Method and System for Dynamic Word Line Based Configuration of a Three-Dimensional Memory Device

• US 20150347229A1
• Filed: 11/17/2014
• Published: 12/03/2015
• Est. Priority Date: 05/30/2014
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: Sandisk Technologies Incorporated (Western Digital Corporation)
• Inventors: Higgins, James M., Ellis, Robert W., Darragh, Neil R., Olbrich, Aaron K., Kankani, Navneeth, Sprouse, Steven
• Granted Patent: US 9,898,364 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 13/0002 using resistive RAM [RRAM] elements
• 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 16/3404 Convergence or correction of memory cell threshold voltages; Repair or recovery of overerased or overprogrammed cells
• CPC Class Codes: G11C 16/349 Arrangements for evaluating degradation, retention or wearout, e.g. by counting erase cycles
• CPC Class Codes: G11C 2029/1202 Word line control
• CPC Class Codes: G11C 2211/5641 Multilevel memory having cells with different number of storage levels
• CPC Class Codes: G11C 2213/71 Three dimensional array
• CPC Class Codes: G11C 29/025 in signal lines
• CPC Class Codes: G11C 29/028 with adaption or trimming of parameters
• CPC Class Codes: G11C 29/42 using error correcting codes [ECC] or parity check
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents
• CPC Class Codes: G11C 8/08 Word line control circuits, e.g. drivers, boosters, pull-up circuits, pull-down circuits, precharging circuits, for word lines
• CPC Class Codes: H10B 43/27 the channels comprising vertical portions, e.g. U-shaped channels

Abstract

A memory controller configures a plurality of word lines associated with a respective block of a 3D memory device in a first configuration, where the first configuration includes a set of configuration parameters for each word line of the plurality of word lines determined at least in part on the vertical positions of each word line relative to a substrate of the 3D memory device and, while the plurality of word lines are configured in the first configuration, writes data to and reads data from the respective block. For the respective block, the memory controller: adjusts a first parameter in the respective set of configuration parameters corresponding to a respective word line of the plurality of word lines in response to detecting a first trigger condition as to the respective word line and, after adjusting the first parameter, writes data to and reads data from the respective word line.

Claims

1. A method of operation in a storage device that includes a three-dimensional array of memory cells, including multiple blocks of memory cells, each block including a plurality of word lines arranged in different vertical positions relative to a substrate of the storage device, the method comprising:

for a first word line of a respective block of the multiple blocks, the first word line having a first vertical position relative to the substrate of the storage device, performing operations including;

determining a first error correction coding (ECC) strength for the first word line according to the first vertical position of the first word line relative to the substrate of the storage device;

writing data to the first word line according to the first ECC strength;

in response to detecting a first trigger condition as to the first word line, adjusting the first ECC strength corresponding to the first word line; and

after adjusting the first ECC strength corresponding to the first word line, writing data to the first word line according to the adjusted first ECC strength.

2. The method of claim 1, further comprising:

after adjusting the first ECC strength corresponding to the first word line, detecting a second trigger condition as to the first word line, wherein the second trigger condition is different from the first trigger condition; and

in response to detecting the second trigger condition as to the first word line, adjusting the adjusted first ECC strength corresponding to the first word line.

3. The method of claim 2, further comprising:

after adjusting the adjusted first ECC strength corresponding to the first word line, detecting a predefined retirement condition as to the first word line; and

in response to detecting the predefined retirement condition as to the first word line, retiring the first word line, wherein subsequent data is not written to the first word line.

4. The method of claim 1, further comprising:

for a second word line of the first block of the multiple blocks, the second word line having a second vertical position, distinct from the first vertical position, relative to the substrate of the storage device, performing operations including;

determining a second error correction coding (ECC) strength for the second word line according to the second vertical position of the second word line relative to the substrate of the storage device, wherein the second ECC strength error is distinct from the first ECC strength; and

writing data to the second word line according to the second ECC strength.

5. The method of claim 4, wherein the second vertical position is closer to the substrate of the storage device than the first vertical position, and the second ECC encoding strength for the second word line is greater than the first ECC encoding strength for the first word line.

6. The method of claim 1, further comprising:

maintaining one or more status metrics for each of the plurality of word lines corresponding to the respective block.

7. The method of claim 6, further comprising:

in accordance with a determination that one of the one or more status metrics for the first word line satisfies one or more predefined criteria, detecting the first trigger condition as to the first word line.

