JP2016114403A - Power cycle testing device and method for power cycle test - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power cycle testing device that can execute a power cycle test and a thermal cycle test concurrently without requiring provision of an adjustment mechanism for adjusting an external environmental temperature of the device.SOLUTION: The power cycle testing device repeats test cycles S1 to S6 each of application of electric power to a test target device and stop of the application and causes repeated temperature changes on the test target device. The power cycle testing device includes an electric-power applying unit for applying electric power to the test target device and a control unit controlling the application by the electric-power applying unit and stop of the application. The control unit adjusts a timing of the application by the electric power applying unit so that initial temperatures T1 to T6 at which application of electric power to the test target device is started will change with repetition of the test cycles S1 to S6.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power cycle test apparatus and a power cycle test method, and more specifically to a power cycle test apparatus and a power cycle test method capable of executing a thermal cycle test together with a power cycle test.

  2. Description of the Related Art Conventionally, as a test for predicting the life of a power semiconductor device, a power cycle test is known in which the device itself generates heat by applying electric power to apply thermal stress. In this power cycle test, thermal stress is mainly applied due to the temperature change of the heat generating part of the device chip by repeating the test cycle by applying and stopping power to the device.

  In addition, there is a thermal cycle test in which a thermal stress different from that in the power cycle test is applied by changing the external environmental temperature of the device. Patent Document 1 describes an apparatus having a superimpose test function for executing a power cycle test so as to be synchronized with the thermal cycle test. According to the superimpose test, it is possible to efficiently reproduce thermal stress assuming a failure mode that occurs during actual use.

JP 2014-20893 A

  In the power cycle test apparatus described in Patent Document 1, a mechanism for adjusting the external environment temperature (chiller, heating, etc.) separately from the mechanism for applying power in order to execute the thermal cycle test in addition to the power cycle test. It was necessary to further provide a cooling plate or the like.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and its purpose is to provide a power cycle test apparatus capable of performing both a power cycle test and a thermal cycle test without the need to provide a mechanism for adjusting the external environmental temperature of the device. And providing a power cycle test method.

  A power cycle test apparatus according to an aspect of the present invention is a power cycle test apparatus that repeats a test cycle by applying and stopping power to a device under test and repeatedly giving a temperature change to the device under test. The power cycle test apparatus includes a power application unit for applying power to the device under test, and a control unit for controlling power application by the power application unit and stopping of the power application. The control unit adjusts the timing of power application by the power application unit so that a start temperature, which is a temperature at which power application to the device under test is started, changes with repetition of the test cycle.

  In the power cycle test apparatus, it is possible to apply power to the device under test so that the start temperature changes as the test cycle is repeated. Therefore, in addition to the power cycle test by repeating the test cycle, it is possible to execute a thermal cycle test that simulates the case where a change in the external environment temperature is given by the change in the start temperature. Therefore, according to the power cycle test apparatus, it is not necessary to provide a mechanism for adjusting the external environmental temperature of the device, and a superimpose test combining a thermal cycle test with a power cycle test can be executed.

  In the power cycle test apparatus, the control unit may adjust the timing of power application by the power application unit so that the start temperature for each test cycle changes along a preset profile.

  Thereby, the said starting temperature can be adjusted along the profile set according to the change of actual external environmental temperature. As a result, the thermal stress generated during actual use can be efficiently applied to the device.

  In the power cycle test apparatus, the control unit follows the profile including a temperature rising step in which the start temperature increases for each test cycle and a temperature decrease step in which the start temperature decreases for each test cycle. You may adjust the timing of the electric power application by the said electric power application part so that the said starting temperature for every said test cycle may change.

  As a result, the thermal stress applied to the device when the external environmental temperature rises and falls can be efficiently reproduced.

  In the power cycle test apparatus, the control unit is configured so that the start temperature for each test cycle changes along the profile further including a temperature maintaining step in which the start temperature is maintained for each test cycle. You may adjust the timing of the electric power application by an application part.

  Thereby, it is possible to efficiently reproduce the thermal stress applied to the device when the external environment temperature is maintained.

