阅读说明：本技术 存储系统及其操作方法 (Storage system and operation method thereof ) 是由 曹永慜 金泰孝 边大锡 李承源 于 2021-05-21 设计创作，主要内容包括：提供了一种存储系统。该存储系统包括：具有多个存储单元的存储器件；以及存储控制器,被配置为控制存储器件以执行以下操作：将写数据存储在多个存储单元中的第一存储单元中,识别包括第一存储单元中的至少一个第一存储单元在内的第一单元串的当前电荷量以及与该第一单元串相邻的第二单元串的当前电荷量,并且基于第一单元串的当前电荷量和第二单元串的当前电荷量,将虚设数据存储在与第一单元串或第二单元串相连的至少一个存储单元中。(A storage system is provided. The storage system includes: a memory device having a plurality of memory cells; and a memory controller configured to control the memory device to perform operations of: the method includes storing write data in a first memory cell of a plurality of memory cells, identifying a current charge amount of a first cell string including at least one first memory cell of the first memory cells and a current charge amount of a second cell string adjacent to the first cell string, and storing dummy data in at least one memory cell connected to the first cell string or the second cell string based on the current charge amount of the first cell string and the current charge amount of the second cell string.)

1. A storage system, comprising:

a memory device including a plurality of memory cells; and

a memory controller configured to control the memory device to perform operations of:

storing write data in a first memory cell of the plurality of memory cells,

identifying a present amount of charge of a first cell string including at least one of the first memory cells and a present amount of charge of a second cell string adjacent to the first cell string, an

Storing dummy data in at least one memory cell connected to the first cell string or the second cell string based on a current charge amount of the first cell string and a current charge amount of the second cell string.

2. The storage system of claim 1, wherein the storage controller is further configured to: generating the dummy data such that a ratio of a final charge amount of the first cell string to a final charge amount of the second cell string after storing the dummy data in the at least one memory cell corresponds to a preset ratio.

3. The storage system of claim 2, wherein the preset ratio is 1: 1.

4. The storage system of claim 3, wherein the storage controller is further configured to:

identifying a first amount of charge based on a current amount of charge of the first cell string and a current amount of charge of the second cell string,

generating first dummy data such that a final charge amount of the first cell string corresponds to the first charge amount, an

Second dummy data is generated such that a final charge amount of the second cell string corresponds to the first charge amount.

5. The storage system of claim 4, wherein the storage controller is further configured to: the first charge amount is identified based on a larger charge amount of the current charge amount of the first cell string and the current charge amount of the second cell string.

6. The storage system of claim 4, wherein the storage controller is further configured to control the storage device to:

storing the first dummy data in at least one second memory cell connected in series to the first cell, an

Storing the second dummy data in at least one third memory cell connected to the second cell string.

7. The storage system of claim 1, wherein the storage controller is further configured to:

identifying a present amount of charge of a fourth memory cell including at least two of the first memory cells and arranged in sequence in the first cell string, an

Identifying a current charge amount of a fifth memory cell included in the second cell string, the fifth memory cell being adjacent to the fourth memory cell in the first cell string.

8. The storage system of claim 7, wherein the storage controller is further configured to: generating the dummy data based on a current charge amount of the fourth memory cell and a current charge amount of the fifth memory cell such that a final charge amount of the fourth memory cell corresponds to a final charge amount of the fifth memory cell.

9. The storage system of claim 8, wherein the storage controller is further configured to: storing the dummy data in at least some of the fourth memory cells and the fifth memory cells.

10. The storage system according to claim 1, wherein the first storage unit is provided in a preset storage area of the storage device.

11. The storage system of claim 1, wherein the storage controller is further configured to: the first memory cell is randomly selected from the plurality of memory cells.

12. A storage system, comprising:

a memory device including a plurality of memory cells; and

a memory controller configured to control the memory device to perform operations of:

storing write data in a first memory cell of the plurality of memory cells,

identifying a group of memory cells corresponding to the first memory cell;

generating dummy data based on the amount of charge of the second memory cell included in the identified group of memory cells, an

Storing the dummy data in the second storage unit.

13. A method of operating a memory system including a memory device, the method of operation comprising:

storing write data in a first memory cell of the memory device;

identifying a present charge amount of a first cell string including at least one of the first memory cells and a present charge amount of a second cell string adjacent to the first cell string; and

storing dummy data in at least one memory cell connected to the first cell string or the second cell string based on a current charge amount of the first cell string and a current charge amount of the second cell string.

14. The method of operation of claim 13, wherein storing the dummy data comprises:

generating the dummy data such that a ratio of a final charge amount of the first cell string to a final charge amount of the second cell string corresponds to a preset ratio; and

storing the dummy data in the at least one memory cell.

15. The operating method according to claim 14, wherein the preset ratio is 1: 1.

16. The method of operation of claim 15, wherein generating the dummy data comprises:

identifying a first amount of charge based on a present amount of charge of the first cell string and a present amount of charge of the second cell string;

generating first dummy data such that a final charge amount of the first cell string corresponds to the first charge amount; and

second dummy data is generated such that a final charge amount of the second cell string corresponds to the first charge amount.

17. The method of operation of claim 16, wherein storing the dummy data in the at least one memory cell comprises:

storing the first dummy data in at least one second memory cell connected in series with the first cell; and

storing the second dummy data in at least one third memory cell connected to the second cell string.

18. The method of operation of claim 13, further comprising:

identifying a present charge amount of a fourth memory cell including at least two of the first memory cells and arranged in sequence in the first cell string; and

identifying a current charge amount of a fifth memory cell among memory cells included in the second cell string, the fifth memory cell being adjacent to the fourth memory cell.

19. The operating method of claim 18, wherein the dummy data is generated based on a current charge amount of the fourth memory cell and a current charge amount of the fifth memory cell such that a final charge amount of the fourth memory cell corresponds to a final charge amount of the fifth memory cell, and

wherein storing the dummy data comprises: storing the dummy data in at least some of the fourth memory cells and the fifth memory cells.

20. The operating method of claim 13, wherein the write data is stored in a first memory cell randomly selected from among memory cells of the memory device when the write data is stored.

Technical Field

Methods, apparatuses, and systems according to example embodiments relate to a memory system and an operating method thereof, and more particularly, to a memory system and an operating method thereof, which additionally perform an operation for storing dummy data after an operation for storing data requiring security.

Background

With the implementation of the fourth industrial revolution based on Artificial Intelligence (AI) and related innovative technologies, the types of data and the throughput of data have been rapidly increasing. Accordingly, security of a wide variety of data becomes important, and interest in security of mass storage devices has increased. With respect to data storage, secure data (e.g., a secure key) needs to be absolutely protected from hacker intrusion.

Disclosure of Invention

Example embodiments provide a memory system for additionally performing an operation for writing dummy data after a write operation of data requiring security to enhance security, and an operating method thereof.

According to an aspect of example embodiments, a memory system includes a memory device including a plurality of memory cells; and the memory controller is configured to control the memory device to perform the following operations: the method includes storing write data in a first memory cell of a plurality of memory cells, identifying a current charge amount of a first cell string including at least one first memory cell of the first memory cells and a current charge amount of a second cell string adjacent to the first cell string, and storing dummy data in at least one memory cell connected to the first cell string or the second cell string based on the current charge amount of the first cell string and the current charge amount of the second cell string.

According to an aspect of example embodiments, a memory system includes a memory device including a plurality of memory cells; and the memory controller is configured to control the memory device to perform the following operations: the method includes storing write data in a first memory cell of a plurality of memory cells, identifying a group of memory cells corresponding to the first memory cell, generating dummy data based on a charge amount of a second memory cell included in the identified group of memory cells, and storing the dummy data in the second memory cell.

According to an aspect of an example embodiment, an operating method of a memory system including a memory device includes: storing write data in a first memory cell of a memory device; the method includes identifying a current charge amount of a first cell string including at least one first cell among the first cell strings and a current charge amount of a second cell string adjacent to the first cell string, and storing dummy data in at least one memory cell connected to the first cell string or the second cell string based on the current charge amount of the first cell string and the current charge amount of the second cell string.

Drawings

The above and other objects and features will become more apparent from the following description of exemplary embodiments with reference to the attached drawings, in which:

FIG. 1 is a block diagram of a storage system according to an example embodiment;

FIG. 2 is a block diagram of a storage controller according to an example embodiment;

FIG. 3 is a block diagram illustrating an example of a memory device according to an example embodiment;

FIG. 4 is a circuit diagram of a memory block included in a memory cell array according to an example embodiment;

FIG. 5 is a perspective view of the memory block of FIG. 4 according to an example embodiment;

fig. 6A is a diagram illustrating a method of measuring an amount of charge by using X-rays according to an example embodiment, and fig. 6B is a diagram illustrating an X-ray image according to an example embodiment;

FIG. 7 is a flow chart of a method of operation of a storage system according to an example embodiment;

FIG. 8 is a flowchart illustrating operations for generating dummy data and writing the dummy data according to an example embodiment;

fig. 9A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 9B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 9C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment;

fig. 10A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 10B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 10C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment;

fig. 11A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 11B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 11C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment;

FIG. 12 is a flowchart illustrating operations for generating dummy data and writing the dummy data according to an example embodiment;

fig. 13A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 13B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 13C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment;

fig. 14A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, and fig. 14B is a diagram illustrating an X-ray image after writing dummy data according to an example embodiment;

FIG. 15 is a flow diagram of a method of operating a memory system according to an example embodiment;

fig. 16A is a diagram illustrating a group of memory cells according to an example embodiment, fig. 16B is a diagram illustrating a dummy data write operation with respect to the group of memory cells according to an example embodiment, and fig. 16C is a diagram illustrating a dummy data write operation with respect to the group of memory cells according to an example embodiment;

FIG. 17 is a block diagram illustrating an SSD system, according to an example embodiment; and

fig. 18 is a diagram illustrating a structure of a memory device 400 according to an example embodiment.

Detailed Description

FIG. 1 is a block diagram illustrating a storage system 10 according to an example embodiment. Referring to fig. 1, a memory system 10 may include a memory controller 100 and a memory device 200. In an example, the memory controller 100 and the memory device 200 may be implemented as separate chips.

Storage system 10 may include a storage medium for storing data. For example, the storage system 10 may include one or more Solid State Drives (SSDs). However, example embodiments are not limited thereto, and the storage system 10 may include any of various types of devices, such as an embedded multimedia card (eMMC), universal flash memory (UFS), compact flash memory (CF), Secure Digital (SD), micro secure digital (micro-SD), mini secure digital (mini-SD), extreme digital (xD), or a memory stick.

