阅读说明：本技术 控制器、包括控制器的存储器系统及其操作方法 (Controller, memory system including the same, and method of operating the same ) 是由 赵赞赫 于 2019-10-24 设计创作，主要内容包括：本申请可以提供一种控制器、包括该控制器的存储器系统以及操作该存储器系统的方法。该控制器可以包括：处理器,被配置为响应于从主机接收的读取命令而控制存储器装置的读取操作；以及错误校正电路,被配置为在读取操作期间对从存储器装置接收的读取数据执行错误校正操作。该处理器可以在读取操作期间确定存储器装置的劣化特性,并控制该存储器装置选择并对已执行读取操作的存储器单元执行重新编程操作和回收操作中的任何一个。(The present application may provide a controller, a memory system including the controller, and a method of operating the memory system. The controller may include: a processor configured to control a read operation of the memory device in response to a read command received from a host; and an error correction circuit configured to perform an error correction operation on read data received from the memory device during a read operation. The processor may determine a degradation characteristic of the memory device during a read operation, and control the memory device to select and perform any one of a reprogramming operation and a reclaiming operation on memory cells on which the read operation has been performed.)

1. A controller, comprising:

a processor controlling a read operation of the memory device in response to a read command received from a host; and

error correction circuitry to perform an error correction operation on read data received from the memory device during the read operation,

wherein the processor further determines a degradation characteristic of the memory device during the read operation, and controls the memory device to select and perform any one of a reprogramming operation and a reclaiming operation on the memory cells having performed the read operation.

2. The controller of claim 1, wherein the processor comprises:

a flash translation layer generating a command queue for controlling the read operation of the memory device in response to the read command; and

a retention characteristic improvement block determining the degradation characteristic by comparing a reference read voltage with an optimum read voltage used during the read operation if the read operation fails, selecting any one of the reprogramming operation and the recycling operation in response to the determined degradation characteristic, and controlling the memory device.

3. The controller according to claim 2, wherein the controller is a microprocessor,

wherein, during the read operation, the flash translation layer controls the memory device to perform a first read operation using the reference read voltage and a read voltage set included in a read retry table, and

wherein if a result of a first error correction operation on first read data read during the first read operation indicates that a failure has occurred, the flash translation layer controls the memory device to perform a second read operation using the optimal read voltage.

4. The controller according to claim 3, wherein the controller is a microprocessor,

wherein the flash translation layer controls the memory device to perform an eBoost operation or a soft decode operation as the second read operation,

wherein the eBoost operation or the soft decode operation comprises performing a plurality of read operations while changing a read voltage.

5. The controller of claim 3, wherein if a result of a second error correction operation on second read data read during the second read operation indicates that no erroneous bits are included or a minimum number of erroneous bits are included, the flash translation layer controls the memory device such that a read voltage is set to the optimal read voltage and the second read operation is performed.

6. The controller according to claim 3, wherein the controller is a microprocessor,

wherein the retention characteristic improvement block detects read voltage difference values respectively corresponding to a plurality of program states by comparing the reference read voltage and the optimum read voltage, and

wherein the retention characteristic improvement block determines the degradation characteristic to be a low temperature data retention degradation characteristic (LTDR degradation characteristic) when the read voltage difference value of at least one or more most significant program states having a high threshold voltage among the plurality of program states is greater than the read voltage difference values of the other program states.

7. The controller according to claim 6, wherein the controller is a microprocessor,

wherein the retention characteristic improvement block controls the memory device to perform the reprogramming operation on the memory cells when the degradation characteristic is the LTDR degradation characteristic; and is

Wherein the retention characteristic improvement block controls the memory device to perform the reclamation operation on the memory unit when the degradation characteristic is not the LTDR degradation characteristic.

8. The controller of claim 6, wherein the retention characteristic improvement block comprises:

a read voltage comparison block comparing the reference read voltage and the optimal read voltage and detecting the read voltage difference values respectively corresponding to the plurality of program states;

an LTDR determination block that determines whether a degradation characteristic of the memory cell is the LTDR degradation characteristic based on the read voltage difference values respectively corresponding to the plurality of program states;

an algorithm selection block that selects any one of a reprogramming algorithm and a recycling algorithm based on a result of determining the degradation characteristic of the memory cell by the LTDR determination block;

a reprogramming control block which controls the memory device to perform the reprogramming operation when the reprogramming algorithm is selected; and

a reclamation control block that controls the memory device to perform the reclamation operation when the reclamation algorithm is selected.

9. A memory system, comprising:

a memory device comprising a plurality of data programmed memory cells; and

a controller controlling the memory device to perform a read operation on the plurality of memory cells in response to a read command received from a host,

wherein, when a failure occurs during the read operation, the controller further determines a degradation characteristic of the plurality of memory cells and controls the memory device to perform a reprogramming operation or a recycling operation on the plurality of memory cells.

10. The memory system of claim 9, wherein the controller comprises:

a processor controlling the memory device to perform a first read operation using a reference read voltage and a read retry voltage during the read operation, and to set an optimal read voltage and perform a second read operation if the first read operation fails; and

an error correction circuit that performs an error correction operation on first read data read as a result of the first read operation and performs an error correction operation on second read data read as a result of the second read operation, and determines that the first read operation and the second read operation have failed based on a result of the error correction operation.

11. The memory system according to claim 10, wherein the memory unit is a single memory unit,

wherein the processor controls the memory device to perform an eBoost operation or a soft decode operation as the second read operation, and

wherein the eBoost operation or the soft decode operation comprises performing a plurality of read operations while changing a read voltage.

12. The memory system of claim 10, wherein the processor includes a retention characteristic improvement block that determines the degradation characteristic by comparing the reference read voltage with the optimal read voltage used during the second read operation if the second read operation fails, selects any one of the reprogramming operation and the reclaiming operation in response to the determined degradation characteristic, and controls the memory device.

13. The memory system according to claim 10, wherein when a result of a second error correction operation on the second read data read during the second read operation indicates that no erroneous bits are included or a minimum number of erroneous bits are included, the processor controls the memory device such that a read voltage is set to the optimum read voltage, and the second read operation is performed.

14. The memory system according to claim 10, wherein the memory unit is a single memory unit,

wherein the retention characteristic improvement block detects read voltage difference values respectively corresponding to a plurality of program states by comparing the reference read voltage and the optimum read voltage, and

wherein the retention characteristic improvement block determines the degradation characteristic to be a low temperature data retention degradation characteristic (LTDR degradation characteristic) when the read voltage difference value of at least one or more most significant program states having a high threshold voltage among the plurality of program states is greater than the read voltage difference values of the other program states.

15. The memory system according to claim 14, wherein the memory unit is a single memory unit,

wherein when the degradation characteristic is the LTDR degradation characteristic, the retention characteristic improvement block controls the memory device to perform the reprogramming operation on the memory cells, and

wherein the retention characteristic improvement block controls the memory device to perform the reclamation operation on the memory cells when the degradation characteristic is not the LTDR degradation characteristic.

16. A method of operating a memory system, comprising:

performing a first read operation on a memory cell included in the memory device using the reference read voltage and the read retry voltage;

performing a second read operation on the memory cell using an optimal read voltage when a result of the first read operation indicates that a failure has occurred;

determining a degradation characteristic of the memory cell by comparing the reference read voltage and the optimal read voltage; and is

Selecting and performing any one of a reprogramming operation and a recycling operation on the memory cell based on the determined degradation characteristic.

17. The method of claim 16, wherein the second read operation comprises an eBoost operation or a soft decoding operation.