  In the power cycle test apparatus, the control unit may calculate the start temperature for each test cycle in the temperature raising step and calculate the start temperature for each test cycle in the temperature drop step.

  By repeating the test cycle based on the start temperature calculated for each test cycle, the transition between the test cycles can be performed smoothly.

  A power cycle test method according to one aspect of the present invention is a power cycle test method in which a test cycle is repeatedly performed by applying and stopping power to a device under test, and a temperature change is repeatedly applied to the device under test. In the power cycle test method, the power application timing is adjusted so that a start temperature, which is a temperature at which power application to the device under test is started, changes with repetition of the test cycle.

  In the power cycle test method, power is applied to the device under test so that the start temperature changes as the test cycle is repeated. Therefore, in addition to the power cycle test by repeating the test cycle, it is possible to execute a thermal cycle test that simulates the case where a change in the external environment temperature is given by the change in the start temperature. Therefore, according to the above power cycle test method, it is not necessary to provide a mechanism for adjusting the external environmental temperature of the device, and a superimpose test in which a thermal cycle test is combined with a power cycle test can be executed.

  In the power cycle test method, the timing of power application may be adjusted so that the start temperature for each test cycle changes along a preset profile.

  Thereby, the said starting temperature can be adjusted along the profile set according to the change of actual external environmental temperature. As a result, the thermal stress generated during actual use can be efficiently applied to the device.

  In the power cycle test method, the temperature rise step for increasing the start temperature for each test cycle, and the temperature decrease step for decreasing the start temperature for each test cycle. The timing of power application may be adjusted so that the start temperature changes.

  As a result, the thermal stress applied to the device when the external environmental temperature rises and falls can be efficiently reproduced.

  In the power cycle test method, the timing of power application is adjusted so that the start temperature for each test cycle varies along the profile further including a temperature maintaining step in which the start temperature is maintained for each test cycle. May be.

  Thereby, it is possible to efficiently reproduce the thermal stress applied to the device when the external environment temperature is maintained.

  In the power cycle test method, the start temperature for each test cycle in the temperature raising step may be calculated, and the start temperature for each test cycle in the temperature lowering step may be calculated.

  By repeating the test cycle based on the start temperature calculated for each test cycle, the transition between the test cycles can be performed smoothly.

  According to the present invention, it is not necessary to provide a mechanism for adjusting the external environmental temperature of the device, and it is possible to provide a power cycle test apparatus capable of executing a thermal cycle test together with a power cycle test.

It is the schematic which shows the structure of the power cycle test apparatus which concerns on one Embodiment of this invention. It is the schematic which shows the structure of an IGBT module. It is a flowchart which shows the procedure of the power cycle test method which concerns on one Embodiment of this invention. It is a graph which shows the time change of device temperature during execution of the above-mentioned power cycle test method. It is a graph which shows the time change of the device temperature in the modification 1 of the said power cycle test method. It is a graph which shows the time change of the device temperature in the modification 2 of the said power cycle test method. It is a graph which shows the time change of the device temperature in the modification 3 of the said power cycle test method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Power cycle test equipment)
First, the configuration of a power cycle test apparatus according to an embodiment of the present invention will be described. FIG. 1 schematically shows a configuration of a power cycle test apparatus 1 according to the present embodiment. FIG. 2 schematically shows the configuration of an IGBT (Insulated Gate Bipolar Transistor) module 2 to be tested.

  The power cycle test apparatus 1 is an apparatus for repeatedly applying a temperature change to the IGBT module 2 by repeating a test cycle by applying and stopping power to the IGBT module 2 (device under test). The power cycle test apparatus 1 mainly includes a power supply unit 10 and a gate control unit 20 (power application unit), a cooling unit 30, a controller 40 (control unit), and a constant current unit 50. The IGBT module 2 includes an IGBT chip 11 and a case 18 for housing the IGBT chip 11.

The power supply unit 10 includes a constant voltage constant current (CV / CC) power supply and is connected to the collector terminal C and the emitter terminal E of the IGBT chip 11. The power supply unit 10 applies a predetermined voltage (collector-emitter voltage: V _CE ) between the collector terminal C and the emitter terminal E based on a command from the controller 40.

