A method and system for testing the avalanche withstand capability of semiconductor diodes

Abstract

The present invention relates to the field of semiconductor testing technology, and in particular to a method and system for testing the avalanche withstand capability of semiconductor diodes. The method comprises: obtaining a thermal imaging image of a semiconductor diode during the process of being stimulated by a spike voltage and returning to a stable state, and determining the peak area of ​​the local temperature; determining a heat dissipation index based on the temperature change and the area of ​​the peak area; determining a local overheating factor of the thermal imaging image in combination with the heat dissipation index and the distance of all peak areas; determining a dissipation rate of the local overheating phenomenon of the diode based on the numerical changes of the local overheating factors of all thermal imaging images in a time sequence; determining the possibility of thermal breakdown based on the local overheating factor and the dissipation rate; and determining avalanche withstand capability based on the numerical changes of all thermal breakdown possibilities of the diode at different spike voltages. The present invention can perform a specific analysis of avalanche withstand capability based on temperature changes, thereby making the avalanche withstand capability more accurate.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor testing technology, and in particular to a method and system for testing the avalanche withstand capability of a semiconductor diode. Background Art

[0002] Avalanche withstand is a measure of a semiconductor device's maximum energy tolerance when subjected to overvoltage or current, resulting in an avalanche state. Avalanche withstand is a key indicator for evaluating semiconductor diode reliability, particularly under high voltage spikes or transient overvoltage conditions, which directly impact the long-term stability and safety of semiconductor diodes.

[0003] Currently, during avalanche withstand testing of semiconductor diodes, voltage is applied until the diode enters an avalanche state, and the current and voltage curves are recorded. The avalanche energy is calculated from the measured current and voltage waveforms. This analysis, based solely on current and voltage changes, fails to consider that during an avalanche, heat may not be dissipated in time, causing a sharp rise in the diode's internal temperature. Conventional avalanche testing primarily determines the diode's withstand capability based on the current-voltage curve. However, the actual diode's limit is due to irreversible damage caused by thermal breakdown due to temperature rise. Consequently, the accuracy and reliability of avalanche withstand analysis in related technologies are poor. Summary of the Invention

[0004] In order to solve the technical problem in the related art that heat accumulation affects the avalanche process, resulting in poor accuracy and reliability in the analysis of avalanche withstand capability, the present invention provides a method and system for testing the avalanche withstand capability of a semiconductor diode. The technical solutions adopted are as follows:

[0005] The present invention provides a method for testing the avalanche withstand capability of a semiconductor diode, the method comprising:

[0006] During the process of spike voltage stimulation and recovery to a stable state, thermal imaging images of the semiconductor diode are periodically acquired to determine the peak area of ​​the local temperature of the diode on the thermal imaging image;

[0007] Determine the heat dissipation deficiency index based on the temperature changes between all peak areas and adjacent areas, as well as the area of ​​the peak areas; and determine the local overheating factor of the thermal imaging image by combining the heat dissipation deficiency index and the distance between all peak areas.

[0008] The dissipation rate of the local overheating phenomenon of the diode is determined based on the numerical changes of the local overheating factors of all thermal imaging images in the time sequence; the possibility of thermal breakdown of the diode under the peak voltage is determined by combining the maximum value and dissipation rate of all local overheating factors;

[0009] Obtain the thermal breakdown probability of the diode under different peak voltages, perform avalanche withstand analysis based on the numerical changes of all thermal breakdown probabilities of the diode under different peak voltages, and determine the avalanche withstand capability of the diode.

[0010] Furthermore, determining the peak area of ​​the local temperature of the diode on the thermal imaging image includes:

[0011] Determine the temperature value corresponding to each pixel on the thermal imaging image based on the temperature and color comparison;

[0012] Perform region growing based on temperature values ​​to determine different temperature regions with the same temperature;

[0013] The average temperature value of all pixels in any temperature zone is taken as the regional temperature of the corresponding temperature zone;

[0014] When the regional temperature of any temperature region is greater than the regional temperatures of all adjacent temperature regions, the temperature region is regarded as a peak region.

