Storage chip, calculation method of temperature acceleration factor value of storage chip, and storage device

Abstract

The invention discloses a storage chip, a calculation method of a temperature acceleration factor value of the storage chip and storage equipment. The calculation method comprises the following steps: recording first storage state data of a first storage chip and second storage state data of a second storage chip; when the deviation between the second storage state data and the first storage state data is smaller than a preset percentage, a simulation temperature acceleration factor is calculated; the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor are substituted into a first formula to calculate activation energy parameters; substituting the activation energy parameter into a second formula to calculate a temperature acceleration factor value; wherein the first experiment temperature is higher than the second experiment temperature. Through the method, the temperature acceleration factor of each storage chip at high temperature can be accurately calculated.

Description

Technical Field

[0001] The present application relates to the field of memory technology, and in particular to a memory chip and a method for calculating a temperature acceleration factor value thereof, and a memory device. Background Art

[0002] As NAND flash memory cell size decreases and storage density increases, its reliability issues become more prominent, and the life of NAND flash memory has become a severe challenge in mass production. Testers usually use high-temperature environments to accelerate the life of NAND flash memory, but how to accurately calculate the temperature acceleration factor under high temperature has always been a difficult problem faced by the industry.

[0003] At present, the mainstream method for calculating the temperature acceleration factor of NAND flash memory at high temperature is to use the classic thermodynamic formula - Arrhenius formula to calculate the temperature acceleration factor. However, the determination of the activation energy (Ea) parameter in the Arrhenius formula has always been a difficult point in the calculation. It has a great influence on the calculation of the temperature acceleration factor (exponential). It is usually provided by the NAND flash memory manufacturer as a fixed value. However, in fact, the Ea value of each NAND FLash wafer is not the same, and the Ea value of the same NAND FLash wafer under different wear life is also different, which leads to significant deviations in the actual calculation results, and it is impossible to accurately calculate the temperature acceleration factor of each NAND FLash wafer at high temperature. Summary of the invention

[0004] The purpose of the present application is to provide a method for calculating a memory chip and a temperature acceleration factor value thereof, and a memory device, so as to accurately calculate the temperature acceleration factor of each memory chip at high temperature.

[0005] The present application discloses a method for calculating a temperature acceleration factor value of a memory chip, the method comprising the steps of:

[0006] Selecting a first experimental temperature and a second experimental temperature;

[0007] placing the first memory chip at the first experimental temperature and heating it for a first time, and recording first storage state data of the first memory chip;

[0008] placing the second storage chip at the second experimental temperature, and recording second storage state data of the second storage chip;

[0009] When the deviation between the second storage state data and the first storage state data is less than a preset percentage, recording a second time when the second storage chip is placed in the second experimental temperature state, and calculating a simulated temperature acceleration factor based on the second time and the first time;

[0010] Calculate the activation energy parameter by substituting the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor into a first formula; and

[0011] Substituting the activation energy parameter into the second formula to calculate the temperature acceleration factor value;

[0012] The first experimental temperature is higher than the second experimental temperature, and the first storage chip and the second storage chip are in the same initial state.

[0013] Optionally, the first storage state data is the number of error bits when the first storage chip is heated for a first time under a first experimental temperature state, and the second storage state data is the number of error bits when the second storage chip is heated at a second experimental temperature; or, the first storage state data is the threshold voltage data when the first storage chip is heated for a first time under the first experimental temperature state, and the second storage state data is the threshold voltage data of the second storage chip at the second experimental temperature.

[0014] Optionally, the first storage state data includes the number of error bits and threshold voltage data of the first storage chip when heated for a first time under a first experimental temperature state, and the second storage state data includes the number of error bits and threshold voltage data of the second storage chip at a second experimental temperature.

[0015] Optionally, in the step of placing the second storage chip at the second experimental temperature and recording the second storage state data of the storage chip, the storage state data of the second storage chip is recorded every ten minutes.

[0016] Optionally, the first formula is: in, y = ln (second time / first time); where T U is the absolute temperature of the second experimental temperature, T A is the absolute temperature of the first experimental temperature, K is the Boltz constant, and Ea is the activation energy parameter.