The gate control unit 20 is connected to the gate terminal G of the IGBT chip 11. The gate control unit 20 applies a predetermined voltage (gate voltage: V _G ) to the gate terminal G based on a command from the control unit 40. When the power supply unit 10 in a state in which the threshold voltage higher than the gate voltage V _G is applied a predetermined collector-emitter voltage V _CE is applied by the gate control unit 20, the stress current I _C flows in the IGBT chip 11. As a result, predetermined power P (I _C × V _CE ) is applied to the IGBT chip 11.

The cooling unit 30 cools the IGBT module 2 that has generated heat due to the consumption of power P, and includes a radiator with an air cooling fan. Constant current unit 50 is for supplying a constant stress current I _C in the IGBT chip 11, including a shunt resistor and a differential amplifier.

The controller 40 is connected to each of the power supply unit 10, the gate control unit 20, the cooling unit 30, and the constant current unit 50 (broken line in FIG. 1), and controls the operation of each unit. More specifically, by operating the power supply unit 10 and the gate control unit 20, the application of the collector-emitter voltage V _CE and the gate voltage V _G is controlled by a command from the controller 40, the power to the IGBT chip 11 Application and its stop are controlled. In addition, by operating the cooling unit 30 according to a command from the controller 40, the heat generated IGBT module 2 can be cooled by the air cooling fan.

  Next, the configuration of the IGBT module 2 will be described in detail with reference to FIG. The IGBT module 2 mainly includes an IGBT chip 11, an insulating substrate 12, a base plate 13, solder layers 14 and 15, a bonding wire 17, and a case 18. The IGBT chip 11 is composed of a semiconductor substrate and an insulating film and electrodes formed thereon, and is joined to the insulating substrate 12 by a solder layer 14. The IGBT chips 11 are connected to each other by bonding wires 17 made of a material such as aluminum.

  The insulating substrate 12 is for insulating the IGBT chip 11 and the base plate 13 from each other, and is made of a material such as ceramics. The insulating substrate 12 is bonded onto the base plate 13 by the solder layer 15. A wiring pattern is drawn on the insulating substrate 12, and a bonding wire 17 is connected to the wiring pattern.

  The base plate 13 is for releasing heat generated by driving the IGBT chip 11 to the outside, and is a heat radiating plate made of a material such as copper. The case 18 is for housing the IGBT chip 11 and the insulating substrate 12 therein, and is made of a resin material or the like. In the case 18, silicone gel or the like is enclosed for protecting the IGBT chip 11.

  The temperature of the heat generating part of the IGBT chip 11 is the Tj temperature, and the surface temperature of the case 18 is the Tc temperature. The Tj temperature is measured by a measurement system built in the gate control unit 20 (FIG. 1), and the Tc temperature is measured by a thermocouple (not shown) provided in the case 18 or the like.

(Power cycle test method)
Next, the procedure of the power cycle test method performed using the power cycle test apparatus 1 will be described. In the power cycle test method described above, as shown in the flowchart of FIG. 3, a test cycle by applying and stopping power to the IGBT module 2 is repeated, and a temperature change is repeatedly applied to the IGBT module 2 to give a predetermined thermal stress. I can be.

  FIG. 4 shows the time change of the Tj temperature of the IGBT module 2 due to the repetition of the test cycles S1 to S6 in the power cycle test method. In the graph of FIG. 4, the horizontal axis indicates time, and the vertical axis indicates Tj temperature. In the power cycle test method, the start temperatures T1 to T6, which are the temperatures at which power application to the IGBT module 2 is started in each test cycle S1 to S6, are changed as the test cycles S1 to S6 are repeated. Specifically, the timing of application of power to the IGBT module 2 is adjusted by the controller 40 so as to change along the temperature profile P1 (one-dot chain line in FIG. 4). In the present embodiment, the temperature profile P1 includes a temperature increase step in which the Tj temperature increases, a temperature maintenance step in which the Tj temperature is maintained, and a temperature decrease step in which the Tj temperature decreases.