[0015] Furthermore, determining the heat dissipation deficiency index based on the temperature changes of all peak areas and adjacent areas, as well as the area of ​​the peak area, includes:

[0016] Determine the temperature heat dissipation index of the peak area based on the difference in regional temperature between the peak area and all adjacent areas, as well as the regional temperature of the peak area;

[0017] The product value of the inverse of the temperature heat dissipation index and the total area of ​​all peak regions is normalized and used as the heat dissipation deficiency index of the corresponding thermal imaging image.

[0018] Furthermore, determining the temperature heat dissipation index of the peak area based on the difference in regional temperature between the peak area and all adjacent areas, and the regional temperature of the peak area, includes:

[0019] Calculating the regional temperature differences between the peak region and all adjacent regions, and taking the average of the regional temperature differences corresponding to all adjacent regions as the first temperature parameter of the peak region;

[0020] The ratio of the first temperature parameter to the regional temperature of the peak region is normalized and used as the temperature heat dissipation index of the peak region.

[0021] Furthermore, the combining of the heat dissipation deficiency index and the distances of all peak areas to determine the local overheating factor of the thermal imaging image includes:

[0022] The morphological center of the peak area is used as the reference point, and the mean of the distance between the reference points of any two peak areas is used as the distance coefficient;

[0023] The ratio of the insufficient heat dissipation index to the distance coefficient is calculated and normalized to obtain the local overheating factor of the thermal imaging image.

[0024] Furthermore, determining the dissipation rate of the local overheating phenomenon of the diode according to the numerical changes of the local overheating factors of all thermal imaging images in a time sequence includes:

[0025] Arrange the local overheating factors of all thermal imaging images according to the time sequence, and take the sequence after the maximum local overheating factor as the overheating recovery sequence;

[0026] The difference between the first local overheating factor and the last local overheating factor in the overheating recovery sequence is used as the recovery range, and the number of intervals between the first local overheating factor and the last local overheating factor in the sequence is used as the recovery time;

[0027] The ratio of the recovery range and the recovery time is calculated as the dissipation rate.

[0028] Furthermore, the step of combining the maximum values ​​and dissipation rates of all local overheating factors to determine the possibility of thermal breakdown of the diode under a peak voltage includes:

[0029] The ratio of the maximum value of the local overheating factor to the dissipation rate is normalized and used as the possibility of thermal breakdown.

[0030] Furthermore, the avalanche withstand analysis is performed based on the numerical changes of all thermal breakdown possibilities of the diode at different peak voltages to determine the avalanche withstand capability of the diode, including:

[0031] The numerical variance of all thermal breakdown probabilities is taken as the breakdown instability;

[0032] Calculate the numerical mean of all thermal breakdown possibilities as the breakdown mean;

[0033] The product of the breakdown mean and the breakdown instability is calculated, and the inverse of the product value is normalized to obtain the avalanche withstand capability.

[0034] Furthermore, the peak voltage is: (1000V, 1100V, 1200V, ..., 2000V).

[0035] On the other hand, a semiconductor diode avalanche withstand test system is also provided, which includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any of the methods described above are implemented.

[0036] The present invention has the following beneficial effects:

[0037] In an embodiment of the present invention, by periodically acquiring thermal imaging images of a semiconductor diode during the process of being stimulated by a spike voltage and returning to a stable state, the peak area of ​​the local temperature of the diode on the thermal imaging image is determined; based on the temperature changes of all peak areas and adjacent areas, as well as the area of ​​the peak area, an insufficient heat dissipation index is determined; based on the insufficient heat dissipation index and the distances of all peak areas, a local overheating factor of the thermal imaging image is determined; based on the numerical changes of the local overheating factors of all thermal imaging images in a time series, a dissipation rate of the local overheating phenomenon of the diode is determined; based on the maximum values ​​and dissipation rates of all local overheating factors, the possibility of thermal breakdown of the diode under a spike voltage is determined; the possibility of thermal breakdown of the diode under different spike voltages is obtained, and based on the numerical changes of all thermal breakdown possibilities of the diode at different spike voltages, an avalanche withstand analysis is performed to determine the avalanche withstand of the diode.

