Memory system and read reclaim method thereof

• US 9,431,117 B2
• Filed: 09/26/2013
• Issued: 08/30/2016
• Est. Priority Date: 10/05/2012
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jung, Young Woo, Kim, Hwan-Chung, Park, Kyoungkuy, Park, Eunju, Seol, Bong-Gwan
• Primary Examiner(s): Park, Ilwoo
• Application Number:
  US14/037,658
• Publication Number:
  US 20140101372A1
• Time in Patent Office: 1,069 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 11/1068 in sector programmable memories, e.g. flash disk G06F11/1072 takes precedence
• CPC Class Codes: G06F 11/1072 in multilevel memories
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• 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 11/5671 using charge trapping in an insulator
• CPC Class Codes: G11C 16/10 Programming or data input circuits
• CPC Class Codes: G11C 16/26 Sensing or reading circuits; Data output circuits
• CPC Class Codes: G11C 29/52 Protection of memory contents; Detection of errors in memory contents

Abstract

A memory system includes a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers, and a memory controller configured to control the nonvolatile memory device. The memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation. The read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area.

Claims

1. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the read reclaim operation is timewise divided into a plural separately executed parts in which respective portions of the valid data of the target memory block are transferred to the one or more memory blocks of the first memory area,

wherein the memory controller is configured to execute at least a part of the read reclaim operation after a write operation requested by a host is completed, and

wherein, in the read reclaim operation, a portion of the valid data is transferred from the target memory block after the write operation is completed and before expiration of a predetermined time period, and wherein a data amount of the portion of the valid data is determined based on a time remaining after the write operation is complete until the predetermined time period.

2. The memory system of claim 1, wherein the memory controller is configured to execute at least a part of the read reclaim operation in response to a write request of a host.

3. The memory system of claim 1, wherein the predetermined time period is a timeout period of the host.

4. The memory system of claim 1, wherein data stored at the one or more memory blocks of the first memory area is transferred to one memory block of the second memory area during a background operation of the memory controller.

5. The memory system of claim 1, wherein n=1and m=3.

6. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area, and

wherein, in the read reclaim operation, an amount of the valid data corresponding to a storage capacity of a memory block of the first memory area is transferred to a memory block of the first memory area when a program operation is requested of the controller.

7. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the read reclaim operation is timewise divided into a plural separately executed parts in which respective portions of the valid data of the target memory block are transferred to the one or more memory blocks of the first memory area, and

wherein the first memory area includes the one or more memory blocks and remaining memory blocks, and, wherein the controller is configured execute a background operation which includes;

transferring data stored in the one or more memory blocks of the first memory area, excepting any memory block having an empty storage space, to a selected one of the memory blocks of the second memory area; and

transferring data stored in at least one of the remaining memory blocks, which is devoid of an empty storage space, of the first memory area to the selected one of the memory blocks of the second memory area,

wherein the selected memory block of the second memory area does not include an open word line after the transfers of data.

8. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the read reclaim operation is timewise divided into a plural separately executed parts in which respective portions of the valid data of the target memory block are transferred to the one or more memory blocks of the first memory area, and

wherein each part of the read reclaim operation is executed in response to a respective write operation request from a host and to satisfy a timeout condition of the host.

9. The memory system of claim 8, wherein, in at least one of the parts of the read reclaim operation, an amount of the valid data of the target memory block which corresponds to a storage capacity of a memory block of the first memory area is transferred to a memory block of the first memory area.

10. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the memory controller includes a buffer memory configured to store queue information indicating the target memory block of the second memory area selected during the read operation, and

wherein at the read operation, the memory controller is configured to execute a software error correction operation on an error of data read from a read memory block of the second memory area, and to store the queue information at the buffer memory indicating the read memory block as the target memory block when the data read from the read memory block is correctable via the software error correction operation.

11. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the memory controller includes a buffer memory configured to store queue information indicating the target memory block of the second memory area selected during the read operation, and

wherein at the read operation, the memory controller is configured to execute a read retry operation when data read from a read memory block of the second memory area is uncorrectable, and to store the queue information at the buffer memory indicating the read memory block as the target memory block when the data read from the read memory block is correctable via the read retry operation.

