Method and system for testing avalanche tolerance of semiconductor diode

Abstract

The invention relates to the technical field of semiconductor testing, in particular to a method and a system for testing avalanche tolerance of a semiconductor diode. The method comprises the following steps: in the process of peak voltage stimulation and recovery to a stable state, obtaining a thermal imaging image of a semiconductor diode, and determining a peak value region of local temperature; determining a heat dissipation insufficiency index according to the temperature change and the area of the peak region; determining a local overheating factor of the thermal imaging image in combination with the heat dissipation insufficiency index and the distances of all peak regions; determining the dissipation rate of the local overheating phenomenon of the diode according to the numerical change of the local overheating factors of all thermal imaging images on the time sequence; determining the possibility of thermal breakdown by combining the local overheating factor and the dissipation rate; and determining the avalanche tolerance according to the numerical change of all thermal breakdown possibilities of the diode at different peak voltages. The avalanche tolerance can be specifically analyzed according to the temperature change, so that the accuracy of the avalanche tolerance is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor testing, and particularly to a method and system for testing the avalanche tolerance of a semiconductor diode. Background Art

[0002] Avalanche tolerance is a measure of the maximum energy tolerance of a semiconductor device in an avalanche state when subjected to overvoltage or overcurrent. Avalanche tolerance is an important indicator for evaluating the reliability of semiconductor diodes, especially under high-voltage spikes or transient overvoltage conditions, which directly affects the long-term stability and safety of semiconductor diodes.

[0003] Currently, during the avalanche tolerance test of a semiconductor diode, a voltage is applied until the semiconductor diode enters the avalanche state, the change curves of current and voltage are recorded, and the avalanche energy is calculated through the measured current and voltage waveforms. Only through the analysis of the changes in current and voltage, the fact that heat may not be dissipated in time during the avalanche process, resulting in a sharp rise in the internal temperature of the diode, is not considered. Conventional avalanche detection mainly judges the tolerance of the diode based on the current-voltage curve, but the actual limit of the diode is due to thermal breakdown caused by temperature rise, resulting in irreversible damage. Based on this, the analysis accuracy and reliability of avalanche tolerance in related technologies are poor. Summary of the Invention

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

[0005] The present invention proposes a method for testing the avalanche tolerance of a semiconductor diode, and the method includes:

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

[0007] According to the temperature changes between all peak regions and adjacent regions, and the area of the peak regions, determine the heat dissipation insufficiency index; combine the heat dissipation insufficiency index and the distances of all peak regions to determine the local overheat factor of the thermal imaging image;

[0008] According to the numerical changes of the local overheat factors of all thermal imaging images in time series, determine the dissipation rate of the local overheating phenomenon of the diode; combine the maximum value of all local overheat factors and the dissipation rate to determine the thermal breakdown possibility of the diode under the spike voltage;

[0009] Obtain the thermal breakdown possibility of the diode under different peak voltages. Based on the numerical changes of all thermal breakdown possibilities of the diode under different peak voltages, conduct avalanche tolerance analysis to determine the avalanche tolerance of the diode.

[0010] Further, the determination of the peak region of the local temperature on the thermal imaging image includes:

[0011] Based on the temperature and color comparison, determine the temperature value corresponding to each pixel point on the thermal imaging image;

[0012] Based on the temperature values, perform region growing processing to determine different temperature regions with the same temperature;

[0013] Take the average value of the temperature values of all pixel points in any temperature region as the region temperature of the corresponding temperature region;

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

[0015] Further, the determination of the heat dissipation insufficiency index according to the temperature changes between all peak regions and adjacent regions, and the area of the peak regions includes:

[0016] According to the difference in region temperature between the peak region and all adjacent regions, and the region temperature of the peak region, determine the temperature heat dissipation index of the peak region;

[0017] Take the product value of the opposite number of the temperature heat dissipation index and the total area of all peak regions, and perform normalization processing as the heat dissipation insufficiency index of the corresponding thermal imaging image.

[0018] Further, the determination of the temperature heat dissipation index of the peak region according to the difference in region temperature between the peak region and all adjacent regions, and the region temperature of the peak region includes:

[0019] Calculate the difference in region temperature between the peak region and all adjacent regions respectively, and take the average value of the region temperature differences corresponding to all adjacent regions as the first temperature parameter of the peak region;

[0020] Take the ratio of the first temperature parameter to the region temperature of the peak region, and perform normalization processing as the temperature heat dissipation index of the peak region.