[0038] Since the heat distribution of the diode under the same spike voltage is analyzed, the local overheating phenomenon caused by the spike voltage is determined. The local overheating factor of the thermal imaging image is determined in combination with the heat dissipation index and the distance of all peak areas. Combined with the heat dissipation effect, the possibility of thermal breakdown of the diode under the spike voltage is determined. Then, the heat change of the diode under different spike voltages is analyzed. Based on the numerical changes of all thermal breakdown possibilities of the diode at different spike voltages, the avalanche withstand capacity is analyzed. This makes it possible to obtain the avalanche withstand capacity of the diode more intuitively and accurately, and to perform specific analysis of the avalanche withstand capacity based on temperature changes, making the avalanche withstand capacity more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 A flow chart of a method for testing the avalanche withstand capability of a semiconductor diode provided by one embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a test circuit provided by one embodiment of the present invention;

[0042] Figure 3 A schematic diagram of a spike voltage gradually decreasing and returning to a stable state provided by an embodiment of the present invention;

[0043] Figure 4 A schematic diagram of diode temperature distribution according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail a method and system for avalanche withstand testing of semiconductor diodes according to the present invention, including its specific implementation, structure, features, and effectiveness. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0045] 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 invention belongs.

[0046] The specific scheme of the avalanche withstand test method of a semiconductor diode provided by the present invention is described in detail below with reference to the accompanying drawings.

[0047] See also Figure 1 , which shows a flow chart of a method for testing the avalanche withstand capability of a semiconductor diode provided by one embodiment of the present invention, the method comprising:

[0048] S101: During the process of spike voltage stimulation and recovery to a stable state, periodically acquire a thermal imaging image of the semiconductor diode, and determine a peak area of ​​the local temperature of the diode on the thermal imaging image.

[0049] The specific scenario targeted by the present invention is: conventional avalanche detection is more based on the current-voltage curve to determine the diode's tolerance, but the actual limit of the diode is due to irreversible damage caused by thermal breakdown due to temperature increase. Therefore, in order to more accurately identify local design anomalies or defects of the diode, it is necessary to detect the heat distribution of the diode and optimize the avalanche tolerance.

[0050] The specific process of avalanche withstand test of semiconductor diodes is as follows:

[0051] (1) Preparation: Select appropriate test equipment, including a controllable DC power supply, inductor, current sensor, voltage sensor, control signal input terminal, and controllable switch-type power device.

[0052] (2) Build the test circuit: Connect the diode to be tested to the test circuit, make sure all connections are correct and the test circuit has been built. Figure 2 , Figure 2 A schematic diagram of a test circuit provided by an embodiment of the present invention.

[0053] (3) Charging energy storage: Use a controllable DC power supply to charge the inductor so that it stores enough energy for avalanche testing.

[0054] (4) Trigger discharge: At the appropriate time, the controllable switch-type power device is triggered by the control signal to discharge the inductor and generate a spike voltage to simulate the voltage spike situation in actual application.

[0055] (5) Voltage setting: For the same semiconductor diode, first perform an avalanche test using a 1000V peak voltage, then increase the voltage by 100V each time and perform another avalanche test until it reaches 2000V.

[0056] (6) Data acquisition: Use current sensors and voltage sensors to monitor and record the current and voltage waveforms at both ends of the diode in real time. Use a thermal imager to capture thermal imaging videos of the semiconductor diode from the peak voltage to the voltage gradually decreasing and finally returning to a stable state. Figure 3 , Figure 3 A schematic diagram of a spike voltage gradually decreasing and returning to a stable state provided by an embodiment of the present invention.

[0057] For different semiconductor diodes of the same type, operations (1) to (6) are repeated to obtain a thermal imaging video of each semiconductor diode at each peak voltage. Then, each frame in the thermal imaging video is used as a thermal imaging image, thereby achieving periodic acquisition of thermal imaging images of the semiconductor diode.

[0058] Among them, the peak area is the area where the diode temperature is higher in the thermal imaging image in the embodiment of the present invention. The high temperature is manifested in that it is at a temperature peak compared to other surrounding areas, that is, the temperature of the peak area is higher than the temperature of the surrounding areas. Combined with this feature, the peak area is analyzed.