8. The method of claim 1, further comprising:

receiving a command as to the first word line; and

in response to receiving the command, detecting the first trigger condition as to the first word line.

9. The method of claim 1, wherein the plurality of word lines include a set of word lines at each vertical position of X distinct vertical positions relative to the substrate of the storage device, wherein X is an integer greater than two.

10. A storage system, comprising:

a storage device that includes a three-dimensional array of memory cells, including multiple blocks of memory cells, each block including a plurality of word lines arranged in different vertical positions relative to a substrate of the storage device; and

a memory controller with one or more processors and memory storing one or more programs to be executed by the one or more processors, the one or more programs comprising instructions for;

for a first word line of a respective block of the multiple blocks, the first word line having a first vertical position relative to the substrate of the storage device, performing operations including;

determining a first error correction coding (ECC) strength for the first word line according to the first vertical position of the first word line relative to the substrate of the storage device;

writing data to the first word line according to the first ECC strength;

in response to detecting a first trigger condition as to the first word line, adjusting the first ECC strength corresponding to the first word line; and

after adjusting the first ECC strength corresponding to the first word line, writing data to the first word line according to the adjusted first ECC strength.

11. The storage system of claim 10, wherein the one or more programs further comprise instructions for:

after adjusting the first ECC strength corresponding to the first word line, detecting a second trigger condition as to the first word line, wherein the second trigger condition is different from the first trigger condition; and

in response to detecting the second trigger condition as to the first word line, adjusting the adjusted first ECC strength corresponding to the first word line.

12. The storage system of claim 11, wherein the one or more programs further comprise instructions for:

after adjusting the adjusted first ECC strength corresponding to the first word line, detecting a predefined retirement condition as to the first word line; and

in response to detecting the predefined retirement condition as to the first word line, retiring the first word line, wherein subsequent data is not written to the first word line.

13. The storage system of claim 10, wherein the one or more programs further comprise instructions for:

for a second word line of the first block of the multiple blocks, the second word line having a second vertical position, distinct from the first vertical position, relative to the substrate of the storage device, performing operations including;

determining a second error correction coding (ECC) strength for the second word line according to the second vertical position of the second word line relative to the substrate of the storage device, wherein the second ECC strength error is distinct from the first ECC strength; and

writing data to the second word line according to the second ECC strength.

14. The storage system of claim 13, wherein the second vertical position is closer to the substrate of the storage device than the first vertical position, and the second ECC encoding strength for the second word line is greater than the first ECC encoding strength for the first word line.

15. The storage system of claim 10, wherein the one or more programs further comprise instructions for maintaining one or more status metrics for each of the plurality of word lines corresponding to the respective block.

16. The storage system of claim 15, wherein the one or more programs further comprise instructions for, in accordance with a determination that one of the one or more status metrics for the first word line satisfies one or more predefined criteria, detecting the first trigger condition as to the first word line.

17. The storage system of claim 15, wherein the one or more programs further comprise instructions for:

receiving a command as to the first word line; and

in response to receiving the command, detecting the first trigger condition as to the first word line.

18. The storage system of claim 10, wherein the plurality of word lines include a set of word lines at each vertical position of X distinct vertical positions relative to the substrate of the storage device, wherein X is an integer greater than two.

19. A non-transitory computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which, when executed by a memory controller with one or more processors, cause the memory controller to perform operations comprising:

for a first word line of a respective block of a storage device communicatively coupled with the memory controller that includes a three-dimensional array of memory cells, including multiple blocks of memory cells, each block including a plurality of word lines arranged in different vertical positions relative to a substrate of the storage device, the first word line having a first vertical position relative to the substrate of the storage device, performing operations including;

determining a first error correction coding (ECC) strength for the first word line according to the first vertical position of the first word line relative to the substrate of the storage device;

writing data to the first word line according to the first ECC strength;

in response to detecting a first trigger condition as to the first word line, adjusting the first ECC strength corresponding to the first word line; and

after adjusting the first ECC strength corresponding to the first word line, writing data to the first word line according to the adjusted first ECC strength.

20. The non-transitory computer readable storage medium of claim 19, wherein the one or more programs further comprise instructions for:

after adjusting the first ECC strength corresponding to the first word line, detecting a second trigger condition as to the first word line, wherein the second trigger condition is different from the first trigger condition; and

in response to detecting the second trigger condition as to the first word line, adjusting the adjusted first ECC strength corresponding to the first word line.