[0021] Further, the determination of the local overheating factor of the thermal imaging image by combining the heat dissipation insufficiency index and the distance of all peak regions includes:

[0022] Take the morphological center of the peak region as the reference point, and take the average value of the reference point distances between any two peak regions as the distance coefficient;

[0023] Calculate the ratio of the heat dissipation insufficiency index to the distance coefficient, and perform normalization processing as the local overheat factor of the thermal imaging image.

[0024] Further, determining the dissipation rate of the local overheat phenomenon of the diode according to the numerical change of the local overheat factor of all thermal imaging images in time sequence includes:

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

[0026] Take the difference between the first local overheat factor and the last local overheat factor in the overheat recovery sequence as the recovery range, and take the number of intervals between the first local overheat factor and the last local overheat factor in the sequence as the recovery time;

[0027] Calculate the ratio of the recovery range to the recovery time as the dissipation rate.

[0028] Further, determining the thermal breakdown possibility of the diode under the spike voltage by combining the maximum value of all local overheat factors and the dissipation rate includes:

[0029] Normalize the ratio of the maximum value of the local overheat factor to the dissipation rate as the thermal breakdown possibility.

[0030] Further, performing avalanche tolerance analysis according to the numerical change of all thermal breakdown possibilities of the diode at different spike voltages to determine the avalanche tolerance of the diode includes:

[0031] Take the numerical variance of all thermal breakdown possibilities as the breakdown instability;

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

[0033] Calculate the product of the breakdown mean and the breakdown instability, and normalize the opposite number of the product value as the avalanche tolerance.

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

[0035] On the other hand, an avalanche tolerance test system for a semiconductor diode is also provided. The system 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 the method described in any one of the foregoing are implemented.

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

[0037] In the embodiments of the present invention, during the process of stimulating the peak voltage and restoring to the stable state, the thermal imaging image of the semiconductor diode is periodically acquired to determine the peak region of the local temperature on the thermal imaging image of the diode; according to the temperature changes between all peak regions and adjacent regions, and the area of the peak regions, the heat dissipation insufficiency index is determined; combining the heat dissipation insufficiency index and the distances of all peak regions, the local overheating factor of the thermal imaging image is determined; according to the numerical changes of the local overheating factors of all thermal imaging images in time sequence, the dissipation rate of the local overheating phenomenon of the diode is determined; combining the maximum value of all local overheating factors and the dissipation rate, the thermal breakdown possibility of the diode under the peak voltage is determined; the thermal breakdown possibilities of the diode under different peak voltages are acquired, and according to the numerical changes of all thermal breakdown possibilities of the diode under different peak voltages, the avalanche tolerance analysis is carried out to determine the avalanche tolerance of the diode.

[0038] Since it is to analyze the heat distribution of the diode under the same peak voltage, determine the local overheating phenomenon caused by the peak voltage, combine the heat dissipation insufficiency index and the distances of all peak regions to determine the local overheating factor of the thermal imaging image, and then combine the heat dissipation effect to determine the thermal breakdown possibility of the diode under the peak voltage. Then, analyze the heat changes of the diode under different peak voltages, and according to the numerical changes of all thermal breakdown possibilities of the diode under different peak voltages, analyze the avalanche tolerance; it enables a more intuitive and accurate acquisition of the avalanche tolerance of the diode, and can perform a specific analysis of the avalanche tolerance according to the temperature changes, making the accuracy of the avalanche tolerance higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0040] Figure 1 It is a flowchart of a method for testing the avalanche tolerance of a semiconductor diode provided by an embodiment of the present invention;

[0041] Figure 2 It is a schematic diagram of a test circuit provided by an embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the peak voltage gradually decreasing and restoring to the stable state provided by an embodiment of the present invention;

[0043] Figure 4 It is a schematic diagram of the temperature distribution of the diode provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following will, in conjunction with the accompanying drawings and preferred embodiments, elaborate in detail on a method and system for testing the avalanche tolerance of a semiconductor diode proposed according to the present invention, its specific implementation manner, structure, features and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0046] The following will specifically describe the specific solution of a method for testing the avalanche tolerance of a semiconductor diode provided by the present invention in conjunction with the accompanying drawings.

[0047] Please refer to Figure 1 , which shows a flowchart of a method for testing the avalanche tolerance of a semiconductor diode provided by an embodiment of the present invention. The method includes:

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

[0049] The specific scenario targeted by the present invention is as follows: Conventional avalanche detection mostly judges the tolerance of the diode according to the current-voltage curve. However, the actual limit of the diode is irreversible damage caused by thermal breakdown due to temperature rise. Therefore, in order to more accurately identify local design abnormalities 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 testing the avalanche tolerance of the semiconductor diode is as follows:

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

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

[0053] (3) Charge and store energy: Use the controllable DC power supply to charge the inductor so that it stores enough energy for the avalanche test.

