A leakage monitoring method for MOS tube during on-state aging process

Abstract

The present application relates to the technical field of leakage detection of semiconductor devices, and specifically to a method for monitoring leakage during the on-state aging process of a MOS tube, the method comprising: obtaining the temperature of the MOS tube in real time during the simulation operation, and controlling the heating device according to the temperature change of the MOS tube; obtaining the leakage stabilization time according to the stability of the numerical change of the leakage current value of the MOS tube; integrating the leakage stabilization time of the MOS tube under different load currents to obtain the comprehensive leakage stabilization time of the MOS tube; obtaining the input power and output power of the MOS tube during the leakage stabilization time under each load current, and calculating the power loss according to the input power and output power; and controlling the heat dissipation device according to the power loss. The present application can improve the leakage monitoring accuracy during the on-state aging process of the MOS tube.

Description

Technical Field

[0001] The present application relates to the technical field of leakage detection of semiconductor devices, and in particular to a leakage monitoring method during the on-state aging process of a MOS tube. Background Art

[0002] With the development of power electronics technology, fully controlled devices, such as IGBT and MOS tubes, have been widely used. During the on-state aging process, the leakage of these MOS tubes will change, which may cause the on-resistance of the device to change, thereby changing the current driving ability of the device and affecting the stability and service life of the device.

[0003] In the existing semiconductor device testing technology, the leakage of the device is usually tested by the test equipment during the aging test process. Although this test method can measure the leakage of the device, it cannot monitor the change characteristics of the leakage of the device over time during the on-state aging process in real time, making the leakage detection lagging and unable to obtain the leakage of the device in time, resulting in inaccurate leakage measurement results. Summary of the invention

[0004] In order to solve the above technical problems, the present application provides a leakage monitoring method during the on-state aging process of a MOS tube to solve the existing problems.

[0005] A leakage monitoring method in a MOS tube on-state aging process of the present application adopts the following technical solution:

[0006] An embodiment of the present application provides a method for monitoring leakage during the on-state aging process of a MOS tube, the method comprising the following steps:

[0007] Set up a test device for monitoring leakage during the on-state aging process of the MOS tube, and install the MOS tube on the test device;

[0008] Simulate the working state of MOS tube in the actual circuit and perform simulation operation;

[0009] Obtain the temperature of the MOS tube in real time during the simulation operation, and control the heating equipment according to the temperature change of the MOS tube;

[0010] The leakage current value of the MOS tube during the simulation operation is obtained in real time, and the current value stable sequence is determined according to the stability of the value change of the leakage current value of the MOS tube; the leakage range is determined according to the numerical distribution of all leakage current values; the leakage stable value is obtained according to the numerical distribution of the leakage current values ​​within the leakage range in the stable sequence of all current values; the leakage stable time is obtained according to the difference between the leakage current value and the leakage stable value in the stable sequence of current values;

[0011] During the simulation operation, different load currents are applied to the MOS tube, and the leakage stabilization time of the MOS tube under different load currents is integrated to obtain the comprehensive leakage stabilization time of the MOS tube; the input power and output power of the leakage stabilization time of the MOS tube under each load current are obtained, and the power loss is calculated according to the input power and output power; and the heat dissipation device is controlled according to the power loss.

[0012] Furthermore, the simulation operation includes: conduction, reverse bias and aging.

[0013] Furthermore, the method for controlling the heating device comprises:

[0014] The preset aging temperature is used as the target value in the PID controller, and the speed of the heating device is adjusted using the PID controller.

[0015] Further, the step of determining a current value steady sequence according to the stability of the value change of the leakage current value of the MOS tube includes:

[0016] The sequence of leakage current values ​​collected at all moments in chronological order is evenly divided into a preset number of subsequences; the variance of all leakage current values ​​in each subsequence is calculated; the variances of all subsequences are arranged in ascending order to obtain a current stable sequence set; and the subsequences in the current stable sequence set with a preset proportion are taken as the current value stable sequence.

[0017] Further, determining the leakage range according to the numerical distribution of all leakage current values ​​includes:

[0018] Calculate the mean and standard deviation of the leakage current values ​​at all times; use the sum of the mean and the standard deviation as the upper limit of the leakage range; use the difference between the mean and the standard deviation as the lower limit of the leakage range; wherein the leakage range is a closed interval.