[0017] Optionally, the second formula is: Among them, Ea is the activation energy parameter, K is the Boltz constant, T′ U is the absolute temperature of the actual room temperature, T′ A is the absolute temperature of the actual high temperature, AF T is the temperature acceleration factor.

[0018] Optionally, the step of calculating the activation energy parameter by substituting the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor into a first formula includes:

[0019] At least three groups of control experiments are counted, each group of control experiments having the first experimental temperature, the second experimental temperature, the first time and the second time;

[0020] The x value of each control experiment is calculated by the first experimental temperature and the second experimental temperature, and the y value of each control experiment is calculated by the first time and the second time;

[0021] Take the x value of each control experiment as the horizontal coordinate and the y value as the horizontal coordinate to obtain the coordinate point corresponding to each control experiment; and

[0022] The coordinate points corresponding to each group of control experiments are connected on the coordinate axis, and the value of Ea / K is calculated according to the slope of the connecting line, and then the activation energy parameter is calculated.

[0023] Optionally, the preset percentage is 5%.

[0024] The present application also discloses a memory chip, wherein the memory chip uses the above-mentioned method for calculating the temperature acceleration factor value of the memory chip to calculate the temperature acceleration factor value.

[0025] The present application also discloses a storage device, which includes the storage chip as described above.

[0026] The beneficial effect of the present application is that since the activation energy parameters of different batches of memory chips or even the same memory chip at different wear lives are different, there will be a large deviation when using this activation energy parameter to calculate the temperature acceleration factor of the memory chip. The present application first tests the actual activation energy parameters of the memory chip through experiments, and then accurately calculates the temperature calculation factor of the memory chip at high temperature through a formula, so as to accurately obtain the temperature acceleration factor value of the memory chip at different actual high temperatures for the actual normal temperature, thereby calculating the life of the memory chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The included drawings are used to provide a further understanding of the embodiments of the present application, which constitute a part of the specification, are used to illustrate the implementation methods of the present application, and together with the text description, explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0028] Figure 1 It is a flow chart of a method for calculating a temperature acceleration factor value of a memory chip provided in an embodiment of the present application;

[0029] Figure 2 It is a schematic diagram of a state of presentation of the number of error bits provided in an embodiment of the present application;

[0030] Figure 3 is a schematic diagram of a threshold voltage data presentation state provided by an embodiment of the present application;

[0031] Figure 4 It is a specific flow chart based on step S5;

[0032] Figure 5 It is a schematic diagram based on step S54. DETAILED DESCRIPTION

[0033] It should be understood that the terms used herein, the specific structures and functional details disclosed are only for describing specific embodiments and are representative, but the present application can be implemented in many alternative forms and should not be construed as being limited to only the embodiments described herein.

[0034] An embodiment of the present application provides a memory chip, which may be a NAND FLASH chip, or may be a NOR Flash or other types of memory chips.

[0035] Taking NAND FLASH as an example, the life test of NAND FLASH chip is required before it leaves the factory to ensure the quality of the products. Usually, the life test of NAND FLASH chip is accelerated by high temperature environment, and the life or reliability of NAND FLASH chip is tested by calculating the temperature acceleration factor of NAND FLASH chip at high temperature.

[0036] The current mainstream method is to use the classic thermodynamic formula - Arrhenius formula to calculate the temperature acceleration factor. However, the determination of the activation energy (Ea) parameter in the Arrhenius formula has always been a difficult point in the calculation. It is usually provided by the NAND flash memory manufacturer as a fixed value. However, in fact, the Ea value of each NAND FLASH chip is not the same, and the Ea value of the same NAND FLASH chip under different wear life is also different, which leads to a significant deviation in the actual calculated temperature acceleration factor. Therefore, it is impossible to accurately calculate the temperature acceleration factor of each NAND FLASH chip at high temperature.

