HTRB testing device and method based on oil cooling

Abstract

The invention provides an HTRB testing device and method based on oil cooling, and relates to the technical field of semiconductor testing. The oil cooling circulation module realizes oil cooling circulation cooling; the test module applies high temperature and bias voltage to the to-be-tested device; the control module monitors the temperature of the to-be-tested device in real time in the testing process, and dynamically adjusts the heating efficiency of the testing module and the heat dissipation efficiency of the oil cooling circulation module through closed-loop feedback, so that the temperature of the to-be-tested device is continuously stabilized in a preset testing temperature range. The device has the beneficial effects that an oil cooling circulation cooling mode is adopted, and compared with traditional air cooling, the heat conductivity coefficient of an oil cooling medium is greatly improved. Moreover, the closed-loop feedback of the control module can dynamically balance the heating power and the heat dissipation flow according to the actual temperature of the device, enables the temperature of the to-be-tested device to be continuously stabilized in a preset range, effectively avoids the failure of the device caused by heat accumulation, and improves the accuracy of test data.

Description

An oil-cooled HTRB testing device and method Technical Field

[0001] This invention relates to the field of semiconductor testing technology, and in particular to an oil-cooled HTRB testing apparatus and method. Background Technology

[0002] HTRB (High Temperature Reverse Bias) testing is one of the core methods for semiconductor device reliability assessment. It is mainly used to evaluate the long-term electrical stability of power semiconductor devices and integrated circuits such as power MOSFETs, IGBTs, and diodes under high temperature and high reverse bias conditions. During the test, the device needs to withstand high temperatures (typically 85℃–150℃) and high reverse bias close to the breakdown voltage. The Joule heat generated by the internal leakage current and the high ambient temperature can combine to cause excessively high local temperatures in the device, affecting the validity of the test.

[0003] Traditional HTRB testing equipment generally relies on air cooling or natural heat dissipation, which has the following main drawbacks:

[0004] Insufficient heat dissipation and low temperature control accuracy: The thermal conductivity of air is only about 0.026 W / (m·K), the heat dissipation efficiency is limited, it is difficult to quickly dissipate the heat generated by the device, resulting in the actual temperature exceeding the set range and large temperature fluctuations (usually ±5℃), which cannot meet the requirements of high-precision testing.

[0005] Poor temperature uniformity affects test reliability: Airflow is easily affected by the test chamber structure and external environment, resulting in uneven temperature distribution on the device surface. Local overheating may cause premature device failure, thus failing to truly reflect the long-term reliability of the device. It also increases the test cost and time cost caused by overheating and burnout.

[0006] Although various improvement solutions have emerged in the existing technology, such as using multi-mode switching or oil immersion cooling, oil immersion cooling has improved heat dissipation performance compared to air cooling, but it still cannot completely solve the problem of heat accumulation in the testing of high-power devices, nor can it achieve the accurate and stable temperature control required for testing. Summary of the Invention

[0007] To address the problems existing in the prior art, the present invention provides an oil-cooled HTRB testing device, comprising:

[0008] The test chamber is equipped with the device to be tested.

[0009] An oil-cooling circulation module is connected to the oil-cooling inlet and outlet of the test chamber to achieve oil-cooling circulation and cooling.

[0010] A test module, disposed on the surface of the test cavity, is used to apply high temperature and bias voltage to the device under test;

[0011] The control module is connected to the oil cooling circulation module and the test module respectively. It is used to monitor the temperature of the device under test in real time during the test, and dynamically adjust the heating efficiency of the test module and the heat dissipation efficiency of the oil cooling circulation module through closed-loop feedback, so that the temperature of the device under test remains stable within the preset test temperature range.

[0012] Preferably, the test chamber includes:

[0013] A cavity base, the surface of which is provided with a mounting groove, and the device to be tested is mounted in the mounting groove;

[0014] An oil cooling channel is disposed inside the cavity and surrounds the mounting groove. The oil cooling inlet and outlet of the oil cooling channel are connected to the oil cooling circulation module.

[0015] Preferably, the oil cooling circulation module includes an oil tank, an oil pump, an oil cooler, a filter, and a flow regulating valve connected in sequence by pipes, with the two ends of the pipes connected to the oil cooling inlet and outlet respectively.

[0016] Preferably, the oil cooling circulation module further includes a medium loss detection unit for monitoring the insulation performance of the oil cooling medium in the pipeline.

[0017] Preferably, the test module includes:

[0018] The temperature control submodule includes:

[0019] Temperature sensors are disposed on the surface of the test chamber and at the oil cooling inlet / outlet.