  First, for each of the temperature raising step, the temperature maintaining step, and the temperature lowering step, the number of repetitions of the test cycle and the Tj temperature before and after each step are input to the controller 40. In the present embodiment, test cycles S1 to S3 are set in the temperature raising step, test cycle S4 is set in the temperature maintaining step, and test cycles S5 and S6 are set in the temperature lowering step. Based on the input information, the controller 40 calculates start temperatures T1 to T3 for each test cycle in the temperature raising step. Similarly, the controller 40 calculates start temperatures T5 and T6 for each test cycle in the temperature lowering step. The start temperatures T1 to T6 are temperatures that serve as a reference when transitioning between test cycles as described later.

<Temperature raising step>
First, the temperature raising step will be described. First, application of power to the IGBT module 2 is started by a command from the controller 40 at the start temperature T1, and the test cycle S1 is started. Thereby, Tj temperature rises. Then, after a certain period of time has elapsed, application of power to the IGBT module 2 is stopped by a command from the controller 40. Thereafter, the IGBT module 2 is cooled by the cooling unit 30, and the Tj temperature decreases. During this cooling, the Tj temperature is measured at regular time intervals. Then, when the Tj temperature reaches the start temperature T2 (> T1) of the next test cycle S2, the test cycle S1 is completed, and the test cycle S2 is started.

  The test cycle S2 starts when the Tj temperature reaches the start temperature T2 and application of power to the IGBT module 2 is started by a command from the controller 40. Then, similarly to the test cycle S1, the power application is performed for a certain time, so that the Tj temperature rises, and then the power application is stopped. Then, when the Tj temperature decreases due to cooling and reaches the start temperature T3 (> T2) of the next test cycle S3, the test cycle S2 is completed, and the test cycle S3 is started.

  The test cycle S3 starts when the Tj temperature reaches the start temperature T3 and the application of power to the IGBT module 2 is started by a command from the controller 40. Then, similarly to the test cycles S1 and S2, the power application is performed for a certain time, so that the Tj temperature rises, and then the power application is stopped. The test cycle S3 is completed when the Tj temperature decreases due to cooling and reaches the start temperature T4 (> T3) of the next test cycle S4.

  Thus, in the temperature raising step, the start temperatures T1 to T3 for each of the test cycles S1 to S3 are set to increase for each of the test cycles S1 to S3. And the timing of the electric power application to the IGBT module 2 is adjusted by the controller 40 so that each test cycle S1-S3 is started based on the set start temperature T1-T3. The start temperatures T1 to T3 may be set so as to increase linearly as shown in FIG. 4, or may be set so as to increase nonlinearly. In addition, the number of test cycles repeated in the temperature raising step is not limited.

<Temperature maintenance step>
Next, the temperature maintenance step will be described. When the Tj temperature reaches the start temperature T4, application of power to the IGBT module 2 is started by a command from the controller 40, and a test cycle S4 is started. Thereby, Tj temperature rises. Then, after a certain period of time has elapsed, power application is stopped by a command from the controller 40. Thereafter, the IGBT module 2 is cooled by the cooling unit 30, and the Tj temperature decreases. During this cooling, the Tj temperature is measured at regular time intervals in the same manner as in the temperature raising step. And test cycle S4 is completed when Tj temperature reaches start temperature T5 which is the same temperature as start temperature T4.

  Thus, in the temperature maintenance step, the start temperatures T4 and T5 are set so as to be maintained for each test cycle.

  In the present embodiment, the number of repetitions of the test cycle is set to 1 in the temperature maintaining step, but it may be set a plurality of times. In this case, the starting temperature is set to be kept constant for each test cycle.

<Cooling step>
Next, the temperature lowering step will be described. When the Tj temperature reaches the start temperature T5, application of power to the IGBT module 2 is started by a command from the controller 40, and a test cycle S5 is started. Thereby, Tj temperature rises. Then, after a certain period of time has elapsed, application of power is stopped by a command from the controller 40, and then the IGBT module 2 is cooled. During this cooling, the Tj temperature is measured at regular time intervals in the same manner as in the temperature raising step and the temperature maintaining step. Then, when the Tj temperature reaches the start temperature T6 (<T5) of the next test cycle S6, the test cycle S5 is completed, and the test cycle S6 is started.

