Temperature control system and method for high acceleration power cycle test of SiC device
The temperature control system for SiC devices addresses the challenge of simultaneous high temperature differences and rapid changes in power cycle tests, enhancing stress testing efficiency and accuracy by using a combined cold water machine and electric heating unit for flexible temperature control.
Patent Information
- Application Number
- CN202510561574.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-30
- Publication Date
- 2025-07-15
AI Technical Summary
Existing power cycle tests for SiC semiconductor devices struggle to simultaneously achieve high temperature differences and rapid temperature changes, limiting the ability to accelerate stress testing and identify reliability issues efficiently.
A temperature control system for SiC devices that combines a temperature control board, a cold water machine, and a load current source, utilizing a circulating water route and electric heating unit to rapidly adjust temperatures, enabling high temperature differences and rapid cooling, allowing for flexible and accurate temperature control during power cycling tests.
The system enables high-stress, accelerated power cycle testing with precise temperature control, facilitating rapid temperature adjustments and efficient identification of reliability issues in SiC devices, thereby improving test efficiency and accuracy.
Smart Images
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Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor test technologies, and particularly to a temperature control system and method for high-acceleration power cycle tests of SiC devices. Background Art
[0002] Power cycling is a core test item for current automotive semiconductor products, mainly examining the thermal matching robustness of product packages, and also having a certain effect on the reliability of chips under high-acceleration stress. Power cycling is widely used in the reliability evaluation of silicon-based and silicon carbide-based power devices and modules. Due to the temperature gradient stress state being close to the actual working conditions, its effectiveness is widely recognized. The power cycling test examines the temperature change tolerance of product packages through the reciprocating cycle of turn-on and turn-off timings. The key condition is the change in junction temperature / case temperature. A load current is applied to the product during the turn-on timing to make the junction temperature reach a high value, generating a temperature gradient in the package and driving the case temperature to rise. During the turn-off timing, the load current is disconnected, and the case temperature is rapidly reduced through forced heat dissipation, thereby gradually reducing the junction temperature to a low value and making the junction temperature difference in one switching cycle meet the requirements. The above process is cycled to be the power cycling. According to the change in case temperature, power cycling can be divided into two categories. One is the △Tj power cycling where the junction temperature fluctuates rapidly while the case temperature changes very little. The other is the △Tc power cycling where the case temperature fluctuates greatly with the junction temperature. According to the regulations of standards such as IEC 60747-34, the △Tj power cycling usually examines bonding wires, and the △Tc power cycling can examine bonding wires and solder layers. The single cycle period of the △Tc power cycling is longer, usually between 4 and 10 minutes, and the examination of the package is more comprehensive, and usually the stress is also stronger.
[0003] With the gradual maturity of the industrialization of third-generation semiconductor power devices / modules such as SiC MOSFETs, the reliability and test stress tolerance of products have been greatly improved. The current stage of test improvement requirements focuses on two aspects. One is to develop high-acceleration tests to shorten the test cycle, and the other is to implement on-line monitoring to obtain accurate degradation data. The power cycling under conventional conditions takes 1000 hours, with a long cycle and small stress, which cannot meet the tight cycle requirements of process research and development, and often cannot effectively identify the weak links in product reliability. Therefore, it is necessary to increase the junction temperature difference, speed up the temperature change, etc. to increase the test stress for high-acceleration tests, thereby shortening the test cycle, quickly causing the product to degrade and fail, and analyzing the mechanism to improve the process. On the other hand, the junction-case thermal resistance and structure function are key indicators for measuring package degradation in power cycling, and on-line monitoring is required during the test to facilitate the identification of the degradation process, verification of the life model, etc.
[0004] Forced heat dissipation during the power cycle in the turn-off timing can be achieved by air cooling and water cooling. Currently, both methods have limitations in achieving high-acceleration tests and refined monitoring. Since the heat dissipation state during the turn-on and turn-off cycles of the air-cooling method is variable, the fan can be turned on and off with the cycle, so it is convenient to achieve a large change in the junction temperature. However, due to the unstable thermal state, it can only measure the junction temperature and roughly estimate the junction-to-ambient thermal resistance, and does not support accurate measurement of the junction-to-case thermal resistance. The water-cooling method has a metal heat sink that can maintain a constant temperature, so it can perform accurate measurement of the junction-to-case thermal resistance and structure function online. However, the heat dissipation state of the water-cooling method is fixed, and it is difficult for the case temperature to fluctuate significantly, which is not convenient for carrying out △Tc power cycle and high-acceleration tests. Because the water-cooling method has strong temperature control ability and the case temperature remains basically constant, when the power of the device under test is small, it is difficult to achieve a high junction temperature difference. If the heat dissipation ability is weakened, such as laying thermal insulation materials between the device and the water-cooled plate, the heat dissipation during the turn-off cycle will be slow, and a fast temperature change rate cannot be obtained, resulting in an inability to ensure a fast switching cycle. High junction temperature difference and fast cooling rate cannot be achieved simultaneously in the power cycle of the traditional water-cooling method. Summary of the Invention
[0005] The present application provides a temperature control system and method for high-acceleration power cycle tests of SiC devices to solve the problem that the prior art cannot simultaneously achieve a high junction temperature difference and a fast cooling rate.