[0020] A ceramic heating element is embedded inside the test chamber;

[0021] The bias application module includes:

[0022] A DC power supply and a bias voltage regulation circuit, wherein the bias voltage regulation circuit is used to convert the high voltage provided by the DC power supply into a bias voltage and apply it to the device under test.

[0023] Preferably, the mounting groove is coated with silicone grease.

[0024] Preferably, it also includes a silicone sealing ring, which is installed on the cavity base to seal the mounting groove.

[0025] The present invention also provides an oil-cooled HTRB testing method, using the HTRB testing apparatus described above, comprising:

[0026] Step S1: The HTRB testing device fixes the device under test in the test chamber, and then starts the oil cooling circulation device to cool the internal oil cooling medium to room temperature.

[0027] Step S2: The HTRB testing device monitors the temperature of the device under test in real time and dynamically adjusts the heating efficiency of the testing module and the heat dissipation efficiency of the oil cooling circulation module through closed-loop feedback, so that the temperature of the device under test remains stable within the preset test temperature range.

[0028] Step S3: The HTRB testing device applies a bias voltage to the device under test to perform HTRB testing until the preset test duration is reached.

[0029] The above technical solution has the following advantages or beneficial effects:

[0030] Compared to traditional air cooling, oil cooling significantly improves the thermal conductivity of the cooling medium by employing an oil-cooled circulating cooling method. Furthermore, the closed-loop feedback of the control module dynamically balances heating power and heat dissipation flow based on the actual temperature of the device, ensuring the temperature of the device under test remains stable within a preset range. This effectively prevents device failure caused by heat buildup and improves the accuracy of test data. Attached Figure Description

[0031] Figure 1 is a schematic diagram of an oil-cooled HTRB testing device in a preferred embodiment of the present invention.

[0032] Figure 2 is a schematic diagram of an oil-cooled HTRB testing device in a preferred embodiment of the present invention.

[0033] Figure 3 is a flowchart illustrating an oil-cooled HTRB testing method in a preferred embodiment of the present invention. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The present invention is not limited to this embodiment; other embodiments that conform to the spirit of the present invention may also fall within the scope of the present invention.

[0035] In a preferred embodiment of the present invention, based on the above-mentioned problems existing in the prior art, an oil-cooled HTRB testing device is provided.

[0036] Example 1:

[0037] As shown in Figures 1 and 2, this embodiment provides an oil-cooled HTRB testing device, including:

[0038] Test chamber 1: Used to mount the device under test;

[0039] Oil cooling circulation module 2 is connected to the oil cooling inlet and outlet of test chamber 1, and achieves oil cooling circulation and cooling through the flow of oil cooling medium;

[0040] Test module 3: Located on the surface of test chamber 1, used to apply a high-temperature environment and electrical bias voltage to the device under test;

[0041] Control module 4: Connects to oil cooling circulation module 2 and test module 3 respectively. This control module 4 is used to monitor the temperature of the device under test in real time during the test, and dynamically adjust the heating efficiency of test module 3 and the heat dissipation efficiency of oil cooling circulation module 2 through closed-loop feedback (such as PID algorithm).

[0042] Specifically, this embodiment solves the temperature drift problem caused by self-heating in high-power devices during HTRB testing through a two-way adjustment mechanism of heating and oil cooling. Compared with traditional air cooling, the thermal conductivity of oil cooling medium (such as synthetic insulating oil) is significantly improved (up to 0.3-0.5 W / (m·K)). The closed-loop feedback of the control module can dynamically balance the heating power and heat dissipation flow according to the actual temperature of the device, so that the temperature of the device under test remains stable within the preset range, effectively avoiding device failure caused by heat accumulation and improving the accuracy of test data.

[0043] Example 2:

[0044] As shown in Figures 1 and 2, this embodiment describes the structure of the test chamber 1 in detail based on embodiment 1. The test chamber includes a chamber base 11 and an oil cooling channel 12.

[0045] Cavity base 11: A mounting groove 13 is provided on the surface, and the device to be tested is directly mounted in the mounting groove. The base is preferably made of oxygen-free copper alloy to take advantage of its excellent thermal conductivity.

[0046] Oil cooling channel 12: Located inside the cavity base 11, and designed to surround the mounting groove 13. The oil cooling inlet and outlet 14 of the oil cooling channel 12 are connected to the external oil cooling circulation module 3.