18. The method of claim 16, wherein determining the degradation characteristic comprises:

comparing the reference read voltage with the optimal read voltage, and detecting read voltage differences corresponding to a plurality of program states, respectively; and is

Determining the degradation characteristic to be a low temperature data retention degradation characteristic, LTDR degradation characteristic, when the read voltage difference value of at least one or more most significant program states having a high threshold voltage among the plurality of program states is greater than the read voltage difference values of other program states.

19. The method of claim 18, wherein the first and second portions are selected from the group consisting of,

wherein when the degradation characteristic is the LTDR degradation characteristic, the reprogramming operation is performed using a first incremental step pulse programming scheme, i.e., a first ISPP scheme, which uses a first start program voltage and a first step voltage, and

wherein when the degradation characteristic is not the LTDR degradation characteristic, the reclamation operation is performed using a second ISPP scheme using a second start program voltage and a second step voltage.

20. The method of claim 19, wherein the first starting programming voltage is higher than the second starting programming voltage, and the first step voltage is lower than the second step voltage.

21. A method of operation of a controller that controls a memory device, the method of operation comprising:

controlling the memory device to perform a first read operation on a memory region using a reference read voltage;

controlling the memory device to perform a second read operation on the memory area with an optimal read voltage when the first read operation fails due to an error of data read from the memory area; and is

Controlling the memory device to perform a re-programming operation on the memory region when a difference between the reference read voltage and the optimal read voltage of a first program state is greater than a difference between the reference read voltage and the optimal read voltage of a second program state,

wherein the first programmed state is a higher effective programmed state than the second programmed state.

22. The method of operation of claim 21, further comprising: controlling the memory device to perform a read reclaim operation on the memory region when the difference in the first program state is not greater than the difference in the second program state.

Technical Field

Various embodiments of the present disclosure generally relate to an electronic device, and in particular, to a controller, a memory system including the controller, and a method of operating the memory system.

Background

More recently, computer environment paradigms have turned into pervasive computing to enable computer systems to be used anytime and anywhere. Therefore, the use of portable electronic devices such as mobile phones, digital cameras, and notebook computers has rapidly increased. In general, portable electronic devices use a memory system employing a memory device to store data, i.e., to serve as a data storage device. The memory device may be used as a primary memory device or a secondary memory device of the portable electronic device.

Since there is no mechanical driving part, the memory system using the memory device provides advantages in that stability and durability are excellent, information access speed is increased, and power consumption is reduced. Examples of the memory system having these advantages may include a Universal Serial Bus (USB) memory device, a memory card having various interfaces, a Solid State Drive (SSD), and the like.

Memory devices may be classified into volatile memory devices and non-volatile memory devices.

Although the nonvolatile memory device has relatively low read and write speeds, the nonvolatile memory device can maintain data stored therein even in the event of power interruption. Therefore, the nonvolatile memory device is used when it is necessary to store data that needs to be held regardless of whether the nonvolatile memory device is connected to a power supply. Representative examples of non-volatile memory devices may include read-only memory (ROM), mask ROM (mrom), programmable ROM (prom), erasable programmable ROM (eprom), electrically erasable programmable ROM (eeprom), flash memory, phase change random access memory (PRAM), magnetic ram (mram), resistive ram (rram), and ferroelectric ram (fram). Flash memories are classified into NOR type memories and NAND type memories.

Disclosure of Invention

Various embodiments of the present disclosure relate to a controller capable of determining a threshold voltage distribution characteristic of a memory cell and performing a retention characteristic improvement operation during a read operation. Various embodiments of the present disclosure also relate to a memory system including a controller and a method of operating the memory system.

Embodiments of the present disclosure may provide a controller, including: a processor configured to control a read operation of the memory device in response to a read command received from a host; and an error correction circuit configured to perform an error correction operation on read data received from the memory device during a read operation. The processor may determine a degradation characteristic of the memory device during a read operation, and control the memory device to select and perform any one of a reprogramming operation and a reclaiming operation on memory cells that have performed the read operation.

Another embodiment of the present disclosure may provide a memory system including: a memory device comprising a plurality of memory cells of programmed data; and a controller configured to control the memory device to perform a read operation on the plurality of memory cells in response to a read command received from the host. When a failure occurs during a read operation, the controller may determine degradation characteristics of the plurality of memory cells and control the memory device to perform a reprogramming operation or a recycling operation on the plurality of memory cells.

Yet another embodiment of the present disclosure may provide a method of operating a memory system, the method including: performing a first read operation on a memory cell included in the memory device using the reference read voltage and the read retry voltage; performing a second read operation on the memory cell using the optimal read voltage when the result of the first read operation indicates that a failure has occurred; determining a degradation characteristic of the memory cell by comparing the reference read voltage and the optimal read voltage; based on the determined degradation characteristic, any one of a reprogramming operation and a recycling operation is selected and performed on the memory cell.

Yet another embodiment of the present disclosure may provide a method of operating a memory system, the method including: controlling a memory device to perform a first read operation on a memory region using a reference read voltage; controlling the memory device to perform a second read operation on the memory area using the optimal read voltage when the first read operation fails due to an error of data read from the memory area; and controlling the memory device to perform a re-programming operation on the memory area when a difference between the reference read voltage and the optimum read voltage of the first program state is greater than a difference between the reference read voltage and the optimum read voltage of the second program state, wherein the first program state is a higher effective program state than the second program state.

These and other advantages and features of the present invention will be better understood by those of ordinary skill in the art from the following detailed description of specific embodiments in conjunction with the following drawings.

Drawings

Fig. 1 is a block diagram illustrating a memory system according to an embodiment of the present disclosure.

Fig. 2 is a block diagram illustrating a configuration of the controller of fig. 1 according to an embodiment of the present disclosure.

Fig. 3 is a block diagram illustrating a retention characteristic improvement block of the controller of fig. 2 according to an embodiment of the present disclosure.

Fig. 4 is a diagram depicting a semiconductor memory of the memory system of fig. 1, in accordance with an embodiment of the present disclosure.

Fig. 5 is a diagram illustrating a memory block of the semiconductor memory of fig. 4 according to an embodiment of the present disclosure.

Fig. 6 is a diagram illustrating a memory block of the semiconductor memory of fig. 4 having a three-dimensional structure according to an embodiment of the present disclosure.

Fig. 7 is a diagram illustrating a memory block of the semiconductor memory of fig. 4 having a three-dimensional structure according to an embodiment of the present disclosure.

FIG. 8 is a flow chart of the operation of a memory system according to an embodiment of the present disclosure.

Fig. 9 is a threshold voltage distribution diagram depicting reference read voltages and eBoost read voltages during a read operation, according to an embodiment of the present disclosure.

Fig. 10 is a diagram illustrating a memory system according to another embodiment of the present disclosure.

11-13 are block diagrams illustrating various memory systems according to embodiments of the present disclosure.

Detailed Description

It is noted that specific structural and functional descriptions in the embodiments of the present disclosure introduced in the specification or application are only for describing the embodiments of the present disclosure. Furthermore, the description should not be construed as limited to the embodiments described in this specification or application.

The present disclosure will now be described in detail based on specific embodiments with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein but should be construed to cover modifications, equivalents, or alternatives falling within the spirit and scope of the inventive concept and technology disclosed herein.

It will be further understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element discussed below could be termed a second element without departing from the teachings of the present disclosure. Similarly, a second element may also be referred to as a first element.

It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being "directly coupled" or "directly connected" to another element, there are no intervening elements present. Other expressions describing the relationship between elements, such as "between … …", "directly between", "adjacent to", or "directly adjacent to".

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. In this disclosure, the singular form is also intended to include the plural form unless the context clearly dictates otherwise. It will be further understood that the terms "comprises," "comprising," "includes," "including," "has," "having," and the like, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, and/or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or combinations thereof.