[0019] Furthermore, the method for obtaining the leakage stability value includes: calculating the average of all leakage current values ​​within the leakage range in all current value stable sequences as the leakage stability value.

[0020] Furthermore, the method for obtaining the leakage stabilization time includes:

[0021] Calculate the differences between all leakage current values ​​and leakage stability values ​​in each current value stable sequence; obtain the current value stable sequence with the smallest difference among all current value stable sequences, and record it as the leakage stable sequence; wherein, if the number of current value stable sequences with the smallest difference is not unique, select the current value stable sequence with the earliest time period as the leakage stable sequence; and take the time difference between the moment corresponding to the initial value in the leakage stable sequence and the initial acquisition moment as the leakage stabilization time.

[0022] Furthermore, the method for obtaining the comprehensive leakage stabilization time includes: calculating the average value of the leakage stabilization time of the MOS tube under all load currents as the comprehensive leakage stabilization time of the MOS tube.

[0023] Furthermore, the power loss calculation method includes: taking the difference between the input power and the output power of the MOS tube at the moment corresponding to the initial value in the leakage stability sequence under each load current as the power loss of the MOS tube under each load current.

[0024] Furthermore, controlling the heat dissipation device according to the power loss includes: taking the power loss of zero as the target value in the PID controller, and using the PID controller to adjust the speed of the heating device.

[0025] This application has at least the following beneficial effects:

[0026] This application analyzes that the monitoring results of leakage conditions during the on-state aging process of the transistor will also be affected by temperature, resulting in inaccurate monitoring results, and ignores the change of leakage conditions over time, resulting in the problem of lag in the monitoring results; by online monitoring of the change of leakage over time during the on-state aging process of the MOS tube, the heating equipment is controlled according to the temperature change of the MOS tube, so that the temperature of the MOS tube during the aging process is maintained at a stable state, reducing the impact of temperature change on leakage detection; on this basis, it is analyzed that in the early stage after power-on, the leakage current of the MOS tube may change due to factors such as temperature and material properties, and the leakage stability value and leakage stability time are obtained according to the change of leakage current value in different time periods; this method can accurately determine the specific time when the leakage of the MOS tube tends to stabilize. This method of judging the specific time when the leakage of the MOS tube tends to stabilize can more accurately judge the reliability of the device and improve the accuracy of leakage monitoring. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. 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.

[0028] Figure 1 A flow chart of the steps of a leakage monitoring method during the on-state aging process of a MOS tube provided in this application;

[0029] Figure 2 A module block diagram of a test device provided for one embodiment of the present application. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0032] The following is a detailed description of a specific scheme of a leakage monitoring method during the on-state aging process of a MOS tube provided by the present application in conjunction with the accompanying drawings.

[0033] An embodiment of the present application provides a method for monitoring leakage during the on-state aging process of a MOS tube. Specifically, the following method for monitoring leakage during the on-state aging process of a MOS tube is provided. Figure 1 , the method comprises the following steps:

[0034] S1, set up a test device for monitoring leakage during the on-state aging process of the MOS tube, and install the MOS tube on the test device.

[0035] A specific implementation scenario of the embodiment of the present application is the leakage monitoring scenario during the on-state aging process of the MOS tube; in practical applications, as a type of MOS tube, the on-state performance of the MOS tube, including the on-current and on-resistance, may be affected by factors such as temperature effect, aging effect and electrical stress. The temperature effect is specifically: as the temperature rises, the on-resistance of the transistor may increase, affecting its on-performance; the aging effect is specifically: as the use time increases, the transistor may cause parameter changes due to the long-term flow of current and thermal effects, affecting its conduction ability; the electrical stress is specifically: being in a high voltage and high current state for a long time may cause the aging of the device and reduce its conduction performance.

[0036] Therefore, the present embodiment first prepares the test equipment; the test equipment includes a power module, a heating system, a test system and an electronic load. The power module adopts a power supply of model DC-1200, with a maximum output voltage of 1200V and a maximum output current of 10A. The heating system adopts a heater of model HT-100, and the temperature sensor adopts a temperature sensor of model PT-100. The test system adopts a digital source meter of model KEITHLEY2400, and the measurement frequency is 1Hz. The electronic load adopts an electronic load of model RLC-3000. The test environment is further set, and the test environment temperature is 25°C, the relative humidity is 50%, and the atmospheric pressure is 101.3kPa.