[0006] In a first aspect, the present application provides a temperature control system for high-acceleration power cycle tests of SiC devices. The system includes a temperature control board, a chiller, and a load current source. The temperature control board includes a circulating water path, an electric heating unit, and a packaging board, and the temperature control board is used to mount the device under test.
[0007] The chiller is connected to the circulating water path and is used to provide circulating water at different temperatures to the circulating water path.
[0008] The circulating water path is arranged within the packaging board and on the side close to the device under test, and is used to control the temperature of the temperature control board according to the temperature of the circulating water.
[0009] The electric heating unit is arranged within the packaging board and on the side far from the device under test, and is used to control the heating rate of the temperature control board during the turn-on period of the power cycle test.
[0010] The load current source is electrically connected to the device under test and is used to apply a preset current to the device under test to control the increase in the junction temperature of the device under test.
[0011] In a second aspect, the present application provides a temperature control method for high-acceleration power cycle tests of SiC devices. The method is based on the temperature control system for high-acceleration power cycle tests of SiC devices described in the first aspect above. During the turn-off period of the power cycle test, the method includes:
[0012] By opening the first solenoid valve, closing the second solenoid valve, opening the first switch and opening the second switch, the DUT and the temperature control board are both in thermal equilibrium at a low temperature. When the DUT and the temperature control board are in thermal equilibrium at a low temperature, the initial junction temperature of the DUT is obtained through the junction temperature monitoring unit, and the initial case temperature of the DUT is obtained through the case temperature monitoring unit;
[0013] When the first solenoid valve is open and the second solenoid valve is closed, circulating water at a first temperature is introduced into the circulating water path by the first chiller. When the first switch is open and the second switch is open, the off-cycle of the power cycle test is executed. After the off-cycle of the power cycle test reaches a preset specified time, the lowest junction temperature of the DUT is obtained through the junction temperature monitoring unit;
[0014] When the first solenoid valve is closed and the second solenoid valve is open, circulating water at a second temperature is introduced into the circulating water wheel by the second chiller. When the first switch is closed and the second switch is closed, the on-cycle of the power cycle test is executed. After the on-cycle of the power cycle test reaches the preset specified time and the first switch is open, the highest junction temperature of the DUT is obtained through the junction temperature monitoring unit;
[0015] Determine the change in the junction temperature of the DUT based on the lowest and highest junction temperatures of the DUT obtained through the junction temperature monitoring unit;
[0016] Judge whether the change in the junction temperature meets the preset requirements;
[0017] If the change in the junction temperature meets the preset requirements, perform the thermal resistance and structure function test or execute the next cycle of the power cycle test;
[0018] If the change in the junction temperature does not meet the preset requirements, adjust the preset current input by the load current source, and return to the step of introducing circulating water at a first temperature into the circulating water path by the first chiller when the first solenoid valve is open and the second solenoid valve is closed, and executing the off-cycle of the power cycle test when the first switch is open and the second switch is open. After the off-cycle of the power cycle test reaches the preset specified time, obtain the lowest junction temperature of the DUT through the junction temperature monitoring unit and continue to execute.