12. A memory system comprising:

a nonvolatile memory device including a first memory area formed of memory blocks which store n-bit data per cell and a second memory area formed of memory blocks which store m-bit data per cell, where n and m are different integers; and

a memory controller configured to control the nonvolatile memory device,

wherein the memory controller is configured to execute a read operation, and to execute a read reclaim operation in which valid data of a target memory block of the second memory area is transferred to one or more memory blocks of the first memory area, the target memory block selected during the read operation,

wherein the read reclaim operation is processed as complete when all the valid data of the target memory block is transferred to the one or more memory blocks of the first memory area,

wherein the memory controller includes a buffer memory configured to store queue information indicating the target memory block of the second memory area selected during the read operation, and

wherein at the read operation, the memory controller is configured to store the queue information at the buffer memory indicating that a read memory block of the second memory area is the target memory block when the number of error bits of data read from read memory block exceeds a reference.

13. A read reclaim method of a memory controller which controls a nonvolatile memory device including first memory blocks which store n-bit data per cell and second memory blocks which store m-bit data per cell, where n and m are different integers, comprising:

identifying a memory block among the second memory blocks as a target of a read reclaim operation; and

executing the read reclaim operation by transferring valid data of the memory block identified as a target of the read reclaim operation to one or more memory blocks among the first memory blocks, wherein the read reclaim operation is processed as complete when all the valid data is transferred to the one or more memory blocks among the first memory blocks,

wherein a read reclaim operation is timewise divided into a plurality of separately executed parts to satisfy a predetermined time period.

14. The read reclaim method of claim 13, wherein the parts of the read reclaim operation are performed when respective write operations are requested by a host.

15. The read reclaim method of claim 13, wherein the parts of the read reclaim operation are performed after respective write operations requested by a host are completed.

16. The read reclaim method of claim 13, wherein, in at least one of the parts of the read reclaim operation, a portion of the valid data is transferred after a write operation is completed and before expiration of the predetermined time period.

17. The read reclaim method of claim 16, wherein the predetermined period of time is a timeout period of the host.

18. The read reclaim method of claim 13, wherein, in at least one of the parts of the read reclaim operation, an amount of the valid data corresponding to a storage capacity of a memory block among the first memory blocks is transferred.

19. The read reclaim method of claim 13, further comprising executing a garbage collection operation in which data stored at the one or more memory blocks among the first memory blocks is transferred to a memory block among the second memory blocks.

20. The read reclaim method of claim 13, wherein the first memory blocks include the one or more memory blocks and remaining memory blocks, and wherein the method further comprises executing a background operation which includes:

transferring data stored in the one or more memory blocks among the first memory blocks, excepting any memory block having an empty storage space, to a selected one of the memory blocks among the second memory blocks; and

transferring data stored in at least one of the remaining memory blocks, which is devoid of an empty storage space, among the first memory blocks to the selected one of the memory blocks among the second memory blocks,

wherein the selected memory block among the second memory blocks does not include an open word line after the transfers of data.

21. The read reclaim method of claim 13, wherein n=1and m=3.

22. The read reclaim method of claim 13, wherein data provided from the memory controller is stored at the first memory blocks via a buffer program operation, and data stored at the first memory blocks is stored at the second memory blocks via a main program operation.

23. An operating method of a memory controller which controls a nonvolatile memory device including first memory blocks which store n-bit data per cell and second memory blocks which store m-bit data per cell, where n and m are different integers, comprising:

storing queue information indicating that a second memory block is a target memory block of a read reclaim operation when an error of data read from the second memory block exceeds a reference;

upon a host request, determining whether the target memory block exists based on the queue information;

programming valid data of the target memory block in at least one or more memory blocks among the first memory blocks when the target memory block is determined to exist; and

programming data stored at the at least one or more memory blocks among the first memory blocks in a memory block among the second memory blocks at a garbage collection operation,

wherein the read reclaim operation is processed as completed when all the valid data of the target memory block is programmed in the at least one or more memory blocks among the first memory blocks.

24. The operating method of claim 23, wherein existence of the target memory block is determined at a write request of a host.

25. The operating method of claim 23, wherein the first memory blocks include the one or more memory blocks and remaining memory blocks, and wherein the garbage collection operation includes:

transferring data stored in the one or more memory blocks among the first memory area, excepting any memory block having an empty storage space, to a selected one of the memory blocks among the second memory blocks; and

transferring data stored in at least one of the remaining memory blocks, which is devoid of an empty storage space, among the first memory blocks to the selected one of the memory blocks among the second memory blocks,

wherein the selected memory block among the second memory blocks does not include an open word line after the transfers of data.

26. The operating method of claim 23, wherein n=1and m=3.

27. The operating method of claim 26, wherein data read from the second memory block is least significant bit (LSB) page data, center significant bit (CSB) page data, or most significant bit (MSB) page data.