[0037] Based on this, an embodiment of the present application provides a method for calculating the temperature acceleration factor value of a memory chip, which is used to manufacture the NAND FLASH chip and the memory chip as described above. The calculation method includes the steps of:

[0038] S1: Select the first experimental temperature and the second experimental temperature;

[0039] S2: placing the first memory chip at the first experimental temperature and heating it for a first time, and recording first storage state data of the first memory chip;

[0040] S3: placing the second storage chip at the second experimental temperature, and recording second storage state data of the second storage chip;

[0041] S4: when the deviation between the second storage state data and the first storage state data is less than a preset percentage, recording a second time when the second storage chip is placed in the second experimental temperature state, and calculating a simulated temperature acceleration factor based on the second time and the first time;

[0042] S5: Calculate the activation energy parameter by substituting the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor into a first formula;

[0043] S6: Substituting the activation energy parameter into the second formula to calculate the temperature acceleration factor value;

[0044] The first experimental temperature is higher than the second experimental temperature, and the first storage chip and the second storage chip are in the same initial state.

[0045] The embodiment of the present application first tests the actual activation energy parameters of the memory chip through experiments, and then accurately calculates the temperature calculation factor of the memory chip at high temperature through a formula. The temperature acceleration factor value of the memory chip at different actual high temperatures relative to the actual normal temperature can be accurately obtained, thereby calculating the life of the memory chip.

[0046] Specifically, in step S1, the first experimental temperature is a high temperature environment, specifically the high temperature environment temperature of the memory chip during the life test, which is generally higher than 100 degrees Celsius; the second experimental temperature can also be a heating temperature not higher than 100, or even a temperature higher than 100 degrees Celsius but lower than the first experimental temperature, which is not limited here.

[0047] In steps S2 and S3, the first storage state data and the second storage state data may be only the number of error bits, and step S4 records the deviation between the number of error bits in step S2 and the number of error bits in step S3; wherein the number of error bits is the number of bits flipped in 16KB data in each page of the memory chip. It should be noted that the number of error bits is presented through a probability density distribution diagram of the number of error bits.

[0048] Alternatively, the first storage state data and the second storage state data may both be threshold voltage data, and step S4 records the deviation between the threshold voltage data in step S2 and the threshold voltage data in step S3; wherein the threshold voltage data is presented via a probability density distribution diagram of the threshold voltage data, which reflects the distribution state of the number of bit1s at different voltages.

[0049] Of course, in order to improve accuracy, the embodiment of the present application preferably includes the first storage state data including the number of error bits and the threshold voltage data, and the second storage state data also includes the number of error bits and the threshold voltage data; step S4 records the deviation between the number of error bits in step S2 and the number of error bits in step S3, and the deviation between the threshold voltage data in step S2 and the threshold voltage data in step S3. By combining the two dimensions of the number of error bits and the threshold voltage data, the deviation result of the state of the memory chip at the second experimental temperature relative to the state at the first experimental temperature is determined.

[0050] Figure 2 It is a schematic diagram showing the number of error bits in a memory chip, that is, a probability density distribution diagram of the number of error bits. Figure 3 It is a schematic diagram of the threshold voltage data presentation state of a storage chip, that is, a probability density distribution diagram of the threshold voltage data. The probability density distribution diagram of the number of error bits and the probability density distribution diagram of the threshold voltage data are both represented by curves. Finally, the deviation between the first storage state data and the second storage state data is calculated by fitting.

[0051] In step S3, the first memory chip that was heated at the first experimental temperature can be re-erased and then continued to be tested at the second experimental temperature, that is, the first memory chip and the second memory chip are the same memory chip, and the second memory chip is a memory chip that restores the first memory chip to its initial state after re-erasing. Alternatively, a new memory chip from the same batch as the memory chip tested last time is placed at the second experimental temperature for testing, that is, the first memory chip and the second memory chip are memory chips from the same batch.

[0052] In step S4, the preset percentage is 5%, that is, when the deviation between the second storage state data and the first storage state data is less than 5%, the second storage state data meets the requirement, heating can be stopped, and the heating time of the second storage chip under the second experimental temperature state is recorded; and when the deviation between the second storage state data and the first storage state data is greater than or equal to 5%, the second storage state data does not meet the requirement, and the second storage chip needs to continue to be heated under the second experimental temperature state until the preset percentage is less than 5%.