[0019] The present application provides a temperature control system and method for a high-acceleration power cycle test of SiC devices. The system includes a temperature control board, a chiller, and a load current source. The temperature control board includes a circulating water path, an electric heating unit, and a packaging board, and the temperature control board is used to mount the device under test. The chiller is connected to the circulating water path and is used to supply circulating water at different temperatures to the circulating water path. The circulating water path is arranged inside the packaging board and on one side close to the device under test, and is used to control the temperature of the temperature control board according to the temperature of the circulating water. The electric heating unit is arranged inside the packaging board and on the side far from the device under test, and is used to control the heating rate of the temperature control board during the on-cycle of the power cycle test. The load current source is electrically connected to the device under test and is used to apply a preset current to the device under test to control the increase of the junction temperature of the device under test. In the present application, the circulating water wheel is arranged inside the packaging board and on one side close to the device under test, and the chiller can quickly supply circulating water at different temperatures to the circulating water path, so that the temperature of the temperature control board can quickly respond to the change of the water temperature, thereby more timely adjusting the temperature of the device under test and improving the real-time performance of temperature control. In addition, in the present application, by supplying circulating water at different temperatures to the circulating water path through the chiller and combining the heating effect of the electric heating unit, a wider range of temperature adjustment can be achieved, which can not only realize the test under low-temperature environment, but also meet the requirements of high-temperature environment, providing more flexible temperature conditions for the power cycle test of different types of devices under test. At the same time, the present application helps to speed up the test process and improve the test efficiency, and accurate temperature and current control can ensure the accuracy and reliability of the test results, providing more effective support for the research and development, production, and quality evaluation of products. Description of the Drawings
[0020] In order to more clearly illustrate the technical solutions in the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0021] Figure 1 is a schematic structural diagram of a temperature control system for a high-acceleration power cycle test of SiC devices provided by an embodiment of the present application;
[0022] Figure 2 is a flowchart for implementing a temperature control method for a high-acceleration power cycle test of SiC devices provided by an embodiment of the present application. Detailed Embodiments
[0023] In the following description, specific details such as specific system architectures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.
[0024] To make the objectives, technical solutions, and advantages of the present application clearer, the following will be described through specific embodiments in conjunction with the accompanying drawings.
[0025] Figure 1 FIG. is a schematic structural diagram of the temperature control system for the high-acceleration power cycle test of the SiC device provided by the embodiment of the present application. As Figure 1 shown, the temperature control system for the high-acceleration power cycle test of the SiC device includes a temperature control board 1, a chiller 2, and a load current source 3. The temperature control board 1 may include a circulating water path 11, an electric heating unit 12, and a packaging board 13, and the temperature control board 1 is used to mount the device under test (DUT).
[0026] The chiller 2 is connected to the circulating water path 11 and is used to supply circulating water at different temperatures to the circulating water path 11.
[0027] The circulating water path 11 is arranged inside the packaging board 13 and is arranged on the side close to the device under test (DUT), and is used to control the temperature of the temperature control board 1 according to the temperature of the circulating water.
[0028] The electric heating unit 12 is arranged inside the packaging board 13 and is arranged on the side far from the device under test (DUT), and is used to control the heating rate of the temperature control board 1 during the turn-on period of the power cycle test.
[0029] The load current source 3 is electrically connected to the device under test (DUT) and is used to apply a preset current to the device under test (DUT) to control the increase in the junction temperature of the device under test (DUT).
[0030] Among them, the power cycle test examines the temperature change tolerance of the product package through the reciprocating cycle of the turn-on timing and the turn-off timing. The turn-on timing is the turn-on period, and the turn-off timing is the turn-off period.
[0031] In this embodiment, the device under test (DUT) can be a device or a module.
[0032] In this embodiment, the circulating water with different temperatures or other types of coolants can be introduced into the circulating water path 11 by the chiller 2. The common coolant is water, and it is specifically selected according to actual needs to accurately control the temperature of the temperature control board 1.
[0033] In this embodiment, the temperature control board 1 is used to regulate the case temperature of the device under test (DUT) in the power cycle test, and its material is stainless steel alloy or other alloy materials with low heat capacity and high thermal conductivity.
[0034] In this embodiment, the load current source 3 uses a general-purpose DC power supply to apply a preset current to the DUT, causing the junction temperature of the DUT to rise.
[0035] To solve the problem that the prior art cannot simultaneously achieve a high junction temperature difference and a fast cooling rate, the temperature control system of the high-acceleration power cycle test using SiC devices in the embodiments of the present application improves the stress level and efficiency of the test, and at the same time achieves high-speed test design indicators of high junction temperature and rapid temperature change. It can also perform on-line monitoring of the junction-to-case thermal resistance and structure function without disassembling the device.
[0036] The embodiments of the present application combine the advantages of two power cycle implementation methods. Compared with the water-cooled power cycle, this embodiment utilizes the variable temperature function of the temperature control board to provide stronger temperature change stress, supports high-acceleration stress tests and △Tc power cycles with specified case temperature changes, and solves the problem that the temperature rise is insufficient when the rated power of the DUT is small or the thermal resistance is small, and it cannot meet the requirements of relevant standards. Compared with the air-cooled power cycle, this embodiment has a stronger temperature control effect, can support higher test power, and can also support on-line testing of thermal resistance and structure function without disassembling the device.
[0037] In a possible implementation, referring to Figure 1 , the chiller 2 may include a first chiller 21 and a second chiller 22. The output ends of the first chiller 21 and the second chiller 22 are both connected to the circulation water path 11.