[0037] Before the leakage test begins, the MOS tube needs to be installed on the test equipment to ensure that the connection between the MOS tube and the test equipment is firm. The monitoring results of the leakage situation during the transistor on-state aging process will also be affected by the temperature, resulting in inaccurate monitoring results, and ignoring the change of the leakage situation over time, making the monitoring results have lag. To solve the above problems, this embodiment monitors the leakage current and temperature changes of the MOS tube in real time online, measures the leakage current when the leakage situation is stable, and obtains accurate monitoring results.

[0038] The module block diagram of the test equipment, such as Figure 2 shown.

[0039] S2, simulating the working state of the MOS tube in the actual circuit and performing simulation operation; obtaining the temperature of the MOS tube in real time during the simulation operation, and controlling the heating device according to the temperature change of the MOS tube.

[0040] Start the power module, which can realize the conduction, reverse bias, and aging of the MOS tube. It mainly simulates the working state of the MOS tube in the actual circuit by controlling the output voltage and current of the power module, so as to accurately test the MOS tube. Specifically, use an oscilloscope or current probe to detect the drain current to confirm whether the MOS tube is turned on; after the MOS tube is turned on, gradually reduce the gate voltage until the MOS tube reaches the off state; in the test, the characteristic changes of the MOS tube can be observed through the reverse bias operation to analyze its performance. Keep the MOS tube working continuously, that is, perform aging operation on the MOS tube. In this embodiment, the aging time of the MOS tube is 100 hours and the aging temperature is 150°C.

[0041] In order to monitor the leakage during the aging process and obtain accurate test results, it is first necessary to use a heating system to heat the device to ensure that the housing reaches the temperature required by the test. To ensure temperature stability during the test and avoid the impact of temperature fluctuations on the test results. This embodiment first uses the temperature sensor of the heating system to obtain the temperature of the MOS tube in real time, and the temperature collection interval is 30s. According to the temperature change of the MOS tube, the heating device is controlled; in this embodiment, a PID controller is selected to control the operating state of the heating device according to the temperature change. The PID controller is a well-known technology, and the specific implementation process will not be repeated.

[0042] Specifically, the temperature of the MOS tube is obtained, the aging temperature is used as the target value in the PID controller, and the PID controller is used to adjust the speed of the heating device. The PID controller is a well-known technology, and the specific implementation process is not repeated. In this embodiment, the gain parameters in the PID controller are: proportional gain 30; integral gain 5; differential gain 5.

[0043] Among them, the operating speed of the heating device is controlled by using a PID controller, thereby controlling the heating temperature; when the difference between the temperature of the MOS tube and the aging temperature is greater, the degree of adjustment of the operating speed of the heating device is greater, so that the temperature of the MOS tube after final adjustment is in a relatively stable state and close to the aging temperature.

[0044] This testing method that takes temperature influence into account and precisely controls temperature can accurately measure the leakage of MOS tubes, avoiding the problem in the prior art that the influence of temperature distribution of MOS tubes on leakage is not considered, which may lead to inaccurate measurement results, thereby more accurately judging the reliability of the device.

[0045] S3, real-time acquisition of the leakage current value of the MOS tube during the simulation operation, and determination of the current value stable sequence according to the stability of the value change of the leakage current value of the MOS tube; determination of the leakage range according to the numerical distribution of all leakage current values; acquisition of the leakage stable value according to the numerical distribution of the leakage current values ​​within the leakage range in the stable sequence of all current values; acquisition of the leakage stable time according to the difference between the leakage current value and the leakage stable value in the stable sequence of the current value.

[0046] Start the test system to collect and record the leakage current value of the MOS tube during the simulated operation at a frequency of 1Hz. Leakage current is a key parameter of the MOS tube, reflecting its static characteristics and power consumption. Monitoring the stability of the leakage current helps to detect potential faults in a timely manner. For example, an abnormal increase in leakage current may indicate that the MOS tube is aging, damaged, or has other problems. In order to obtain an accurate leakage current value, it is necessary to check whether there is a significant fluctuation in the change of the leakage current value to determine its stability.

[0047] Specifically, the sequence of leakage current values ​​collected at all moments in time sequence is evenly divided into a preset number of subsequences; the number of subsequences divided in this embodiment is 100. The variance of all leakage current values ​​in each subsequence is calculated; the variances of all subsequences are arranged in order from small to large to obtain a current stable sequence set; the first 20% of the subsequences in the current stable sequence set are taken as the current value stable sequence.