  The test cycle S6 starts when the Tj temperature reaches the start temperature T6 and the application of power to the IGBT module 2 is started by a command from the controller 40. Then, similarly to the test cycle S5, the power application is performed for a certain time, so that the Tj temperature rises, and then the power application is stopped. The test cycle S6 is completed when the Tj temperature is decreased by cooling and reaches the temperature T7 (<T6).

  Thus, in the temperature lowering step, the start temperatures T5 and T6 are set so as to decrease every test cycle S5 and S6. Then, the timing of application of power to the IGBT module 2 is adjusted by the controller 40 so that the test cycles S5 and S6 are started based on the set start temperatures T5 and T6.

  In the present embodiment, the number of repetitions of the test cycle is set to 2 in the temperature lowering step, but may be set to 3 times or more. In this case, the starting temperature of each test cycle may be set so as to decrease linearly or may be set so as to decrease nonlinearly.

  As described above, in the power cycle test method, the timing of applying power to the IGBT module 2 is adjusted by the controller 40 so that the start temperatures T1 to T6 for each of the test cycles S1 to S6 change as the test cycle is repeated. Is done. More specifically, the timing of power application to the IGBT module 2 is adjusted by the controller 40 so that the start temperatures T1 to T6 change along a preset temperature profile P1.

  In each of the temperature raising step, the temperature maintaining step, and the temperature lowering step, the number of repetitions of the test cycle is not particularly limited, and can be appropriately set according to the test conditions. Further, in each test cycle, the power application may be stopped after power is applied for a certain time. However, the present invention is not limited to this, and the power application is stopped after the Tj temperature reaches a predetermined target value by the power application. The timing may be adjusted. The IGBT module 2 may be cooled by natural heat dissipation.

(Effects of power cycle test equipment and power cycle test method)
Next, the effects of the power cycle test apparatus 1 and the power cycle test method using the power cycle test apparatus 1 will be described.

  In the power cycle test apparatus 1 and the power cycle test method, it is possible to apply power to the IGBT module 2 so that the start temperatures T1 to T6 change with the repetition of the test cycles S1 to S6. Therefore, in addition to the power cycle test by repeating the test cycles S1 to S6, it is possible to execute a thermal cycle test that simulates the case where a change in the external environment temperature of the IGBT module 2 is given by a change in the start temperature T1 to T6. become. Therefore, according to the power cycle test apparatus 1 and the power cycle test method, it is not necessary to provide a mechanism for adjusting the external environmental temperature of the device, and a superimpose test in which a thermal cycle test is combined with a power cycle test can be executed. it can.

  In the power cycle test apparatus 1, the controller 40 uses the power from the power supply unit 10 and the gate control unit 20 so that the start temperatures T1 to T6 for the test cycles S1 to S6 change along the preset temperature profile P1. Adjust the timing of application. Thereby, start temperature T1-T6 can be adjusted along the temperature profile P1 set according to the change of actual external environmental temperature. As a result, the thermal stress generated during actual use can be efficiently applied to the device.

  In the power cycle test apparatus 1, the controller 40 includes a temperature raising step in which the start temperatures T1 to T3 are increased for each of the test cycles S1 to S3, and a temperature lowering step in which the start temperatures T5 and T6 are decreased for each of the test cycles S5 and S6. The power application timing by the power supply unit 10 and the gate control unit 20 is adjusted so that the start temperature for each test cycle changes along the temperature profile P1 including As a result, the thermal stress applied to the device when the external environmental temperature rises and falls can be efficiently reproduced.

  In the power cycle test apparatus 1, the controller 40 controls the power supply so that the start temperature for each test cycle changes along the temperature profile P <b> 1 further including a temperature maintenance step in which the start temperatures T <b> 4 and T <b> 5 are maintained for each test cycle. The timing of power application by the unit 10 and the gate control unit 20 is adjusted. Thereby, it is possible to efficiently reproduce the thermal stress applied to the device when the external environment temperature is maintained.

