Defect recording method and apparatus for a NAND flash memory device

Abstract

This application provides a defect recording method for a NAND flash memory device, used in a NAND flash memory device comprising multiple memory cells, wherein the multiple memory cells form multiple blocks and multiple columns; the method includes the following steps: S1, establishing a block status list, a column status list, a block defect record table, and a column defect record table for the NAND flash memory device; S2, performing defect testing on the NAND flash memory device, and updating the block status list, column status list, block defect record table, and column defect record table according to the defect test results; S3, merging the updated block status list, column status list, block defect record table, and column defect record table to form defect recording data for the NAND flash memory device. This application also provides an apparatus for implementing the above method.

Description

Technical Field

[0001] This application relates to the field of data storage technology, and more specifically to a method and apparatus for recording defects in NAND flash memory devices. Background Technology

[0002] NAND flash memory devices are a type of non-volatile memory increasingly used in modern electronic equipment. Compared to NOR flash memory devices, NAND flash memory devices are more widely used for high-capacity storage due to their higher storage density and capacity, as well as their higher sequential access speed.

[0003] NAND flash memory devices contain multiple memory cells arranged in an array to form rows (or blocks) and columns. These rows (or blocks) and columns can generally be divided into data rows (or data blocks) and data columns used to form the main memory array and directly store data, and redundant rows (or redundant blocks) and redundant columns used to repair defects in the NAND flash memory device. If one or more data rows or columns develop defects during manufacturing, such as one or more memory cells in a data column being found to be faulty during testing, and if the defect severity is within a certain range, the NAND flash memory device does not need to be scrapped directly. Instead, a repair process can be performed, disabling each defective data row or column and replacing it with one of the redundant rows or columns. This allows the NAND flash memory device to continue operating normally, effectively improving the fault tolerance rate in the NAND flash memory manufacturing process.

[0004] Based on the above repair principle, in the production and testing process of NAND flash memory devices, at least one redundancy replacement process is usually required. That is, before the NAND flash memory device leaves the factory, it is checked for defects, and the defects found are recorded and counted. If the statistics show that the degree of defects in the entire NAND flash memory device does not exceed the repairable range, the above repair process is performed, and the redundant rows or columns in the NAND flash memory device are used to replace the defective rows or columns in the main storage array.

[0005] In the redundant replacement process, to achieve ideal repair efficiency, it is necessary to record the condition of all memory cells in the entire NAND flash memory device to accurately calculate the defect level and determine the optimal replacement strategy. However, due to the continuous shrinking of chip feature sizes, the storage capacity of NAND flash memory devices is also constantly increasing. Consequently, the computing power and storage space required to record the condition of all memory cells in the NAND flash memory device also increase, which places higher demands on the hardware and software configuration of the NAND flash memory device testing system.

[0006] In existing technologies, the following recording methods are generally used to record the condition of all memory cells in a NAND flash memory device: (1) A simple recording method with a 1:1 ratio to the capacity of the NAND flash memory device is used, that is, 1 bit of recording data is used for each 1-bit NAND flash memory cell to indicate whether it has a defect; (2) Recording is performed using the smallest replaceable column unit as the smallest unit of recording. For example, if the column replacement of a certain NAND flash memory device is performed in units of 1 byte (1 byte = 8 columns), that is, the column replacement is performed in units of 8 columns together, then 1 bit of recording data is used to indicate whether each 1 byte in the device has a defect; (3) Based on the above method (2), the smallest replaceable row unit is further used as the smallest unit of recording in the row direction. For example, if the row replacement of a certain NAND flash memory device is performed in units of 1 block (assuming 1 block = 64 rows), that is, the row replacement is performed in units of 64 rows together, then the defect status of 64 rows can be merged into 1 row for recording.