[0048] In practical applications, the leakage current value is continuously monitored, and it is necessary to ensure that the change in the measured leakage current value is within the set stable value range. If obvious deviations are found, troubleshooting is required. This embodiment determines the leakage range based on the numerical distribution of all leakage current values; specifically, the mean and standard deviation of the leakage current values ​​at all times are calculated; the sum of the mean and the standard deviation is used as the upper limit of the leakage range; the difference between the mean and the standard deviation is used as the lower limit of the leakage range; wherein the leakage range is a closed interval.

[0049] Furthermore, in order to obtain a more accurate leakage stability value, the leakage stability value is obtained according to the numerical distribution of the leakage current values ​​within the leakage range interval in all current value stable sequences. Specifically, the mean of all leakage current values ​​within the leakage range interval in all current value stable sequences is calculated as the leakage stability value.

[0050] By analyzing the change of leakage current in different time periods, the leakage current value in a relatively stable time period is selected to calculate the leakage stability value, thereby improving the calculation accuracy of the leakage stability value. Furthermore, in the initial stage after power-on, the leakage current of the MOS tube may change due to factors such as temperature and material properties. In order to judge the reliability and stability of the MOS tube reflected in the aging operation process according to the leakage situation, judge the fault situation, and avoid misleading results. This embodiment obtains the leakage stability time according to the difference between the leakage current value and the leakage stability value in the current value stable sequence.

[0051] Specifically, the difference between all leakage current values ​​and leakage stability values ​​in each current value stable sequence is calculated; the difference calculation in this embodiment is to calculate the absolute value of the difference between two variables. The current value stable sequence with the smallest difference in all current value stable sequences is obtained and recorded as the leakage stable sequence; wherein, if the number of current value stable sequences with the smallest difference is not unique, the current value stable sequence with the earliest time period is selected as the leakage stable sequence; the time difference between the time corresponding to the initial value in the leakage stable sequence and the initial acquisition time is taken as the leakage stable time.

[0052] Among them, the shorter the current stabilization time is, the more quickly the MOS tube can reach a thermal equilibrium state during the test, indicating that its heat dissipation performance is good and it is not easy to cause leakage current fluctuations due to temperature changes.

[0053] S4, applying different load currents to the MOS tube during the simulation operation, integrating the leakage stabilization time of the MOS tube under different load currents to obtain the comprehensive leakage stabilization time of the MOS tube; obtaining the input power and output power of the leakage stabilization time of the MOS tube under each load current, and calculating the power loss according to the input power and output power; and controlling the heat dissipation device according to the power loss.

[0054] The electronic load test module is used to apply different load currents to the MOS tube during the simulation operation, so as to test the performance of the MOS tube under different conditions. By gradually increasing the current of the electronic load and observing the output voltage and temperature changes of the MOS tube, the stability of its performance can be determined.

[0055] First, the leakage stabilization time of the MOS tube under different load currents is integrated to obtain the comprehensive leakage stabilization time of the MOS tube; specifically, the average of the leakage stabilization time of the MOS tube under all load currents is calculated as the comprehensive leakage stabilization time of the MOS tube. The comprehensive leakage stabilization time represents the comprehensive level of the leakage stabilization time of the MOS tube under different load currents.

[0056] Power loss is one of the important indicators for evaluating the performance of MOS tubes. In applications such as switching power supplies and power amplifiers, power loss affects the overall efficiency of the system. MOS tubes generate heat when working, and power loss directly affects their temperature. Excessive temperature may cause the MOS tube to fail or shorten its life, affecting the stability of the temperature during the test. Because, this embodiment first obtains accurate power loss based on the input power and output power of the leakage stabilization time of the MOS tube under different load currents; specifically, the difference between the input power and the output power of the MOS tube at the leakage stabilization time under each load current is used as the power loss of the MOS tube under each load current.

[0057] When the power loss of the MOS tube increases, more heat will be generated, causing its temperature to rise. Therefore, this embodiment controls the operating speed of the heat dissipation device according to the power loss situation; in this embodiment, the heat dissipation device is a fan, that is, the speed of the fan is controlled. Specifically, the power loss is zero as the target value in the PID controller, and the PID controller is used to adjust the speed of the heating device. In this embodiment, the gain parameters in the PID controller are: proportional gain 30; integral gain 5; differential gain 5.