[0038] The first chiller 21 is used to introduce circulating water at a first temperature into the circulation water path 11 during the off-cycle of the power cycle test to control the temperature of the temperature control board 1 to decrease.
[0039] The second chiller 22 is used to introduce circulating water at a second temperature into the circulation water path 11 during the on-cycle of the power cycle test to control the temperature of the temperature control board 1 to increase and to control the temperature state of the temperature control board 1 to be stable at a high temperature state. The first temperature is less than the second temperature.
[0040] Optionally, referring to Figure 1, the chiller 2 includes a first chiller 21 and a second chiller 22. The first chiller 21 is set to provide low-temperature water (the common coolant is water, and other coolants set to low temperature can also be used. In this embodiment, low-temperature water is used to represent them all). The temperature of the low-temperature water, i.e., the first temperature, is 25°C or below. The first chiller 21 passes low-temperature water into the circulation water path 11 during the off cycle of the power cycle test to reduce the temperature of the temperature control board 1 and make it gradually stabilize at a low temperature state. The second chiller 22 is set to provide high-temperature water (the common coolant is water, and other coolants set to high temperature can also be used. In this embodiment, high-temperature water is used to represent them all). The temperature of the high-temperature water is determined by the highest case temperature designed in the test, but it must be higher than the temperature of the low-temperature water. The second chiller 22 passes high-temperature water into the circulation water path 11 during the on cycle of the power cycle test to increase the temperature of the temperature control board 1 and make it gradually stabilize at a high temperature state. And after the device junction temperature exceeds the highest case temperature, high-temperature water continues to be passed into the circulation water path 11 to control the temperature of the temperature control board 1, which first heats and then cools the temperature control board 1.
[0041] In a possible implementation, referring to Figure 1 , the system may further include a first solenoid valve 23 and a second solenoid valve 24. The first end of the first solenoid valve 23 is connected to the output end of the first chiller 21, and the second end of the first solenoid valve 23 is connected to the circulation water path 11. The first end of the second solenoid valve 24 is connected to the output end of the second chiller 22, and the second end of the second solenoid valve 24 is connected to the circulation water path 11.
[0042] Optionally, referring to Figure 1 , the system may further include a first solenoid valve 23 and a second solenoid valve 24. The first solenoid valve 23 serves as the outlet valve of the first chiller 21 to control the on-off of the low-temperature coolant. The second solenoid valve 24 serves as the outlet valve of the second chiller 22 to control the on-off of the high-temperature coolant.
[0043] In a possible implementation, referring to Figure 1 , the system may further include a first switch 4. The first end of the first switch 4 is connected to the first end of the load current source 3, and the second end of the first switch 4 and the second end of the load current source 3 are both connected to the device under test DUT.
[0044] Optionally, referring to Figure 1 , the first switch 4, the load current source 3, and the device under test DUT together form a path, and the first switch 4 is used to control the on-off of the load current source 3.
[0045] In a possible implementation, referring to Figure 1, the electric heating unit 12 may include an electric heating wire 121, a second switch 122, and an AC power supply AC. The first end of the electric heating wire 121 is connected to the first end of the AC power supply AC, the second end of the electric heating wire 121 is connected to the first end of the second switch 122, and the second end of the AC power supply AC is connected to the second end of the second switch 122.
[0046] Optionally, referring to Figure 1 , the electric heating wire 121 is placed inside the temperature control plate 1, below the circulating water path. Heat conduction and insulation between the electric heating wire 121 and the temperature control plate 1 are achieved through insulating paint, insulating thermal grease, etc. During the on-cycle of the power cycle test, it aids in heating to accelerate the heating rate of the temperature control plate 1, and the heating is disconnected when the case temperature monitoring value reaches the test design value or when performing thermal resistance and structure function tests.
[0047] In addition, the second switch 122 controls the on / off of the electric heating unit 12.
[0048] In a possible implementation, referring to Figure 1 , when the device under test DUT is gate-controlled, the system may further include a load voltage source 5, and the load voltage source 5 is connected to the device under test DUT.
[0049] The load voltage source 5 is used to control the device under test DUT to be in the on state.
[0050] Optionally, when the device under test has gate control, an additional load voltage source 5 is required to keep the device under test DUT in the on state, so as to apply a preset current to the device under test DUT through the load current source 3. For example, when the device under test can be the PN junction of a MOSFET body diode, the load voltage source is needed to keep it in the on state and the load current source is used to apply the preset current.