Unless otherwise defined, all terms used herein, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs in view of this disclosure. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

A detailed description of functions and configurations well known to those skilled in the art will be omitted so as not to obscure the subject matter of the present disclosure. This is intended to omit unnecessary description in order to make the subject matter of the present disclosure clear.

Various embodiments of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the disclosure are shown, so that those skilled in the art can implement the technical idea of the invention without undue experimentation.

Fig. 1 is a block diagram illustrating a memory system 1000 according to an embodiment of the present disclosure.

Referring to fig. 1, a memory system 1000 may include a memory device 1100, a controller 1200, and a host 1300. The memory device 1100 may include a plurality of semiconductor memories 100. The plurality of semiconductor memories 100 may be divided into a plurality of groups GRP 1-GRPn. Although the host 1300 has been illustrated and described as being included in the memory system 1000 in the present embodiment, the memory system 1000 may include only the controller 1200 and the memory device 1100, and the host 1300 may be provided outside the memory system 1000.

In fig. 1, a plurality of banks of the memory device 1100 are shown to communicate with the controller 1200 through the first to nth channels CH1 to CHn, respectively. Each semiconductor memory 100 will be described below with reference to fig. 4.

Each of the plurality of groups of semiconductor memories 100 may communicate with the controller 1200 through one common channel. The controller 1200 may control the plurality of semiconductor memories 100 of the memory device 1100 through the plurality of channels CH1 through CHn.

The controller 1200 may be coupled between the host 1300 and the memory device 1100. In operation, the controller 1200 can access the memory device 1100 in response to a request received from the host 1300. For example, the controller 1200 may control a read operation, a write operation, an erase operation, or a background operation of the memory device 1100 in response to a Host command Host _ CMD received from the Host 1300. During a write operation, the Host 1300 may transfer data and an address together with the Host command Host _ CMD. During a read operation, the Host 1300 may transfer an address along with the Host command Host _ CMD. The controller 1200 may provide an interface between the memory device 1100 and the host 1300. The controller 1200 may run firmware for controlling the memory device 1100.

The controller 1200 may control a read operation of the memory device 1100 in response to a Host command Host _ CMD received from the Host 1300 and corresponding to the read operation. Based on the result of the read operation, the controller 1200 may determine the degradation characteristics of the memory cells on which the read operation has been performed. Based on the result of the determination, the controller 1200 may perform a reprogramming algorithm or a recycling algorithm to improve the retention characteristics of the memory cell. For example, during a read operation, if threshold voltage distributions of some program states having relatively higher threshold voltage values among a plurality of program states of the memory cell are more deteriorated than threshold voltage distributions of other program states, the controller 1200 may determine that retention characteristics of the memory cell are deteriorated due to Low Temperature Data Retention (LTDR), and perform a reprogramming algorithm to improve the retention characteristics of the memory cell. Further, during a read operation, if a plurality of program states of the memory cell are uniformly deteriorated, the controller 1200 may determine that the retention characteristics of the memory cell are deteriorated due to other reasons other than Low Temperature Data Retention (LTDR), and perform a reclamation algorithm to improve the retention characteristics of the memory cell.

The host 1300 may include a portable electronic device such as a computer, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), an MP3 player, a camera, a camcorder, or a mobile phone. The Host 1300 may request a write operation, a read operation, an erase operation, etc. to the memory system 1000 using a Host command Host _ CMD. To perform a write operation of the memory device 1100, the Host 1300 may transfer a Host command Host _ CMD, data, and an address corresponding to the write command to the controller 1200. To perform a read operation, the Host 1300 may transfer a Host command Host _ CMD and an address corresponding to the read command to the controller 1200. For example, the address may be a logical address.

The controller 1200 and the memory device 1100 may be integrated into a single semiconductor device. In an embodiment, the controller 1200 and the memory device 1100 may be integrated into a single semiconductor device to form a memory card. For example, the controller 1200 and the memory device 1100 may be integrated into a single semiconductor device and form a memory card such as a Personal Computer Memory Card International Association (PCMCIA), a compact flash Card (CF), a smart media card (SM or SMC), a memory stick, a multimedia card (MMC, RS-MMC, or micro MMC), an SD card (SD, mini SD, micro SD, or SDHC), or a universal flash memory (UFS).

The controller 1200 and the memory device 1100 may be integrated into a single semiconductor device to form a Solid State Drive (SSD). The SSD may include a storage device configured to store data in the semiconductor memory 100.

In an embodiment, the memory system 1000 may be provided as one of various elements of an electronic device such as: a computer, an ultra mobile pc (umpc), a workstation, a netbook, a Personal Digital Assistant (PDA), a portable computer, a web tablet, a wireless phone, a mobile phone, a smart phone, an electronic book, a Portable Multimedia Player (PMP), a game machine, a navigation device, a black box, a digital camera, a 3-dimensional television, a digital audio recorder, a digital audio player, a digital picture recorder, a digital picture player, a digital video recorder, a digital video player, a device capable of transmitting/receiving information in a wireless environment, one of various devices for forming a home network, one of various electronic devices for forming a computer network, one of various electronic devices for forming a telematics network, an RFID device, one of various elements for forming a computing system, and the like.

In an embodiment, memory device 1100 or memory system 1000 may be embedded in various types of packages. For example, memory device 1100 or memory system 1000 may be packaged in packaging types such as: package on package (PoP), Ball Grid Array (BGA), Chip Scale Package (CSP), Plastic Leaded Chip Carrier (PLCC), plastic dual in-line package (PDIP), Die in package (Die in Wafer Pack), Die in Wafer Form (Die in Wafer Form), Chip On Board (COB), ceramic dual in-line package (CERDIP), plastic Metric Quad Flat Pack (MQFP), Thin Quad Flat Pack (TQFP), Small Outline Integrated Circuit (SOIC), Shrink Small Outline Package (SSOP), Thin Small Outline Package (TSOP), System In Package (SIP), Multi Chip Package (MCP), Wafer scale manufacturing package (WFP), or Wafer scale processing package on package (WSP).

Fig. 2 is a diagram illustrating a configuration of the controller 1200 of fig. 1 according to an embodiment of the present disclosure.

Referring to FIG. 2, controller 1200 may include host control circuitry 1210, a processor 1220, a buffer memory 1230, error correction circuitry 1240, flash control circuitry 1250, and a bus 1260.

Bus 1260 may provide a channel between the components of controller 1200.

The host control circuit 1210 may control data transfer between the host 1300 and the buffer memory 1230 of fig. 1. For example, the host control circuit 1210 may control an operation of buffering data input from the host 1300 to the buffer memory 1230. In an embodiment, the host control circuit 1210 may control an operation of outputting data that has been buffered in the buffer memory 1230 to the host 1300.

The host control circuitry 1210 may include a host interface.

The processor 1220 may control the overall operation of the controller 1200 and perform logical operations. The processor 1220 may communicate with the host 1300 of fig. 1 through the host control circuit 1210 and with the memory device 1100 of fig. 1 through the flash memory control circuit 1250. Processor 1220 may control the operation of memory system 1000 by using buffer memory 1230 as an operation memory, cache memory, or buffer. Processor 1220 may rearrange a plurality of host commands received from host 1300 based on priority and generate a command queue, and may control flash control circuit 1250 based on the command queue. Further, based on the results of error correction operations on data read during read operations, processor 1220 may control memory device 1100 and error correction circuitry 1240 to perform read retry operations, eBoost operations, or soft decode operations. In addition, during the read operation, the processor 1220 may determine a degradation characteristic of the memory cell on which the read operation has been performed, and control the memory device 1100 to selectively perform any one of a reprogramming operation and a recycling operation to improve a retention characteristic of the memory cell based on the determined degradation characteristic.