[0007] However, these existing recording methods all require the NAND flash memory device testing system to consume a large amount of memory to record the defects of the NAND flash memory devices. Specifically, method (3) consumes the least memory among the three methods mentioned above, but the commonly used NAND flash memory devices have reached the GB level in capacity, with the smallest replaceable column unit usually being 8 columns and the smallest replaceable row unit usually being 64 rows. For this standard NAND flash memory device, even using method (3), it generally requires tens of MB of memory to record the defects of each NAND flash memory device, and storing and transmitting tens of MB of defect record data already requires a significant amount of processing time. The bigger problem is that in actual production processes, in order to improve efficiency and reduce costs, it is usually necessary to use the same NAND flash memory device testing system to record defects of a large number (hundreds or even thousands) of NAND flash memory devices at the same time. That is to say, the host of the testing system needs to process hundreds or even thousands of defect record data of tens of MB at the same time, which places very demanding requirements on the host's hardware and software configuration, so that commonly used personal computers (PCs) are usually difficult to meet such testing needs. Using a distributed testing system with multiple test sites (the smallest unit for testing a single chip) for distributed redundant computation can reduce data transmission time to some extent. However, the memory of the MCU core used by each test site in a distributed testing system is generally only a few MB, which is insufficient to meet the defect recording requirements of tens of MB for each NAND flash memory device. Expanding memory by adding external DRAM chips will further increase data transmission time, thus increasing testing costs.

[0008] In addition, although the existing recording methods mentioned above can record the defects in NAND flash memory devices in a relatively intuitive way, in order to obtain the specific defect location during redundancy calculation, it is necessary to traverse and judge every bit of data in the record. Moreover, this traversal often needs to be performed multiple times during the testing of a chip, which consumes more working time.

[0009] Therefore, it is necessary to provide a defect recording method and apparatus for NAND flash memory devices that requires less storage space and has higher operating efficiency. Summary of the Invention

[0010] To address the aforementioned technical problems, one aspect of this application provides a defect recording method for a NAND flash memory device, used in a NAND flash memory device comprising multiple memory cells, wherein the multiple memory cells constitute multiple blocks and multiple columns; the method includes the following steps:

[0011] S1, Create a block status list, column status list, block defect record table, and column defect record table for the NAND flash memory device;

[0012] S2, perform defect testing on the NAND flash memory device, and update the block status list, column status list, block defect record table and column defect record table according to the defect test results;

[0013] S3, the updated block status list, column status list, block defect record table and column defect record table are merged to form the defect record data of the NAND flash memory device.

[0014] In some implementations, step S2 includes: updating the block status of each block in the block status list based on the defect test results; wherein the block status of each block is one of four states: intact, defective, bad block, replaced / used.

[0015] In some implementations, step S2 further includes: when the block status of a block in the block status list is updated from intact to defective, adding a record to the block defect record table to record its block number, defect quantity and defect address, and marking the record of the block as valid.

[0016] In some implementations, step S2 further includes: when a block's block status in the block status list is defective, and a new defect is found in the block during the defect test, updating the block's record in the block defect record table.

[0017] In some implementations, step S2 further includes: if the number of defects exceeds the repairable range when updating the defect record of the block, then mark the record of the block as invalid in the block defect record table, delete its defect address record, and update the block status of the block to bad block in the block status list.

[0018] In some embodiments, step S2 further includes: when adding a record to the block defect record table, if there is a record marked as invalid in the block defect record table, the added record will preferentially overwrite the record marked as invalid in the block defect record table.

[0019] In some embodiments, step S2 further includes: when adding a record to the block defect record table, if there is no record marked as invalid in the current block defect record table, then adding a record to the end of the block defect record table.

[0020] In some implementations, step S2 further includes: when a new defect that was not previously recorded is found in the NAND flash memory device during the defect test, incrementing the defect count of the column containing each new defect by 1 in the defect record table.

[0021] In some implementations, step S2 further includes: if the number of defects in a column containing a new defect exceeds the repair capacity of the block repair, then the status of the column is updated to bad column in the column status list.

[0022] Another aspect of this application provides a defect recording apparatus for a NAND flash memory device, for a NAND flash memory device including multiple memory cells, wherein the multiple memory cells form multiple blocks and multiple columns; the apparatus includes: a list generation module, used to establish a block status list, a column status list, a block defect record table, and a column defect record table for the NAND flash memory device; a data update module, used to perform defect testing on the NAND flash memory device and update the block status list, column status list, block defect record table, and column defect record table according to the defect test results; and a data processing module, used to merge the updated block status list, column status list, block defect record table, and column defect record table to form defect recording data for the NAND flash memory device.

[0023] Compared with the prior art, the defect recording method and apparatus for NAND flash memory devices provided by the embodiments of this application have a more practical working mode in many aspects, which can effectively reduce the total amount of defect recording data and simplify the calculation process during data processing, require less storage space, and have higher working efficiency, thereby effectively solving the problems in the prior art. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart of a defect recording method for NAND flash memory devices provided in a preferred embodiment of this application.

