A method for quickly testing flash memory using flash memory weak pages and their distribution types

Abstract

The present invention discloses a flash memory fast test method based on finding flash memory weak pages and distribution types, comprising the following steps: 1) reading the configuration information of the specified block of the flash memory; 2) reading the areas corresponding to the three positions of the page head, page middle and page end in the specified block, and recording the number of error bit flips of the page page corresponding to each area of ​​the page head, page middle and page end without erasing; 3) determining the distribution type of the flash memory weak page in the specified block and the position of the flash memory weak page in the corresponding area according to the number of error bit flips of the page page corresponding to each area of ​​the page head, page middle and page end; 4) according to the distribution type of the flash memory weak page in the specified block and the position of the flash memory weak page in the corresponding area, real-time monitoring of the flash memory weak page quickly evaluates the reliability of the entire flash memory chip. The present invention characterizes the quality and reliability of the flash memory chip through the flash memory weak page and distribution characteristics, and only needs to monitor the flash memory weak page status to efficiently evaluate the quality of the entire flash memory.

Description

Technical Field

[0001] The invention relates to memory technology, and in particular to a method for rapidly testing a flash memory by utilizing a flash memory weak page and its distribution type. Background Art

[0002] Being able to quickly discover problems with key core components during the production process of storage products is an important step to ensure product quality and improve production efficiency. An efficient flash memory testing solution can detect and repair flash memory reliability problems in advance, reducing the cost of product recalls and after-sales service. In addition, formulating an efficient flash memory testing program based on clear and effective flash memory characteristic research results is an important step in efficiently testing flash memory chips.

[0003] After the flash memory chip packaging test is completed, the tested flash memory chips are usually shipped to the module factory as finished products. The module factory will surface mount the above flash memory chips, controller chips and other components in the SMT workshop. In order to ensure the reliability of storage products, flash memory particles are generally tested and screened before SMT mounting to eliminate flash memory chips that do not meet quality requirements. However, mass production lines have very high requirements for production efficiency, and how to efficiently screen flash memory within an effective time is particularly important. Therefore, both original manufacturers and module manufacturers in the industry are trying various methods to study the characteristics of flash memory chips in order to quickly evaluate the quality and quality of flash memory. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a flash memory fast testing method based on finding flash memory weak pages and distribution types in view of the defects in the prior art.

[0005] The technical solution adopted by the present invention to solve the technical problem is: a flash memory fast testing method based on finding flash memory weak pages and distribution types, comprising the following steps:

[0006] 1) Read the configuration information of the specified block of the flash memory, the configuration information includes: the total number of pages of the block;

[0007] 2) Read the areas corresponding to the page header, page middle and page end in the specified block, and record the number of error bit flips of the page corresponding to each area at the page header, page middle and page end without erasing or writing;

[0008] 3) According to the number of error bit flips of the Page page corresponding to each area of ​​the page head, page middle, and page tail, determine the distribution type of the flash memory weak page in the specified block and the location of the flash memory weak page in the corresponding area;

[0009] The flash memory weak page is a flash memory chip in which the number of error bit flips per KB of raw data on a page in a certain block is greater than or equal to twice or more of the average number of error bit flips per KB of raw data on other pages in the same block;

[0010] The flash memory weak page distribution types include: edge type, intermediate type and mixed type;

[0011] Edge type: Flash memory weak pages are distributed in the page header and / or page footer area of ​​the page range within the Block;

[0012] The intermediate type is: the weak pages of the flash memory are distributed in the middle of the page range within the Block;

[0013] The mixed type is: the flash memory weak pages are distributed in at least one of the middle area of ​​the page range within the Block and the head or tail area of ​​the page;

[0014] 4) According to the distribution type of the flash memory weak pages in the specified block and the flash memory weak page positions in the corresponding area, the reliability of the entire flash memory chip is quickly evaluated by real-time monitoring of the flash memory weak pages to obtain the flash memory test results.

[0015] According to the above scheme, in step 2), the corresponding areas selected at the top, middle and end of the page are: the area corresponding to the top of the page is 0 to 20% of the total number of pages, the area corresponding to the middle of the page is 30%-60% of the total number of pages, and the area corresponding to the end of the page is 80-100% of the total number of pages.

[0016] According to the above solution, in step 2), the corresponding areas selected at the top, middle and end of the page are: three consecutive Page pages with two intervals each are selected from the top, middle and end of the page.