The processor 1220 may include a flash translation layer (hereinafter, referred to as "FTL") 1221 and a retention characteristic improvement block 1222.

FTL 1221 may be stored in buffer memory 1230, additional memory (not shown) coupled directly to processor 1220, or storage space defined within processor 1220. During a read operation, FTL 1221 may check a physical address mapped to a logical address input from host 1300.

During read operations, FTL 1221 may generate a command queue for controlling flash control circuit 1250 in response to host commands received from host 1300. Further, during a read operation, if a failure occurs as a result of an error correction operation on data read from the memory device 1100 during the read operation, the FTL 1221 may control the memory device 1100 and the error correction circuit 1240 to perform a read retry operation, an eBoost operation, or a soft decoding operation.

In the case where an eBoost operation or a soft decoding operation is performed because a failure occurs during a read operation, the retention characteristic improvement block 1222 may control the memory device 1100 to check the degradation characteristics of the memory cells during the eBoost or decoding operation, and perform a reprogramming operation or a recycling operation. The reprogramming operation may perform a programming operation on the selected memory block during the read operation and raise the threshold voltage distribution of the memory cells, which have been reduced below the normal range, to the normal range to improve the retention characteristics of the memory cells. The reclamation operation may read data programmed in a selected memory block during a read operation and program the read data to another memory block, i.e., a memory block having an erase state, in order to improve retention characteristics of the memory block.

The buffer memory 1230 may be used as an operation memory, a cache memory, or a buffer of the processor 1220. The buffer memory 1230 may store code and commands to be executed by the processor 1220. The buffer memory 1230 may store data processed by the processor 1220.

Buffer memory 1230 may include a write buffer 1231 and a read buffer 1232. The write buffer 1231 may temporarily store data received from the host 1300 during a write operation and then transfer the temporarily stored data to the memory device 1100 when an internal command corresponding to the write operation is transferred to the memory device 1100. During a read operation, the read buffer 1232 may temporarily store data received from the memory device 1100 and then transfer the temporarily stored data to the host 1300.

Buffer memory 1230 may include static ram (sram) or dynamic ram (dram).

Error correction circuitry 1240 may perform error correction operations. Error correction circuitry 1240 may perform ECC (error correction code) encoding operations based on data to be written to memory device 1100 of fig. 1 by flash control circuitry 1250. The ECC encoded data may be transferred to the memory device 1100 through the flash control circuit 1250. Error correction circuitry 1240 may perform ECC decoding operations on data received from memory device 1100 by flash control circuitry 1250. The error corrected data may be transferred to read buffer 1232 of buffer memory 1230. Further, if the error correction operation has failed, error correction circuitry 1240 may transmit a signal to processor 1220 indicating the failure. The error corrected data may be transferred to read buffer 1232 of buffer memory 1230.

Note that although error correction circuitry 1240 and flash control circuitry 1250 are shown as separate circuits in fig. 2, in another embodiment, error correction circuitry 1240 may be included in flash control circuitry 1250 as a component of flash control circuitry 1250.

Flash control circuit 1250 may generate and output internal commands for controlling memory device 1100 in response to a command queue generated by processor 1220. During a write operation, the flash control circuit 1250 may control an operation of transferring and writing data buffered in the write buffer 1232 of the buffer memory 1230 to the memory device 1100. In an embodiment, during a read operation, flash control circuitry 1250 may control the operation of buffering data read from memory device 1100 in read buffer 1232 of buffer memory 1230 in response to the command queue.

Flash control circuitry 1250 may include a flash interface for interfacing with memory device 1100.

Fig. 3 is a block diagram illustrating a configuration of the retention characteristic improvement block 1222 of fig. 2 according to an embodiment of the present disclosure.

Referring to fig. 3, the retention characteristic improvement block 1222 may include a read voltage comparison block 1222A, LTDR determination block 1222B, an algorithm selection block 1222C, a reprogramming control block 1222D, and a reclamation control block 1222E.

The read voltage comparison block 1222A may compare an optimal read voltage set during an eBoost operation or a soft decoding operation with a reference read voltage for identifying or detecting a plurality of program states. In an embodiment, the reference read voltage may be a read voltage for identifying or detecting each desired program state. For example, the reference read voltage may be an initial set read voltage of the memory device. The optimal read voltage may be a read voltage of a read operation that generates no erroneous bits or only a minimum of erroneous bits during an eBoost operation or a soft decoding operation.

The read voltage comparison block 1222A may detect a read voltage difference value corresponding to each program state by comparing a reference read voltage of each program state with an optimal read voltage.

Based on the read voltage difference values corresponding to the respective program states detected by the read voltage comparison block 1222A, the LTDR determination block 1222B may determine whether a degradation phenomenon due to LTDR has occurred on the memory cells of the memory device on which the read operation has been performed. The degradation phenomenon caused by LTDR refers to a phenomenon in which the threshold voltage distribution of memory cells is reduced due to a charge sharing phenomenon between memory cells at room temperature. In particular, the degradation phenomenon may be exacerbated in a program state having a high threshold voltage distribution. Accordingly, LTDR determination block 1222B may determine that a degradation phenomenon due to LTDR has occurred on memory cells having performed a read operation when a read voltage difference value of at least one or more most significant program states having a relatively high threshold voltage among a plurality of program states is greater than read voltage difference values of other program states.

Based on the result of determining the degradation characteristic of the memory cell by LTDR determination block 1222B, algorithm selection block 1222C may select any of a variety of algorithms to improve retention characteristics. For example, when the LTDR determination block 1222B determines that a degradation phenomenon due to LTDR has occurred on the memory cell, the algorithm selection block 1222C may select a reprogramming algorithm of a plurality of algorithms. When the LTDR determination block 1222B determines that a degradation phenomenon due to a cause other than LTDR has occurred on the memory unit, the algorithm selection block 1222C may select a reclamation algorithm among the plurality of algorithms.

When the algorithm selection block 1222C selects a reprogramming algorithm, the reprogramming control block 1222D may control the memory device 1100 to perform a reprogramming operation on the memory cells on which the read operation has been performed.

When the algorithm selection block 1222C selects a reclamation algorithm, the reclamation control block 1222E may control the memory device 1100 to perform a reclamation operation on a memory block including memory cells on which a read operation has been performed.

Fig. 4 is a diagram of a configuration of the semiconductor memory 100 of fig. 1 according to an embodiment.

Referring to fig. 4, the semiconductor memory 100 may include a memory cell array 10 configured to store data. The semiconductor memory 100 may include a peripheral circuit 200, the peripheral circuit 200 being configured to perform a program operation for storing data in the memory cell array 10, a read operation for outputting the stored data, and an erase operation for erasing the stored data. The semiconductor memory 100 may include a control logic 300 configured to control the peripheral circuit 200 under the control of a controller (1200 of fig. 1).

Memory cell array 10 may include a plurality of memory blocks MB1 through MBk, represented generally by the numeral 11, where k is a positive integer. Local lines LL and bit lines BL1 through BLm (where m is a positive integer) may be coupled to each memory block 11. For example, the local line LL may include a first selection line, a second selection line, and a plurality of word lines arranged between the first and second selection lines. The local line LL may include dummy (dummy) lines disposed between the first selection line and the word line and between the second selection line and the word line. For example, the first selection line may be a source selection line, and the second selection line may be a drain selection line. For example, the local lines LL may include word lines, drain and source selection lines, and source lines SL. For example, the local line LL may further include a dummy line. For example, the local line LL may further include a pipeline. The local line LL may be coupled to each memory block 11. The bit lines BL1 through BLm may be commonly coupled to the memory block 11. The memory block 11 may be implemented in a two-dimensional or three-dimensional structure. For example, in the memory block 11 having a two-dimensional structure, memory cells may be arranged in a direction parallel to the substrate. For example, in the memory block 11 having a three-dimensional structure, memory cells may be stacked in a direction perpendicular to the substrate.