[0026] Figure 2 yes Figure 1 A schematic diagram of the block state list used in the method shown.

[0027] Figure 3 yes Figure 1 A schematic diagram of the block defect record table used in the method shown.

[0028] Figure 4 yes Figure 1 A schematic diagram of the column status list used in the method shown.

[0029] Figure 5 yes Figure 1 A schematic diagram of the defect record table used in the method shown.

[0030] Figure 6 This is a schematic diagram of the functional modules of a defect recording device for a NAND flash memory device provided in a preferred embodiment of this application. Detailed Implementation

[0031] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be particularly noted that the following embodiments are for illustrative purposes only and do not limit the scope of the application. Similarly, the following embodiments are only some, not all, embodiments of the present application, and all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present application.

[0032] One embodiment of this application provides a defect recording method for NAND flash memory devices, which is applicable to existing NAND flash memory devices. According to common knowledge in the art, the NAND flash memory device internally has multiple storage cells arranged in a certain array configuration, forming multiple rows (or blocks) and columns composed of storage cells. These rows (or blocks) and columns can generally be divided into data rows (or data blocks) and data columns used to constitute the main storage array and directly store data, and redundant rows (or redundant blocks) and redundant columns used to repair defects in the NAND flash memory device.

[0033] Figure 1 A flowchart of the method is shown, as follows: Figure 1 As shown, the method may include the specific steps detailed below. Note that in the following detailed description, "block" and "row" have the same meaning, both referring to a row of storage cells within a NAND flash memory device.

[0034] S1, Create a block status list, column status list, block defect record table, and column defect record table for the NAND flash memory device.

[0035] Specifically, in step S1, a block status list, a column status list, a block defect record table, and a column defect record table for the NAND flash memory device are first established. For example, all block statuses can be recorded as a block status list according to a predetermined recording order; the predetermined recording order can be any predetermined order that facilitates querying, and in this embodiment, the block address order is preferred. Alternatively, all column statuses can be recorded as a column status list according to a predetermined recording order; the predetermined recording order can be any predetermined order that facilitates querying, and in this embodiment, the column address order is preferred.

[0036] It is understandable that if the NAND flash memory device being recorded has not undergone defect testing before, its block status list, column status list, block defect record table, and column defect record table are all newly created. In this case, it can be assumed that all blocks and columns are completely defect-free. That is, all block statuses in the block status list and all column statuses in the column status list are set to "intact" by default, the number of defect records in the block defect record table is set to 0, and the number of defects in each column of the column defect record table is set to 0. If the NAND flash memory device being recorded has been previously tested and defect data has been recorded, its block status list, column status list, block defect record table, and column defect record table may have other variations, which will be explained in detail later.

[0037] S2, perform defect testing on the NAND flash memory device, and update the block status list, column status list, block defect record table and column defect record table according to the defect test results.

[0038] Specifically, in step S2, defects in the NAND flash memory device are first tested to obtain the block status of each block and the column status of each column in the NAND flash memory device. The specific testing methods can employ existing memory cell testing methods, which will not be elaborated here.

[0039] After obtaining the block status of each block and the column status of each column in the NAND flash memory device, the block status list, column status list, block defect record table, and column defect record table are updated based on the test results. The specific update operations include: if no defects are found in any block or column in the test results, the initial states of the block status list, column status list, block defect record table, and column defect record table remain unchanged. If any block or column is found to have at least one defect, the block status list, column status list, block defect record table, and column defect record table are modified according to the following specific operation methods.

[0040] The specific modification method for the block status list can be implemented as follows: In this embodiment, the preferred method for recording the block status in the block status list is to use 2-bit encoded data to record the block status of each block. Specifically, for each block, its block status can include four states: "Intact", meaning that there are no defects in the block; "Defective", meaning that the block contains defects, that is, it contains faulty storage units, but the degree of defect has not exceeded the range that can be repaired by column replacement, and there is still a chance to repair the block by column replacement; "Bad Block", meaning that the degree of defect in the block exceeds the range that can be repaired by column replacement, and it cannot be repaired by column replacement; "Replaced / Used", this state indicates that for blocks in the main storage array, the block has been replaced by a redundant block, and for redundant blocks, it indicates that the block has been used to replace a defective block in the main storage array. Since the 2-bit encoded data is two binary numbers, it can be used to represent the four block states respectively. Therefore, when a defective block is found in the block status list during testing, based on the above rules, the block status data of the defective block can be changed from "intact" to one of the aforementioned "defective," "bad block," and "replaced / used" statuses, depending on the actual situation of the defective block. For example... Figure 2 The diagram illustrates a block state list used in a defect recording method for a NAND flash memory device according to a preferred embodiment of this application. The block state of each block can be one of the four states described above.