When the memory system 10 includes an SSD, the memory device 200 may include a plurality of flash memory chips (e.g., NAND memory chips) that nonvolatilely store data. Alternatively, the storage device 200 may correspond to one flash memory device, or the storage device 200 may include a memory card including one or more flash memory chips.

When memory system 10 includes a flash memory device, the flash memory device may include a 2D NAND memory array or a 3D (or vertical) NAND (vnand) memory array. The 3D memory array includes an array of memory cells arranged on a silicon substrate and having an active area or circuit related to an operation of the memory cells, and is monolithically formed on the substrate or in at least one physical level of the circuit formed in the substrate. The term "monolithic" indicates that the layers making up the levels of the 3D memory array are stacked directly on the layers of the lower levels of the 3D memory array.

In an example embodiment, a 3D memory array includes vertical NAND strings arranged in a vertical direction such that at least one memory cell is disposed on top of another memory cell. The at least one memory cell may include a charge trapping layer.

U.S. patent nos. 7,679,133, 8,553,466, 8,654,587 and 8,559,235 and U.S. patent application publication No.2011/0233648, the entire contents of which are incorporated herein by reference, disclose suitable configurations for 3D memory arrays in which multiple levels are provided and word lines and/or bit lines are shared between levels.

In another example, storage system 10 may include various other types of memory. For example, the memory system 10 may include a non-volatile memory, and the non-volatile memory may be any of various types of memory, such as magnetic memory (MRAM), spin transfer torque MRAM, conductive bridge RAM (cbram), ferroelectric RAM (feram), phase RAM (pram), resistive RAM, nanotube RAM, polymer RAM (ponam), Nano Floating Gate Memory (NFGM), holographic memory, molecular electronic memory, or insulator resistance change memory.

The memory device 200 may include a memory cell array MCA, the memory cell array MCA may include a plurality of memory blocks BLK1 through BLKz, and a memory block BLK1 may include a plurality of pages PG1 through PGk. Here, z and k may be positive integers, respectively, and may vary according to example embodiments. In one example embodiment, the memory block may be an erase unit and the page may be a write/read unit.

The memory cells of the memory blocks BLK1 to BLKz may be connected to cell strings, word lines, and bit lines constituting the memory cell array MCA. One or more bits may be written to each memory cell. For example, each memory cell may be a Single Level Cell (SLC), a multi-level cell (MLC), a three-level cell (TLC), or a four-level cell (QLC). Hereinafter, for convenience of explanation, it is assumed that each memory cell is an SLC.

The memory controller 100 may perform control operations with respect to the memory device 200. For example, the memory controller 100 may control the memory device 200 to write DATA to the memory device 200 according to a write request from a host, or control the memory device 200 to read DATA from the memory device 200 according to a read request from a host. For example, the memory controller 100 may control the memory device 200 to write the DATA by sending a command CMD, an address ADDR, and the DATA to the memory device 200 through the input/output line. In another example, the memory controller 100 may control the memory device 200 to read DATA by sending a command CMD and an address ADDR to the memory device 200 through the input/output line.

The memory controller 100 may include a data write module 110, the data write module 110 providing functionality related to data write operations. The data write module 110 may perform data write operations with enhanced security. In an example embodiment, the DATA write module 110 may write DATA to the memory device 200 and additionally write DUMMY DATA for security to the memory device 200.

Here, the DATA is DATA requiring security, and may include various types of information, for example, user DATA, user information, information about the storage system 10, security key information, and the like. The DATA may be received from a host or may be generated during operation of the memory system 10. The DUMMY DATA is not valid actual DATA, but only nominally present DATA. The DUMMY DATA may be generated by the DATA write module 110. Hereinafter, a write operation of the data write module 110 with enhanced security will be described in detail.

First, the DATA writing module 110 may write the DATA by dividing the DATA and distributing the divided DATA in one storage area of the memory device 200. For example, the DATA writing module 110 may randomly divide the DATA, randomly select some of a plurality of memory cells included in one memory area of the memory device 200, and write the divided DATA in the selected memory cells.

Here, one storage area of the storage device 200 may be an area set to store secure data, but example embodiments are not limited thereto. For example, the data write module 110 may select one of the plurality of memory regions of the memory device 200 whenever a write operation with enhanced security is performed. The unit of one memory area of the memory device 200 may be a memory cell, a page, a block, a plane, a die, a chip, etc. In addition, the DATA writing module 110 may store address information corresponding to storage locations of the respective divided DATA. The method in which the DATA writing module 110 writes by distributing the DATA is not limited to the above-described example, and the DATA writing module 110 may write the DATA by distributing the DATA in various ways. As described above, the DATA write module 110 may distribute the DATA in the memory device 200, thereby making it more difficult for an unauthorized user to recognize the DATA.

In addition, the DATA writing module 110 may write the DUMMY DATA to a memory cell adjacent or not adjacent to the memory cell where the divided DATA is written. In one example embodiment, the DATA writing module 110 may write the divided DATA to a first memory cell and the DUMMY DATA to other memory cells included in at least one first cell string (i.e., memory cells included in the first cell string to which the divided DATA is not written) and/or memory cells included in a second cell string adjacent to the first cell string.

In an example embodiment, the DATA write module 110 may randomly generate DUMMY DATA. However, example embodiments are not limited thereto, and the DATA writing module 110 may generate the DUMMY DATA based on an amount of charge related to the first memory cell to which the divided DATA is written.

Specifically, the data writing module 110 may calculate the charge amount of at least one first cell string including each of the first memory cells, and calculate the charge amount of a second cell string adjacent to the first cell string. The charge amount of the corresponding cell string may be calculated based on the value of data written to the memory cells connected to the cell string.

For example, data "0" or "1" may be written to a memory cell that is an SLC, and a memory cell to which data "1" is written may have a larger amount of charge than a memory cell to which data "0" is written. In another example, data "00", "01", "10", or "11" may be written to a memory cell as an MLC, where the charge amount of the memory cell to which the data is written may increase in the order of the data "00", "01", "10", and "11". Also, the TLC memory cell or the QLC memory cell may have different charge amounts according to the value of data written therein. Accordingly, the data writing module 110 may calculate the charge amount of each cell string by using the value of the data of the memory cell connected to the corresponding cell string.

In addition, based on the calculation result of the charge amount, the DATA writing module 110 may generate DUMMY DATA that causes a ratio of a final charge amount of the first cell string to a final charge amount of the second cell string after writing the DUMMY DATA to correspond to (substantially equal to) a preset ratio. For example, the preset ratio may be 1: 1 or the like. However, example embodiments are not limited thereto, and various ratios may be applied.

For example, the DATA writing module 110 may generate DUMMY DATA that makes a ratio of a final charge amount of the first cell string to a final charge amount of the second cell string 1: 1 (i.e., the final charge amounts are the same) after writing the DUMMY DATA. When writing DUMMY DATA as described above, similar DATA (but DATA having no meaning in practice) exists around the distributed DATA, and thus it may be difficult for an unauthorized user to recognize the DATA having a meaning in practice. As described above, the DATA writing module 110 may additionally write the DUMMY DATA in an area adjacent or not adjacent to the storage area where the divided DATA is written, thereby making it more difficult for an unauthorized user to recognize the DATA. A detailed description of the operation of the data write module 110 to calculate dummy data will be given later with reference to fig. 7 and 8.

In the above example, the DATA writing module 110 calculates or writes dummy DATA based on a "cell string" including a memory cell in which DATA is written, but example embodiments are not limited thereto. For example, in a modified example embodiment, the DATA writing module 110 may calculate or write dummy DATA based on "word lines" including memory cells to which the DATA is written. Specifically, the DATA writing module 110 may calculate an amount of charge of a first word line including a first memory cell to which the DATA is written, calculate an amount of charge of a second word line adjacent to the first word line, and generate the DUMMY DATA based on the calculation result. In addition, the DATA writing module 110 may write the DUMMY DATA to other memory cells included in the first word line (i.e., memory cells included in the first word line to which the DATA is not written) and/or memory cells included in the second word line.

For example, in another modified example embodiment, the DATA write module 110 may calculate or write dummy DATA based on "bit lines" including memory cells to which the DATA is written. Specifically, the DATA write module 110 may calculate the charge amount of a first bit line including a first memory cell to which the DATA is written, calculate the charge amount of a second bit line adjacent to the first bit line, and generate the DUMMY DATA based on the calculation result. In addition, the DATA write module 110 may write the DUMMY DATA to other memory cells included in the first bit line (i.e., memory cells included in the first bit line to which the DATA is not written) and/or memory cells included in the second bit line.

The data writing module 110 may be implemented in various forms and provided in the memory controller 100. For example, the data writing module 110 may be implemented as hardware HW, e.g. a circuit. Alternatively, the data writing module 110 may be implemented as software SW including a program, and when the processing unit executes the data writing module 110 loaded to the operation memory, various processes related to the data writing operation are performed. Alternatively, the data writing module 110 may be implemented as a combination of hardware HW and software SW. Furthermore, although fig. 1 illustrates the data writing module 110 included in the memory controller 100, example embodiments are not limited thereto. For example, the data write module 110 may be disposed outside of the storage controller 100 within the storage system 10.

The memory system 10 may divide DATA requiring security and write the divided DATA to the distributed memory units, thereby enhancing security. In addition, the memory system 10 can further improve security by writing the DUMMY DATA into memory cells adjacent or not adjacent to the memory cells into which the divided DATA is written.

Hereinafter, for convenience of explanation, data requiring security is referred to as security data, and a storage unit to which the security data is written is referred to as a first storage unit.

FIG. 2 is a block diagram illustrating a memory controller 100 according to an example embodiment. In particular, fig. 2 is a block diagram illustrating the memory controller 100 of fig. 1.

Referring to fig. 1 and 2, the memory controller 100 may include a processor 120, a memory 130, a host interface 140, a memory interface 150, and a bus 160. In addition, the memory 130 may include a data writing module 110. The data writing module 110 may correspond to the data writing module 110 of fig. 1.

The processor 120 may include a Central Processing Unit (CPU) or microprocessor, and may control the overall operation of the memory controller 100 by executing instructions stored in the memory 130. Although FIG. 2 shows one processor 120, memory controller 100 may include multiple processors 120, according to an example embodiment.