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

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

[0056] (6) Data acquisition: Current sensors and voltage sensors are used to monitor and record the current and voltage waveforms across the diode in real time. And a thermal imaging camera is used to collect the thermal imaging video of the semiconductor diode during the process from the spike voltage starting, to the voltage gradually decreasing and finally returning to the stable state. See Figure 3 , Figure 3 which is a schematic diagram of the spike voltage gradually decreasing and returning to the stable state provided by an embodiment of the present invention.

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

[0058] Among them, the peak region is the region where the temperature of the diode in the thermal imaging image of the embodiment of the present invention is relatively high. This high temperature is manifested in that: compared with other surrounding regions, it is at the temperature peak, that is, the temperature in the peak region is higher than the temperature of the surrounding regions. Combining this feature, the peak region is analyzed.

[0059] Further, in some embodiments of the present invention, determining the peak region 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 the temperature and color comparison situation; performing region growing processing based on the temperature value to determine different temperature regions with the same temperature; taking the average value of the temperature values of all pixel points in any temperature region as the region temperature of the corresponding temperature region; when the region temperature of any temperature region is greater than the region temperatures of all adjacent temperature regions, taking this temperature region as the peak region.

[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 the heat dissipation insufficiency index according to the temperature changes between all peak regions and adjacent regions, and the area of the peak region; combine the heat dissipation insufficiency index and the distance between all peak regions to determine the local overheating factor of the thermal imaging image.

[0062] During the process of the peak voltage gradually decreasing, the change in heat 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 elements (such as resistors, capacitors, etc.). As the energy dissipates, the peak voltage begins to decrease. Refer to Figure 4 , Figure 4 which is a schematic diagram of the diode temperature distribution provided by an embodiment of the present invention. If the heat dissipation capacity of the diode is insufficient, these heats will accumulate rapidly, resulting in a sharp rise in temperature. When thermal breakdown occurs due to local overheating inside the diode, the PN junction of the diode will be damaged.

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

[0064] Further, in some embodiments of the present invention, according to the temperature change between all peak regions and adjacent regions, and the area of the peak region, the heat dissipation insufficiency index is determined, including: determining the temperature heat dissipation index of the peak region according to the temperature difference between the peak region and all adjacent regions in the regional temperature, and the regional temperature of the peak region; taking the product value of the opposite number of the temperature heat dissipation index and the total area of all peak regions, and normalizing it as the heat dissipation insufficiency index of the corresponding thermal imaging image.

[0065] It can be understood that the higher the hot spot temperature and the higher the temperature around the hot spot, the worse the heat dissipation, and it is easy to cause local overheating. According to the heat conduction effect, the greater the temperature difference, the faster the heat conduction. For example, when the central temperature is 500 degrees Celsius and the surrounding temperature is 400 degrees Celsius, its heat dissipation effect is not as good as when the surrounding temperature is 300 degrees Celsius. Combining this feature, the analysis of the temperature heat dissipation index is carried out.

[0066] Further, in some embodiments of the present invention, according to the temperature difference between the peak region and all adjacent regions in the regional temperature, and the regional temperature of the peak region, the temperature heat dissipation index of the peak region is determined, including: calculating the regional temperature difference between the peak region and all adjacent regions respectively, and taking the average value of the regional temperature differences corresponding to all adjacent regions as the first temperature parameter of the peak region; taking the ratio of the first temperature parameter to the regional temperature of the peak region, and normalizing it as the temperature heat dissipation index of the peak region.

[0067] In the embodiments of the present invention, the first temperature parameter is the temperature difference between the peak region centered and the adjacent surrounding regions, which is obtained by directly calculating the temperature difference and averaging. The higher the central temperature, the greater the influence of the central temperature on the environment, and the surrounding environment is also affected by the high temperature, resulting in poorer heat conduction. Combining this feature, the ratio of the first temperature parameter to the regional temperature of the peak region is directly calculated and normalized as the temperature dissipation index of the peak region.

[0068] Also, since the larger the total area of the peak regions, the more it affects the overall heat dissipation effect. Based on this, the product value of the opposite number of the temperature dissipation index and the total area of all peak regions is normalized as the heat dissipation insufficiency index of the corresponding thermal imaging image.

[0069] The heat dissipation insufficiency index characterizes the heat dissipation insufficiency effect of the semiconductor diode in the corresponding thermal imaging image. That is, the worse the heat dissipation effect, the larger the value of the heat dissipation insufficiency index, and the more likely it is to cause fuse breakdown due to insufficient heat dissipation subsequently.