[0041] Correspondingly, when the block status list is modified in the manner described above, the block defect record table should also be modified synchronously. The specific methods for modifying the block defect record table can include the following two categories:

[0042] For NAND flash memory devices that have not been tested before, when the status of a block in the block status list is changed from "intact" to "defective," a new record should be added to the block defect record table; this record can be formatted as follows: Figure 3 The format shown records the block number, the number of defects, and the address of each defect for a block whose status is changed to "defective", and marks the record as "valid".

[0043] For NAND flash memory devices that have been tested at least once before, their block status list may contain blocks with statuses of "intact," "defective," and "bad," and their block defect record table may contain valid records corresponding to blocks with a status of "defective" and invalid records corresponding to blocks with a status of "bad." When the status of a block in the block status list is changed from "intact" to "defective" after this test, it can also be handled according to, for example... Figure 3 The format shown adds a new record to the block defect record table. Specifically, if a record marked "invalid" already exists in the block defect record table, to save storage space, the newly added record can first overwrite the "invalid" record. Only if there is no "invalid" record in the current block defect record table is the newly added record added to the end of the table. If a block previously recorded as "defective" in the block status list is found to have a new defect during this test, its defect record is updated in the block defect record table, for example, in... Figure 3 The format shown updates the defect count of this block and adds a new defect address record. If, when updating the defect count of this block, it is found that the defect count has increased beyond the repairable range, the record of this block is remarked as "invalid" in the block defect record table, its defect address record is deleted to save space, and the status of this block is changed to "bad block" in the block status list.

[0044] On the other hand, based on the updated content of the block status list and block status record table, the column status list and column defect record table can be further updated.

[0045] In this embodiment, the preferred method for recording column states in the column state list is to use 1-bit encoded data to record the column state of each column. Specifically, for each column, its column state can include two states: "Good column," meaning that the column has no defects or the number of defects is within the range that can be repaired by block replacement (i.e., row replacement), and it can be used for normal operation; or "Bad column," meaning that the number of defects in the column exceeds the range that can be repaired by block replacement. The 1-bit encoded data is a binary number, so it can represent the two possible states of the column, for example... Figure 4 The diagram shown is a schematic representation of a column state list used in a defect recording method for a NAND flash memory device according to a preferred embodiment of this application. The column state of each column can be one of the two states described above.

[0046] In this embodiment, if a new, previously unrecorded defect is discovered in the NAND flash memory device during defect testing, whether the defect is found in a block whose status was originally recorded as "intact" or in a block whose status was originally recorded as "defective," the status list and defect record table should be updated. Specifically, this may include updating the status list and defect record table if a defect is found in a block whose status was originally recorded as "intact" or in a block whose status was originally recorded as "defective," for example... Figure 5The defect count in the column record table shown is incremented by 1 for each new defect. If the incremented defect count in a column exceeds the block repair capacity, then... Figure 4 The column status in the column status list shown is changed to "bad column".

[0047] S3, the updated block status list, column status list, block defect record table and column defect record table are merged to form the defect record data of the NAND flash memory device.

[0048] In step S3, after updating the block status list, column status list, block defect record table, and column defect record table according to the specific operations of steps S1 and S2 above, the block status list, column status list, block defect record table, and column defect record table are merged and stored as defect record data of the NAND flash memory device. This data can then be used for subsequent data processing, such as data query, data statistics, data transmission, etc., thereby reflecting the quality status of the NAND flash memory device through the defect record data.

[0049] As can be easily understood from the specific technical solutions described above, compared with the prior art, the defect recording method for NAND flash memory devices provided by the above embodiments has a more practical working mode in many aspects and can achieve significantly superior technical effects, as detailed below.

[0050] First, the method provided in this application only needs to record the specific location of the defective storage unit, and does not record the intact storage unit, thus reducing the total amount of defect record data.