The memory 130 may operate under the control of the processor 120 and may be used as an operation memory, a buffer memory, a cache memory, and the like. The memory 130 may be implemented using a volatile memory such as a DRAM or an SRAM, or the memory 130 may be implemented using a non-volatile memory such as a PRAM or a flash memory. In addition, a plurality of memories 130 may be provided.

The data writing module 110 may be implemented as firmware or software, and may be loaded to the memory 130. Although fig. 2 illustrates the data writing module 110 being loaded into the memory 130, example embodiments are not limited thereto. For example, the data write module 110 may be loaded into the memory 130 external to the storage controller 100, or may be provided as a separate hardware component, either internal or external to the storage controller 100.

HOST interface 140 may communicate with HOST through various interfaces. In an example embodiment, the HOST interface 112 may communicate with the HOST over various interfaces including Universal Serial Bus (USB), multimedia card (MMC), PCI Express (PCI-E), AT attachment (ATA), serial AT attachment (SATA), parallel AT attachment (PATA), Small Computer System Interface (SCSI), serial attached SCSI (sas), Enhanced Small Disk Interface (ESDI), and Integrated Drive Electronics (IDE). In addition, a non-volatile memory standard (NVMe) has been proposed as an interface optimized for a storage system such as an SSD, and the NVMe interface may be applied to the host interface 140. According to an example embodiment, the HOST interface 140 may receive a write request and DATA requiring security from the HOST.

The memory interface 150 may provide a channel between the memory controller 100 and the memory device 200. For example, commands CMD, addresses ADDR, and DATA may be transmitted and received between the memory controller 100 and the memory device 200 through the memory interface 150.

Communication between memory controller 100, processor 120, memory 130, host interface 140, and memory interface may be performed over bus 160.

FIG. 3 is a block diagram illustrating an example implementation of a memory device 200 according to an example embodiment. In particular, fig. 3 is a block diagram illustrating the memory device 200 of fig. 1.

Referring to fig. 3, the memory device 200 may include a memory cell array 210, a voltage generator 220, a control logic device 230, a row decoder 240, and a page buffer 250. Although not shown in fig. 3, the memory device 200 may also include various other components related to memory operations, such as data input/output circuits, input/output interfaces, or buses.

The memory cell array 210 includes a plurality of memory blocks BLK1 through BLKz, and memory cells of the memory blocks BLK1 through BLKz may be connected to word lines WL, string selection lines SSL, ground selection lines GSL, and bit lines BL. The memory cell array 210 may be connected to the row decoder 240 through word lines WL, string select lines SSL, and ground select lines GSL, and may be connected to a page buffer 250 through bit lines BL.

The control logic device 230 may output various internal control signals for writing data to the memory cell array 210 or reading data from the memory cell array 210 based on a command CMD, an address ADDR, and a control signal CTRL received from the memory controller 100. For example, the control logic device 230 may supply a row address X-ADDR and a column address Y-ADDR corresponding to a storage location of the DATA to the row decoder 240 and the page buffer 250, respectively, and supply a control voltage CTRL _ vol to the voltage generator 220.

Fig. 4 is a circuit diagram illustrating a memory block included in the memory cell array 210 according to an example embodiment. In particular, fig. 4 is a circuit diagram illustrating a memory block BLK1 included in the memory cell array 210 of fig. 3.

Referring to fig. 3 and 4, the memory cell array 210 may be a memory cell array of a vertical NAND flash memory, and may include a plurality of memory blocks. Each memory block BLK1 may include a plurality of NAND cell strings NS11 to NS33, a plurality of word lines WL1 to WL8, a plurality of bit lines BL1 to BL3, a plurality of ground select lines GSL1 to GSL3, a plurality of cell string select lines SSL1 to SSL3, and a common source line CSL. Here, the number of NAND cell strings, the number of word lines, the number of bit lines, the number of ground select lines, and the number of cell string select lines may vary according to example embodiments.

The NAND cell strings NS11, NS21, and NS31 are disposed between the first bit line BL1 and the common source line CSL, the NAND cell strings NS12, NS22, and NS32 are disposed between the second bit line BL2 and the common source line CSL, and the NAND cell strings NS13, NS23, and NS33 are disposed between the third bit line BL3 and the common source line CSL. Each NAND cell string (e.g., NS11) may include a cell string selection transistor SST, a plurality of memory cells MC1 through MC8, and a ground selection transistor GST coupled in series.

The NAND cell strings commonly coupled to one bit line constitute one column. For example, the NAND cell strings NS11, NS21, and NS31 commonly coupled to the first bit line BL1 may correspond to a first column, the NAND cell strings NS12, NS22, and NS32 commonly coupled to the second bit line BL2 may correspond to a second column, and the NAND cell strings NS13, NS23, and NS33 commonly coupled to the third bit line BL3 may correspond to a third column.

The NAND cell strings coupled to one cell string selection line constitute one row. For example, NAND cell strings NS11, NS12, and NS13 coupled to the first cell string select line SSL1 may correspond to a first row, NAND cell strings NS21, NS22, and NS23 coupled to the second cell string select line SSL2 may correspond to a second row, and NAND cell strings NS31, NS32, and NS33 coupled to the third cell string select line SSL3 may correspond to a third row.

The cell string selection transistors SST are coupled to corresponding string selection lines SSL1 through SSL 3. The memory cells MC 1-MC 8 are coupled to corresponding word lines WL 1-WL 8, respectively. The ground selection transistors GST are coupled to corresponding ground selection lines GSL1 through GSL 3. The cell string selection transistors SST are coupled to the corresponding bit lines BL1 to BL3, respectively, and the ground selection transistors GST are coupled to the common source line CSL.

Word lines of the same height (e.g., WL1) are commonly coupled to each other, cell string select lines SSL 1-SSL 3 are separated from each other, and ground select lines GSL 1-GSL 3 are also separated from each other. For example, when memory cells coupled to the first word line WL1 and belonging to the NAND cell strings NS11, NS12, and NS13 are programmed, the first word line WL1 and the first cell string select line SSL1 are selected. The ground selection lines GSL1 through GSL3 may be commonly coupled to each other.

The memory system 10 of fig. 1 according to example embodiments may store the DATA and the DUMMY DATA in areas adjacent or not adjacent to each other within the memory cell array 210. For example, the secure data may be stored in the eighth memory cell MC8 connected to the eighth word line WL8 of the NAND cell string NS13 of the memory block BLK1, and the dummy data may be stored in the eighth memory cell MC8 connected to the eighth word line WL8 of the NAND cell string NS23 adjacent to the NAND cell string NS 13.

Fig. 5 is a perspective view of the memory block of fig. 4.

Referring to fig. 4 and 5, memory blocks included in the memory cell array 210 are formed in a vertical direction with respect to the substrate SUB. Although fig. 5 shows that the memory block includes two select lines GSL and SSL, eight word lines WL1 to WL8, and three bit lines BL1 to BL3, the actual number may be less than or greater than the above number.

The substrate SUB has a first conductivity type (e.g., p-type), and a common source line CSL extending in a first direction (e.g., Y-direction) and doped with impurities of a second conductivity type (e.g., n-type) is disposed in the substrate SUB. A plurality of insulating films IL extending in the first direction are sequentially disposed in a third direction (e.g., Z direction) on a region of the substrate SUB between two adjacent common source lines CSL, and the insulating films IL are spaced apart from each other by a certain distance in the third direction. For example, the insulating film IL may include an insulating material such as silicon oxide.

A plurality of pillars P sequentially arranged in the first direction and penetrating the insulating film IL in the third direction are disposed on a region of the substrate SUB between two adjacent common source lines CSL. For example, the pillars P will be in contact with the substrate SUB by penetrating the insulating film IL. Specifically, the surface layer S of each pillar P may include a silicon-based material doped with impurities of the first conductivity type and serve as a channel region. On the other hand, the inner layer I of each pillar P may include an insulating material such as silicon oxide or an air gap.

The charge storage layer CS is disposed in a region between two adjacent common source lines CSL along the exposed surfaces of the insulating film IL, the pillars P, and the substrate SUB. The charge storage layer CS may include a gate insulating layer (also referred to as a "tunnel insulating layer"), a charge trapping layer, and a blocking insulating layer. For example, the charge storage layer CS may have an oxide-nitride-oxide (ONO) structure. In addition, gate electrodes GE such as selected gate lines GSL and SSL and word lines WL1 to WL8 are disposed on the exposed surface of the charge storage layer CS in a region between two adjacent common source lines CSL.

A drain or drain contact DR is provided on the pillar P, respectively. For example, the drain or drain contact DR may comprise a silicon-based material doped with impurities of the second conductivity type. Bit lines BL1 to BL3 extending in the second direction (e.g., the X direction) and spaced apart from each other by a certain distance in the first direction are disposed on the drain.

Fig. 6A is a diagram illustrating a method of measuring an amount of charge by using X-rays according to an example embodiment, and fig. 6B is a diagram illustrating an X-ray image according to an example embodiment. In fig. 6A and 6B, for easy understanding, a method of measuring the amount of electric charge by using X-rays and X-ray images with respect to a memory block BLK1 of a two-dimensional semiconductor (or a planar semiconductor) will be described. In addition, it is assumed that the memory cells connected to memory block BLK1 are SLCs.

Referring to fig. 6A, the memory block BLK1 may include word lines WL1 to WLn extending in a first direction (e.g., Y direction), and bit lines BL1 to BLm extending in a second direction (e.g., X direction). In addition, the memory cells MC1 to MCn-1 may be connected to points at which the word lines WL1 to WLn intersect the bit lines BL1 to BLm, respectively.

The memory cells MC1 through MCn-1 of each bit line included in the memory block BLK1 may each have an amount of charge corresponding to a value of data stored therein. In addition, the amount of charge of the imaging target can be measured by using the X-ray image. Accordingly, when X-ray imaging is performed on the memory block BLK1 in the third direction (e.g., Z direction), the respective charge amounts of the memory cells MC1 to MCn-1 can be measured. Hereinafter, for convenience of explanation, it is assumed that the value of the charge amount of the memory cell to which data "1" is written is 2, and the value of the charge amount of the memory cell to which data "0" is written is 1. However, the above assumption is only an example to aid understanding, and does not limit that the charge amount of the memory cell having data "1" and the charge amount of the memory cell having data "0" have a multiple relationship.