[0051] In addition, referring to Figure 1 , there is also a third switch 9 between the load voltage source 5 and the connection to the device under test DUT. A loop is formed among the third switch 9, the load voltage source 5, and the device under test DUT. The first end of the third switch 9 is connected to the first end of the load voltage source 5, and the second end of the load voltage source 5 and the second end of the third switch 9 are both connected to the device under test DUT.
[0052] In a possible implementation, referring to Figure 1 , the system may further include a junction temperature monitoring unit 6, and the junction temperature monitoring unit 6 is connected to the device under test DUT.
[0053] The junction temperature monitoring unit 6 is used to monitor the junction temperature of the device under test DUT during the off-cycle of the power cycle test.
[0054] Optionally, in this embodiment, the junction temperature of the device under test is monitored by the electrical method. By pre-calibrating the forward voltage drop of the PN junction of the device under test (DUT) at a specified small current, the load current source 3 applies the same small current to the DUT during the test, and the corresponding junction temperature is calculated based on the temperature coefficient of the forward voltage drop. Typically, for example, the PN junction of a diode itself or the PN junction of the body diode of a MOSFET, junction temperature monitoring is performed during the off period of the power cycle test.
[0055] In a possible implementation, referring to Figure 1 , the system may further include a case temperature monitoring unit 7, and the case temperature monitoring unit 7 is embedded in the temperature control board 1 on the side close to the DUT.
[0056] The case temperature monitoring unit 7 is used to monitor the case temperature of the DUT.
[0057] Optionally, referring to Figure 1 , the case temperature monitoring unit 7 is embedded in the temperature control board 1 on the side close to the DUT, that is, the temperature sensor in the case temperature monitoring unit 7 is embedded in the position of the temperature control board 1 close to the DUT. Among them, the temperature sensor in the case temperature monitoring unit can be a thermocouple or a temperature-sensitive element.
[0058] In a possible implementation, referring to Figure 1 , the system may further include a water tank 8, and the water tank 8 is communicated with the circulating water path 11.
[0059] The water tank 8 is used to store the circulating water at different temperatures flowing out of the circulating water path 11.
[0060] Optionally, the water tank in this embodiment is used to store the cooling water or other types of coolant flowing out of the circulating water path.
[0061] The present application provides a temperature control system for high-acceleration power cycling tests of SiC devices. The system includes a temperature control board, a chiller, and a load current source. The temperature control board includes a circulating water path, an electric heating unit, and a packaging board, and the temperature control board is used to mount the device under test. The chiller is connected to the circulating water path and is used to supply circulating water at different temperatures to the circulating water path. The circulating water path is arranged inside the packaging board and on the side close to the device under test, and is used to control the temperature of the temperature control board according to the temperature of the circulating water. The electric heating unit is arranged inside the packaging board and on the side far from the device under test, and is used to control the heating rate of the temperature control board during the turn-on period of the power cycling test. The load current source is electrically connected to the device under test and is used to apply a preset current to the device under test to control the increase in the junction temperature of the device under test. In the present application, by arranging the circulating water path inside the packaging board and on the side close to the device under test, the chiller can quickly supply circulating water at different temperatures to the circulating water path, enabling the temperature of the temperature control board to quickly respond to the change in water temperature, thereby more timely adjusting the temperature of the device under test and improving the real-time performance of temperature control. In addition, by supplying circulating water at different temperatures to the circulating water path through the chiller and combining with the heating effect of the electric heating unit, a wider range of temperature adjustment can be achieved. It can not only perform tests in a low-temperature environment but also meet the requirements of a high-temperature environment, providing more flexible temperature conditions for power cycling tests of different types of devices under test. At the same time, the present application helps to speed up the test process and improve the test efficiency, and accurate temperature and current control can ensure the accuracy and reliability of the test results, providing more effective support for the research and development, production, and quality assessment of products.
[0062] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not mean the order of execution. The order of execution of each process should be determined according to its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.
[0063] The following is the temperature control method for high-acceleration power cycling tests of SiC devices implemented by the temperature control system for high-acceleration power cycling tests of SiC devices of the present application. For the details not described in detail, reference can be made to the corresponding system embodiments above.
[0064] Figure 2 The flowchart of the temperature control method for high-acceleration power cycling tests of SiC devices implemented by the temperature control system for high-acceleration power cycling tests of SiC devices provided by the embodiments of the present application is shown. For the sake of convenience of description, only the parts related to the embodiments of the present application are shown. During the turn-off period of the power cycling test, it is described in detail as follows:
[0065] In step 201, the first solenoid valve is opened, the second solenoid valve is closed, the first switch is tripped, and the second switch is tripped, so that both the device under test and the temperature control board are in thermal equilibrium at a low temperature. When the device under test and the temperature control board are in thermal equilibrium at a low temperature, the initial junction temperature of the device under test is obtained through the junction temperature monitoring unit, and the initial case temperature of the device under test is obtained through the case temperature monitoring unit.