[0047] Specifically, in this embodiment, by setting an oil-cooling channel 12 surrounding the mounting groove 13 inside the cavity, a wraparound heat dissipation for the device mounting area is achieved. This structural design minimizes the heat transfer path and improves heat exchange efficiency. Compared to simple unilateral cooling, the surrounding channel ensures a more uniform temperature distribution around the mounting groove, eliminates local hot spots, and thus significantly improves the temperature uniformity of the device surface.

[0048] Example 3:

[0049] As shown in Figures 1 and 2, this embodiment, based on embodiment 1, specifies the specific composition of the oil cooling circulation module. The oil cooling circulation module 2 includes:

[0050] The oil tank 21, oil pump 22, oil cooler 23, filter 24 and flow regulating valve 25 are connected in sequence by pipelines.

[0051] The oil tank 21 stores standard synthetic insulating oil (preferably synthetic insulating oil conforming to GB / T7595-2007 standard, with a dielectric loss factor ≤0.005 at 90℃, an operating temperature range of 40℃-200℃, and a thermal conductivity of 0.3-0.5W / (m·K)); the oil pump 22 (preferably rated flow rate 5-20L / min, rated pressure 0.5-1.0MPa) provides circulation power to drive the oil flow; the oil cooler 23 (preferably a water-cooled heat exchanger with a heat dissipation area of ​​0.5-1.0㎡) cools the returning oil; the filter 24 filters out impurities in the oil; the flow regulating valve 24 is used to regulate the flow rate of the oil entering the test chamber; and the two ends of the pipeline are respectively connected to the oil cooling inlet and outlet 14 of the test chamber.

[0052] Specifically, this embodiment constructs a complete forced oil cooling circulation system. The flow regulating valve 25 is a key component for dynamically adjusting the heat dissipation efficiency as described in Embodiment 1. The filter 24 (preferably with an accuracy ≤10μm) effectively prevents impurities from entering the flow channel and causing blockage or degradation of electrical insulation performance. The oil cooler 23 ensures a constant temperature for the circulating medium, providing a stable cold source for the test chamber.

[0053] Example 4:

[0054] As shown in Figures 1 and 2, based on Embodiment 3, the oil cooling circulation module 2 further includes:

[0055] Medium loss detection unit 26: Used to monitor the insulation performance of oil-cooled medium in pipelines. This unit can be equipped with a fully automatic medium loss tester to monitor the oil's medium loss factor in real time.

[0056] Specifically, in HTRB testing, the device is under high voltage. Under long-term high-temperature cycling, the oil may age or become damp, leading to a decline in insulation performance. This embodiment introduces a dielectric loss detection unit, which can monitor the health status of the oil in real time during the test (e.g., ensuring the dielectric loss factor is ≤0.005 at 90°C). Once insulation performance degradation is detected, an alarm can be triggered or the system can be shut down in time to prevent high-voltage breakdown accidents caused by oil insulation failure, thereby ensuring the safety of the test equipment and devices.

[0057] Example 5:

[0058] As shown in Figures 1 and 2, this embodiment, based on embodiment 1, provides a detailed description of the composition of test module 3, including:

[0059] The temperature control submodule 31 includes temperature sensors 311 disposed on the surface of the test chamber and at the oil cooling inlet and outlet, and ceramic heating elements 312 embedded inside the test chamber.

[0060] The bias application submodule 32 includes a DC power supply and a bias adjustment circuit. The bias adjustment circuit (preferably using a resistor divider + operational amplifier feedback structure with an adjustment accuracy of 0.01V) is used to convert the high voltage provided by the DC power supply into a precise bias voltage and apply it to the device under test.

[0061] Specifically, in this embodiment, by arranging temperature sensors 311 at multiple points on the cavity surface and oil cooling inlet and outlet, the control module 4 can obtain more comprehensive temperature field data, calculate the inlet and outlet temperature difference, and thus adjust the heating power and oil flow more accurately.

[0062] Moreover, the ceramic heating element 312 is embedded inside the cavity, which has a fast thermal response speed. Combined with the oil cooling system, it can achieve rapid heating and cooling.

[0063] The bias voltage adjustment circuit converts the voltage supplied by the DC power supply into a stable DC bias voltage required by the device under test (DUT) and applies it to the DUT. This ensures that the high voltage applied to the device is stable (low ripple factor), meeting the stringent voltage stability requirements of HTRB testing. The bias voltage application module can adopt common implementation schemes in the field of HTRB (High Temperature Reverse Bias) testing, such as a typical circuit structure based on resistor voltage divider and operational amplifier feedback, to achieve high-precision and stable DC bias voltage output. The specific circuit configuration and implementation of this module are well known to those skilled in the art and are not the focus of this invention; therefore, its internal circuit details will not be elaborated further.

