Non-volatile semiconductor storage apparatus

• US 9,940,192 B2
• Filed: 10/30/2014
• Issued: 04/10/2018
• Est. Priority Date: 07/31/2012
• Status: Active Grant

• Current Assignee: Kioxia Corporation
• Original Assignee: Toshiba Memory Corporation (Kioxia Corporation)
• Inventors: Igari, Fubito, Suto, Hiroyuki, Ozawa, Yasuyuki
• Primary Examiner(s): CHAUDRY, MUJTABA M
• Application Number:
  US14/528,825
• Publication Number:
  US 20150052414A1
• Time in Patent Office: 1,258 Days
• Field of Search: None
• CPC Class Codes: G06F 11/1008 in individual solid state devices G06F11/1004 takes precedence
• CPC Class Codes: G06F 11/1048 using arrangements adapted for a specific error detection or correction feature
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0653 Monitoring storage devices or systems
• CPC Class Codes: G06F 3/0679 Non-volatile semiconductor memory device, e.g. flash memory, one time programmable memory [OTP]
• CPC Class Codes: G11C 2029/0411 Online error correction
• CPC Class Codes: G11C 7/04 with means for avoiding disturbances due to temperature effects

Abstract

According to one embodiment, a non-volatile semiconductor storage apparatus is configured to decide determination periods respectively corresponding to each of management blocks based on rewrite count information items and a temperature, and to perform a determination processing for each of management blocks for each determination period. The determination processing includes determining whether first data read from a block in the blocks is normal based on the number of errors that are occurred in the first data. The apparatus is configured to perform a rewrite processing of rewriting the first data to second data which is error-corrected when it is determined that the first data is not normal.

Claims

1. A non-volatile semiconductor storage apparatus comprising:

a non-volatile semiconductor memory in which data is erased in units of one block;

a temperature sensor mounted on a board in the non-volatile semiconductor storage apparatus; and

a controller configured to continuously repeat confirming of data in a block at fixed intervals of a first period,

wherein the controller is further configured to continuously repeat confirming of data in the block at fixed intervals of a second period different from the first period,

wherein the first period and the second period are based on the temperature measured by the temperature sensor and a number of rewrites, an execution period factor and a reference period.

2. The apparatus of claim 1, wherein the controller is configured to:

determine the execution period factor based on the number of rewrites and the temperature; and

determine the second period as a function of multiplying the determined execution period factor by the reference period.

3. The apparatus of claim 1, wherein the controller is configured to determine that the data in the block is not normal based on a bit error rate.

4. The apparatus of claim 1, wherein the controller is configured to request a rewrite of data in the block if the data in the block is not normal based on confirming normalcy of the data stored in the block for the second period.

5. The apparatus of claim 1, wherein the controller is configured to:

read out the data in the block;

acquire a number of errors in the data read from the block;

calculate a bit error rate based on the number of errors; and

determine that the data in the block is not normal based on the bit error rate.

6. The apparatus of claim 1, wherein the second period is determined based on a change of the temperature information measured during the first period.

7. A non-volatile semiconductor storage apparatus comprising:

a non-volatile semiconductor memory in which data is erased in units of one block;

a temperature sensor mounted on a board in the non-volatile semiconductor storage apparatus; and

a controller configured to continuously repeat an operation of obtaining error information of data in a block at fixed intervals of a first period and confirm data in a block using the error information,

wherein the controller is further configured to continuously repeat an operation of obtaining the error information of data in the block at fixed intervals of a second period different from the first period,

wherein the first period and the second period are based on the temperature measured by the temperature sensor and a number of rewrites, an execution period factor and a reference period.

8. The apparatus of claim 7, wherein the second period is determined based on a change of the temperature information measured during the first period.