Referring to fig. 6A, the n-1 st memory cell MCn-1 connected to the second bit line BL2 of the memory block BLK1 may be a memory cell to which data "1" is written, and the n-1 th memory cell MCn connected to the second bit line BL2 of the memory block BLK1 may be a memory cell to which data "0" is written. Therefore, referring to fig. 6B, when viewed in the third direction, the value of the charge amount of the n-1 th memory cell MCn-1 may be 2, and the value of the charge amount of the n-th memory cell MCn may be 1. In addition, X-ray imaging can be performed on the two storage units MCn-1 and MCn in the third direction.

As the amount of charge of the imaging target increases, the X-ray image becomes dark. Therefore, referring to FIG. 6B, an X-ray image of the n-1 st memory cell MCn-1 of the second bit line BL2 taken in the third direction may have a darker color than an X-ray image of the n-th memory cell MCn of the second bit line BL2 taken in the third direction. In this way, by using the X-ray image, the charge amount of each storage unit can be measured, and a data value corresponding to the measured charge amount can be inferred.

Although fig. 6A and 6B illustrate a method of measuring the charge amount of the memory blocks of the two-dimensional semiconductor by using X-rays, the charge amount of the memory blocks of the three-dimensional semiconductor may also be measured by X-ray imaging.

Specifically, the memory block BLK1 of fig. 5 may include a plurality of cell strings extending in a third direction (e.g., Z direction). In addition, when X-ray imaging is performed on the storage units arranged in a line, the X-ray image may represent an image in which the charge amounts of the storage units are accumulated. Therefore, when the X-ray imaging is performed on the memory block BLK1 of fig. 5 in the third direction (for example, the Z direction), the X-ray image may represent an image in which the amount of charges of the memory cells connected to each cell string is accumulated. Therefore, when X-ray imaging is performed on a memory block of a three-dimensional semiconductor, the amount of charge of each cell string can be measured.

As described above, by using the X-ray image, the charge amount of the memory cell of the two-dimensional semiconductor can be measured, or the charge amount of the cell string of the three-dimensional semiconductor can be measured. Since the amount of charge and the data value are correlated with each other, the data value of the memory cell can be inferred by using the X-ray image.

In order to prevent the data value of the memory cell from being inferred by using the X-ray image, the data writing module 110 of fig. 1 may distribute and store data (security data) requiring security to a first memory cell, and write dummy data to a memory cell adjacent or not to the first memory cell where the security data is written. In particular, the data writing module 110 of fig. 1 may generate dummy data that makes the charge amounts of the cell strings of the semiconductor memory identical to each other, and write the generated dummy data into adjacent or non-adjacent memory cells, thereby making the X-ray images of the cell strings identical to each other and preventing data values from being inferred from the X-ray images.

FIG. 7 is a flow diagram of a method of operating a memory system according to an example embodiment. In particular, FIG. 7 is a flow chart of a method of operating the memory system 10 of FIG. 1. At least some of the operations making up the method shown in fig. 7 may be performed by the storage controller 100 of the storage system 10.

Referring to fig. 1 and 7, the storage system 10 may write data (e.g., security data requiring security) to a first storage unit of the storage device 200 (operation S110). Specifically, the storage system 10 may divide the security data requiring security, and distribute the divided security data in one storage area of the storage device 200. For example, the data write module 110 may randomly divide the security data, randomly select a first memory cell from a plurality of memory cells included in one memory area of the memory device 200, and write the divided security data to the selected first memory cell.

In addition, the memory system 10 may calculate the charge amount of at least one first cell string including each of the first memory cells and the charge amount of a second cell string adjacent to the first cell string. The charge amount of the corresponding cell string may be calculated based on the value of data written to the memory cells connected to the cell string.

Further, the storage system 10 may write dummy data to at least one memory cell connected to the first cell string or the second cell string based on the calculation result (operation S130). Specifically, based on the calculation result, the memory system 10 may generate dummy data such that the ratio of the final charge amount of the first cell string to the final charge amount of the second cell string after writing the dummy data corresponds to a preset ratio. For example, the preset ratio may be 1: 1 or the like, but example embodiments are not limited thereto. Further, the storage system 10 may write the generated dummy data to at least one storage unit connected to the first cell string or the second cell string. In FIG. 8 below, a specific exemplary embodiment with a preset ratio of 1: 1 will be described.

Fig. 8 is a flowchart illustrating operations for generating and writing dummy data according to an example embodiment. Specifically, fig. 8 is a diagram illustrating a detailed operation of operation S130 of fig. 7. Fig. 8 illustrates an example embodiment for generating dummy data such that a preset ratio between a final charge amount of a first cell string and a final charge amount of a second cell string is 1: 1.

Referring to fig. 1, 7, and 8, the memory system 10 may determine a first charge amount, which is a basis for generating dummy data, based on a current charge amount of the first cell string and a current charge amount of the second cell string (operation S210). Specifically, after the secure data is written to the first memory cell, the memory system 10 may determine the first charge amount based on the charge amount of the first cell string and the charge amount of the second cell string. In one example embodiment, the first charge amount may be determined based on a larger charge amount of the current charge amount of the first cell string and the current charge amount of the second cell string. When the dummy data is written, the charge amount of the cell string is maintained (e.g., when the dummy data is "0") or increased, and thus the first charge amount may be determined to be a value equal to or greater than the maximum charge amount. For example, when the value of the current charge amount of the first cell string is 4 and the value of the current charge amount of the second cell string is 2, the memory system 10 may determine a value equal to or greater than 4 as the first charge amount.

Next, the memory system 10 may generate first dummy data that causes a final charge amount of the first cell string to correspond to (substantially equal to) the first charge amount (operation S220). Specifically, the memory system 10 may calculate a difference between the current charge amount of the first cell string and the first charge amount, and may generate first dummy data corresponding to the calculated difference.

For example, when the current charge amount of the first cell string has a value of 10 and the first charge amount has a value determined to be 12, the memory system 10 may generate the first dummy data that may increase the charge amount of the first cell string by 2. In another example, when the value of the current charge amount of the first cell string is 8 and the value of the first charge amount is also determined to be 8, dummy data does not have to be written to the first cell string, and thus the memory system 10 may omit an operation for generating the first dummy data.

Next, the memory system 10 may generate second dummy data that causes the final charge amount of the second cell string to correspond to (substantially equal to) the first charge amount (operation S230). Specifically, the memory system 10 may calculate a difference between the current charge amount of the second cell string and the first charge amount, and may generate second dummy data corresponding to the calculated difference. For example, when the current charge amount of the second cell string has a value of 8 and the first charge amount has a value of 10, the memory system 10 may generate the second dummy data that may increase the charge amount of the second cell string by 2.

In addition, the storage system 10 may write the first dummy data to at least one second storage unit among the second storage units connected to the first cell string (operation S240). Specifically, the storage system 10 may write the first dummy data to the remaining second storage units, other than the first storage unit to which the secure data is written, of all the storage units connected to the first cell string.

In addition, the memory system 10 may write second dummy data to at least one third memory cell connected to the second cell string (operation S250). Specifically, the memory system 10 may write the second dummy data to at least one third memory cell among all the memory cells connected to the second cell string. The at least one third storage unit may correspond to a storage unit connected to the second cell string except for the first storage unit to which the security data is written, among all storage units connected to the second cell string. When it is determined in operations S220 and S230 that dummy data does not have to be written, operations S240 and S250 may be omitted.

The order of operations in the flowchart of fig. 8 is only an example, and the order of operations S220 and S230 and the order of operations S240 and S250 may be changed.

Fig. 9A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 9B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 9C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment.

Fig. 9A shows cell strings NS11 and NS21 connected to a first bit line BL1 and cell strings NS12 and NS22 connected to a second bit line BL2 in the memory cell array of the memory block BLK 1. Referring to fig. 9A, the storage system 10 of fig. 1 may partition security data requiring security and store the partitioned security data in the storage cells MC13, MC15, and MC18 connected to the cell string NS 12. Next, the memory system 10 may determine to write dummy data to the cell string NS22 that is adjacent to the cell string NS12 and connected to the second bit line BL2 together with the cell string NS 12. For convenience of description, it is assumed below that each of the divided security data has data "1".

Referring to fig. 9B, it can be seen that the amount of charge of each of the memory cells MC11 through MC18 and the memory cells MC21 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in a first direction (e.g., Y direction) after the secure data is written. Since the security data is written to the memory cells MC13, MC15, and MC18 connected to the cell string NS12, the value of the charge amount of each of the memory cells MC13, MC15, and MC18 may be 2, which corresponds to data "1". Since the security data is not written to the remaining memory cells MC11, MC12, MC14, MC16, MC17, and MC21 to MC28, the value of the charge amount of each of the memory cells MC11, MC12, MC14, MC16, MC17, and MC21 to MC28 may be 1.

Referring to fig. 9B, it can be seen that the accumulated charge amount of each of the cell strings NS12 and NS22 is observed in the third direction (e.g., Z direction) after the secure data is written. In other words, it can be seen that the total charge amount of the memory cells MC11 to MC18 connected to the cell string NS12 is 11, and the total charge amount of the memory cells MC21 to MC28 connected to the cell string NS22 is 8. In addition, referring to fig. 9B, X-ray images of the cell strings NS12 and NS22 photographed in the third direction after the writing of the security data can be seen. Since the charge amount of the cell string NS12 is larger than that of the cell string NS22, the X-ray image of the cell string NS12 may be darker than that of the cell string NS 22. Although fig. 9B shows that the X-ray image of the cell string NS12 is black and the X-ray image of the cell string NS22 is white, this is merely to aid understanding, and the X-ray image may have brightness corresponding to the magnitude of the amount of charge.

When performing X-ray imaging on the cell strings NS12 and NS22, the storage system 10 may generate dummy data for making the X-ray images identical or similar to each other, and store the generated dummy data in at least one storage cell connected to the cell strings NS12 and NS 22. The memory system 10 can recognize the final charge amount of each of the cell strings NS12 and NS 22. The final charge amount may be the same. The final amount of charge may correspond to a current amount of charge stored in one of the cell strings. The final amount of charge may be greater than the current amount of charge stored on each of the cell strings. The dummy data may be generated based on the final charge amount. Specifically, the memory system 10 may generate dummy data based on the charge amount (i.e., the value of 11) of the cell string NS12 having the larger charge amount among the cell strings NS12 and NS 22. In other words, the memory system 10 may generate dummy data such that the value of the final charge amount of the cell strings NS12 and NS22 is equal to or greater than 11. For example, when the final amount of charge is determined to be 11, the memory system 10 may determine that the first dummy data to be written to the cell string NS12 is unnecessary. Next, the memory system 10 may generate second dummy data for increasing the current charge amount of the cell string NS22 by 3. Next, the storage system 10 may write the generated second dummy data to at least some of the memory cells MC21 to MC28 connected to the cell string NS 22.