[0058] Among them, the operating speed of the heat dissipation device is controlled by using a PID controller to maintain the temperature stability; when the power loss of the MOS tube is greater, the degree of adjustment of the operating speed of the heat dissipation device is greater, so that the temperature of the MOS tube after the final adjustment is in a relatively stable state.

[0059] By analyzing the test data, the present application can monitor the leakage of the MOS tube in real time during the on-state aging process. This real-time monitoring method can timely understand the leakage of the MOS tube, avoiding the problem of the leakage of the MOS tube that cannot be monitored online during the on-state aging process in the prior art, so that timely measures can be taken to ensure the reliability of the device. At the same time, by obtaining the accurate changes of the observed parameters over time, the specific time when the leakage of the MOS tube tends to stabilize can be determined, thereby accurately measuring the leakage of the MOS tube. This method of determining the specific time when the leakage of the MOS tube tends to stabilize can provide important reference data for the use of the MOS tube, avoiding the problem of the inability to determine the specific time when the leakage of the MOS tube tends to stabilize in the prior art, thereby more effectively ensuring the stability and service life of the device.

[0060] Through the above description of the implementation method in combination with the accompanying drawings, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0061] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A method for monitoring leakage during the on-state aging process of a MOS tube, characterized in that: The method comprises the following steps: Set up a test device for monitoring leakage during the on-state aging process of the MOS tube, and install the MOS tube on the test device; Simulate the working state of MOS tube in the actual circuit and perform simulation operation; Obtain the temperature of the MOS tube in real time during the simulation operation, and control the heating equipment according to the temperature change of the MOS tube; The leakage current value of the MOS tube during the simulation operation is obtained in real time, the leakage current value is formed into a sequence and evenly divided to obtain a subsequence, and the subsequence is sorted according to the current variance to obtain a current stable sequence set; the front subsequence of the current stable sequence set is used as a current value stable sequence; the sum of the mean and standard deviation of the leakage current value at all times is used as the upper limit of the leakage range, and the difference between the mean and the standard deviation is used as the lower limit of the leakage range to form the leakage range; the mean of all leakage current values ​​within the leakage range interval in all current value stable sequences is calculated as the leakage stable value; the difference between all leakage current values ​​and the leakage stable value in each current value stable sequence is calculated; the current value stable sequence with the smallest difference in all current value stable sequences is obtained, and recorded as the leakage stable sequence; wherein, if the number of the current value stable sequences with the smallest difference is not unique, the current value stable sequence with the earliest time period is selected as the leakage stable sequence; the time difference between the time corresponding to the initial value in the leakage stable sequence and the initial acquisition time is used as the leakage stable time; During the simulation operation, different load currents are applied to the MOS tube, and the leakage stabilization time of the MOS tube under different load currents is integrated to obtain the comprehensive leakage stabilization time of the MOS tube; the input power and output power of the leakage stabilization time of the MOS tube under each load current are obtained, and the power loss is calculated according to the input power and output power; and the heat dissipation device is controlled according to the power loss.

2. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The analog operations include: turn-on, reverse bias and aging.

3. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The method for controlling a heating device comprises: The preset aging temperature is used as the target value in the PID controller, and the speed of the heating device is adjusted using the PID controller.

4. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The method for obtaining the current value steady sequence includes: The sequence of leakage current values ​​collected at all moments in chronological order is evenly divided into a preset number of subsequences; the variance of all leakage current values ​​in each subsequence is calculated; the variances of all subsequences are arranged in ascending order to obtain a current stable sequence set; and the subsequences in the current stable sequence set with a preset proportion are taken as the current value stable sequence.

5. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The method for obtaining the comprehensive leakage stabilization time includes: calculating the average value of the leakage stabilization time of the MOS tube under all load currents as the comprehensive leakage stabilization time of the MOS tube.

6. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The power loss calculation method includes: taking the difference between the input power and the output power of the MOS tube at the time corresponding to the initial value in the leakage stability sequence under each load current as the power loss of the MOS tube under each load current.

7. A method for monitoring leakage during on-state aging of a MOS tube as claimed in claim 1, characterized in that: The controlling of the heat dissipation device according to the power loss comprises: taking the power loss of zero as the target value in the PID controller, and using the PID controller to adjust the speed of the heating device.

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