Memory system temperature management

• US 9,837,146 B2
• Filed: 06/28/2016
• Issued: 12/05/2017
• Est. Priority Date: 01/08/2016
• Status: Active Grant

• Current Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Original Assignee: SanDisk Technologies LLC (Western Digital Corporation)
• Inventors: Yang, Nian Niles, Yip, Chris Nga Yee
• Primary Examiner(s): Tran, Anthan
• Assistant Examiner(s): Siddique, Mushfique
• Application Number:
  US15/195,927
• Publication Number:
  US 20170200492A1
• Time in Patent Office: 525 Days
• Field of Search: 36518517
• CPC Class Codes: G11C 11/5628 Programming or writing circuits; Data input circuits
• CPC Class Codes: G11C 11/5642 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 7/04 with means for avoiding disturbances due to temperature effects

Abstract

Systems, methods and/or devices are used to adjust a read property for a memory portion of non-volatile memory. In one aspect, in response to receiving a program request, the device: detects a first temperature of the memory portion; and stores first temperature data corresponding to the detected first temperature. In response to receiving a read request, the device performs an adjustment determination, including: detecting a second temperature of the memory portion of the non-volatile memory, retrieving the stored first temperature data, and determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property. In accordance with a determination to perform the read using the adjusted read property, the device performs a read on the memory portion using the adjusted read property.

Claims

1. A method for adjusting a read property for a memory portion of non-volatile memory in a storage device, the method comprising:

receiving a program request;

in response to receiving the program request;

detecting a first temperature of the memory portion of the non-volatile memory, and

storing first temperature data corresponding to the detected first temperature, wherein the stored first temperature data includes a series of bits, each stored in an individual non-volatile memory cell, wherein the stored first temperature data indicates a respective temperature range of N predefined temperature ranges, wherein the respective temperature range is indicated by how many bits in the series of bits for the stored first temperature have an erase state, and wherein storing the first temperature data includes;

appending the first temperature data to a data payload of the program request, and

storing, to the memory portion of the non-volatile memory,

the data payload with the appended first temperature data;

after storing the first temperature data, receiving a read request;

in response to receiving the read request,

performing an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, performing a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, performing a read on the memory portion using a default read property.

2. The method of claim 1, wherein the first temperature data is stored in a data structure that is stored in the storage device.

3. The method of claim 1, wherein:

the storage device includes a plurality of memory cells;

the plurality of memory cells each store one of N distinct data values as a cell voltage, wherein the N distinct data values correspond to N sequential voltage ranges; and

each bit in the series of bits for the stored first temperature is stored in a memory cell having a programmed state indicated by a cell voltage within either a lowest range of the N sequential voltage ranges or a predefined range that is a fourth or higher range of the N sequential voltage ranges, and wherein N is an integer greater than or equal to four.

4. The method of claim 1, wherein the storage device includes a respective non-volatile memory device that includes the memory portion, and the first temperature is detected using a temperature sensor of the respective non-volatile memory device that includes the memory portion.

5. The method of claim 1, wherein the storage device includes a respective non-volatile memory device that includes the memory portion, and the first temperature is detected using a temperature sensor of a controller device that is different from the respective non-volatile memory device that includes the memory portion.

6. The method of claim 1, further comprising:

in accordance with the determination to perform the read using the adjusted read property, performing a subsequent write to a respective non-volatile memory device, which is included in the storage device, using an adjusted write property.

7. The method of claim 1, wherein the storage device comprises one or more three-dimensional (3D) memory devices and circuitry associated with operation of memory elements in the one or more 3D memory devices.

8. A method for adjusting a read property for a memory portion of non-volatile memory in a storage device, the method comprising:

receiving a program request;

in response to receiving the program request;

detecting a first temperature of the memory portion of the non-volatile memory; and

storing first temperature data corresponding to the detected first temperature;

after storing the first temperature data, receiving a read request;

in response to receiving the read request,

performing an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, performing a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, performing a read on the memory portion using a default read property;

wherein

determining whether to perform the read using an adjusted read property includes determining, for a word line corresponding to the memory portion, a ratio of a number of programmed memory cells of the word line to a total number of memory cells of the word line, wherein the total number of memory cells of the word line is equal to the number of programmed memory cells plus a number of erased memory cells of the word line; and

in accordance with a determination that the determined ratio does not meet predefined ratio criteria, determining to perform the read using the adjusted read property.

9. A storage device, comprising:

non-volatile memory, the non-volatile memory having a plurality of distinct memory portions;

one or more processors;

memory storing one or more programs, which when executed by the one or more processors cause the storage device to;

receive a program request;

in response to receiving the program request;

detect a first temperature of the memory portion of the non-volatile memory; and

store first temperature data corresponding to the detected first temperature, wherein the stored first temperature data includes a series of bits, each stored in an individual non-volatile memory cell, wherein the stored first temperature data indicates a respective temperature range of N predefined temperature ranges, wherein the respective temperature range is indicated by how many bits in the series of bits for the stored first temperature have an erase state, and wherein storing the first temperature data includes;

appending the first temperature data to a data payload of the program request, and

storing, to the memory portion of the non-volatile memory,

the data payload with the appended first temperature data;

after storing the first temperature data, receive a read request;

in response to receiving the read request,

perform an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, perform a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, perform a read on the memory portion using a default read property.