Referring to fig. 9C, it can be seen that the charge amount of each of the memory cells MC11 through MC18 and the memory cells MC21 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in the first direction (e.g., the Y direction) after the dummy data is written. It can be seen that the second dummy data is written to the memory cells MC24, MC25, and MC27 connected to the cell string NS 22.

In addition, referring to fig. 9C, it can be seen that the accumulated charge amount of each of the cell strings NS12 and NS22 observed in the third direction (for example, the Z direction) after the dummy data is written. In other words, it can be seen that both the total charge amount of the memory cells MC11 to MC18 connected to the cell string NS12 and the total charge amount of the memory cells MC21 to MC28 connected to the cell string NS22 are 11.

In addition, referring to fig. 9C, X-ray images of the cell strings NS12 and NS22 photographed in the third direction after the dummy data is written can be seen. Since the cell string NS12 and the cell string NS22 have the same amount of charge, the X-ray images of the cell strings NS12 and NS22 may have the same color.

Although fig. 9A to 9C illustrate an example embodiment in which the storage system 10 splits the security data and writes the split security data to only one unit string NS12, the example embodiment is not limited thereto. The storage system 10 may write the partitioned security data to two cell strings. An example embodiment in which the storage system 10 writes split secure data to two cell strings will be described below with reference to fig. 10A to 10C.

Fig. 10A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 10B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 10C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment.

Referring to fig. 10A, the storage system 10 of fig. 1 may partition security data requiring security and store the partitioned security data to the storage cell MC18 connected to the cell string NS12 and the storage cells MC22 and MC24 connected to the cell string NS 22. Next, the storage system 10 may determine to write dummy data to the cell string NS12 and the cell string NS 22.

Referring to fig. 10B, it can be seen that the amount of charge of each of the memory cells MC11 through MC18 and the memory cells MC21 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in a first direction (e.g., Y direction) after the secure data is written. Since the security data is written to the memory cell MC18 connected to the cell string NS12 and the memory cells MC22 and MC24 connected to the cell string NS22, the value of the charge amount of each of the memory cells MC18, MC22, and MC24 may be 2, which corresponds to data "1". Since the security data is not written to the remaining memory cells MC11 through MC17, MC21, MC23, and MC25 through MC28, the value of the charge amount of each of the memory cells MC11 through MC17, MC21, MC23, and MC25 through MC28 may be 1.

Referring to fig. 10B, it can be seen that the accumulated charge amount of each of the cell strings NS12 and NS22 observed in the third direction (e.g., Z direction) after the secure data is written. In other words, it can be seen that the total charge amount of the memory cells MC11 to MC18 connected to the cell string NS12 is 9, and the total charge amount of the memory cells MC21 to MC28 connected to the cell string NS22 is 10. In addition, referring to fig. 10B, X-ray images of the cell strings NS12 and NS22 taken in the third direction after the writing of the security data can be seen. Since the charge amount of the cell string NS22 is larger than that of the cell string NS12, the X-ray image of the cell string NS22 may be darker than that of the cell string NS 12.

When performing X-ray imaging on the cell strings NS12 and NS22, the storage system 10 may generate dummy data for making the X-ray images identical or similar to each other, and store the generated dummy data in at least one storage cell connected to the cell strings NS12 and NS 22. The memory system 10 can recognize the final charge amount of each of the cell strings NS12 and NS 22. The final charge amount may be the same. The final amount of charge may correspond to a current amount of charge stored in one of the cell strings. The final amount of charge may be greater than the current amount of charge stored on each of the cell strings. The dummy data may be generated based on the final charge amount. Specifically, the memory system 10 may generate dummy data based on the charge amount (i.e., the value of 10) of the cell string NS22 having the larger charge amount among the cell strings NS12 and NS 22. In other words, the memory system 10 may generate dummy data such that the value of the final charge amount of the cell strings NS12 and NS22 is equal to or greater than 10. For example, when the final charge amount is determined to be 11, the memory system 10 may generate the first dummy data for increasing the current charge amount of the cell string NS12 by 2. Next, the memory system 10 may generate second dummy data for increasing the current charge amount of the cell string NS22 by 1. Next, the storage system 10 may write the generated first dummy data to at least some of the storage cells MC11 to MC18 connected to the cell string NS12, and write the generated second dummy data to at least some of the storage cells MC21 to MC28 connected to the cell string NS 22.

Referring to fig. 10C, it can be seen that the charge amount of each of the memory cells MC11 through MC18 and the memory cells MC21 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in the first direction (e.g., the Y direction) after the dummy data is written. It can be seen that the first dummy data is written to the memory cells MC13 and MC17 connected to the cell string NS12, and the second dummy data is written to the memory cell MC27 connected to the cell string NS 22.

In addition, referring to fig. 10C, it can be seen that the accumulated charge amount of each of the cell strings NS12 and NS22 observed in the third direction (for example, the Z direction) after the dummy data is written. In other words, it can be seen that both the total charge amount of the memory cells MC11 to MC18 connected to the cell string NS12 and the total charge amount of the memory cells MC21 to MC28 connected to the cell string NS22 are 11.

In addition, referring to fig. 10C, X-ray images of the cell strings NS12 and NS22 photographed in the third direction after the dummy data is written can be seen. Since the cell string NS12 and the cell string NS22 have the same amount of charge, the X-ray images of the cell strings NS12 and NS22 may have the same color.

On the other hand, although fig. 10A to 10C illustrate example embodiments in which the storage system 10 writes secure data to the cell strings NS12 and NS22 and writes dummy data only to the cell strings NS12 and NS22 to which the secure data is written, example embodiments are not limited thereto. Specifically, even when the secure data is written to the unit strings NS12 and NS22, the storage system 10 may write dummy data to the unit strings that are adjacent to the unit strings NS12 and NS22 and that do not store the secure data.

In addition, a description has been given above of the memory system 10 generating and writing dummy data by comparing the charge amounts of the cell strings connected to the same bit line BL2 and adjacent to each other with reference to fig. 9A to 10C, but example embodiments are not limited thereto. The memory system 10 may generate and write dummy data by comparing the amount of charge between cell strings connected to different bit lines and adjacent to each other. A detailed description thereof will be given below with reference to fig. 11A to 11C.

Fig. 11A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 11B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 11C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment.

Referring to fig. 1, the storage system 10 of fig. 1 may divide security data requiring security and store the divided security data in the storage cells MC15 and MC18 connected to the cell string NS 12. Next, the memory system 10 may determine to write dummy data to the cell string NS22 that is adjacent to the cell string NS12 but connected to a different bit line (i.e., the first bit line BL 1).

Referring to fig. 11B, it can be seen that the amount of charge of each of the memory cells MC11 through MC18 and the memory cells MC31 through MC38 connected to the cell strings NS11 and NS12, respectively, is observed in the second direction (e.g., the X direction) after the secure data is written. Since the security data is written to the memory cells MC15 and MC18 connected to the cell string NS12, the charge amount of each of the memory cells MC15 and MC18 may have a value of 2, which corresponds to data "1". Since the security data is not written to the remaining memory cells MC11 through MC14, MC16, MC17, and MC31 through MC38, the value of the charge amount of each of the memory cells MC11 through MC14, MC16, MC17, and MC31 through MC38 may be 1.

Referring to fig. 11B, it can be seen that the accumulated charge amount of each of the cell strings NS11 and NS12 observed in the third direction (e.g., Z direction) after the secure data is written. In other words, it can be seen that the total charge amount of the memory cells MC31 to MC38 connected to the cell string NS11 is 8, and the total charge amount of the memory cells MC11 to MC18 connected to the cell string NS12 is 10. In addition, referring to fig. 11B, X-ray images of the cell strings NS11 and NS12 photographed in the third direction after the writing of the security data can be seen. Since the charge amount of the cell string NS12 is larger than that of the cell string NS11, the X-ray image of the cell string NS12 may be darker than that of the cell string NS 11.

When performing X-ray imaging on the cell strings NS11 and NS12, the storage system 10 may generate dummy data for making the X-ray images identical or similar to each other, and store the generated dummy data in at least one storage cell connected to the cell strings NS11 and NS 12. The memory system 10 can recognize the final charge amount of each of the cell strings NS12 and NS 22. The final charge amount may be the same. The final amount of charge may correspond to a current amount of charge stored in one of the cell strings. The final amount of charge may be greater than the current amount of charge stored on each of the cell strings. The dummy data may be generated based on the final charge amount. Specifically, the memory system 10 may generate dummy data such that the final charge amount of the cell strings NS11 and NS12 has a value equal to or greater than 10. For example, when the final amount of charge is determined to be 10, the memory system 10 may determine that the first dummy data to be written to the cell string NS12 is unnecessary. Next, the memory system 10 may generate second dummy data for increasing the current charge amount of the cell string NS11 by 2.

Referring to fig. 11C, it can be seen that the charge amount of each of the memory cells MC11 through MC18 and the memory cells MC31 through MC38 connected to the cell strings NS11 and NS12, respectively, is observed in the second direction (e.g., the X direction) after the dummy data is written. It can be seen that the second dummy data is written to the memory cells MC33 and MC38 connected to the cell string NS 11.

In addition, referring to fig. 11C, it can be seen that the accumulated charge amount of each of the cell strings NS11 and NS12 observed in the third direction (for example, the Z direction) after the dummy data is written. In other words, it can be seen that the total charge amount of the memory cells MC31 to MC38 connected to the cell string NS11 and the total charge amount of the memory cells MC21 to MC28 connected to the cell string NS12 are both 10.

In addition, referring to fig. 11C, X-ray images of the cell strings NS11 and NS12 photographed in the third direction after the dummy data is written can be seen. Since the cell string NS11 and the cell string NS12 have the same amount of charge, the X-ray images of the cell strings NS11 and NS12 may have the same color.

Example embodiments of writing dummy data to memory cells connected to a first cell string to which secure data is written or a second cell string adjacent to the first cell string are described above with reference to fig. 9A to 11C. However, example embodiments are not limited thereto, and dummy data may also be written to a third cell string that is not adjacent to the first cell string in the above-described manner.