[0017] According to the above scheme, in step 2), the corresponding areas selected from the three positions of the page head, page middle and page end are: the corresponding area selected from the page head position is: Page0 to Page 2 and Page6 to Page 8; the corresponding area selected from the page middle position is: Page (N / 2-8) to Page (N / 2-6) and Page (N / 2-2) to Page (N / 2); the corresponding area selected from the page end position is: Page (N-8) to Page (N-6) and Page (N-2) to PageN, where N represents the maximum number of pages configured for the flash memory chip and 0 represents the page head.

[0018] According to the above solution, in step 3), the distribution type of the weak pages of the flash memory is determined by analyzing the difference in the number of bit flips.

[0019] According to the above scheme, in step 3), the bit flip number differentiation model is used to analyze and determine the distribution type of "flash memory weak page", which is as follows:

[0020] 3.1) In the areas corresponding to the top, middle and end of the page, two word lines are selected in each of the three areas, and each word line consists of three adjacent pages;

[0021] 3.2) Record the maximum value of the error bit flip number and the corresponding position page of the page head, page middle and page tail in the 6 pages respectively; record the maximum error bit flip number of the "page head group" as Max1; similarly, record the maximum error bit flip number of the "page middle group" as Max2; and record the maximum error bit flip number of the "page tail group" as Max3;

[0022] Take the minimum value of the three and record it as Min{ Max1, Max2, Max3}, calculate the maximum error bit difference rate corresponding to the "page head group", "page middle group" and "page end group", and record them as E 1 、E 2 、E 3 :

[0023] Error bit difference rate of "header group": E 1 = Max1 / Min{ Max1, Max2, Max3};

[0024] Error bit difference rate of "group in page": E 2 = Max2 / Min{ Max1, Max2, Max3};

[0025] Error bit difference rate of "page end group": E 3 = Max3 / Min{ Max1, Max2, Max3};

[0026] In E 1 、E 2 、E 3 In: When E 1 = 1:

[0027] If E 2 ≥2 and E 3 ≥2, record “flash memory weak page” as the page corresponding to Max2 and Max3, and determine that the distribution of flash memory weak page types belongs to mixed type;

[0028] If E 2 ≥2, "flash memory weak page" is the page corresponding to Max2, and the flash memory weak page type distribution belongs to the intermediate type;

[0029] If E 3≥2, the “flash memory weak page” is the page corresponding to Max3, and the flash memory weak page type distribution belongs to the marginal type;

[0030] When E 2 =1:

[0031] If E 1 ≥2 and E 3 ≥2, record “flash memory weak page” as the page corresponding to Max1 and Max3, and determine that the distribution of flash memory weak page type belongs to marginal type;

[0032] If E 2 ≥2, the “flash memory weak page” is the page corresponding to Max2, and the flash memory weak page type distribution belongs to the marginal type;

[0033] If E 3 ≥2, the “flash memory weak page” is the page corresponding to Max3, and the flash memory weak page type distribution belongs to the marginal type.

[0034] According to the above scheme, in step 4), the location of the flash memory weak page monitored by the flash memory test is determined according to the distribution type of the flash memory weak page in the specified block and the location of the flash memory weak page in the corresponding area, and the reliability of the entire flash memory chip is quickly evaluated by real-time monitoring of the flash memory weak page.

[0035] According to the above solution, in step 4), the flash memory weak page position monitored by the flash memory test is determined to be the flash memory weak page position in the area corresponding to the distribution type of the flash memory weak page in the block.

[0036] According to the above scheme, in the step 4), the position of the flash memory weak page monitored by the flash memory test is determined, specifically as follows: after determining the type of the flash memory weak page, find three adjacent pages before and after the flash memory weak page position in the area corresponding to the distribution type of the flash memory weak page in the Block as flash memory weak page candidate items, and then perform a wear test on the Block where the Page page is located, and count the maximum error bit flip numbers of the flash memory weak page candidate items under 7 conditions with erase times of 1, 501, 1001, 1501, 2001, 2501, and 3001, respectively, count the number of times the maximum error bit flip number of the three pages of the "flash memory weak page candidate items" occurs under the above 7 conditions, and take the flash memory page with the largest number of occurrences as the flash memory weak page of the entire flash memory chip for flash memory test monitoring.

[0037] The beneficial effects produced by the present invention are:

[0038] 1. The present invention proposes a test process and method for quickly finding flash memory weak pages and weak page distribution, and characterizes the quality and reliability of flash memory chips through the characteristics of flash memory weak pages and weak page distribution. It only needs to read the status of the flash memory weak pages monitored by the test, and the quality of the entire flash memory can be accurately and efficiently evaluated through the error bit flipping of the flash memory weak pages. In mass production testing, the flash memory testing time can be greatly reduced, and the mass production test efficiency of flash memory screening can be improved.