At least one memory block 11 may be defined as a system memory block. A read retry table including information on a plurality of read voltages to be used during a read retry operation may be stored in the system memory block. The read retry table may be read during a boot operation of the memory system 1000 and stored in the buffer memory 1230 of the controller 1200.

Under the control of the control logic 300, the peripheral circuit 200 may perform a program operation, a read operation, or an erase operation on the selected memory block 11. For example, the peripheral circuitry 200 may include voltage generation circuitry 210, a row decoder 220, a page buffer bank 230, a column decoder 240, input/output circuitry 250, pass/fail check circuitry 260, and source line drivers 270.

The voltage generation circuit 210 may generate various operation voltages Vop to be used for a program operation, a read operation, and an erase operation in response to the operation signal OP _ CMD. In addition, the voltage generation circuit 210 may selectively discharge the local line LL in response to the operation signal OP _ CMD. For example, under the control of control logic 300, voltage generation circuit 210 may generate a program voltage, a verify voltage, a pass voltage, and a select transistor operating voltage.

The row decoder 220 may transfer the operation voltage Vop to the local line LL coupled to a selected memory block among the memory blocks 11 in response to the control signal AD _ signals. For example, the row decoder 220 may selectively apply the operating voltages (e.g., the program voltage, the verify voltage, and the pass voltage) generated from the voltage generation circuit 210 to the word line among the local lines LL in response to the row decoder control signal AD _ signals.

During the program voltage applying operation, the row decoder 220 may apply the program voltage generated by the voltage generating circuit 210 to a selected word line of the local line LL and apply the pass voltage generated by the voltage generating circuit 210 to other unselected word lines in response to the control signal AD _ signals. During a read operation, the row decoder 220 may apply a read voltage generated by the voltage generation circuit 210 to a selected word line of the local line LL and apply a pass voltage generated by the voltage generation circuit 210 to other unselected word lines in response to the control signal AD _ signals.

The page buffer bank 230 may include a plurality of page buffers PB1 through PBm, generally indicated by the numeral 231, coupled to bit lines BL1 through BLm, a plurality of page buffers PB1 through PBm. The page buffer 231 may operate in response to the page buffer control signals PBSIGNALS. For example, the page buffer 231 may temporarily store data to be programmed during a program operation, or sense a voltage or current of the bit lines BL1 to BLm during a read or verify operation.

The column decoder 240 may transfer data between the input/output circuit 250 and the page buffer group 230 in response to a column address CADD. For example, the column decoder 240 may exchange data with the page buffer 231 through the data lines DL or with the input/output circuit 250 through the column lines CL.

The input/output circuit 250 may transfer an internal command CMD or an address ADD received from the controller (1200 of fig. 1) to the control logic 300 or exchange data with the column decoder 240.

During a read operation, the PASS/FAIL check circuit 260 may generate a reference current in response to the enable BIT VRY _ BIT < # >, and may compare the sensing voltage VPB received from the page buffer group 230 with a reference voltage generated by the reference current and output a PASS signal PASS or a FAIL signal FAIL.

The source line driver 270 may be coupled to the memory cells included in the memory cell array 10 through the source lines SL, and may control voltages to be applied to the source lines SL. The source line driver 270 may receive a source line control signal CTRL _ SL from the control logic 300 and control a source line voltage to be applied to the source line SL based on the source line control signal CTRL _ SL.

The control logic 300 may control the peripheral circuit 200 by outputting an operation signal OP _ CMD, a control signal AD _ signals, a page buffer control signal PBSIGNALS, and an enable BIT VRY _ BIT < # > in response to the internal command CMD and the address ADD. In addition, in response to PASS signal PASS or FAIL signal FAIL, control logic 300 may determine whether the target memory cell has passed verification during a verification operation.

Fig. 5 is a diagram illustrating a configuration of the memory block MB1 of fig. 4 according to an embodiment. Note that each memory block 11 may have the same configuration as the MB 1.

Referring to fig. 5, in memory block MBl, a plurality of word lines arranged in parallel with each other may be coupled between a first select line and a second select line. For example, the first selection line may be a source selection line SSL, and the second selection line may be a drain selection line DSL. In more detail, the memory block MB1 may include a plurality of strings ST coupled between the bit lines BL1 to BLm and the source lines SL. The bit lines BL1 to BLm may be respectively coupled to the strings ST, and the source lines SL may be commonly coupled to the strings ST. The strings ST may have the same configuration; therefore, the string ST coupled to the first bit line BL1 will be described in detail by way of example.

The string ST may include a source select transistor SST, a plurality of memory cells F1 through F16, and a drain select transistor DST, which are coupled in series with each other between a source line SL and a first bit line BL. At least one source select transistor SST and at least one drain select transistor DST may be included in each string ST, and a greater number of memory cells than the number of memory cells F1 through F16 shown in the drawings may be included in each string ST.

A source of the source select transistor SST may be coupled to a source line SL, and a drain of the drain select transistor DST may be coupled to a first bit line BLl. The memory cells F1 through F16 may be coupled in series between the source select transistor SST and the drain select transistor DST. The gates of the source select transistors SST included in different strings ST may be coupled to a source select line SSL, the gates of the drain select transistors DST may be coupled to a drain select line DSL, and the gates of the memory cells F1 to F16 may be coupled to a plurality of word lines WL1 to WL 16. Among the memory cells included in the different strings ST, a group of memory cells coupled to each word line may be referred to as a physical page PPG. Accordingly, the number of physical pages PPG included in the memory block MB1 may correspond to the number of word lines WL1 to WL 16.

Each memory cell may store 1 bit of data. The memory cell is commonly referred to as a single-level cell (SLC). In this case, each physical page PPG may store data of a single logical page LPG. The data of each logical page LPG may comprise data bits corresponding to the number of cells comprised in a single physical page PPG. Each memory cell may store 2 or more bits of data. The memory cell is commonly referred to as a multi-level cell (MLC). In this case, each physical page PPG may store data of two or more logical pages LPG.

Fig. 6 is a diagram illustrating an example of a memory block MB1 having a three-dimensional structure according to an embodiment of the present disclosure.

Referring to fig. 6, the memory cell array 10 may include a plurality of memory blocks 11, the plurality of memory blocks 11 including memory blocks MB1 through MBk. Each memory block 11 may have a configuration of a memory block MB1 as shown in fig. 6. Specifically, the memory block MB1 may include a plurality of strings ST11 to ST1m and ST21 to ST2 m. In an embodiment, each of the strings ST11 to ST1m and the strings ST21 to ST2m may be formed in a "U" shape. In the memory block MB1, m strings may be arranged in the row direction (i.e., the X direction). Fig. 6 shows that two strings are arranged in the column direction (i.e., Y direction), but this is for illustration only. For example, three or more strings may be arranged in the column direction (Y direction).

Each of the plurality of strings ST11 to ST1m and ST21 to ST2m may include at least one source select transistor SST, first to nth memory cells MC1 to MCn, a pipe transistor PT, and at least one drain select transistor DST.