[0059] Furthermore, in some embodiments of the present invention, determining the peak area of ​​the local temperature of the diode on the thermal imaging image includes: determining the temperature value corresponding to each pixel point on the thermal imaging image based on temperature and color comparison; performing region growing processing based on the temperature value to determine different temperature regions with the same temperature; taking the average temperature value of all pixels in any temperature region as the regional temperature of the corresponding temperature region; when the regional temperature of any temperature region is greater than the regional temperatures of all adjacent temperature regions, taking the temperature region as the peak area.

[0060] In the embodiment of the present invention, different temperature regions are divided by region growing, and the peak region is determined.

[0061] S102: Determine a heat dissipation deficiency index based on temperature changes between all peak regions and adjacent regions, as well as the area of ​​the peak regions; and determine a local overheating factor of the thermal imaging image based on the heat dissipation deficiency index and the distances between all peak regions.

[0062] The change in heat during the process of the peak voltage gradually decreasing is as follows: the PN junction of the diode absorbs the energy generated by the peak voltage, and then the diode dissipates the absorbed energy in the form of heat through the internal resistance and external circuit components (such as resistors, capacitors, etc.). As the energy dissipates, the peak voltage begins to decrease. Figure 4 , Figure 4 This diagram illustrates the temperature distribution of a diode according to one embodiment of the present invention. If the diode's heat dissipation capacity is insufficient, this heat will quickly accumulate, causing a sharp temperature rise. When localized overheating within the diode leads to thermal breakdown, the diode's PN junction will be destroyed.

[0063] Based on this, in an embodiment of the present invention, the local overheating factor is first analyzed through the heat distribution and temperature on the semiconductor diode in each frame of the thermal imaging video.

[0064] Furthermore, in some embodiments of the present invention, a heat dissipation deficiency index is determined based on the temperature changes between all peak areas and adjacent areas, as well as the area of ​​the peak area, including: determining the temperature heat dissipation index of the peak area based on the difference in regional temperature between the peak area and all adjacent areas, as well as the regional temperature of the peak area; and normalizing the product value of the opposite of the temperature heat dissipation index and the total area of ​​all peak areas as the heat dissipation deficiency index of the corresponding thermal imaging image.

[0065] It is understandable that the higher the hot spot temperature is and the higher the temperature around the hot spot is, the worse the heat dissipation is, which can easily cause local overheating. According to the heat conduction effect, the greater the temperature difference, the faster the heat conduction. For example, when the center temperature is 500 degrees Celsius and the surrounding temperature is 400 degrees Celsius, the heat dissipation effect is not as good as when the surrounding temperature is 300 degrees Celsius. Combined with this feature, the temperature heat dissipation index is analyzed.

[0066] Furthermore, in some embodiments of the present invention, the temperature heat dissipation index of the peak area is determined based on the difference in regional temperature between the peak area and all adjacent areas, as well as the regional temperature of the peak area, including: calculating the regional temperature difference between the peak area and all adjacent areas, and taking the average of the regional temperature differences corresponding to all adjacent areas as the first temperature parameter of the peak area; and normalizing the ratio of the first temperature parameter to the regional temperature of the peak area as the temperature heat dissipation index of the peak area.

[0067] In an embodiment of the present invention, the first temperature parameter is the regional temperature difference between the central peak area and the surrounding adjacent areas, which is obtained by directly calculating the temperature difference and averaging it. The higher the central temperature, the greater the impact of the central temperature on the environment. The surrounding environment is also affected by high temperature, and the heat conduction is worse. Combined with this feature, the ratio of the first temperature parameter to the regional temperature of the peak area is directly calculated and normalized as the temperature heat dissipation index of the peak area.

[0068] Since the larger the total area of ​​the peak area, the greater the impact on the overall heat dissipation effect, based on this, the product value of the inverse of the temperature heat dissipation index and the total area of ​​all peak areas is normalized and used as the heat dissipation deficiency index of the corresponding thermal imaging image.

[0069] The insufficient heat dissipation index characterizes the effect of insufficient heat dissipation of the semiconductor diode in the thermal imaging image under corresponding conditions. That is, the worse the heat dissipation effect, the larger the value of the insufficient heat dissipation index, and the more likely it is that the device will subsequently fail due to insufficient heat dissipation.