10. The storage device of claim 9, wherein the first temperature data is stored in a data structure that is stored in the storage device.

11. The storage device of claim 9, wherein:

the storage device includes a plurality of memory cells;

the plurality of memory cells each store one of N distinct data values as a cell voltage, wherein the N distinct data values correspond to N sequential voltage ranges; and

each bit in the series of bits for the stored first temperature is stored in a memory cell having a programmed state indicated by a cell voltage within either a lowest range of the N sequential voltage ranges or a predefined range that is a fourth or higher range of the N sequential voltage ranges, and wherein N is an integer greater than or equal to four.

12. A non-transitory computer readable storage medium, storing one or more programs configured for execution by one or more processors of a storage device, the one or more programs including instructions, which when executed by the one or more processors cause the storage device to:

receive a program request;

in response to receiving the program request;

detect a first temperature of the memory portion of the non-volatile memory; and

store first temperature data corresponding to the detected first temperature, wherein the stored first temperature data includes a series of bits, each stored in an individual non-volatile memory cell, wherein the stored first temperature data indicates a respective temperature range of N predefined temperature ranges, wherein the respective temperature range is indicated by how many bits in the series of bits for the stored first temperature have an erase state, and wherein storing the first temperature data includes;

appending the first temperature data to a data payload of the program request, and

storing, to the memory portion of the non-volatile memory,

the data payload with the appended first temperature data;

after storing the first temperature data, receive a read request;

in response to receiving the read request,

perform an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, perform a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, perform a read on the memory portion using a default read property.

13. The non-transitory computer readable storage medium of claim 12, wherein the first temperature data is stored in a data structure that is stored in the storage device.

14. The non-transitory computer readable storage medium of claim 12, wherein:

the storage device includes a plurality of memory cells;

the plurality of memory cells each store one of N distinct data values as a cell voltage, wherein the N distinct data values correspond to N sequential voltage ranges; and

each bit in the series of bits for the stored first temperature is stored in a memory cell having a programmed state indicated by a cell voltage within either a lowest range of the N sequential voltage ranges or a predefined range that is a fourth or higher range of the N sequential voltage ranges, and wherein N is an integer greater than or equal to four.

15. A storage device, comprising:

non-volatile memory, the non-volatile memory having a plurality of distinct memory portions;

one or more processors;

memory storing one or more programs, which when executed by the one or more processors cause the storage device to;

receive a program request;

in response to receiving the program request;

detect a first temperature of the memory portion of the non-volatile memory; and

store first temperature data corresponding to the detected first temperature; and

after storing the first temperature data, receive a read request;

in response to receiving the read request,

perform an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, perform a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, perform a read on the memory portion using a default read property;

wherein

determining whether to perform the read using an adjusted read property includes determining, for a word line corresponding to the memory portion, a ratio of a number of programmed memory cells of the word line to a total number of memory cells of the word line, wherein the total number of memory cells of the word line is equal to the number of programmed memory cells plus a number of erased memory cells of the word line; and

in accordance with a determination that the determined ratio does not meet predefined ratio criteria, determining to perform the read using the adjusted read property.

16. A storage device, comprising:

non-volatile memory, the non-volatile memory having a plurality of distinct memory portions;

data write means for storing data in the non-volatile memory, by performing operations including;

receiving a program request;

in response to receiving the program request;

detecting a first temperature of the memory portion of the non-volatile memory; and

storing first temperature data corresponding to the detected first temperature; and

data read means for reading data from in the non-volatile memory, by performing operations including;

after the first temperature data has been stored, receiving a read request;

in response to receiving the read request,

performing an adjustment determination, wherein the adjustment determination includes;

detecting a second temperature of the memory portion of the non-volatile memory;

retrieving the stored first temperature data; and

determining, in accordance with the detected second temperature and the retrieved first temperature data, whether to perform the read using an adjusted read property, wherein determining whether to perform the read using the adjusted read property includes comparing a second temperature value corresponding to the detected second temperature with a first temperature value corresponding to the retrieved first temperature data;

in accordance with a determination to perform the read using the adjusted read property, performing a read on the memory portion using the adjusted read property; and

in accordance with a determination not to perform the read using the adjusted read property, performing a read on the memory portion using a default read property;

wherein

determining whether to perform the read using an adjusted read property includes determining, for a word line corresponding to the memory portion, a ratio of a number of programmed memory cells of the word line to a total number of memory cells of the word line, wherein the total number of memory cells of the word line is equal to the number of programmed memory cells plus a number of erased memory cells of the word line; and

in accordance with a determination that the determined ratio does not meet predefined ratio criteria, determining to perform the read using the adjusted read property.