The source selection transistor SST, the drain selection transistor DST, and the memory cells MC1 through MCn may have structures similar to each other. For example, each of the source selection transistor SST, the drain selection transistor DST, and the memory cells MC1 through MCn may include a channel layer, a tunnel insulation layer, a charge extraction layer, and a blocking insulation layer. For example, a pillar (pilar) for providing a channel layer may be provided in each string. For example, pillars for providing at least one of a channel layer, a tunnel insulating layer, a charge extraction layer, and a blocking insulating layer may be provided in each string.

The source select transistor SST of each string may be coupled between a source line SL and the memory cells MC1 through MCn.

In an embodiment, the source select transistors of the strings arranged in the same row may be coupled to a source select line extending in the row direction. The source select transistors of the strings arranged in different rows may be coupled to different source select lines. In fig. 6, the source select transistors of the strings ST 11-ST 1m in the first row may be coupled to a first source select line SSL 1. The source select transistors of strings ST 21-ST 2m in the second row may be coupled to a second source select line SSL 2.

In an embodiment, the source select transistors of strings ST 11-ST 1m and ST 21-ST 2m may be commonly coupled to a single source select line.

The first to nth memory cells MC1 to MCn in each string may be coupled between the source selection transistor SST and the drain selection transistor DST.

The first to nth memory cells MC1 to MCn may be divided into first to pth memory cells MC1 to MCp and p +1 to nth memory cells MCp +1 to MCn. The first to pth memory cells MC1 to MCp may be sequentially arranged in a vertical direction (i.e., in the Z direction), and coupled in series to each other between the source select transistor SST and the tunnel transistor PT. The p +1 th to nth memory cells MCp +1 to MCn may be sequentially arranged in a vertical direction (Z direction), and are coupled in series with each other between the pipe transistor PT and the drain select transistor DST. The first to pth memory cells MC1 to MCp and the p +1 to nth memory cells MCp +1 to MCn may be coupled to each other through a pipe transistor PT. The gates of the first to nth memory cells MC1 to MCn of each string may be coupled to the first to nth word lines WL1 to WLn, respectively.

In an embodiment, at least one of the first to nth memory cells MC1 to MCn may be used as a dummy memory cell. In the case where the dummy memory cell is disposed, the voltage or current of the corresponding string may be stably controlled. The gates of the pipe transistors PT of the respective strings may be coupled to the line PL.

The drain select transistor DST of each string may be coupled between a corresponding bit line and the memory cells MCp +1 to MCn. The strings arranged in the row direction may be coupled to respective drain select lines extending in the row direction. The drain select transistors of the strings ST 11-ST 1m in the first row may be coupled to a first drain select line DSL 1. The drain select transistors of the strings ST 21-ST 2m in the second row may be coupled to a second drain select line DSL 2.

Strings arranged in a column direction may be coupled to respective bit lines extending in the column direction. In fig. 6, the strings ST11 and ST21 in the first column may be coupled to a first bit line BL 1. The strings ST1m and ST2m in the mth column may be coupled to the mth bit line BLm.

Among the strings arranged in the row direction, memory cells coupled to the same word line may form one page. For example, the memory cells coupled to the first word line WL1 in the strings ST 11-ST 1m of the first row may form a single page. The memory cells in the strings ST 21-ST 2m of the second row that are coupled to the first word line WL1 may form another single page. When any one of the drain select lines DSL1 and DSL2 is selected, strings arranged in the corresponding row may be selected. When any one of the word lines WL1 to WLn is selected, a corresponding single page may be selected from the selected string.

Fig. 7 is a diagram illustrating an example of a memory block MB1 having a three-dimensional structure according to an embodiment of the present disclosure.

Referring to fig. 7, memory cell array 10 may include a plurality of memory blocks MB1 through MBk, generally indicated by the numeral 11. Each memory block 11 may have a configuration of a memory block MB1 as shown in fig. 7. Specifically, the memory block MB1 may include a plurality of strings ST11 'to ST1m' and ST21 'to ST2 m'. Each of the strings ST11 'to ST1m' and ST21 'to ST2m' may extend in the vertical direction (i.e., Z direction). In each memory block 11, m strings may be arranged in the row direction (i.e., the X direction). Fig. 7 shows that two columns are arranged in the column direction (i.e., Y direction), but this is for illustration only. For example, three or more strings may be arranged in the column direction (Y direction).

Each of the strings ST11 'to ST1m' and ST21 'to ST2m' may include at least one source select transistor SST, first to nth memory cells MC1 to MCn, and at least one drain select transistor DST.

The source select transistor SST of each string may be coupled between a source line SL and the memory cells MC1 through MCn. The source select transistors of strings arranged in the same row may be coupled to the same source select line. The source select transistors of the strings ST11 'to ST1m' arranged in the first row may be coupled to a first source select line SSL 1. The source select transistors of the strings ST21 'to ST2m' arranged in the second row may be coupled to a second source select line SSL 2. In an embodiment, the source select transistors of strings ST11 'to ST1m' and ST21 'to ST2m' may be commonly coupled to a single source select line.

The first to nth memory cells MC1 to MCn in each string may be coupled in series between the source selection transistor SST and the drain selection transistor DST. The gates of the first to nth memory cells MC1 to MCn may be coupled to the first to nth word lines WL1 to WLn, respectively.

In an embodiment, at least one of the first to nth memory cells MC1 to MCn may be used as a dummy memory cell. In the case where the dummy memory cell is disposed, the voltage or current of the corresponding string may be stably controlled. Thus, the reliability of the data stored in each memory block 11 can be improved.

The drain select transistor DST of each string may be coupled between a respective bit line and the memory cells MC1 through MCn. The drain select transistors DST of the strings arranged in the row direction may be coupled to respective drain select lines extending in the row direction. The drain select transistors DST of the strings ST11 'to ST1m' in the first row may be coupled to a first drain select line DSL 1. The drain select transistors DST of the strings ST21 'to ST2m' in the second row may be coupled to the second drain select line DSL 2.

FIG. 8 is a flow chart of the operation of a memory system according to an embodiment of the present disclosure.

Fig. 9 is a threshold voltage distribution diagram for describing a reference read voltage and an eBoost read voltage during a read operation according to an embodiment of the present disclosure. FIG. 9 illustrates threshold voltage distributions of Triple Layer Cells (TLC) having seven programmed states P1-P7 and an erased state E. As illustrated in fig. 9, the program state P6 or P7 may be a higher effective program state than any of the remaining program states P1 through P5. The more efficient programming states P6 and P7 may have higher threshold voltage distributions than the less efficient programming states P1 through P5. The dotted lines shown in fig. 9 may represent the degraded threshold voltage distributions of the respective program states P1 through P7. As described above and illustrated in fig. 9, degradation may be exacerbated in the higher effective programmed states (e.g., programmed states P6 and P7) having higher threshold voltage distributions.

The operation of the memory system according to an embodiment of the present disclosure will be described with reference to fig. 1 to 9.

In step S810, when a Host command Host _ CMD, i.e., a read command, is received from the Host 1300, the processor 1220 of the controller 1200 generates a command queue by queuing the received read command Host _ CMD.

Then, the flash control circuit 1250 may generate an internal command CMD for controlling a read operation of the memory device 1100 in response to the read command Host _ CMD queued in the command queue and transmit the internal command CMD to the memory device 1100.

In step S820, the memory device 1100 may perform a read operation in response to the internal command CMD received from the controller 1200. For example, a semiconductor memory selected from among the plurality of semiconductor memories 100 included in the memory device 1100 may perform a read operation in response to a received internal command CMD. For example, the read voltage may be performed using an initial reference read voltage (e.g., R1-R7 of fig. 9). The memory device 1100 may transfer data read as a result of a read operation to the controller 1200.