[0066] In step 202, when the first solenoid valve is opened and the second solenoid valve is closed, circulating water at a first temperature is introduced into the circulating water path through the first chiller. When the first switch is tripped and the second switch is tripped, the off period of the power cycle test is executed. After the off period of the power cycle test reaches the preset specified time, the lowest junction temperature of the device under test is obtained through the junction temperature monitoring unit.
[0067] In step 203, when the first solenoid valve is closed and the second solenoid valve is opened, circulating water at a second temperature is introduced into the circulating water turbine through the second chiller. When the first switch is closed and the second switch is closed, the on period of the power cycle test is executed. After the on period of the power cycle test reaches the preset specified time and the first switch is tripped, the highest junction temperature of the device under test is obtained through the junction temperature monitoring unit.
[0068] In step 204, the change in the junction temperature of the device under test is determined based on the lowest and highest junction temperatures of the device under test obtained through the junction temperature monitoring unit.
[0069] In step 205, it is judged whether the change in the junction temperature meets the preset requirements.
[0070] In step 206, if the change in the junction temperature meets the preset requirements, the thermal resistance and structure function test is performed or the next cycle of the power cycle test is executed.
[0071] In step 207, if the change in the junction temperature does not meet the preset requirements, the preset current input by the load current source is adjusted, and the process returns to the step of introducing circulating water at a first temperature into the circulating water path through the first chiller when the first solenoid valve is opened and the second solenoid valve is closed, and executing the off period of the power cycle test when the first switch is tripped and the second switch is tripped. After the off period of the power cycle test reaches the preset specified time, the lowest junction temperature of the device under test is obtained through the junction temperature monitoring unit and continues to execute.
[0072] Temperature control system for high-accelerated power cycling test of SiC devices. In the embodiments of the present application, a temperature control method for high-accelerated power cycling test of SiC devices can also be carried out, that is, the online monitoring technology of junction temperature and structure function. In the off period of the power cycling test, according to the provisions of JESD51-14-2010, the electrothermal method can be used. According to the temperature characteristic curve of the diode, the cooling curve can be obtained during the test, and the thermal resistance and structure function of the device under test can be measured online. Among them, the diode can be a common diode or a MOSFET body diode.
[0073] The specific implementation process is as follows:
[0074] Step 1: Build a test platform according to the Figure 1 temperature control system for high-accelerated power cycling test of SiC devices as shown. Install the device under test (DUT), connect the equipment, and initialize. Install the DUT on the temperature control board 1, connect the load current source 3 and the junction temperature monitoring unit 6, open the first solenoid valve 23, close the second solenoid valve 24, introduce low-temperature water by using the first chiller 21, open the first switch 4 and the second switch 122 to turn off the electric heating power supply 12 and turn off the load current source 3, so that the DUT and the temperature control board 1 reach thermal equilibrium under low-temperature conditions, use the junction temperature monitoring unit 6 to measure the initial junction temperature, and use the case temperature monitoring unit 7 to measure the initial case temperature, and check the status of the monitoring function of the system.
[0075] Step 2: Keep the first solenoid valve 23 open, close the second solenoid valve 24, introduce low-temperature water, open the first switch 4 and the second switch 122, execute the off period of the power cycling test, and after the off period of the power cycling test reaches the preset specified time, use the junction temperature monitoring unit 6 to measure the lowest junction temperature.
[0076] Step 3: Open the second solenoid valve 24, close the first solenoid valve 23, introduce high-temperature water by using the second chiller 22, close the first switch 4 and the second switch 122 to turn on the electric heating unit 12 and turn on the load current source 3, execute the on period of the power cycling test, and after the on period of the power cycling test reaches the preset specified time, open the first switch 4, that is, turn off the load current source 3, and use the junction temperature monitoring unit 6 to measure the highest junction temperature.
[0077] Step 4: Use the difference between the lowest junction temperature and the highest junction temperature of the DUT as the junction temperature change amount of the DUT.
[0078] Step 5: Debug the test conditions at the beginning of the power cycling test. When the junction temperature change amount in the first cycle meets the preset requirements, perform the thermal resistance and structure function test or execute the next cycle of the power cycling test. When the junction temperature change amount does not meet the preset requirements, the preset current applied by the load current source 3 needs to be adjusted, and return to Step 2 to continue execution.