[0053] In step S5, the first formula is: in, y = ln (second time / first time); where T U is the absolute temperature of the second experimental temperature, T A is the absolute temperature of the first experimental temperature, K is the Boltz constant, and Ea is the activation energy parameter.

[0054] The absolute temperature of the first experimental temperature is the first experimental temperature plus 273.15 degrees Celsius, and the absolute temperature of the second experimental temperature is the second experimental temperature plus 273.15 degrees Celsius.

[0055] In step S6, the second formula is: Among them, Ea is the activation energy parameter, K is the Boltz constant, T′ U is the absolute temperature of the actual room temperature, T′ A is the absolute temperature of the actual high temperature, AF T is the temperature acceleration factor.

[0056] Among them, the absolute temperature of the actual normal temperature is the actual normal temperature plus 273.15 degrees Celsius, and the absolute temperature of the actual high temperature is the actual high temperature plus 273.15 degrees Celsius.

[0057] In step S2, the first time is 1 hour. Since the first time is an integer, it is convenient to calculate the y value in the first formula, which is beneficial to improving detection efficiency.

[0058] For ease of understanding, the embodiment of the present application also provides a specific example, with the first experimental temperature being 125 degrees Celsius, the second experimental temperature being 85 degrees Celsius, and the first time being 1 hour. First, record the number of error bits and threshold voltage data achieved by the memory chip when heated at 125 degrees Celsius for 1 hour; then, re-erase the memory chip, and place it in a high-temperature storage test at 85°C after erasing. Take out the memory chip every ten minutes and read its number of error bits and threshold voltage data until its number of error bits and threshold voltage data are closest to the number of error bits and threshold voltage data measured at 125 degrees Celsius. At this point, stop the test and record the time the memory chip is baked at 85°C, that is, the second time; since the first time is an integer, that is, 1 hour, the size of the second time at this time is ln (second time / first time), that is, the temperature acceleration factor of the memory chip at 125°C relative to 85°C.

[0059] Further, such as Figure 4 As shown, in step S5, it also includes:

[0060] S51: At least three groups of control experiments are counted, each group of control experiments having the first experimental temperature, the second experimental temperature, the first time and the second time;

[0061] S52: Calculate the x value of each control experiment by using the first experimental temperature and the second experimental temperature, and calculate the y value of each control experiment by using the first time and the second time;

[0062] S53: Taking the x value of each control experiment as the horizontal coordinate and the y value as the horizontal coordinate, the coordinate point corresponding to each control experiment is obtained;

[0063] S54: Connect the coordinate points corresponding to each group of control experiments on the coordinate axis, calculate the value of Ea / K according to the slope of the connecting line, and then calculate the activation energy parameter.

[0064] In order to further improve the accuracy of the measured activation energy parameters, the present embodiment performs multiple control experiments and calculates the activation energy parameters by combining coordinates with slopes. Figure 5 It is a schematic diagram of the coordinates of a control experiment. First, the coordinates of 5 groups of control experiments are marked on the coordinate axis, and then the lines passing through most of the coordinate points are drawn. Finally, the slope of the lines is tested to obtain the activation energy parameters. At this time, the activation energy parameters are obtained by multiple groups of experimental tests, so they have higher accuracy. Of course, in order to further improve the accuracy of the activation energy parameters, more groups of control experiments can be conducted.

[0065] Finally, in step S6, since the activation energy parameters with higher accuracy have been obtained, K in the second formula is the Boltz constant, which is generally 8.617×10-5eV / K. At this time, the temperature acceleration factor of the memory chip at different high temperatures (actual high temperatures) relative to normal temperature (actual normal temperature, generally 25°C) can be calculated based on the actual normal temperature and the actual high temperature, so as to perform reliability testing, life testing or high-temperature accelerated aging testing on the memory chip.