In addition, the example embodiments of calculating the charge amount based on the cell string and writing the dummy data are described above with reference to fig. 9A to 11C, but the example embodiments are not limited thereto. Specifically, the amount of charge may be calculated based on the word line (or bit line), dummy data may be generated based on the calculated amount of charge, and the dummy data may be written to a first word line (or first bit line) or an adjacent second word line (or adjacent second bit line) to which the secure data is written. Since the present exemplary embodiment can be performed in substantially the same manner as the exemplary embodiment based on the cell string, the same description as that already given above will be omitted.

Fig. 12 is a flowchart illustrating an operation for generating and writing dummy data according to an example embodiment. Specifically, fig. 12 is a diagram for describing a modified example embodiment of operations S120 and S130 of fig. 7.

Referring to fig. 1, 7 and 12, the memory system 10 may calculate the current charge amount of a preset number of fourth memory cells, which are sequentially arranged and include the first memory cell, among the memory cells connected to the first cell string (operation S310). Specifically, the memory system 10 may identify a first cell string corresponding to a first memory cell to which the security data has been written, identify a preset number of fourth memory cells, which include the first memory cell and are sequentially arranged, among the memory cells connected to the first cell string, and calculate the current charge amount based on the data values written to the fourth memory cells.

Next, the memory system 10 may calculate the current charge amount of a fifth memory cell adjacent to the fourth memory cell of the first cell string among the memory cells connected to the second cell string (operation S320). Specifically, the memory system 10 may identify a second cell string adjacent to the first cell string, identify fifth memory cells, respectively adjacent to fourth memory cells, among the memory cells connected to the second cell string, and calculate the current charge amount based on the data values written to the fifth memory cells.

Next, the memory system 10 may generate dummy data that causes the final charge amount of the fourth memory cell and the final charge amount of the fifth memory cell to have the same value (operation S330). Specifically, the memory system 10 may determine the first charge amount, which is a basis for generating the dummy data, based on the current charge amount of the fourth memory cell and the current charge amount of the fifth memory cell. For example, the first charge amount may be determined by the memory system 10, and may be equal to or greater than a maximum charge amount of a current charge amount of the fourth memory cell and a current charge amount of the fifth memory cell.

Next, the memory system 10 may generate dummy data for making the final charge amount of the fourth memory cell and the final charge amount of the fifth memory cell the first charge amount. For example, the memory system 10 may calculate a difference between the first charge amount and the current charge amount of the fourth memory cell, and may generate first dummy data corresponding to the calculated difference. Next, the memory system 10 may calculate a difference between the first charge amount and the current charge amount of the fifth memory cell, and may generate second dummy data corresponding to the calculated difference.

Next, the memory system 10 may write the generated dummy data to at least some of the fourth memory cells and the fifth memory cells (operation S340). Specifically, the memory system 10 may write the first dummy data to the remaining memory cells except for the first memory cell in the fourth memory cell, and write the second dummy data to the fifth memory cell. On the other hand, when the fifth storage unit includes another first storage unit in which data requiring security is written, the storage system 10 may write the second dummy data to the remaining storage units other than the other first storage units in the fifth storage unit.

Although fig. 12 illustrates the memory system 10 generating dummy data such that the final charge amount of the fourth memory cell and the final charge amount of the fifth memory cell have the same value in operation S330, example embodiments are not limited thereto. For example, the memory system 10 may generate the final charge amount of the fourth memory cell and the final charge amount of the fifth memory cell to have a preset ratio such as 1: 1 or another preset ratio different from 1: 1.

Fig. 13A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, fig. 13B is a diagram illustrating an X-ray image after writing of security data according to an example embodiment, and fig. 13C is a diagram illustrating an X-ray image after writing of dummy data according to an example embodiment. In particular, fig. 13A to 13C are diagrams for describing in detail a method of operating the memory system of fig. 12.

Fig. 13A shows cell strings NS11 and NS21 connected to a first bit line BL1 and cell strings NS12 and NS22 connected to a second bit line BL2 in the memory cell array of the memory block BLK 1. Referring to fig. 13A, the storage system 10 of fig. 1 may partition security data and store the partitioned security data in the storage cells MC17 and MC18 connected to the cell string NS 12.

Next, the storage system 10 may identify the cell string NS12 to which the storage cells MC17 and MC18, to which the security data has been written, are connected, and identify a preset number (e.g., 3) of the storage cells MC16, MC17, and MC18, including the storage cells MC17 and MC18, to which the security data has been written, among the storage cells connected to the cell string NS 12. Next, the memory system 10 may identify the memory cells MC26, MC27, and MC28 adjacent to the memory cells MC16, MC17, and MC18, respectively, among the memory cells connected to the cell string NS22 adjacent to the cell string NS 12. Next, the storage system 10 may determine to write dummy data to at least some of the identified storage cells MC16, MC17, MC18, MC26, MC27, and MC 28.

Referring to fig. 13B, it can be seen that the amount of charge of each of the memory cells MC16 through MC18 and the memory cells MC26 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in a first direction (e.g., Y direction) after the secure data is written. Since the security data is written to the memory cells MC17 and MC18 connected to the cell string NS12, the charge amount of each of the memory cells MC17 and MC18 may have a value of 2, which corresponds to data "1". Since the security data is not written to the remaining memory cells MC16 and MC26 through MC28, the value of the charge amount of each of the remaining memory cells MC16 and MC26 through MC28 may be 1.

Referring to fig. 13B, it can be seen that the accumulated charge amounts of the memory cells MC16 through MC18 of the cell string NS12 and the memory cells MC26 through MC28 of the cell string NS22 are observed in the third direction (e.g., the Z direction) after the security data is written. In other words, it can be seen that the total charge amount of the memory cells MC16 to MC18 connected to the cell string NS12 is 5, and the total charge amount of the memory cells MC26 to MC28 connected to the cell string NS22 is 3. In addition, referring to fig. 13B, X-ray images of the cell strings NS12 and NS22 taken in the third direction after the writing of the security data can be seen. Since the charge amount of the cell string NS12 is larger than that of the cell string NS22, the X-ray image of the cell string NS12 may be darker than that of the cell string NS 22.

When performing X-ray imaging on the cell strings NS12 and NS22, the storage system 10 may generate dummy data for making the X-ray images identical or similar to each other, and store the generated dummy data in at least one storage cell connected to the cell strings NS12 and NS 22. The memory system 10 can recognize the final charge amount of each of the cell strings NS12 and NS 22. The final charge amount may be the same. The final amount of charge may correspond to a current amount of charge stored in one of the cell strings. The final amount of charge may be greater than the current amount of charge stored on each of the cell strings. The dummy data may be generated based on the final charge amount. Specifically, the memory system 10 may generate dummy data such that the value of the final charge amount of the cell strings NS12 and NS22 is equal to or greater than 5. For example, when the final amount of charge is determined to be 5, the memory system 10 may determine that the first dummy data to be written to the cell string NS12 is unnecessary. Next, the memory system 10 may generate second dummy data for increasing the current charge amount of the cell string NS22 by 2.

Referring to fig. 13C, it can be seen that the charge amount of each of the memory cells MC16 through MC18 and the memory cells MC26 through MC28 connected to the cell strings NS12 and NS22, respectively, is observed in the first direction (e.g., the Y direction) after the dummy data is written. It can be seen that the second dummy data is written to the memory cells MC26 and MC27 connected to the cell string NS 22.

Referring to fig. 13C, it can be seen that the accumulated charge amounts of the memory cells MC16 through MC18 of the cell string NS12 and the memory cells MC26 through MC28 of the cell string NS22 are observed in the third direction (e.g., the Z direction) after the dummy data is written. In other words, it can be seen that the total charge amount of the memory cells MC16 to MC18 of the cell string NS12 and the total charge amount of the memory cells MC26 to MC28 of the cell string NS22 are both 5.

In addition, referring to fig. 13C, X-ray images of the cell strings NS12 and NS22 photographed in the third direction after the dummy data is written can be seen. Since the cell string NS12 and the cell string NS22 have the same amount of charge, the X-ray images of the cell strings NS12 and NS22 may have the same color.

Fig. 14A is a diagram illustrating an X-ray imaging operation of a memory block according to an example embodiment, and fig. 14B is a diagram illustrating an X-ray image after writing dummy data according to an example embodiment. Specifically, fig. 14A and 14B are diagrams for describing a dummy data write operation that may be additionally performed after the operation of the memory system 10 shown in fig. 13A to 13C.

Even after writing dummy data to the memory cells MC27 and MC28 of the cell string NS22, the memory system 10 can additionally write dummy data to the memory cells. Referring to fig. 14A, the memory system 10 may determine to additionally write dummy data to a preset number of consecutive memory cells MC13 through MC15, excluding the preset number of memory cells MC16 through MC18, of memory cells connected to the cell string NS 12.

In addition, according to example embodiments, the memory system 10 may determine to additionally write dummy data to a preset number of consecutive memory cells MC23 through MC25, excluding the preset number of memory cells MC26 through MC28, of memory cells connected to the cell string NS 22.

Since data is not written to the memory cells MC13 through MC15 and the memory cells MC23 through MC25, the value of the charge amount of each of the memory cells MC13 through MC15 and the memory cells MC23 through MC25 may be 1. In other words, the charge amount of the memory cells MC13 to MC15 and MC23 to MC25 may be the same as the charge amount of the memory cells MC26 to MC28 of fig. 13B. Accordingly, the memory system 10 may write the second dummy data generated in fig. 13C to at least some of the memory cells MC13 through MC15 and at least some of the memory cells MC23 through MC 25.

Referring to fig. 14B, it can be seen that the charge amount of each of the memory cells MC13 to MC15 and the memory cells MC23 to MC25 connected to the cell strings NS12 and NS22, respectively, as viewed in the first direction (e.g., the Y direction) after the dummy data is written. It can be seen that the second dummy data is written to the memory cells MC13 and MC14 connected to the cell string NS12 and the memory cells MC23 and MC24 connected to the cell string NS 22.

Referring to fig. 14B, it can be seen that the accumulated charge amounts of the memory cells MC13 through MC15 of the cell string NS12 and the memory cells MC23 through MC25 of the cell string NS22 are observed in the third direction (e.g., the Z direction) after the dummy data is written. In other words, it can be seen that the total charge amount of the memory cells MC13 to MC15 of the cell string NS12 and the total charge amount of the memory cells MC23 to MC25 of the cell string NS22 are both 5.