[0079] In a possible implementation, the thermal resistance and structure function tests are as follows:
[0080] After ensuring that the device under test (DUT) reaches thermal equilibrium in the on state, keep the high-temperature water flowing and open the second switch 122 and the first switch 4. Use the electrical method to continuously and real-time test the junction temperature cooling curve of the DUT after the load current source 3 is disconnected until the junction temperature of the DUT drops to the same as the case temperature (i.e., the temperature of the temperature control board 1 and the high-temperature water at this time). According to the provisions of JESD51-14-2010, calculate the thermal resistance and structure function from the cooling curve.
[0081] It should be noted that the thermal resistance and structure function tests must be carried out at least in the first cycle after the start of the test and before the end of the test.
[0082] The discrimination condition for the end of the thermal resistance and structure function tests is: when the DUT fails or reaches the designed test time, the test ends.
[0083] The present application provides a temperature control method for high-acceleration power cycle tests of SiC devices, which is implemented based on a temperature control system for high-acceleration power cycle tests of SiC devices. During the off period of the power cycle test, by opening the first solenoid valve, closing the second solenoid valve, opening the first switch and opening the second switch, the device under test and the temperature control board are both in thermal equilibrium at a low temperature. When the device under test and the temperature control board are in thermal equilibrium at a low temperature, the initial junction temperature of the device under test is obtained through the junction temperature monitoring unit, and the initial case temperature of the device under test is obtained through the case temperature monitoring unit; when the first solenoid valve is open and the second solenoid valve is closed, the first chiller passes circulating water at a first temperature into the circulating water path, and when the first switch is open and the second switch is open, the off period of the power cycle test is executed. After the off period of the power cycle test reaches a preset specified time, the lowest junction temperature of the device under test is obtained through the junction temperature monitoring unit; when the first solenoid valve is closed and the second solenoid valve is open, the second chiller passes circulating water at a second temperature into the circulating water wheel, and when the first switch is closed and the second switch is closed, the on period of the power cycle test is executed. After the on period of the power cycle test reaches a preset specified time and the first switch is open, the highest junction temperature of the device under test is obtained through the junction temperature monitoring unit; the change in the junction temperature of the device under test is determined based on the lowest and highest junction temperatures of the device under test obtained by the junction temperature monitoring unit; it is judged whether the change in the junction temperature meets the preset requirements; if the change in the junction temperature meets the preset requirements, the thermal resistance and structure function test is performed or the next cycle of the power cycle test is executed; if the change in the junction temperature does not meet the preset requirements, the preset current input by the load current source is adjusted, and the steps of passing the first chiller to pass circulating water at a first temperature into the circulating water path when the first solenoid valve is open and the second solenoid valve is closed, and executing the off period of the power cycle test when the first switch is open and the second switch is open, and obtaining the lowest junction temperature of the device under test through the junction temperature monitoring unit after the off period of the power cycle test reaches the preset specified time are returned and continued to be executed. The present application utilizes the circulating water wheel arranged inside the packaging board and close to the device under test. The chiller can quickly provide circulating water at different temperatures to the circulating water path, enabling the temperature of the temperature control board to quickly respond to the change in water temperature, thereby more timely adjusting the temperature of the device under test and improving the real-time performance of temperature control; in addition, the present application passes circulating water at different temperatures to the circulating water path through the chiller, and combined with the heating effect of the electric heating unit, a wider range of temperature regulation can be achieved, which can not only realize tests in a low-temperature environment but also meet the requirements of a high-temperature environment, providing more flexible temperature conditions for power cycle tests of different types of devices under test; at the same time, the present application helps to speed up the test process and improve the test efficiency, and accurate temperature and current control can ensure the accuracy and reliability of the test results, providing more effective support for the research and development, production and quality evaluation of products.
[0084] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A temperature control system for high-acceleration power cycling tests of SiC devices, characterized in that, The system includes a temperature control board, a chiller, and a load current source. The temperature control board includes a circulating water path, an electric heating unit, and a packaging board, and the temperature control board is used for mounting the device under test; The chiller is connected to the circulating water path and is used to supply circulating water at different temperatures to the circulating water path; The circulating water path is arranged inside the packaging board and on one side close to the device under test, and is used to control the temperature of the temperature control board according to the temperature of the circulating water; The electric heating unit is arranged inside the packaging board and on one side away from the device under test, and is used to control the heating rate of the temperature control board during the turn-on period of the power cycling test; The load current source is electrically connected to the device under test and is used to apply a preset current to the device under test to control the increase in the junction temperature of the device under test.