[0070] After determining the heat dissipation deficiency index and analyzing the heat dissipation, since there is more than one peak area in the same thermal imaging image, based on this, when there are multiple peak areas, it is necessary to analyze the distance between the peak areas. That is, the shorter the distance between the peak areas, the denser the corresponding peak areas are distributed, and the heat dissipation is also affected.

[0071] Furthermore, in some embodiments of the present invention, the local overheating factor of the thermal imaging image is determined by combining the insufficient heat dissipation index and the distance of all peak areas, including: taking the morphological center of the peak area as the reference point, and taking the average of the distance between the reference points of any two peak areas as the distance coefficient; calculating the ratio of the insufficient heat dissipation index to the distance coefficient, and normalizing it as the local overheating factor of the thermal imaging image.

[0072] Since the smaller the value of the distance coefficient is, the more peak areas there are in the corresponding local area, and the denser the distribution of the peak areas is, the greater the possibility of local overheating is. The larger the value of the insufficient heat dissipation index is, the greater the possibility of local overheating is. The local overheating factor is used to represent the possibility of local overheating of the semiconductor diode in the thermal imaging image, and the specific local overheating factor is calculated based on the above logic.

[0073] S103: Determine the dissipation rate of the local overheating phenomenon of the diode based on the numerical changes of the local overheating factors of all thermal imaging images in the time sequence; and determine the possibility of thermal breakdown of the diode under the peak voltage by combining the maximum value and dissipation rate of all local overheating factors.

[0074] During the initial spike, energy absorption and dissipation occur almost simultaneously. However, due to thermal inertia, the internal temperature doesn't immediately reach its peak. As the spike continues, the diode's internal temperature gradually rises, and heat begins to dissipate outward through the heat dissipation path. After the spike ends, the diode's internal heat continues to dissipate until the temperature returns to normal operating levels.

[0075] Based on this, when gradually returning to a stable state under a spike voltage, the faster the heat drops and the smaller the impact of local overheating, the better the overall thermal control of the corresponding diode. This spike voltage has a smaller impact on the semiconductor diode, and the higher the semiconductor diode's avalanche withstand capability. Therefore, it is necessary to analyze the possibility of thermal breakdown.

[0076] Furthermore, in some embodiments of the present invention, the dissipation rate of the local overheating phenomenon of the diode is determined based on the numerical changes of the local overheating factors of all thermal imaging images in a time sequence, including: arranging the local overheating factors of all thermal imaging images according to the time sequence, and taking the sequence after the maximum local overheating factor as the overheating recovery sequence; taking the difference between the first local overheating factor and the last local overheating factor in the overheating recovery sequence as the recovery range, and taking the number of intervals between the first local overheating factor and the last local overheating factor in the sequence as the recovery time; and calculating the ratio of the recovery range to the recovery time as the dissipation rate.

[0077] The dissipation rate is the rate at which local overheating disappears, that is, the speed at which heat distribution returns to uniformity. The ratio of the dissipated temperature value to the time is taken as the dissipation rate.

[0078] During an avalanche, heat may not be dissipated quickly enough, causing a sharp rise in the temperature inside the semiconductor diode. This can lead to uneven heat distribution and thermal breakdown. A high-efficiency heat sink for the semiconductor diode can quickly dissipate the localized overheating and restore uniform heat distribution. Therefore, the possibility of thermal breakdown needs to be analyzed.

[0079] Furthermore, in some embodiments of the present invention, the maximum value and dissipation rate of all local overheating factors are combined to determine the possibility of thermal breakdown of the diode under peak voltage, including: normalizing the ratio of the maximum value of the local overheating factor to the dissipation rate as the thermal breakdown possibility.

[0080] Since a greater dissipation rate indicates that the temperature dissipates more easily and the likelihood of thermal breakdown decreases, the maximum local overheating factor represents the maximum overheating situation. The larger the value, the more likely thermal breakdown will occur. Based on this, the ratio of the maximum local overheating factor to the dissipation rate is normalized to represent the likelihood of thermal breakdown. In other words, the larger the maximum local overheating factor, the slower the local overheating phenomenon dissipates, and the slower the heat distribution returns to uniformity, the more likely thermal breakdown will occur.

