Thermal region tags and thermal region outlier detection

Patent metadata

Field	Value
Publication number	US-2022011967-A1
Application number	US-202016923849-A
Country	US
Kind code	A1
Filing date	Jul 8, 2020
Priority date	Jul 8, 2020
Publication date	Jan 13, 2022
Grant date	—

Abstract

A method, device, and system for improving read performance in frequently changing device temperature conditions through detecting thermal region tags and thermal region outliers in a memory device. A plurality of thermal regions may be configured for the memory device. A first temperature may be measured corresponding to opening a storage block of the memory device for programming. A second temperature may then be measured corresponding to closing the storage block for programming. A range between the first temperature and the second temperature may be determined. The range may span N≥2 of the thermal regions. Finally, the storage block may be assigned to a thermal region that includes the second temperature, on condition that N satisfies a threshold.

First claim

What is claimed is:

1 . A method, comprising:
measuring a first temperature corresponding to opening a storage block of the memory device for programming; measuring a second temperature corresponding to closing the storage block for programming; determining a range between the first temperature and the second temperature, the range spanning N≥2 pre-configured thermal regions; and assigning the storage block to a thermal region that includes the second temperature, on condition that N satisfies a threshold.

2 . The method of claim 1 , further comprising:
marking the storage block as a thermal outlier block if N does not satisfy the threshold.

3 . The method of claim 2 , wherein marking the storage block as the thermal outlier block triggers evacuation of data from the storage block.

4 . The method of claim 1 , further comprising:
tracking a temperature of the block while the block is open for programming; determining one or more of a number of cross-temperature events, a temperature range of one or more cross-temperature event, and a frequency of cross-temperature events; and marking the storage block as a thermal outlier block conditionally based on one or more of the number of cross-temperature events, the temperature range of one or more cross-temperature event, and the frequency of cross-temperature events.

5 . The method of claim 1 , wherein read parameters to apply to storage blocks assigned to a particular thermal region are applied particularly to blocks assigned to the particular thermal region.

6 . The method of claim 5 , wherein the thermal regions are configured such that for at least a subset M≥2 of the thermal regions, the read parameters for any N adjacent thermal regions of the subset M are compatible.

7 . A device, comprising:
a non-volatile memory array; a controller; and first logic to configure the controller to:
measure a first temperature corresponding to opening a storage block of the non-volatile memory array for programming, the first temperature located within a first of a plurality of pre-configured thermal regions;
measure a second temperature corresponding to closing the storage block for programming, the second temperature located within a second of the plurality of pre-configured thermal regions in an N-hop neighborhood of the first of the pre-configured thermal regions, where N≥1; and
assign the storage block to the second of the pre-configured thermal regions;
wherein the plurality of pre-configured thermal regions are configured such that memory read parameters for thermal regions in the N-hop neighborhood are compatible.

8 . The device of claim 7 , further comprising second logic to:
detect a cross-temperature event; and update the read parameters for one or more of the pre-configured thermal regions as a result of the cross-temperature event.

9 . The device of claim 8 , wherein the update of the read parameters is conditioned on the cross-temperature event being an extreme cross-temperature event.

10 . The device of claim 7 , further comprising third logic to:
detect a cross-temperature event; test a bit error rate for a storage block closed after the cross-temperature event; and distinguish the storage block closed after the cross-temperature event from a storage block closed before the cross-temperature event, wherein the storage block closed after the cross-temperature event and the storage block closed before the cross-temperature event are assigned to a same thermal region.

11 . The device of claim 10 , wherein the bit error rate test is performed on condition that the storage block closed after the cross-temperature event is a first closed storage block, after the cross-temperature event, and the storage block closed after the cross-temperature event is assigned to the same thermal region as the storage block closed before the cross-temperature event.

12 . The device of claim 10 , wherein distinguishing the storage block closed after the cross-temperature event from the storage block closed before the cross-temperature event comprises:
creating a new thermal region tag including the same thermal region assigned to the storage block closed before the cross-temperature event; assigning the storage block closed after the cross-temperature event to the new thermal region tag; and marking the new thermal region tag to invoke additional read verification on storage blocks associated with the new thermal region tag.

13 . The device of claim 10 , further comprising fourth logic to:
deactivate the thermal region tag of the block programmed before the cross-temperature event, such that storage blocks closed after the cross-temperature event cannot be assigned to the thermal region tag of the storage block closed before the cross-temperature event.

14 . The device of claim 10 , wherein the bit error rate test and distinguishing comprise:
applying read parameters assigned to the storage block closed before the cross-temperature event to read data from the storage block closed after the cross-temperature event; comparing bit error rates for the storage block closed before the cross-temperature event and the storage block closed after the cross-temperature event; and distinguishing the storage block closed after the cross-temperature event from the storage block closed before the cross-temperature event on condition that the comparing satisfies a threshold.

15 . The device of claim 10 , wherein distinguishing the storage block closed after the cross-temperature event from the storage block closed before the cross-temperature event is independent of a time interval of the cross-temperature event.

16 . A system, comprising:
a memory array; and a controller configured to:
measure a first temperature when a block of the memory array is opened;
measure a second temperature when the block is closed;
assign the block a tag corresponding to one of a plurality of pre-configured thermal regions including the second temperature, on condition that a range between the first temperature and the second temperature spans 1≤N≤M contiguous thermal regions of the pre-configured thermal regions; and
relocate blocks having a same tag to be adjacent in the memory array.

17 . The system of claim 16 , the controller further configured to:
mark blocks for which the range between the first temperature and the second temperature spans more than M contiguous thermal regions as thermal outlier blocks.

18 . The system of claim 17 , the controller further configured to:
marking the storage block as a thermal outlier block conditionally based on one or more of a number of cross-temperature events, a temperature range of one or more cross-temperature event, and a frequency of cross-temperature events while the block is open for programming.

19 . The system of claim 16 , the controller further configured to:
detect an extreme cross-temperature event; distinguish blocks closed after the extreme cross-temperature event and assigned a particular tag from blocks closed before the extreme cross-temperature event having the particular tag; and relocate the blocks having the particular tag and closed after the extreme cross-temperature event to be adjacent in the memory array distinct from the blocks having the particular tag and closed before the extreme cross-temperature event.

20 . The system of claim 19 , the controller further configured to:
distinguish the blocks closed before the extreme cross-temperature event from the bl

Assignees

• Western Digital Tech Inc

Inventors

• Mekhanik Evgeny
• Eliash Tomer Tzvi
• Goldberg Barak

Classifications

• G01K3/08

  giving differences of values (using thermoelectric elements G01K7/02); giving differentiated values · CPC title

• G11C16/34

  Determination of programming status, e.g. threshold voltage, overprogramming or underprogramming, retention · CPC title

• G11C16/10 Primary

  Programming or data input circuits · CPC title

• G11C7/04 Primary

  with means for avoiding disturbances due to temperature effects · CPC title

• G06F3/0679

  Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP] · CPC title