[0039] 2. After the "flash memory weak page" is found using the present invention, the reliability of the entire flash memory chip can be quickly evaluated by real-time monitoring of the flash memory weak page, which can be used to optimize the entire firmware periodic inspection algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0041] Figure 1 is a method flow chart of an embodiment of the present invention;

[0042] Figure 2 is a schematic diagram of weak page distribution types of a flash memory according to an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of analyzing the weak page distribution type of flash memory according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] like Figure 1 As shown, a flash memory fast testing method based on finding flash memory weak pages and distribution types includes the following steps:

[0046] 1) Reading the configuration information of the flash memory particles through the flash memory test device, wherein the configuration information includes: the flash memory particle type, the total number of blocks, and the total number of pages of each block;

[0047] 2) Read the areas corresponding to the page header, page middle and page end in the specified block, and record the number of error bit flips of the page corresponding to each area at the page header, page middle and page end without erasing or writing;

[0048] Each area of ​​the header, middle, and footer corresponds to 1 / 3 of the total number of pages in the block;

[0049] In this embodiment, the corresponding areas selected at the top, middle and end of the page can be reduced to: the corresponding area selected at the top of the page is: 0 to 20% of the total number of pages, the corresponding area selected at the middle of the page is: 30%-60% of the total number of pages, and the corresponding area selected at the end of the page is: 80-100% of the total number of pages.

[0050] The corresponding areas selected at the top, middle and end of the page can also be reduced to: select three consecutive Page pages with two intervals each in the top, middle and end of the page.

[0051] In this embodiment, the corresponding areas selected at the top, middle and end of the page are directly set as follows: the corresponding area selected at the top of the page is: Page0 to Page 2 and Page6 to Page 8; the corresponding area selected at the middle of the page is: Page (N / 2-8) to Page (N / 2-6) and Page (N / 2-2) to Page (N / 2); the corresponding area selected at the end of the page is: Page (N-8) to Page (N-6) and Page (N-2) to PageN, where N represents the maximum number of pages configured for the flash memory chip and 0 represents the top of the page.

[0052] 3) According to the number of error bit flips of the Page page corresponding to each area of ​​the page head, page middle, and page tail, determine the distribution type of the flash memory weak page in the specified block and the location of the flash memory weak page in the corresponding area;

[0053] A flash memory weak page is a flash memory weak page in a given flash memory chip. If the number of raw data error bit flips per KB on a page in a certain block is greater than or equal to twice or more of the average number of raw data error bit flips per KB on other pages in the same block, then the page is a flash memory weak page.

[0054] Flash memory weak page distribution types include: marginal type, intermediate type and mixed type; Figure 2 ;

[0055] Edge type: Flash memory weak pages are distributed in the page header and / or page footer area of ​​the page range within the Block;

[0056] The intermediate type is: the weak pages of the flash memory are distributed in the middle of the page range within the Block;

[0057] The mixed type is: the flash memory weak pages are distributed in at least one of the middle area of ​​the page range within the Block and the head or tail area of ​​the page;

[0058] In step 3), the weak page distribution type of the flash memory is determined by analyzing the difference in the number of bit flips.

[0059] like Figure 3, through the bit flip number differentiation model, the distribution type of "flash memory weak page" is determined as follows:

[0060] 3.1) In the areas corresponding to the top, middle and end of the page, two word lines are selected in each of the three areas, and each word line consists of three adjacent pages;

[0061] 3.2) Record the maximum value of the error bit flip number and the corresponding position page of the page head, page middle and page tail in the 6 pages respectively; record the maximum error bit flip number of the "page head group" as Max1; similarly, record the maximum error bit flip number of the "page middle group" as Max2; and record the maximum error bit flip number of the "page tail group" as Max3;

[0062] Take the minimum value of the three and record it as Min{ Max1, Max2, Max3}, calculate the maximum error bit difference rate corresponding to the "page head group", "page middle group" and "page end group", and record them as E 1 、E 2 、E 3 :

[0063] Error bit difference rate of "header group": E 1 = Max1 / Min{ Max1, Max2, Max3};

[0064] Error bit difference rate of "group in page": E 2 = Max2 / Min{ Max1, Max2, Max3};

[0065] Error bit difference rate of "page end group": E 3 = Max3 / Min{ Max1, Max2, Max3};

[0066] In E 1 、E 2 、E 3 In: When E 1 = 1:

[0067] If E 2 ≥2 and E 3 ≥2, record “flash memory weak page” as the page corresponding to Max2 and Max3, and determine that the distribution of flash memory weak page types belongs to mixed type;

[0068] If E 2 ≥2, "flash memory weak page" is the page corresponding to Max2, and the flash memory weak page type distribution belongs to the intermediate type;

[0069] If E 3 ≥2, the “flash memory weak page” is the page corresponding to Max3, and the flash memory weak page type distribution belongs to the marginal type;

[0070] When E 2 =1:

[0071] If E 1 ≥2 and E 3 ≥2, record “flash memory weak page” as the page corresponding to Max1 and Max3, and determine that the distribution of flash memory weak page type belongs to marginal type;

[0072] If E 2 ≥2, the “flash memory weak page” is the page corresponding to Max2, and the flash memory weak page type distribution belongs to the marginal type;

[0073] If E 3 ≥2, the “flash memory weak page” is the page corresponding to Max3, and the flash memory weak page type distribution belongs to the marginal type.

[0074] 4) According to the distribution type of the flash memory weak pages in the specified block and the flash memory weak page positions in the corresponding area, the reliability of the entire flash memory chip is quickly evaluated by real-time monitoring of the flash memory weak pages to obtain the flash memory test results.

[0075] In step 4), the location of the weak flash page monitored by the flash memory test is determined according to the distribution type of the weak flash page in the specified block and the location of the weak flash page in the corresponding area, and the reliability of the entire flash memory chip is quickly evaluated by real-time monitoring of the weak flash page.

[0076] The flash memory weak page position monitored by the flash memory test can be directly determined as the flash memory weak page position in the area corresponding to the distribution type of the flash memory weak page in the block.

[0077] In order to further improve the accuracy of the test results, we optimized the method for determining the flash memory weak page position of the flash memory test monitoring, as follows: after determining the flash memory weak page type, find three adjacent pages before and after the flash memory weak page position in the area corresponding to the distribution type of the flash memory weak page in the Block as flash memory weak page candidates, and then perform a wear test on the Block where the Page page is located, and count the maximum error bit flip numbers of the flash memory weak page candidates corresponding to the seven conditions of erase and write times of 1, 501, 1001, 1501, 2001, 2501, and 3001, respectively, and count the number of times the maximum error bit flip number of the three pages of the "flash memory weak page candidate" occurs under the above seven conditions, and take the flash memory page with the largest number of occurrences as the flash memory weak page of the entire flash memory chip for flash memory test monitoring.

[0078] When the final test results are given, if the monitored flash memory weak page distribution type is edge type, and the number of flash memory error bit flips corresponding to the edge weak page is less than the preset threshold value T1, then the quality of the flash memory chip is judged to meet the requirements; if the monitored flash memory weak page distribution type is mixed and both the edge weak page and the middle weak page are less than the preset threshold value T1, then the quality of the flash memory chip is judged to meet the requirements; otherwise, it does not meet the requirements.

[0079] Using the above method, we conducted flash memory tests on 18 mainstream TLC particles on the market and found that all of them are applicable.

[0080] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A flash memory fast testing method based on finding flash memory weak pages and distribution types, characterized in that: The following steps are involved: 1) Read the configuration information of the specified block of the flash memory, the configuration information includes: the total number of pages of the block; 2) Read the areas corresponding to the page header, page middle and page end in the specified block, and record the number of error bit flips of the page corresponding to each area at the page header, page middle and page end without erasing or writing; The corresponding areas selected at the top, middle and end of the page are: the area selected at the top of the page is 0 to 20% of the total number of pages, the area selected at the middle of the page is 30%-60% of the total number of pages, and the area selected at the end of the page is 80%-100% of the total number of pages; 3) According to the number of error bit flips of the Page page corresponding to each area of ​​the page head, page middle, and page tail, determine the distribution type of the flash memory weak page in the specified block and the location of the flash memory weak page in the corresponding area; The flash memory weak page is a flash memory chip in which the error bit flip number RBER of each KB of raw data on a page in a certain block is greater than or equal to 2 times or more of the average value of the error bit flip number RBER of other pages in the same block; The flash memory weak page distribution types include: edge type, intermediate type and mixed type; Edge type: Flash memory weak pages are distributed in the page header and / or page footer area of ​​the page range within the Block; The intermediate type is: the weak pages of the flash memory are distributed in the middle of the page range within the Block; The mixed type is: the flash memory weak pages are distributed in at least one of the middle area of ​​the page range within the Block and the head or tail area of ​​the page; 4) According to the distribution type of the flash memory weak pages in the specified block and the location of the flash memory weak pages in the corresponding area, the flash memory weak pages are monitored in real time to quickly evaluate the reliability of the entire flash memory chip and obtain the flash memory test results.

2. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 1, characterized in that: In the step 2), the corresponding areas selected at the top, the middle and the end of the page are: three consecutive Page pages with two intervals are selected from each of the top, the middle and the end of the page.

3. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 1, characterized in that: In the step 2), the corresponding areas selected from the three positions of the page head, page middle and page end are: the corresponding area selected from the page head position is: Page0 to Page 2 and Page6 to Page 8; the corresponding area selected from the page middle position is: Page (N / 2-8) to Page (N / 2-6) and Page (N / 2-2) to Page (N / 2); the corresponding area selected from the page end position is: Page (N-8) to Page (N-6) and Page (N-2) to PageN, where N represents the maximum number of pages configured for the flash memory chip and 0 represents the page head.

4. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 1, characterized in that: In the step 3), the distribution type of the flash memory weak pages is determined by analyzing the difference in the number of bit flips.

5. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 4, characterized in that: In step 3), the bit flip number differentiation model is used to analyze and determine the distribution type of "flash memory weak page", which is as follows: 3.1) In the areas corresponding to the top, middle and end of the page, two word lines are selected in each of the three areas, and each word line consists of three adjacent pages; 3.2) Record the maximum value of the error bit flip number in the head, middle and tail of the 6 pages and the corresponding position page respectively; record the maximum error bit flip number of the "header group" as Max1; similarly, record the maximum error bit flip number of the "middle group" as Max2; and record the maximum error bit flip number of the "tail group" as Max3; Take the minimum value of the three and record it as Min{ Max1, Max2, Max3}, calculate the maximum error bit difference rate corresponding to the "page head group", "page middle group", and "page tail group", and record them as E1, E2, and E3 respectively: Error bit difference rate of "header group": E1= Max1 / Min{ Max1, Max2, Max3}; Error bit difference rate of "group in page": E2 = Max2 / Min{ Max1, Max2, Max3}; Error bit difference rate of "page end group": E3 = Max3 / Min{ Max1, Max2, Max3}; In E1, E2, E3: When E1 = 1: If E2≥2 and E3≥2, record "flash memory weak page" as the page corresponding to Max2 and Max3, and determine that the flash memory weak page type distribution belongs to mixed type; If E2≥2, the "flash memory weak page" is the page corresponding to Max2. At this time, the distribution of flash memory weak page types belongs to the intermediate type. If E3≥2, the "flash memory weak page" is the page corresponding to Max3. At this time, the distribution of the flash memory weak page type belongs to the marginal type; When E2=1: If E1≥2 and E3≥2, record "flash memory weak page" as the page corresponding to Max1 and Max3, and determine that the flash memory weak page type distribution belongs to the marginal type; If E2≥2, the "flash memory weak page" is the page corresponding to Max2. At this time, the distribution of the flash memory weak page type belongs to the marginal type; If E3≥2, the "flash memory weak page" is recorded as the page corresponding to Max3. At this time, the distribution of the flash memory weak page type belongs to the marginal type.

6. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 1, characterized in that: In the step 4), the location of the weak flash page monitored by the flash memory test is determined according to the distribution type of the weak flash page in the specified block and the location of the weak flash page in the corresponding area, and the reliability of the entire flash memory chip is quickly evaluated by real-time monitoring of the weak flash page.

7. The flash memory fast testing method based on finding flash memory weak pages and distribution types according to claim 6, characterized in that: In the step 4), the position of the flash memory weak page monitored by the flash memory test is determined, specifically as follows: after determining the type of the flash memory weak page, find three adjacent pages before and after the flash memory weak page position in the area corresponding to the distribution type of the flash memory weak page in the Block as flash memory weak page candidate items, and then perform a wear test on the Block where the Page page is located, and count the maximum error bit flip numbers of the flash memory weak page candidate items corresponding to the seven conditions of erase and write times of 1, 501, 1001, 1501, 2001, 2501, and 3001, respectively, count the number of times the maximum error bit flip number of the three pages of the "flash memory weak page candidate items" occurs under the above seven conditions, and take the flash memory page with the largest number of occurrences as the flash memory weak page of the entire flash memory chip for flash memory test monitoring.

8. An electronic device, characterized in that: include: one or more processors; as well as a storage device for storing one or more programs, When the one or more programs are executed by the one or more processors, the one or more processors are caused to execute the method according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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