[0081] S104: Obtain the thermal breakdown probability of the diode at different peak voltages, perform avalanche withstand analysis based on the numerical changes of all thermal breakdown probabilities of the diode at different peak voltages, and determine the avalanche withstand capability of the diode.

[0082] In the embodiment of the present invention, the peak voltage is set to 1000V, 1100V, 1200V, ..., 2000V. Based on this, each peak voltage has a different temperature rise performance. Combining this feature and integrating it can cope with different voltage scenarios.

[0083] Since the possibility of thermal breakdown refers to the thermal breakdown effect of a semiconductor diode caused by excessive heat that is difficult to dissipate, this characteristic can be combined with avalanche withstand analysis.

[0084] Furthermore, in some embodiments of the present invention, an avalanche withstand analysis is performed based on the numerical changes of all thermal breakdown possibilities of the diode at different peak voltages to determine the avalanche withstand capability of the diode, including: taking the numerical variance of all thermal breakdown possibilities as breakdown instability; calculating the numerical mean of all thermal breakdown possibilities as breakdown mean; calculating the product of the breakdown mean and the breakdown instability, and normalizing the inverse of the product value as the avalanche withstand capability.

[0085] In the embodiment of the present invention, the analysis of avalanche withstand is divided into two dimensions: one is the value of the thermal breakdown possibility, and the other is the stability of the thermal breakdown possibility under different peak voltages.

[0086] A larger variance in the thermal breakdown probability indicates a more unstable distribution of the probability at different peak voltages, and therefore, less stable overall semiconductor diode quality. A larger mean value for the thermal breakdown probability indicates a greater susceptibility to thermal breakdown. Based on this analysis, the product of the mean breakdown value and the breakdown instability is calculated, and the inverse of this product is normalized to obtain the avalanche withstand capability.

[0087] In an embodiment of the present invention, by periodically acquiring thermal imaging images of a semiconductor diode during the process of being stimulated by a spike voltage and returning to a stable state, the peak area of ​​the local temperature of the diode on the thermal imaging image is determined; based on the temperature changes of all peak areas and adjacent areas, as well as the area of ​​the peak area, an insufficient heat dissipation index is determined; based on the insufficient heat dissipation index and the distances of all peak areas, a local overheating factor of the thermal imaging image is determined; based on the numerical changes of the local overheating factors of all thermal imaging images in a time series, a dissipation rate of the local overheating phenomenon of the diode is determined; based on the maximum values ​​and dissipation rates of all local overheating factors, the possibility of thermal breakdown of the diode under a spike voltage is determined; the possibility of thermal breakdown of the diode under different spike voltages is obtained, and based on the numerical changes of all thermal breakdown possibilities of the diode at different spike voltages, an avalanche withstand analysis is performed to determine the avalanche withstand of the diode.

[0088] Since the heat distribution of the diode under the same spike voltage is analyzed and the local overheating phenomenon caused by the spike voltage is determined, the heat dissipation index is determined based on the temperature changes of all peak areas and adjacent areas, as well as the area of ​​the peak area; the local overheating factor of the thermal imaging image is determined in combination with the heat dissipation index and the distance of all peak areas; and the possibility of thermal breakdown of the diode under the spike voltage is determined in combination with the heat dissipation effect; then, the heat changes of the diode under different spike voltages are analyzed, and the avalanche withstand capacity is analyzed based on the numerical changes of all thermal breakdown possibilities of the diode at different spike voltages. This allows the avalanche withstand capacity of the diode to be obtained more intuitively and accurately, making it possible to conduct a specific analysis of the avalanche withstand capacity based on temperature changes, making the avalanche withstand capacity more accurate.

[0089] The present invention also provides an avalanche withstand test system for semiconductor diodes. The system includes a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, the steps of the avalanche withstand test method for semiconductor diodes as described above are implemented.