In step S830, the error correction circuit 1240 of the controller 1200 may perform an error correction operation on the read data received from the memory device 1100 and determine the result of the error correction operation. For example, error correction circuitry 1240 may perform ECC decoding operations on read data received from memory device 1100 by flash control circuitry 1250. The error corrected read data may be transferred to the read buffer 1232 of the buffer memory 1230. For example, from the number of error bits included in the read data received from the memory device 1100, it may be determined whether the error correction operation has passed or failed. For example, in the case where the number of error bits included in read data received from the memory device 1100 is equal to or smaller than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 normally performs an ECC decoding operation and determines that the error correction operation has passed. On the other hand, in the case where the number of error bits included in the read data received from the memory device 1100 is greater than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 determines that the error correction operation has failed.

If the result of the above-described determination operation (S830) indicates that the error correction operation has Passed (PASS), the read data transferred and stored in the read buffer 1232 of the buffer memory 1230 may be transferred to the host 1300 through the host control circuit 1210 in step S840.

If the result of the above operation S830 indicates that the error correction operation has Failed (FAIL), the processor 1220 may determine whether the number of times the read operation has failed is equal to or greater than a preset value (e.g., "a") in step S850. The preset value "a" may be equal to or less than the number of read voltage sets included in the read retry table.

If the result of step S850 indicates that the number of times the read operation has failed is less than the preset value a (NO), one of the plurality of read voltage sets included in the read retry table is selected and the read voltages respectively corresponding to the plurality of program states P1 through P7 are changed in step S860.

Thereafter, the process may be repeated from step S820 using the read voltage changed according to the read retry table.

If the result of step S850 indicates that the number of times the read operation has failed is equal to or greater than the preset value a (yes), the processor 1220 may determine that the threshold voltage distribution of the memory cells having performed the read operation has deteriorated and control the memory device 1100 to perform the eBoost operation to more accurately read data in step S870.

The eBoost operation may determine (e.g., find) an optimal read voltage that minimizes the number of erroneous bits. The eBoost operation may set an optimal read voltage to an eBoost read voltage (e.g., R1_1 to R7_1 of fig. 9), and then perform a read operation using the eBoost read voltages R1_1 to R7_ 1.

The memory device 1100 may transfer data read as a result of the eBoost operation to error correction circuitry 1240 of the controller 1200. The error correction circuitry 1240 may perform ECC decoding operations on the received read data. The error corrected read data may be transferred to the read buffer 1232 of the buffer memory 1230. For example, in the case where the number of error bits included in the received read data is equal to or less than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 may normally perform an ECC decoding operation and determine that the error correction operation has passed. On the other hand, in the case where the number of error bits included in the read data received from the memory device 1100 is greater than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 may determine that the correction operation has failed.

If the result of the determination operation (S880) indicates that the error correction operation has Passed (PASS), the read voltage comparison block 1222A of the retention characteristic improvement block 1222 may compare the reference read voltages R1 through R7 and the optimal read voltage, i.e., the eBoost read voltages R1_1 through R7_1, and detect read voltage differences corresponding to the respective program states based on the comparison result, in step S890.

Based on the read voltage difference values corresponding to the respective program states detected by the read voltage comparison block 1222A, the LTDR determination block 1222B may determine whether a degradation phenomenon due to LTDR has occurred on the memory cells of the memory device on which the read operation has been performed. In other words, LTDR determination block 1222B may determine that a degradation phenomenon due to LTDR has occurred on memory cells having performed a read operation when a read voltage difference value of at least one or more most significant program states (e.g., program states P6 and P7) having relatively higher threshold voltages among the plurality of program states is greater than that of the other program states. Although the two program states P6 and P7 are defined as the most effective program states in the present embodiment, the present disclosure is not limited thereto, and at least one or more program states having the highest threshold voltage among the plurality of program states may be defined as the most effective program states.

In step S900, the algorithm selection block 1222C may determine whether to perform a reprogramming operation based on the result of determining the degradation characteristic of the memory cell through the LTDR determination block 1222B.

If the result of the above-described determination operation (S900) indicates that the reprogramming operation is not to be performed (no), the read data transferred and stored in the read buffer 1232 of the buffer memory 1230 may be transmitted as an output to the host 1300 through the host control circuit 1210 in step S840.

If the result of the above determination operation (S900) indicates that a reprogramming operation is to be performed (yes), the reprogramming control block 1222D controls the memory device 1100 to perform a reprogramming operation on the memory cells on which the read operation has been performed, in step S910. The reprogramming operation may be performed in an Incremental Step Pulse Programming (ISPP) manner. For example, the program voltage may be gradually increased from the first initial program voltage by the first step voltage Vstep 1.

After the reprogramming operation has been performed on the memory cells on which the read operation has been performed, the read data transferred and stored in the read buffer 1232 of the buffer memory 1230 may be transmitted to the host 1300 as an output through the host control circuit 1210 in step S840.

If the result of the determination operation (S880) indicates that the error correction operation has Failed (FAIL), the processor 1220 may determine that the eBoost operation has failed and control the memory device 1100 and the error correction circuit 1240 to perform a soft decoding operation in step S920.

In an embodiment, the soft decoding operation may be a decoding operation using soft decision data read with a soft decoding read voltage. The soft decoding read voltages may include the above-described eBoost read voltages R1_1 through R7_ 1.

In step S930, if the result of the soft decoding operation indicates that the number of error bits included in the soft decision data is equal to or less than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 may normally perform the ECC decoding operation and determine that the error correction operation has passed. However, when the number of error bits included in the soft decision data is greater than the maximum allowable number of error bits of the error correction circuit 1240, the error correction circuit 1240 may determine that the error correction operation has failed.

When the result of the determination operation (S930) indicates that the error correction operation has Passed (PASS), the read voltage comparison block 1222A of the retention characteristic improvement block 1222 may compare the reference read voltages R1 through R7 and the optimal read voltage, i.e., the soft decoding read voltage, and detect read voltage difference values corresponding to the respective program states based on the comparison result in step S940.

Based on the read voltage difference values corresponding to the respective program states detected by the read voltage comparison block 1222A, the LTDR determination block 1222B may determine whether a degradation phenomenon due to LTDR has occurred on the memory cells of the memory device on which the read operation has been performed. In other words, LTDR determination block 1222B may determine that a degradation phenomenon due to LTDR has occurred on memory cells having performed a read operation when a read voltage difference value of at least one or more most significant program states (e.g., program states P6 and P7) having a relatively high threshold voltage among the plurality of program states is greater than that of the other program states.

In step S950, the algorithm selection block 1222C determines whether to perform a reprogramming operation or a recycling operation based on the result of the degradation characteristic of the memory cell determined by the LTDR determination block 1222B. For example, the algorithm selection block 1222C may select a reprogramming algorithm when the LTDR determination block 1222B determines that a degradation phenomenon due to LTDR has occurred on the memory cell. The algorithm selection block 1222C may select a reclamation algorithm when the LTDR determination block 1222B determines that a degradation phenomenon has occurred on the memory unit due to a reason other than LTDR.

When the RE-programming algorithm (RE-PROGRAM) has been selected in step S950, the reprogramming control block 1222D controls the memory device 1100 to perform a reprogramming operation on the memory cells on which the read operation has been performed, in step S960.

When the reclamation algorithm (recycling) has been selected in step S950, the reclamation control block 1222E controls the memory device 1100 to perform a reclamation operation on a memory block including memory cells on which a read operation has been performed in step S970. During the reclaim operation, valid data of a memory block including memory cells on which the read operation has been performed is read. The read valid data is programmed into a new memory block having an erased state. During the recycling operation, a program operation may be performed on a new memory block in an ISPP manner using the second start program voltage and the second step voltage Vstep 2. The second start program voltage may be lower than the first start program voltage. The second step voltage may be higher than the first step voltage. Further, after the reclamation operation has been performed, a mapping data update operation may be performed that newly maps a logical address mapped to a physical address of the selected memory block to a physical address of the new memory block.