[0051] Secondly, the method provided in this application can further reduce the total amount of defect recording data when recording bad block and bad column information. Since the resources of redundant rows or columns available for replacement and repair in a NAND flash memory device are limited, if the number of defects in a block exceeds the repair capacity of column replacement, this block cannot be repaired by column replacement and can only be treated as a bad block and repaired by block replacement (row replacement). Similarly, if the number of defects in a column exceeds the repair capacity of row replacement, this column cannot be repaired by row replacement and can only be treated as a bad column and repaired by column replacement. Based on this principle, as described in the aforementioned specific embodiments, once a block or column in a NAND flash memory device is recorded as a bad block or bad column, the specific number and location information of the defective storage cells in this block or column do not need to be recorded. This allows for the direct deletion of data recording the number and location of defects in the bad block or bad column, thereby reducing the total amount of recorded data. Furthermore, since bad blocks or columns will inevitably be repaired through replacement, and the replaced blocks or columns are no longer accessible to users, the information on the specific location of the defects is meaningless in redundant calculations. Therefore, there is no need to perform redundant calculations for defects in bad blocks or columns in the future, which helps to save computing resources and processing time.

[0052] Third, the method provided in this application directly records the total number of defects in blocks and columns. Based on this recording method, it is possible to intuitively determine whether each block can be replaced and repaired by a column, and whether each column can be replaced and repaired by a block, without the need for complex calculations. This helps to further save computing resources and processing time.

[0053] Fourth, each defective block and each column corresponds to a record, making the operation of updating the defect count simple and time-consuming. For example, if a new defect is discovered during testing, and the block corresponding to the newly discovered defect does not have a record, a new record is added; if the block corresponding to the newly discovered defect already has a record, the record is directly updated to add the position of the newly discovered defect.

[0054] Fifth, the defect record data format obtained by the above method provided in this application can participate in the redundancy calculation throughout the entire process. As the redundancy calculation proceeds, the content in the record can be changed in real time, that is, redundancy calculation can be completed without the assistance of additional recording equipment, which helps to reduce costs.

[0055] The following example uses a commonly used 512MB NAND flash memory device to illustrate the superiority of the method provided in this application compared to the prior art. The structural parameters of this NAND flash memory device are: 4096 bytes of main columns + 32 bytes of redundant columns, 2048 main blocks + 32 redundant blocks, each block has 64 rows, the smallest replaceable column unit is 1 byte, and the smallest replaceable row unit is 1 block.

[0056] For this type of NAND flash memory device, if the existing method (3) described in the background section is used to record the defect situation, each block requires (4096+32) / 8 = 516 bytes to record the number of defects, so a total of 516*(2048+32) = 1073280 bytes are needed for recording.

[0057] In contrast, if the method described above provided in the implementation of this application is used to record the number of defects, the specific data statistics are as follows: the block status list requires (2048+32)*2 / 8 = 520 bytes; the column status list requires (4096+32) / 8 = 516 bytes; the column defect record table requires 4096+32 = 4128 bytes; the limit of the block defect record table is that 32 columns are defective in different blocks, that is, these 32 columns can be repaired by column redundancy replacement. In addition, there are still 32 blocks with defects in columns other than the above 32 columns, that is, these 32 blocks can be repaired by block redundancy replacement. Therefore, the block defect record table in this example has a maximum of 32*32+32 = 1056 records, of which each record requires 1+2+1+2*32 = 68 bytes, so the block defect record table requires a maximum of 1056*68 = 71808 bytes. Thus, the total data required for the four types of record tables is 520 + 516 + 4128 + 71808 = 76972 bytes, which is far less than the total data generated by the existing method. Only 76972 / 1073280 ≈ 7.17% of the data capacity of the existing method is needed to complete the defect recording of the entire NAND flash memory device.

[0058] Furthermore, in redundancy calculations, for this type of NAND flash memory device, existing technologies typically require 4096 + 32 = 4128 single-bit data checks per block to determine the location of each defect within the block. However, the method provided in this application, through its block defect record table, requires a maximum of only 32 checks (each record holds a maximum of 32 defect addresses, as this is the upper limit for repair using column replacement) to determine the location of each defect in the block, greatly simplifying the data processing for redundancy calculations. During the redundancy calculation process, the data in the block status list, column status list, block defect record table, and column defect record table can be changed in real time. Specifically, during the calculation process, columns determined to be replaced can be marked as bad columns in the column status list, and blocks determined to be replaced can be marked as bad blocks in the block status list. Then, the final global redundancy replacement can be completed solely based on the block status list and column status list. This significantly simplifies the redundancy calculation operation compared to existing technologies.