In addition, referring to fig. 14B, X-ray images of the cell strings NS12 and NS22 photographed in the third direction after the dummy data is written can be seen. Since the cell string NS12 and the cell string NS22 have the same amount of charge, the X-ray images of the cell strings NS12 and NS22 may have the same color.

The memory system 10 as described above may generate dummy data based on memory cells (which are smaller units than one cell string) arranged in sequence, and write the generated dummy data. Therefore, it may be more difficult for an unauthorized user to distinguish data having a practical meaning from dummy data than in the case of writing dummy data based on a cell string.

In addition, the example embodiments of calculating the charge amount based on the memory cells included in the cell string and writing dummy data are described above with reference to fig. 13A to 14B, but the example embodiments are not limited thereto. Specifically, the amount of charge may be calculated based on memory cells included in a word line (or a bit line), dummy data may be generated based on the calculated amount of charge, and the dummy data may be written to memory cells connected to a first word line (or a first bit line) or an adjacent second word line (or an adjacent second bit line) to which data requiring security is written. Since the present exemplary embodiment can be performed in substantially the same manner as the exemplary embodiment based on the memory cells included in the cell string, the same description as that already given above will be omitted.

FIG. 15 is a flow diagram of a method of operating a memory system according to an example embodiment. Specifically, fig. 15 is a diagram for describing a modified example embodiment of fig. 7. At least some of the operations making up the method shown in fig. 15 may be performed by the storage controller 100 of the storage system 10.

Referring to fig. 1 and 15, the memory system 10 may write data to a first memory cell of the memory device 200 (operation S410). Specifically, the storage system 10 may divide the security data requiring security, and distribute the divided security data in one storage area of the storage device 200. For example, the data write module 110 may randomly divide the security data, randomly select a first memory cell from a plurality of memory cells included in one memory area of the memory device 200, and write the divided security data to the selected first memory cell.

Next, the memory system 10 may select a memory cell group corresponding to each of the first memory cells (operation S420). Specifically, for each of the first memory cells, memory system 10 may select a group of memory cells that includes the first memory cell and at least some of the memory cells located within a predetermined distance from the first memory cell. However, example embodiments are not limited thereto, and the memory system 10 may select the memory cell group corresponding to the first memory cell in various ways. For example, the memory system 10 may be implemented to identify a memory cell group corresponding to a first memory cell based on information on memory cell groups respectively corresponding to the memory cells. The memory cell group corresponding to the first memory cell may be implemented to include not only adjacent memory cells but also non-adjacent memory cells.

Next, the memory system 10 may generate dummy data based on the charge amounts of the second memory cells included in the selected memory cell group (operation S430). Specifically, the memory system 10 may calculate the charge amount of each of the second memory cells included in the memory cell group, and generate dummy data that makes the final charge amounts of the plurality of strings included in the memory cell group the same based on the calculation result. Here, the string may include at least one of: a plurality of word lines included in the memory cell group, a plurality of bit lines included in the memory cell group, and a plurality of cell strings included in the memory cell group.

In one example embodiment, the memory system 10 may generate dummy data that makes the final charge amount of the cell strings included in the memory cell group the same. For example, when the memory system 10 includes four cell strings, the memory system 10 may calculate respective current charge amounts of the four cell strings based on respective data values of memory cells connected to the four cell strings and generate dummy data that makes final charge amounts of the four cell strings the same as each other.

In another example embodiment, the memory system 10 may generate dummy data that makes the final charge amount of the word lines (or bit lines) included in the memory cell group the same. For example, when the memory system 10 includes four word lines (or bit lines), the memory system 10 may calculate respective current charge amounts of the four word lines (or bit lines) based on respective data values of memory cells connected to the four word lines (or bit lines), and generate dummy data that makes final charge amounts of the four word lines (or bit lines) the same as each other.

Next, the memory system 10 may write the generated dummy data to the second memory cell included in the memory cell group (operation S440). Specifically, the memory system 10 may write the generated dummy data to at least some of the remaining memory cells other than the first memory cell in the memory cell group.

Fig. 16A is a diagram illustrating a group of memory cells according to an example embodiment, fig. 16B is a diagram illustrating a dummy data write operation with respect to the group of memory cells according to an example embodiment, and fig. 16C is a diagram illustrating a dummy data write operation with respect to the group of memory cells according to an example embodiment. Specifically, fig. 16A to 16C are diagrams for describing in detail a method of operating the memory system of fig. 15.

Fig. 16A shows cell strings NS11, NS21, and NS31 connected to the first bit line BL1, cell strings NS12, NS22, and NS32 connected to the second bit line BL2, and cell strings NS13, NS23, and NS33 connected to the third bit line BL3 in the memory cell array of the memory block BLK 1. Referring to fig. 16A, the memory system 10 of fig. 1 may partition security data requiring security and write one of a plurality of the partitioned security data to the memory cells MC5 of the cell string NS22 connected to the second bitline BL 2.

The memory system 10 may select a group of memory cells corresponding to the memory cell MC5 to which the secure data is written. Specifically, the memory system 10 may select a memory cell group including at least some of the memory cells within a preset distance (e.g., a distance between memory cells adjacent to each other) from the memory cell MC5 to which the security data is written.

For example, referring to fig. 16A, the memory system 10 may select a memory cell group including the memory cells MC4, MC5, and MC6 of the cell string NS21 of the first bit line BL1, the memory cells MC4, MC5, and MC6 of each of the cell strings NS12, NS22, and NS32 of the second bit line BL2, and the memory cells MC4, MC5, and MC6 of the cell string NS23 of the third bit line BL 3. Next, memory system 10 may determine to write dummy data to the selected group of memory cells.

Referring to fig. 16B, it can be seen that the amount of charge of each of the memory cells included in the memory cell group is observed in the second direction (e.g., the X direction) after the secure data is written. Since only the secure data is written to the memory cell MC5 of the cell string NS22, the charge amount of only the memory cell MC5 may be 2, and the charge amounts of the remaining memory cells may be 1, respectively.

The memory system 10 may generate dummy data that makes the final charge amounts of a plurality of strings (e.g., a plurality of cell strings NS12, NS21, NS22, NS23, and NS32) included in a memory cell group the same. Since the current charge amount of the cell string NS22 of the memory cell group is 4 and the current charge amount of each of the cell strings NS12, NS21, NS23, and NS32 is 3, the memory system 10 may generate dummy data in which the value of the final charge amount of each of the cell strings NS12, NS21, NS23, and NS32 is equal to or greater than 4. For example, the memory system 10 may determine the final charge amount of each of the cell strings NS12, NS21, NS23, and NS 32. The final charge amount may be the same. The final charge amount may correspond to a current charge amount stored in one of the cell strings NS12, NS21, NS23, and NS 32. The final charge amount may be greater than the current charge amount stored on each of the cell strings NS12, NS21, NS23, and NS 32. The dummy data may be generated based on the final charge amount. For example, referring to fig. 16B, when it is determined that the final charge amount of each of the cell strings NS12, NS21, NS23, and NS32 is 4, the memory system 10 may generate dummy data for increasing the current charge amount of each of the cell strings NS12, NS21, NS23, and NS32 by 1. Further, the storage system 10 may write the generated dummy data to at least one storage cell of each of the cell strings NS12, NS21, NS23, and NS 32.

Example embodiments are not limited to the operation of memory system 10 generating and writing dummy data with respect to a group of memory cells, and memory system 10 may generate and write dummy data in various ways. For example, the memory system 10 may generate dummy data that causes only some of the strings included in the group of memory cells to have the same charge amount, and write the calculated dummy data to memory cells connected to at least some of the strings.

For example, referring to fig. 16C, dummy data may be generated such that only some of the cell strings NS21, NS22, NS23, and NS32 among the cell strings NS12, NS21, NS22, NS23, and NS32 constituting the memory cell group have the same charge amount. Since the secure data is written to the cell strings NS21 and NS22, the value of the charge amount of each of these cell strings is 4. On the other hand, since the secure data is not written to the cell strings NS23 and NS32, the value of the charge amount of each of these cell strings is 3. Accordingly, the memory system 10 may generate dummy data such that the final charge amount of the cell strings NS23 and NS32 has a value of 4. Next, the storage system 10 may write the generated dummy data to the storage cells of the cell strings NS23 and NS 32.

Although the description has been given above with reference to fig. 1 to 16C assuming that the memory cells are SLCs, example embodiments are not limited thereto, and the memory cells may all be SLCs, MLCs, TLCs, or QLCs. When the memory cell is an MLC, TLC, or QLC, only the values of data stored in the memory cell and information on the magnitude of the amount of charge corresponding to the values are changed, and the memory system may operate in the same manner as in the above-described exemplary embodiments. Therefore, the same description as that already given above will be omitted.

Fig. 17 is a block diagram illustrating an SSD system according to an example embodiment.

Referring to fig. 17, an SSD system 1000 may include a host 1100 and an SSD 1200. SSD1200 may exchange Signals (SIG) with host 1100 through an interface and may receive Power (PWR) through a power interface. SSD1200 may include an SSD controller 1210, an auxiliary power supply device 1220, and a plurality of storage devices 1230, 1240, and 1250. SSD controller 1210 may be connected to memory devices 130, 1240, and 1250 via channels Ch1, Ch2, and Chn. Here, the SSD1200 may be implemented according to the example embodiments described above with reference to fig. 1 to 16C.

In an example embodiment, SSD controller 1210 may split secure data that requires security and write the split secure data to a distributed storage unit of at least one of storage devices 1230, 1240, and 1250. In addition, SSD controller 1210 may additionally write dummy data to a memory location adjacent or not adjacent to the memory location where the secure data is written.

According to the above-described example embodiments, SSD system 1000 may provide write functionality with enhanced security. In particular, SSD system 1000 can enhance security by splitting and storing data that requires security, and can further enhance security by writing dummy data to adjacent or non-adjacent memory locations.

Referring to fig. 18, the memory device 400 may have a chip-to-chip (C2C) structure. The C2C structure may refer to a structure formed by: an upper chip including a CELL region CELL is fabricated on a first wafer, a lower chip including a peripheral circuit region PERI is fabricated on a second wafer different from the first wafer, and then the upper chip is connected to the lower chip in a bonding manner. For example, the bonding means may include a method of electrically connecting a bonding metal formed on the uppermost metal layer of the upper chip and a bonding metal formed on the uppermost metal layer of the lower chip. For example, when the bonding metal is formed of copper (Cu), the bonding manner is Cu — Cu bonding. However, example embodiments are not limited thereto, and the bonding metal may also be formed of aluminum or tungsten.