After step 960 or step S970, the read data transferred and stored in the read buffer 1232 of the buffer memory 1230 may be transmitted to the host 1300 as an output through the host control circuit 1210 in step S840.

As described above, in various embodiments of the present disclosure, during an eBoost operation and a soft decoding operation, it is determined whether a degradation phenomenon of a memory cell having performed a read operation is a degradation phenomenon due to LTDR. If it is determined that the degradation phenomenon is due to LTDR, a reprogramming operation is performed. If it is determined that the deterioration phenomenon is caused by a cause other than LTDR, a recovery operation is performed. Accordingly, the threshold voltage distribution of the memory cell in which the degradation phenomenon due to LTDR has occurred is restored to the normal range, so that the data retention characteristic of the memory system may be improved. Further, when the degradation phenomenon is due to LTDR, instead of the reclamation operation, a reprogramming operation having a relatively short program time and requiring no map data update operation is performed. Accordingly, the operating speed and current consumption of the memory system can be improved.

Fig. 10 is a diagram illustrating a memory system 30000 according to an embodiment of the present disclosure.

Referring to fig. 10, the memory system 30000 may be implemented in a cellular phone, a smart phone, a tablet PC, a Personal Digital Assistant (PDA), or a wireless communication device. The memory system 30000 can include a memory device 1100 and a controller 1200 capable of controlling the operation of the memory device 1100. Under the control of the processor 3100, the controller 1200 may control data access operations, such as a program operation, an erase operation, or a read operation, of the memory device 1100.

Data programmed to memory device 1100 may be transmitted as output by display 3200 under the control of controller 1200.

The radio transceiver 3300 may transmit and receive a radio signal through an antenna ANT. For example, the radio transceiver 3300 may change a radio signal received through the antenna ANT into a signal that can be processed in the processor 3100. Accordingly, the processor 3100 may process a signal output from the radio transceiver 3300 and transmit the processed signal to the controller 1200 or the display 3200. The controller 1200 may program signals processed by the processor 3100 to the memory device 1100. In addition, the radio transceiver 3300 may change a signal output from the processor 3100 into a radio signal and output the changed radio signal to an external device through an antenna ANT. The input device 3400 may be used to input a control signal that controls the operation of the processor 3100 or data to be processed by the processor 3100. The input device 3400 may be implemented in a pointing device such as a touch pad, a computer mouse, and a keypad or keyboard. The processor 3100 may control the operation of the display 3200 such that data output from the memory controller 1200, data output from the radio transceiver 3300, or data output from the input device 3400 is output through the display 3200.

In one embodiment, the controller 1200 capable of controlling the operation of the memory device 1100 may be implemented as a part of the processor 3100 or a chip provided separately from the processor 3100. Alternatively, the controller 1200 may be implemented by the example of the controller shown in fig. 2.

Fig. 11 is a diagram illustrating a memory system 40000 according to an embodiment of the present disclosure.

Referring to fig. 11, the memory system 40000 may be implemented in a Personal Computer (PC), a tablet PC, a netbook, an e-reader, a Personal Digital Assistant (PDA), a Portable Multimedia Player (PMP), an MP3 player, or an MP4 player.

The memory system 40000 may include a memory device 1100 and a controller 1200 capable of controlling data processing operations of the memory device 1100.

The processor 4100 may output data stored in the memory device 1100 through the display 4300 according to data input from the input device 4200. For example, the input device 4200 may be implemented in a pointing device such as a touch pad, computer mouse, keypad, or keyboard.

The processor 4100 may control the overall operation of the memory system 40000 and control the operation of the controller 1200. In an embodiment, the controller 1200 capable of controlling the operation of the memory device 1100 may be implemented as a part of the processor 4100 or a chip provided separately from the processor 4100. Alternatively, the controller 1200 may be implemented by the example of the controller shown in fig. 2.

Fig. 12 is a diagram illustrating a memory system 50000 according to an embodiment of the present disclosure.

Referring to fig. 12, the memory system 50000 may be implemented in an image processing apparatus such as: a digital camera, a portable telephone equipped with a digital camera, a smartphone equipped with a digital camera, or a tablet PC equipped with a digital camera.

The memory system 50000 may include a memory device 1100 and a controller 1200, the controller 1200 being capable of controlling data processing operations of the memory device 1100, such as a program operation, an erase operation, or a read operation.

The image sensor 5200 of the memory system 50000 may convert the optical image to a digital signal. The converted digital signal may be transmitted to the processor 5100 or the controller 1200. The converted digital signal may be transmitted as output through the display 5300 or stored in the memory device 1100 through the controller 1200 under the control of the processor 5100. The data stored in the memory device 1100 may be transmitted as output through the display 5300 under the control of the processor 5100 or the controller 1200.

In an embodiment, the controller 1200 capable of controlling the operation of the memory device 1100 may be implemented as part of the processor 5100 or as a chip provided separately from the processor 5100. Alternatively, the controller 1200 may be implemented by the example of the controller shown in fig. 2.

Fig. 13 is a diagram illustrating a memory system 70000 according to an embodiment of the present disclosure.

Referring to fig. 13, the memory system 70000 may be implemented in a memory card or a smart card. The memory system 70000 may include a memory apparatus 1100, a controller 1200, and a card interface 7100.

The controller 1200 may control data exchange between the memory device 1100 and the card interface 7100. In an embodiment, the card interface 7100 may be a Secure Digital (SD) card interface or a multimedia card (MMC) interface, but is not limited thereto. The controller 1200 may be implemented by the example of the controller shown in fig. 2.

The card interface 7100 can interface data exchange between the host 60000 and the controller 1200 according to a protocol of the host 60000. In an embodiment, the card interface 7100 may support a Universal Serial Bus (USB) protocol and an inter-chip (IC) -USB protocol. For example, the card interface may refer to hardware capable of supporting a protocol used by the host 60000, software installed in hardware, or a signal transmission scheme.

When the memory system 70000 is connected to a host interface 6200 of a host 60000 such as a PC, a tablet computer, a digital camera, a digital audio player, a cellular phone, console video game hardware, or a digital set-top box, the host interface 6200 can perform data communication with the memory device 1100 through the card interface 7100 and the controller 1200 under the control of the microprocessor 6100.

In various embodiments of the present disclosure, during a read operation of a memory system, a degradation characteristic is determined according to a threshold voltage distribution of memory cells. A reprogramming operation or a recycling operation is performed based on the degradation characteristic, so that the retention characteristic of the memory cell can be improved.

Although embodiments of the present disclosure have been disclosed, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the disclosure.

The scope of the disclosure, therefore, is not to be restricted except in light of the foregoing description, by the appended claims and their equivalents.

In the embodiments discussed above, all steps may be selectively performed or skipped. In addition, the steps in each embodiment may not always be performed in a fixed order. Furthermore, the embodiments disclosed in the specification and the drawings are intended to help those of ordinary skill in the art clearly understand the present disclosure, and are not intended to limit the scope of the present disclosure. In other words, those having ordinary skill in the art to which the present disclosure pertains will readily appreciate that various modifications are possible based on the technical scope of the present disclosure.

The embodiments of the present disclosure have been described with reference to the accompanying drawings, and specific terms or words used in the description should be construed according to the spirit of the present disclosure without limiting the subject matter thereof. It should be understood that many variations and modifications of the basic inventive concepts described herein will still fall within the spirit and scope of the present disclosure, as defined by the appended claims and their equivalents.