[0064] Example 6:

[0065] This embodiment is based on Embodiment 2, except that silicone grease (thermal conductive silicone grease) is applied to the mounting slot 13. The device to be tested is installed in the mounting slot coated with silicone grease.

[0066] Specifically, in this embodiment, the cavity base 11 is made of oxygen-free copper alloy, and a groove 13 matching the device under test is opened on its surface. Thermal grease fills the tiny gap between the bottom surface of the device and the surface of the mounting groove 13, which greatly reduces the contact thermal resistance (down to ≤0.01℃ / W). This ensures that the heat generated by the device can be quickly conducted to the cavity base and carried away by the oil cooling channel, further improving the heat dissipation efficiency and the response speed of temperature control.

[0067] Example 7:

[0068] As shown in Figures 1 and 2, this embodiment, based on embodiment 2, also includes a silicone sealing ring 5, which is installed on the cavity base 11 to seal the mounting groove 13.

[0069] Specifically, in this embodiment, the silicone sealing ring effectively seals the test area. On the one hand, it prevents external impurities from entering and affecting the test results; on the other hand, in scenarios requiring immersion or prevention of oil and gas leakage, it ensures the sealing and safety of the test environment, avoiding pollution of the laboratory environment by high-temperature oil and gas.

[0070] Example 8

[0071] This embodiment provides an oil-cooled HTRB testing method, using the apparatus of any of the above embodiments, as shown in Figure 3, including the following steps:

[0072] Step S1: Fix the device under test in the test chamber (e.g., apply silicone grease and seal the chamber), and then start the oil cooling circulation device to cool the internal oil cooling medium to room temperature.

[0073] Step S2: The testing device monitors the temperature of the device under test in real time and dynamically adjusts the heating efficiency of the testing module (e.g., adjusting the power of the ceramic heating element) and the heat dissipation efficiency of the oil cooling circulation module (e.g., adjusting the flow valve opening) through closed-loop feedback to ensure that the temperature of the device under test remains stable within the preset test temperature range (e.g., 150℃ or 175℃, with an accuracy controlled within ±).

[0074] 0.5℃).

[0075] Step S3: After the temperature stabilizes, apply a bias voltage to the device under test and perform HTRB testing until the preset test duration (e.g., 1000 hours) is reached.

[0076] Specifically, the advantage of the method in this embodiment lies in the standardization of the operation of the oil-cooled HTRB test. Step S1 ensures the consistency of the test start state and pre-establishes a heat dissipation cycle.

[0077] Step S2 overcomes the risk of thermal runaway caused by device self-heating through a dynamic balancing strategy, and achieves high-precision constant temperature control.

[0078] Step S3 applies electrical stress under a stable thermal environment, ensuring that the test results accurately reflect the inherent reliability of the device under high temperature and high pressure, rather than false failures caused by fluctuations in the test environment. The overall method significantly reduces the device failure rate and supports long-term unattended testing.

[0079] Furthermore, the dynamic adjustment process for step S2 is as follows:

[0080] First, the PDI temperature controller acquires the high-precision thermocouple signal installed on the device under test in real time, uses it as the current actual temperature value (T_actual), and compares it with the set target temperature (T_set = 175℃) to calculate the temperature deviation (ΔT = T_set - T_actual) and the rate of change of deviation.

[0081] Subsequently, the advanced PID algorithm (proportional-integral-derivative) integrated within the temperature controller calculates and outputs two independent control signals in real time based on ΔT: a heating control signal and a cooling control signal.

[0082] For the heating control signal (output to the ceramic heating element in the test module): when T_actual is below the target lower limit (e.g., 174.8℃), the PID algorithm calculates a higher heating power percentage (e.g., 80%), driving the heating element to heat up rapidly. As T_actual approaches T_set, the heating power is smoothly attenuated.

[0083] For the cooling control signal (output to the proportional control valve of the oil cooling circulation module): when the device starts to generate self-heating due to the applied bias voltage, causing T_actual to tend to exceed the target upper limit (e.g., 175.2℃), the PID algorithm does not simply shut off the heating, but simultaneously strengthens the cooling control signal and proportionally increases the valve opening of the cooling oil circuit (e.g., from 30% to 60%) to improve heat dissipation efficiency and offset the device's self-heating.