Each of the peripheral circuit region PERI and the CELL region CELL of the memory device 40 may include an outer pad bonding region PA, a word line bonding region WLBA, and a bit line bonding region BLBA.

The peripheral circuit region PERI may include a first substrate 410, an interlayer insulating layer 415, a plurality of circuit elements 420a, 420b, and 420c formed on the first substrate 410, first metal layers 430a, 430b, and 430c connected to the plurality of circuit elements 420a, 420b, and 420c, respectively, and second metal layers 440a, 440b, and 440c formed on the first metal layers 430a, 430b, and 430 c. In example embodiments, the first metal layers 430a, 430b, and 430c may be formed of tungsten having a relatively high resistance, and the second metal layers 440a, 440b, and 440c may be formed of copper having a relatively low resistance.

Although the first metal layers 430a, 430b, and 430c and the second metal layers 440a, 440b, and 440c are shown and described, example embodiments are not limited thereto, and one or more metal layers may be further formed on the second metal layers 440a, 440b, and 440 c. At least a portion of one or more metal layers formed on the second metal layers 440a, 440b, and 440c may be formed of aluminum or the like, which has a lower resistance than copper forming the second metal layers 440a, 440b, and 440 c.

An interlayer insulating layer 415 may be disposed on the first substrate 410 and cover the plurality of circuit elements 420a, 420b, and 420c, the first metal layers 430a, 430b, and 430c, and the second metal layers 440a, 440b, and 440 c. The interlayer insulating layer 415 may include an insulating material such as silicon oxide, silicon nitride, or the like.

Lower bonding metals 471b and 472b may be formed on the second metal layer 440b in the word line bonding area WLBA. In the word line bonding region WLBA, the lower bonding metals 471b and 472b in the peripheral circuit region PERI may be electrically connected to the upper bonding metals 371b and 372b in a bonding manner, and the lower bonding metals 471b and 472b and the upper bonding metals 371b and 372b may be formed of aluminum, copper, tungsten, or the like. In addition, the upper bonding metals 371b and 372b in the CELL region CELL may be referred to as first metal pads, and the lower bonding metals 471b and 472b in the peripheral circuit region PERI may be referred to as second metal pads.

The CELL region CELL may include at least one memory block. The CELL region CELL may include a second substrate 310 and a common source line 320. On the second substrate 310, a plurality of word lines 331 to 338 (i.e., 330) may be stacked in a direction (Z-axis direction) perpendicular to an upper surface of the second substrate 310. At least one string selection line and at least one ground selection line may be disposed above and below the plurality of word lines 330, respectively, and the plurality of word lines 330 may be disposed between the at least one string selection line and the at least one ground selection line.

In the bit line bonding area BLBA, the channel structure CH may extend in a direction perpendicular to the upper surface of the second substrate 310 and pass through the plurality of word lines 330, the at least one string selection line, and the at least one ground selection line. The channel structure CH may include a data storage layer, a channel layer, a buried insulation layer, and the like, and the channel layer may be electrically connected to the first and second metal layers 350c and 360 c. For example, the first metal layer 350c may be a bit line contact and the second metal layer 360c may be a bit line. In example embodiments, the bit line 360c may extend in a first direction (Y-axis direction) parallel to the upper surface of the second substrate 310.

In the example embodiment shown in fig. 18, a region in which the channel structure CH, the bit line 360c, and the like are disposed may be defined as a bit line bonding region BLBA. In the bit line bonding area BLBA, the bit line 360c may be electrically connected to the circuit elements 420c in the peripheral circuit area PERI, which provide the page buffer 393. For example, the bit line 360c may be connected to the upper bonding metals 371c and 372c in the CELL region CELL, and the upper bonding metals 371c and 372c may be connected to the lower bonding metals 471c and 472c, and the lower bonding metals 471c and 472c are connected to the circuit elements 420c of the page buffer 393.

In the word line bonding region WLBA, the plurality of word lines 330 may extend in a second direction (X-axis direction) parallel to the upper surface of the second substrate 310, and may be connected to the plurality of cell contact plugs 341 to 347 (i.e., 340). The plurality of word lines 330 and the plurality of cell contact plugs 340 may be connected to each other in a pad provided by at least a portion of the plurality of word lines 330 extending in the second direction by different lengths. The first and second metal layers 350b and 360b may be sequentially connected to upper portions of the plurality of cell contact plugs 340, wherein the plurality of cell contact plugs 340 are connected to the plurality of word lines 330. The plurality of CELL contact plugs 340 may be connected to the peripheral circuit region PERI through the upper bonding metals 371b and 372b of the CELL region CELL and the lower bonding metals 471b and 472b of the peripheral circuit region PERI in the word line bonding region WLBA.

The plurality of cell contact plugs 340 may be electrically connected to the circuit elements 420b in the peripheral circuit region PERI, which provide the row decoder 394. In an example embodiment, the operating voltage of the circuit element 420b providing the row decoder 394 may be different from the operating voltage of the circuit element 420c providing the page buffer 393. For example, the operating voltage of the circuit element 420c providing the page buffer 393 may be greater than the operating voltage of the circuit element 420b providing the row decoder 394.

The common source line contact plug 380 may be disposed in the outer pad bonding region PA. The common source line contact plug 380 may be formed of a conductive material such as metal, metal compound, polysilicon, etc., and may be electrically connected to the common source line 320. The first metal layer 350a, the second metal layer 360a, and the upper bonding metal 371a may be sequentially stacked on the upper portion of the common source line contact plug 380. For example, a region in which the common source line contact plug 380, the first metal layer 350a, and the second metal layer 360a are disposed may be defined as the outer pad bonding region PA.

The input-output pads 405 and 305 may be disposed in the outer pad bonding area PA. Referring to fig. 18, a lower insulating film 401 covering a lower surface of a first substrate 410 may be formed under the first substrate 410, and a first input-output pad 405 may be formed on the lower insulating film 401. The first input-output pad 405 may be connected to at least one of the plurality of circuit elements 420a, 420b, and 420c disposed in the peripheral circuit region PERI through a first input-output contact plug 403, and may be separated from the first substrate 410 through the lower insulating film 401. In addition, a side insulating film may be disposed between the first input and output contact plug 403 and the first substrate 410 to electrically separate the first input and output contact plug 403 and the first substrate 410.

Referring to fig. 18, an upper insulating film 301 covering an upper surface of a second substrate 310 may be formed on the second substrate 310, and a second input-output pad 305 may be disposed on the upper insulating film 301. The second input-output pad 305 may be connected to at least one of the plurality of circuit elements 420a, 420b, and 420c disposed in the peripheral circuit region PERI through the second input-output contact plug 303.

According to example embodiments, the second substrate 310 and the common source line 320 may not be disposed in a region in which the second input and output contact plug 303 is disposed. In addition, the second input/output pad 305 may not overlap the word line 330 in the third direction (Z-axis direction). Referring to fig. 18, the second input and output contact plug 303 may be separated from the second substrate 310 in a direction parallel to an upper surface of the second substrate 310, and may pass through the interlayer insulating layer 315 of the CELL region CELL to be connected to the second input and output pad 305.

According to example embodiments, the first input and output pad 405 and the second input and output pad 305 may be selectively formed. For example, the memory device 400 may include only the first input and output pads 405 disposed on the first substrate 410, or only the second input and output pads 305 disposed on the second substrate 310. Alternatively, the memory device 400 may include both the first input output pad 405 and the second input output pad 305.

In each of the outer pad bonding area PA and the bit line bonding area BLBA included in the CELL area CELL and the peripheral circuit area PERI, respectively, the metal pattern in the uppermost metal layer may be provided as a dummy pattern, or the uppermost metal layer may not be present.

In the outer pad bonding region PA, the memory device 400 may include a lower metal pattern 473a in the uppermost metal layer of the peripheral circuit region PERI, the lower metal pattern 473a corresponding to the upper metal pattern 372a formed in the uppermost metal layer of the CELL region CELL and having the same shape as the upper metal pattern 372a of the CELL region CELL. In the peripheral circuit region PERI, the lower metal pattern 473a formed in the uppermost metal layer of the peripheral circuit region PERI may not be connected to the contact. Similarly, in the outer pad bonding area PA, an upper metal pattern, which corresponds to and has the same shape as the lower metal pattern of the peripheral circuit region PERI, may be formed in the uppermost metal layer of the CELL region CELL. In the outer pad bonding region PA, the lower bonding metals 471a and 472a of the peripheral circuit region PERI may be electrically connected to the upper bonding metal 473 a.

Lower bonding metals 471b and 472b may be formed on the second metal layer 440b in the word line bonding area WLBA. In the word line bonding region WLBA, the lower bonding metals 471b and 472b of the peripheral circuit region PERI may be electrically connected to the upper bonding metals 371b and 372b of the CELL region CELL by Cu — Cu bonding.

In addition, in the bit line bonding area BLBA, an upper metal pattern 392 may be formed in the uppermost metal layer of the CELL area CELL, the upper metal pattern 392 corresponding to the lower metal pattern 452 formed in the uppermost metal layer of the peripheral circuit area PERI and having the same shape as the lower metal pattern 452 of the peripheral circuit area PERI. A contact may not be formed on the upper metal pattern 392 formed in the uppermost metal layer of the CELL region CELL. In the bit line bonding area BLBA, the lower metal 451 of the peripheral circuit area PERI may be electrically connected to the lower metal pattern 452.

In example embodiments, corresponding to a metal pattern formed in an uppermost metal layer in one of the CELL region CELL and the peripheral circuit region PERI, an enhanced metal pattern having the same shape as the metal pattern may be formed in the uppermost metal layer in the other of the CELL region CELL and the peripheral circuit region PERI, and a contact may not be formed on the enhanced metal pattern.

According to example embodiments, the memory device 400 may be implemented according to the above-described example embodiments with reference to fig. 1 to 16C. For example, the memory device 400 may store the secure data in a first memory cell and the dummy data in a second memory cell adjacent to the first memory cell. A method of storing dummy data may be substantially the same as the method described above with reference to fig. 1 to 16C, and thus redundant description will be omitted.

While example embodiments have been particularly shown and described, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the appended claims.