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

[0071] Further, in some embodiments of the present invention, combining the heat dissipation insufficiency index and the distance of all peak regions, a local overheating factor of the thermal imaging image is determined, including: taking the morphological center of the peak region as a reference point, and taking the average value of the reference point distances between any two peak regions as the distance coefficient; calculating the ratio of the heat dissipation insufficiency 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, the more peak regions there are in the corresponding local area and the denser the distribution of the peak regions, based on this, the greater the possibility of local overheating. And the larger the value of the heat dissipation insufficiency index, the greater the possibility of local overheating. 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 according to the numerical change of the local overheating factor of all thermal imaging images in time series; combine the maximum value of all local overheating factors and the dissipation rate to determine the thermal breakdown possibility of the diode under the peak voltage.

[0074] Since at the initial stage of the peak voltage application, the absorption and dissipation of energy occur almost simultaneously, but due to the existence of thermal inertia, the internal temperature will not immediately rise to the highest point. As the peak voltage continues, the temperature inside the diode will gradually increase, and heat begins to diffuse outward through the heat dissipation path. After the peak voltage ends, the heat inside the diode will continue to dissipate outward until the temperature returns to the normal operating level.

[0075] Based on this, during the process of gradually returning to the stable state under the peak voltage, the faster the heat drops, the smaller the impact of local overheating, which indicates that the overall heat control of the corresponding diode is better. The smaller the impact of this peak voltage on the semiconductor diode, the higher the avalanche tolerance of the semiconductor diode. Therefore, it is necessary to analyze the possibility of thermal breakdown.

[0076] Furthermore, in some embodiments of the present invention, according to the numerical change of the local overheating factor of all thermal imaging images in time sequence, the dissipation rate of the local overheating phenomenon of the diode is determined, 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; calculating the ratio of the recovery range to the recovery time as the dissipation rate.

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

[0078] During the avalanche process, heat may not be dissipated in time, resulting in a sharp rise in the internal temperature of the semiconductor diode, which will cause uneven heat distribution and produce a thermal breakdown effect. If the efficiency of the semiconductor diode radiator is high, it will cause the local overheating phenomenon to dissipate quickly and make the heat distribution return to uniformity quickly. Based on this, it is necessary to analyze the possibility of thermal breakdown.

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

[0080] Since a greater dissipation rate indicates that the temperature is more likely to dissipate, the possibility of thermal breakdown is smaller. The maximum value of the local overheating factor represents the maximum overheating condition. The larger its value, the more likely the thermal breakdown effect will occur. Based on this, 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. That is, the larger the maximum local overheating factor and the slower the local overheating phenomenon dissipates, and the slower the heat distribution returns to uniformity, the more likely the thermal breakdown effect will occur.

[0081] S104: Obtain the thermal breakdown possibility of the diode at different peak voltages. According to the numerical changes of all the thermal breakdown possibilities of the diode at different peak voltages, conduct avalanche tolerance analysis to determine the avalanche tolerance of the diode.

[0082] In the embodiments of the present invention, the peak voltages are set to 1000V, 1100V, 1200V, …, 2000V. Based on this, each peak voltage has a different temperature rise performance. By integrating this feature, different voltage scenarios can be handled.

[0083] Since the possibility of thermal breakdown represents the thermal breakdown effect caused by excessive heat and difficult dissipation in the semiconductor diode, avalanche tolerance analysis can be carried out in combination with this feature.

[0084] Further, in some embodiments of the present invention, according to the numerical changes of all the thermal breakdown possibilities of the diode at different peak voltages, conduct avalanche tolerance analysis to determine the avalanche tolerance of the diode, including: taking the numerical variance of all the thermal breakdown possibilities as the breakdown instability; calculating the numerical mean of all the thermal breakdown possibilities as the breakdown mean; calculating the product of the breakdown mean and the breakdown instability, and normalizing the opposite value of the product value as the avalanche tolerance.

[0085] In the embodiments of the present invention, the avalanche tolerance analysis is divided into two dimensions, one is the numerical value of the thermal breakdown possibility, and the other is the stability of the thermal breakdown possibility at different peak voltages.

[0086] The larger the numerical variance of the thermal breakdown possibility, the more unstable the distribution of the thermal breakdown possibility at different peak voltages. Based on this, the quality of the overall semiconductor diode is more unstable. And the larger the numerical mean of the thermal breakdown possibility, the more likely the semiconductor diode is to produce the thermal breakdown effect. Through combined analysis, calculate the product of the breakdown mean and the breakdown instability, and normalize the opposite value of the product value as the avalanche tolerance.