[0090] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0091] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. A method for testing the avalanche withstand capability of a semiconductor diode, characterized in that: The method comprises: During the process of spike voltage stimulation and recovery to a stable state, thermal imaging images of the semiconductor diode are periodically acquired to determine the peak area of ​​the local temperature of the diode on the thermal imaging image; Determine the heat dissipation deficiency index based on the temperature changes between all peak areas and adjacent areas, as well as the area of ​​the peak areas; and determine the local overheating factor of the thermal imaging image by combining the heat dissipation deficiency index and the distance between all peak areas. The dissipation rate of the local overheating phenomenon of the diode is determined based on the numerical changes of the local overheating factors of all thermal imaging images in the time sequence; the possibility of thermal breakdown of the diode under the peak voltage is determined by combining the maximum value and dissipation rate of all local overheating factors; Obtain the thermal breakdown probability of the diode under different peak voltages, perform avalanche withstand analysis based on the numerical changes of all thermal breakdown probabilities of the diode under different peak voltages, and determine the avalanche withstand capability of the diode.

2. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 1, wherein: The step of determining a peak area of ​​a local temperature of a diode on a thermal imaging image includes: Determine the temperature value corresponding to each pixel on the thermal imaging image based on the temperature and color comparison; Perform region growing based on temperature values ​​to determine different temperature regions with the same temperature; The average temperature value of all pixels in any temperature zone is taken as the regional temperature of the corresponding temperature zone; When the regional temperature of any temperature region is greater than the regional temperatures of all adjacent temperature regions, the temperature region is regarded as a peak region.

3. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 2, wherein: Determining the heat dissipation deficiency index based on the temperature changes of all peak areas and adjacent areas, as well as the area of ​​the peak area, includes: Determine the temperature heat dissipation index of the peak area based on the difference in regional temperature between the peak area and all adjacent areas, as well as the regional temperature of the peak area; The product value of the inverse of the temperature heat dissipation index and the total area of ​​all peak regions is normalized and used as the heat dissipation deficiency index of the corresponding thermal imaging image.

4. A method for testing the avalanche withstand capability of a semiconductor diode according to claim 3, characterized in that: Determining the temperature heat dissipation index of the peak area based on the difference in regional temperature between the peak area and all adjacent areas, and the regional temperature of the peak area, includes: Calculating the regional temperature differences between the peak region and all adjacent regions, and taking the average of the regional temperature differences corresponding to all adjacent regions as the first temperature parameter of the peak region; The ratio of the first temperature parameter to the regional temperature of the peak region is normalized and used as the temperature heat dissipation index of the peak region.

5. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 1, wherein: The method of combining the heat dissipation deficiency index and the distances of all peak areas to determine the local overheating factor of the thermal imaging image includes: The morphological center of the peak area is used as the reference point, and the mean of the distance between the reference points of any two peak areas is used as the distance coefficient; The ratio of the insufficient heat dissipation index to the distance coefficient is calculated and normalized to obtain the local overheating factor of the thermal imaging image.

6. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 1, wherein: The method of determining the dissipation rate of the local overheating phenomenon of the diode according to the numerical changes of the local overheating factors of all thermal imaging images in a time sequence includes: Arrange the local overheating factors of all thermal imaging images according to the time sequence, and take the sequence after the maximum local overheating factor as the overheating recovery sequence; The difference between the first local overheating factor and the last local overheating factor in the overheating recovery sequence is used as the recovery range, and the number of intervals between the first local overheating factor and the last local overheating factor in the sequence is used as the recovery time; The ratio of the recovery range and the recovery time is calculated as the dissipation rate.

7. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 1, wherein: The combination of the maximum value and dissipation rate of all local overheating factors to determine the possibility of thermal breakdown of the diode under peak voltage includes: The ratio of the maximum value of the local overheating factor to the dissipation rate is normalized and used as the possibility of thermal breakdown.

8. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 1, wherein: The avalanche withstand analysis is performed based on the numerical changes of all thermal breakdown possibilities of the diode at different peak voltages to determine the avalanche withstand capability of the diode, including: The numerical variance of all thermal breakdown probabilities is taken as the breakdown instability; Calculate the numerical mean of all thermal breakdown possibilities as the breakdown mean; The product of the breakdown mean and the breakdown instability is calculated, and the inverse of the product value is normalized to obtain the avalanche withstand capability.

9. The method for testing the avalanche withstand capability of a semiconductor diode according to claim 8, wherein: The peak voltage is: 1000V, 1100V, 1200V, ..., 2000V.

10. A semiconductor diode avalanche withstand test system, the system comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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