[0084] During the test, the device's self-generated heat is not constant. The PDI temperature controller dynamically adjusts the temperature through rapid sampling and calculation every few milliseconds.

[0085] If the self-heating increases instantaneously, the thermostat will slightly reduce the heating power while slightly increasing the cooling flow rate, forming a combined regulation to prevent temperature overshoot.

[0086] If there is a slight external disturbance (such as fluctuations in ambient temperature), the thermostat will make a fine adjustment in the opposite direction to ensure that T_actual is always "locked" within the range of 174.5℃ to 175.5℃.

[0087] In summary, compared with the prior art, the present invention has the following beneficial effects:

[0088] 1. Breakthrough in heat dissipation efficiency: The forced circulation oil cooling (thermal conductivity 0.3-0.5W / (m·K)) improves heat dissipation efficiency by more than 300% compared with air cooling (0.026W / (m·K)), solving the limitations of simple oil immersion cooling in high-power scenarios;

[0089] 2. Dual protection of temperature control and insulation: Combining PID closed-loop control and dielectric loss monitoring (compliant with GB / T7595 standard), the temperature control accuracy reaches ±0.5℃, avoiding test failure caused by oil aging;

[0090] 3. High reliability and compatibility: Device failure rate is reduced by more than 80%, it can be adapted to different packaged devices, and supports long-term testing of more than 1000 hours;

[0091] 4. Intelligent safety protection: Multi-parameter linkage control and hierarchical alarm mechanism reduce manual intervention and adapt to the testing needs of high-precision devices.

[0092] The above are merely preferred embodiments of the present invention and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should recognize that any equivalent substitutions and obvious changes made using the content of this specification and illustrations should be included within the protection scope of the present invention.

Claims

1. An oil-cooled HTRB testing device, characterized in that, include: The test chamber is equipped with the device to be tested. An oil-cooling circulation module is connected to the oil-cooling inlet and outlet of the test chamber to achieve oil-cooling circulation and cooling; a test module is disposed on the surface of the test chamber and is used to apply high temperature and bias voltage to the device under test; a control module is connected to the oil-cooling circulation module and the test module respectively, and is used to monitor the temperature of the device under test in real time during the test, and dynamically adjust the heating efficiency of the test module and the heat dissipation efficiency of the oil-cooling circulation module through closed-loop feedback, so that the temperature of the device under test remains stable within the preset test temperature range.

2. The HTRB testing apparatus according to claim 1, characterized in that, The test chamber includes: a chamber base, on the surface of which is provided an installation groove, and the device to be tested is installed in the installation groove; an oil cooling channel, disposed inside the chamber and surrounding the installation groove, wherein the oil cooling inlet and outlet of the oil cooling channel are connected to the oil cooling circulation module.

3. The HTRB testing apparatus according to claim 1, characterized in that, The oil cooling circulation module includes an oil tank, an oil pump, an oil cooler, a filter, and a flow regulating valve connected in sequence by pipes, with the two ends of the pipes connected to the oil cooling inlet and outlet respectively.

4. The HTRB testing apparatus according to claim 3, characterized in that, The oil cooling circulation module also includes a medium loss detection unit for monitoring the insulation performance of the oil cooling medium in the pipeline.

5. The HTRB testing apparatus according to claim 1, characterized in that, The test module includes: a temperature control submodule, including: a temperature sensor disposed on the surface of the test chamber and the oil cooling inlet / outlet; a ceramic heating element embedded inside the test chamber; and a bias application module, including: a DC power supply and a bias adjustment circuit, wherein the bias adjustment circuit is used to convert the high voltage provided by the DC power supply into a bias voltage applied to the device under test.

6. The HTRB testing apparatus according to claim 2, characterized in that, The mounting slot is coated with silicone grease.

7. The HTRB testing apparatus according to claim 2, characterized in that, It also includes a silicone sealing ring, which is installed on the cavity base to seal the mounting groove.

8. An oil-cooled HTRB testing method, characterized in that, The application of the HTRB testing device as described in claims 1-7 includes: Step S1, the HTRB testing device fixes the device under test in the test chamber, and then starts the oil cooling circulation device to cool the internal oil cooling medium to room temperature; Step S2, the HTRB testing device monitors the temperature of the device under test in real time, and dynamically adjusts the heating efficiency of the test module and the heat dissipation efficiency of the oil cooling circulation module through closed-loop feedback, so that the temperature of the device under test remains stable within a preset test temperature range; Step S3, the HTRB testing device applies a bias voltage to the device under test to perform HTRB testing until a preset test duration is reached.

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