2. The temperature control system for the high-acceleration power cycling test of the SiC device according to claim 1, characterized in that, The chiller includes a first chiller and a second chiller. The output ends of the first chiller and the second chiller are both connected to the circulating water path; The first chiller is used to introduce circulating water at a first temperature into the circulating water path during the turn-off period of the power cycling test to control the temperature of the temperature control board to decrease; The second chiller is used to introduce circulating water at a second temperature into the circulating water path during the turn-on period of the power cycling test to control the temperature of the temperature control board to increase and to control the temperature state of the temperature control board to be stable at a high temperature state. The first temperature is less than the second temperature.
3. The temperature control system for the high-acceleration power cycling test of the SiC device according to claim 2, characterized in that, The system further includes a first solenoid valve and a second solenoid valve. The first end of the first solenoid valve is connected to the output end of the first chiller, the second end of the first solenoid valve is connected to the circulating water path, the first end of the second solenoid valve is connected to the output end of the second chiller, and the second end of the second solenoid valve is connected to the circulating water path.
4. The temperature control system for the high-acceleration power cycling test of the SiC device according to claim 1, characterized in that, The system further includes a first switch. The first end of the first switch is connected to the first end of the load current source, and the second end of the first switch and the second end of the load current source are both connected to the device under test.
5. The temperature control system for the high-acceleration power cycling test of the SiC device according to claim 1, wherein The electric heating unit includes an electric heating wire, a second switch, and an AC power supply. The first end of the electric heating wire is connected to the first end of the AC power supply, the second end of the electric heating wire is connected to the first end of the second switch, and the second end of the AC power supply is connected to the second end of the second switch.
6. The temperature control system for the high-acceleration power cycle test of the SiC device according to claim 1, characterized in that, When the device under test is gate-controlled, the system further includes a load voltage source, and the load voltage source is connected to the device under test; The load voltage source is used to control the device under test to be in an on state.
7. The temperature control system for the high-acceleration power cycle test of the SiC device according to claim 1, wherein The system further includes a junction temperature monitoring unit, and the junction temperature monitoring unit is connected to the device under test; The junction temperature monitoring unit is used to monitor the junction temperature of the device under test during the turn-off period of the power cycling test.
8. The temperature control system for the high-acceleration power cycle test of the SiC device according to claim 1, wherein The system further includes a case temperature monitoring unit, and the case temperature monitoring unit is buried in the temperature control board on one side close to the device under test; The case temperature monitoring unit is used to monitor the case temperature of the device under test.
9. The temperature control system for the high-acceleration power cycle test of the SiC device according to claim 1, characterized in that, The system further includes a water tank, and the water tank is connected to the circulating water path; The water tank is used to store the circulating water at different temperatures flowing out of the circulating water path.
10. A temperature control method for high-acceleration power cycling test of SiC devices, characterized in that, The method is based on the temperature control system for the high-acceleration power cycle test of the SiC device described in any one of claims 1 to 9. During the turn-off period of the power cycle test, the method includes: Opening the first solenoid valve, closing the second solenoid valve, opening the first switch, and opening the second switch to enable the device under test and the temperature control board to be in thermal equilibrium at a low temperature. When the device under test and the temperature control board are in thermal equilibrium at a low temperature, obtain the initial junction temperature of the device under test through the junction temperature monitoring unit, and obtain the initial case temperature of the device under test through the case temperature monitoring unit; When the first solenoid valve is open and the second solenoid valve is closed, pass circulating water at a first temperature into the circulating water path through the first chiller. When the first switch is open and the second switch is open, execute the turn-off period of the power cycle test. After the turn-off period of the power cycle test reaches a preset specified time, obtain the lowest junction temperature of the device under test through the junction temperature monitoring unit; When the first solenoid valve is closed and the second solenoid valve is open, pass circulating water at a second temperature into the circulating water wheel through the second chiller. When the first switch is closed and the second switch is closed, execute the turn-on period of the power cycle test. When the turn-on period of the power cycle test reaches the preset specified time and the first switch is open, obtain the highest junction temperature of the device under test through the junction temperature monitoring unit; Determine the change in the junction temperature of the device under test based on the lowest and highest junction temperatures of the device under test obtained by the junction temperature monitoring unit; Judge whether the change in the junction temperature meets the preset requirements; If the change in the junction temperature meets the preset requirements, perform the thermal resistance and structure function test or execute the next cycle of the power cycle test; If the change in the junction temperature does not meet the preset requirements, adjust the preset current input by the load current source, and return to the step of passing circulating water at a first temperature into the circulating water path through the first chiller when the first solenoid valve is open and the second solenoid valve is closed, executing the turn-off period of the power cycle test when the first switch is open and the second switch is open, and obtaining the lowest junction temperature of the device under test through the junction temperature monitoring unit after the turn-off period of the power cycle test reaches the preset specified time, and continue to execute.