[0087] In the embodiments of the present invention, during the process of stimulating the peak voltage and restoring to the stable state, the thermal imaging image of the semiconductor diode is periodically acquired to determine the peak region of the local temperature of the diode on the thermal imaging image; according to the temperature changes between all peak regions and adjacent regions, and the area of the peak regions, the heat dissipation insufficiency index is determined; combining the heat dissipation insufficiency index and the distances of all peak regions, the local overheat factor of the thermal imaging image is determined; according to the numerical changes of the local overheat factors of all thermal imaging images in time sequence, the dissipation rate of the local overheating phenomenon of the diode is determined; combining the maximum value of all local overheat factors and the dissipation rate, the thermal breakdown possibility of the diode under the peak voltage is determined; the thermal breakdown possibilities of the diode under different peak voltages are acquired, and according to the numerical changes of all thermal breakdown possibilities of the diode under different peak voltages, the avalanche tolerance analysis is carried out to determine the avalanche tolerance of the diode.

[0088] Since it is to analyze the heat distribution of the diode under the same peak voltage to determine the local overheating phenomenon caused by the peak voltage, according to the temperature changes between all peak regions and adjacent regions, and the area of the peak regions, the heat dissipation insufficiency index is determined; combining the heat dissipation insufficiency index and the distances of all peak regions, the local overheat factor of the thermal imaging image is determined; then, combining the heat dissipation effect, the thermal breakdown possibility of the diode under the peak voltage is determined; then, analyzing the heat changes of the diode under different peak voltages, according to the numerical changes of all thermal breakdown possibilities of the diode under different peak voltages, analyzing the avalanche tolerance, the avalanche tolerance of the diode can be obtained more intuitively and accurately, so that the specific analysis of the avalanche tolerance can be carried out according to the temperature changes, and the accuracy of the avalanche tolerance is higher.

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

[0090] It should be noted that: the above sequence of the embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0091] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other, and the key points of each embodiment are 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: In the process of spike voltage stimulation and recovery to a stable state, a thermal imaging image of the semiconductor diode is 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 area; determine the local overheating factor of the thermal imaging image by combining the heat dissipation deficiency index and the distances of all peak areas; According to the numerical changes of the local overheating factors of all thermal imaging images in the time series, the dissipation rate of the local overheating phenomenon of the diode is determined; 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; The thermal breakdown probability of the diode under different peak voltages is obtained, and the avalanche withstand capacity analysis is performed according to the numerical changes of all thermal breakdown probabilities of the diode under different peak voltages to determine the avalanche withstand capacity of the diode.

2. A semiconductor diode avalanche withstand test method as claimed in claim 1, characterized in that: The step of determining a peak area of ​​a local temperature of a diode on a thermal imaging image comprises: Based on the temperature and color comparison, determine the temperature value corresponding to each pixel on the thermal imaging image; 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. A semiconductor diode avalanche withstand test method as claimed in claim 2, characterized in that: Determining the heat dissipation deficiency index according to the temperature changes of all peak areas and adjacent areas, and the area of ​​the peak area, includes: Determine the temperature heat dissipation index of the peak area according to the difference in regional temperature between the peak area and all adjacent areas, and 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 corresponding to the thermal imaging image.

4. A semiconductor diode avalanche withstand test method as claimed in claim 3, characterized in that: Determining the temperature heat dissipation index of the peak area according to the difference in regional temperature between the peak area and all adjacent areas, and the regional temperature of the peak area, includes: Calculate the regional temperature differences between the peak region and all adjacent regions, and use 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 semiconductor diode avalanche withstand test method according to claim 1, characterized in that: 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 taken as the reference point, and the mean of the distance between the reference points of any two peak areas is taken as the distance coefficient; The ratio of the heat dissipation deficiency index to the distance coefficient is calculated and normalized to be the local overheating factor of the thermal imaging image.

6. A semiconductor diode avalanche withstand test method as claimed in claim 1, characterized in that: 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 the 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 taken 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 taken as the recovery time; The ratio of the recovery range and the recovery time is calculated as the dissipation rate.

7. A semiconductor diode avalanche withstand test method as claimed in claim 1, characterized in that: 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 the 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. A semiconductor diode avalanche withstand test method as claimed in claim 1, characterized in that: The avalanche withstand analysis is performed according to the numerical changes of all thermal breakdown possibilities of the diode at different peak voltages to determine the avalanche withstand capacity 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 value and the breakdown instability is calculated, and the inverse of the product value is normalized to obtain the avalanche withstand capability.

9. A semiconductor diode avalanche withstand test method as claimed in claim 8, characterized in that: 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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