[0066] An embodiment of the present application also provides a storage device, which includes the storage chip as described above. The storage device can be a solid-state hard disk, a USB flash drive, or other storage or electronic products.

[0067] It should be noted that the limitations on the various steps involved in this solution, without affecting the implementation of the specific solution, are not deemed to limit the order of the steps. The steps written in front can be executed first, or later, or even simultaneously. As long as this solution can be implemented, it should be deemed to fall within the scope of protection of this application.

[0068] The above content is a further detailed description of the present application in combination with specific optional implementation methods, and it cannot be determined that the specific implementation of the present application is limited to these descriptions. For ordinary technicians in the technical field to which the present application belongs, several simple deductions or substitutions can be made without departing from the concept of the present application, which should be deemed to fall within the scope of protection of the present application.

Claims

1. A method for calculating the temperature acceleration factor value of a memory chip, characterized in that: Includes steps: Selecting a first experimental temperature and a second experimental temperature; placing the first memory chip at the first experimental temperature and heating it for a first time, and recording first storage state data of the first memory chip; placing the second storage chip at the second experimental temperature, and recording second storage state data of the second storage chip; When the deviation between the second storage state data and the first storage state data is less than a preset percentage, recording a second time when the second storage chip is placed in the second experimental temperature state, and calculating a simulated temperature acceleration factor based on the second time and the first time; The activation energy parameter is calculated by substituting the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor into a first formula; as well as Substituting the activation energy parameter into the second formula to calculate the temperature acceleration factor value; The first experimental temperature is higher than the second experimental temperature, and the first storage chip and the second storage chip are in the same initial state.

2. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: The first storage state data is the number of error bits of the first storage chip heated for a first time at a first experimental temperature state, and the second storage state data is the number of error bits of the second storage chip at a second experimental temperature; or The first storage state data is threshold voltage data of the first storage chip when heated for a first time at a first experimental temperature state, and the second storage state data is threshold voltage data of the second storage chip at a second experimental temperature.

3. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: The first storage state data includes the error bit number and threshold voltage data of the first storage chip heated for a first time under a first experimental temperature state, and the second storage state data includes the error bit number and threshold voltage data of the second storage chip under a second experimental temperature.

4. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: In the step of placing the second storage chip at the second experimental temperature and recording the second storage state data of the storage chip, the storage state data of the second storage chip is recorded every ten minutes.

5. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: The first formula is: in, y = ln (second time / first time); Among them, T U is the absolute temperature of the second experimental temperature, T A is the absolute temperature of the first experimental temperature, K is the Boltz constant, and Ea is the activation energy parameter.

6. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: The second formula is: Among them, Ea is the activation energy parameter, K is the Boltz constant, T U ' is the absolute temperature of the actual room temperature, T A is the absolute temperature of the actual high temperature, AF T is the temperature acceleration factor.

7. The method for calculating the temperature acceleration factor value of a memory chip according to claim 5, characterized in that: The step of calculating the activation energy parameter by substituting the first experimental temperature, the second experimental temperature and the simulation temperature acceleration factor into the first formula includes: At least three groups of control experiments are counted, each group of control experiments having the first experimental temperature, the second experimental temperature, the first time and the second time; The x value of each control experiment is calculated by the first experimental temperature and the second experimental temperature, and the y value of each control experiment is calculated by the first time and the second time; Take the x value of each control experiment as the horizontal coordinate and the y value as the horizontal coordinate to obtain the coordinate point corresponding to each control experiment; and The coordinate points corresponding to each group of control experiments are connected on the coordinate axis, and the value of Ea / K is calculated according to the slope of the connecting line, and then the activation energy parameter is calculated.

8. The method for calculating the temperature acceleration factor value of a memory chip according to claim 1, characterized in that: The preset percentage is 5%.

9. A memory chip, characterized in that: The temperature acceleration factor value is calculated using the method for calculating the temperature acceleration factor value of the storage chip as described in any one of claims 1 to 8.

10. A storage device, characterized in that: Comprising the memory chip as claimed in claim 9.

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