages;
perform a second program on the fourth memory cell as a second or higher one of the D4 stages, after the first program is performed;
perform a third program on the second memory cell as a first one of the D2 stages, after the second program is performed;
perform a fourth program on the third memory cell as a second or higher one of the D3 stages, after the third program is performed;
perform a fifth program on the first memory cell as a first one of the D1 stages, after the fourth program is performed; and
perform a sixth program on the second memory cell as a second or higher one of the D2 stages, after the fifth program is performed.
14. The system according to claim 13 , wherein
the sixth program on the second memory cell is performed as the second one of the D2 stages, and
the controller further causes the nonvolatile semiconductor memory device to:
perform a seventh program on the second memory cell as a third or higher one of the D2 stages, after the sixth program is performed.
15. The system according to claim 14 , wherein
the second program on the fourth memory cell is performed as the second one of the D4 stages,
the fourth program on the third memory cell is performed as the second one of the D3 stages, and
the controller device further causes the nonvolatile semiconductor memory device to:
perform an eighth program on the fourth memory cell as a third or higher one of the D4 stages, after the third program is performed and before the fifth program is performed, and
perform a ninth program on the third memory cell as a third or higher one of the D3 stages, after the fifth program is performed and before the seventh program is performed.
16. The system according to claim 13 , wherein
D1 is 1,
D2 is 3,
D3 is 3, and
D4 is 3.
17. The system according to claim 13 , wherein
the memory cell array further includes:
a first dummy cell having a structure same as one of the memory cells between the second selection gate transistor and the first memory cell, and
a second dummy cell having a structure same as one of the memory cells between the first selection gate transistor and the fourth memory cell.
18. The system according to claim 13 , wherein
the nonvolatile semiconductor memory device further includes:
a source line connected to a source of the first selection gate transistor, and
a bit line connected to a drain of the second selection gate transistor.
19. A memory system comprising:
a nonvolatile semiconductor memory device; and
a controller device configured to control the nonvolatile semiconductor memory device,
the nonvolatile semiconductor memory device comprising:
a memory cell array including:
a first selection gate transistor,
a second selection gate transistor, and
a plurality of serially-connected memory cells provided between the first selection gate transistor and the second selection gate transistor,
the memory cells including:
a first memory cell connected with a first word line and capable of being programmable in D1 stages to thereby store data of D1 bits, D1 being an integer of 1 or more,
a second memory cell connected with a second word line and capable of being programmable in D2 stages to thereby store data of D2 bits, D2 being an integer of 3 or more and greater than D1, the second memory cell being closer to the first selection gate transistor than the first memory cell,
a third memory cell connected with a third word line and capable of being programmable in D3 stages to thereby store data of D3 bits, D3 being an integer of 3 or more and greater than D1, the third memory cell being closer to the first selection gate transistor than the second memory cell, and
a fourth memory cell connected with a fourth word line and capable of being programmable in D4 stages to thereby store data of D4 bits, D4 being an integer of 3 or more and greater than D1, the fourth memory cell being closer to the first selection gate transistor than the third memory cell,
the controller device further causing the nonvolatile semiconductor memory device to:
perform a first program on the third memory cell as a second or lower one of the D3 stages;
perform a second program on the fourth memory cell as a final one of the D4 stages, after the first program is performed;
perform a third program on the second memory cell as a second or lower one of the D2 stages, after the second program is performed;
perform a fourth program on the third memory cell as a final one of the D3 stages, after the third program is performed;
perform a fifth program on the first memory cell as a first or higher one of the D1 stages, after the fourth program is performed; and
perform a sixth program on the second memory cell as a final one of the D2 stages, after the fifth program is performed.
20. The system according to claim 19 , wherein
the third program on the second memory cell is performed as the second one of the D2 stages, and
the controller device further causes the nonvolatile semiconductor memory device to:
perform a seventh program on the second memory cell as a first one of the D2 stages, before the first program is performed.
21. The system according to claim 20 , wherein
the first program on the third memory cell is performed as the second one of the D3 stages, and
the controller device further causes the nonvolatile semiconductor memory device to:
perform an eighth program on the third memory cell as a first one of the D4 stages, before the seventh program is performed.
22. The system according to claim 19 , wherein
D1 is 1,
D2 is 3,
D3 is 3, and
D4 is 3.
23. The system according to claim 19 , wherein
the memory cell array further includes:
a first dummy cell having a structure same as one of the memory cells between the second selection gate transistor and the first memory cell, and
a second dummy cell having a structure same as one of the memory cells between the first selection gate transistor and the fourth memory cell.
24. The system according to claim 19 , wherein
the nonvolatile semiconductor memory device further includes:
a source line connected to a source of the first selection gate transistor, and
a bit line connected to a drain of the second selection gate transistor.