[0059] Therefore, the defect recording method for NAND flash memory devices provided by the embodiments of this application can effectively reduce the total amount of defect recording data and simplify the calculation process during data processing compared with the prior art, with smaller storage space requirements and higher work efficiency.

[0060] Please see Figure 6 This application also provides a defect recording apparatus 1 for NAND flash memory devices, which can be used to implement the defect recording method for NAND flash memory devices provided in the above embodiments. The apparatus may include:

[0061] The list generation module 10 is used to create a block status list, a column status list, a block defect record table, and a column defect record table for NAND flash memory devices.

[0062] The data update module 20 is used to perform defect testing on the NAND flash memory device and update the block status list, column status list, block defect record table and column defect record table according to the defect test results.

[0063] The data processing module 30 is used to merge the updated block status list, column status list, block defect record table and column defect record table into defect record data of the NAND flash memory device.

[0064] The device is preferably integrated into a test system for NAND flash memory devices, and its various modules can be implemented in hardware, software, or a combination of hardware and software.

[0065] The above description is only a part of the embodiments of this application and does not limit the scope of protection of this application. Any equivalent device or equivalent process transformation made based on the content of this application specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this application.

Claims

1. A defect recording method for a NAND flash memory device, used in a NAND flash memory device comprising multiple storage cells, wherein the multiple storage cells form multiple blocks and multiple columns; characterized in that, The method includes the following steps: S1, Create a block status list, column status list, block defect record table, and column defect record table for the NAND flash memory device; S2, perform defect testing on the NAND flash memory device, and update the block status list, column status list, block defect record table and column defect record table according to the defect test results; S3, the updated block status list, column status list, block defect record table and column defect record table are merged to form the defect record data of the NAND flash memory device.

2. The method as described in claim 1, characterized in that, Step S2 includes: Based on the defect test results, update the block status of each block in the block status list; wherein the block status of each block is one of four states: intact, defective, bad block, replaced / used.

3. The method as described in claim 2, characterized in that, Step S2 further includes: When the block status of a block in the block status list is updated from intact to defective, a record is added to the block defect record table to record its block number, defect quantity and defect address, and the record of the block is marked as valid.

4. The method as described in claim 3, characterized in that, Step S2 further includes: When a block has a defective status in the block status list, and a new defect is found in the block during the defect test, the record of the block is updated in the block defect record table.

5. The method as described in claim 4, characterized in that, Step S2 further includes: If, when updating the defect record of a block, it is found that the number of defects exceeds the repairable range, the record of the block is marked as invalid in the block defect record table, its defect address record is deleted, and the block status of the block is updated to bad block in the block status list.

6. The method according to any one of claims 3-5, characterized in that, Step S2 further includes: when adding a record to the block defect record table, if there is a record marked as invalid in the block defect record table, the added record will preferentially overwrite the record marked as invalid in the block defect record table.

7. The method as described in claim 6, characterized in that, Step S2 further includes: when adding a record to the block defect record table, if there is no record marked as invalid in the current block defect record table, then add a record to the end of the block defect record table.

8. The method as described in claim 1, characterized in that, Step S2 further includes: When a new defect that was not previously recorded is found in the NAND flash memory device during the defect test, the defect count in the column containing each new defect is incremented by 1 in the defect record table.

9. The method as described in claim 8, characterized in that, Step S2 further includes: If the number of defects in a column containing a new defect exceeds the repair capacity of the block repair, then the status of that column in the column status list is updated to bad column.

10. A defect recording apparatus for a NAND flash memory device, for a NAND flash memory device comprising a plurality of memory cells, wherein the plurality of memory cells form a plurality of blocks and a plurality of columns; characterized in that, The device includes: The list generation module is used to create block status lists, column status lists, block defect record tables, and column defect record tables for NAND flash memory devices. The data update module is used to perform defect testing on the NAND flash memory device and update the block status list, column status list, block defect record table and column defect record table according to the defect test results. The data processing module is used to merge the updated block status list, column status list, block defect record table, and column defect record table into defect record data for the NAND flash memory device.

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