  In the power cycle test apparatus 1, the controller 40 calculates the start temperatures T1 to T3 for the test cycles S1 to S3 in the temperature raising step, and calculates the start temperatures T5 and T6 for the test cycles S5 and S6 in the temperature drop step. calculate. By repeating the test cycle based on the start temperature calculated for each test cycle, the transition between the test cycles can be performed smoothly.

(Modification)
Finally, a modified example of the present embodiment will be described with reference to FIGS. 5-7, the temperature profile which changes the starting temperature for every test cycle is shown with the dashed-dotted line similarly to FIG. 4, the horizontal axis shows time, and the vertical axis | shaft shows Tj temperature.

  As shown in Modification 1 in FIG. 5, power is applied by the controller 40 so that the start temperature for each test cycle changes along a temperature profile P2 that includes a temperature increase step and a temperature decrease step but does not include a temperature maintenance step. The timing may be adjusted. Further, as shown in Modification 2 in FIG. 6, the controller 40 controls the power so that the start temperature for each test cycle changes along the temperature profile P3 including the temperature raising step and the temperature maintaining step and not including the temperature lowering step. The timing of application may be adjusted. Further, as shown in Modification 3 in FIG. 7, the controller 40 controls the power so that the start temperature for each test cycle changes along the temperature profile P4 including the temperature lowering step and the temperature maintaining step and not including the temperature increasing step. The timing of application may be adjusted.

  In addition to the above modification, the controller 40 adjusts the timing of power application so that the start temperature for each test cycle changes along a temperature profile that is an arbitrary combination of the temperature raising step, the temperature maintaining step, and the temperature lowering step. May be. Further, in the present invention, it is only necessary to adjust the power application timing so that the start temperature changes as the test cycle repeats, and the power application timing is set so that the start temperature changes along a preset temperature profile. It is not limited to adjusting.

  Further, the present invention is not limited to the case where the IGBT module 2 is used as a device under test as in the above embodiment, and other power semiconductor devices such as a MOSFET (Metal Oxide Field Effect Transistor) may be used similarly.

  In addition, the said embodiment and modification are illustrations, and it should be thought that the range of this invention is not restrict | limited to these. The scope of the present invention is shown not by the above-described embodiments and modifications but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Power cycle test apparatus, 2 IGBT module (device under test), 10 Power supply part (power application part), 20 Gate control part (power application part), 40 Control controller (control part), P1-P4 Temperature profile (profile) , S1-S6 test cycle, T1-T6 starting temperature.

Claims (10)

A power cycle test apparatus that repeats a test cycle by applying and stopping power to a device under test and repeatedly giving a temperature change to the device under test,
A power application unit for applying power to the device under test;
A control unit for controlling power application by the power application unit and stopping of the power application,
The control unit adjusts the timing of power application by the power application unit so that a start temperature, which is a temperature at which power application to the device under test is started, changes with repetition of the test cycle. Test equipment.   The power cycle test apparatus according to claim 1, wherein the control unit adjusts the timing of power application by the power application unit so that the start temperature for each test cycle changes along a preset profile.   The control unit includes the temperature rising step in which the start temperature increases for each test cycle and the temperature decreasing step in which the start temperature decreases for each test cycle. The power cycle test apparatus according to claim 2, wherein the timing of power application by the power application unit is adjusted so that the temperature changes.   The control unit includes a timing of power application by the power application unit such that the start temperature for each test cycle changes along the profile further including a temperature maintaining step in which the start temperature is maintained for each test cycle. The power cycle test apparatus according to claim 3, wherein the power cycle test apparatus is adjusted.   5. The power cycle test according to claim 3, wherein the control unit calculates the start temperature for each test cycle in the temperature raising step and calculates the start temperature for each test cycle in the temperature decrease step. 6. apparatus. A power cycle test method that repeats a test cycle by applying and stopping power to a device under test and repeatedly giving a temperature change to the device under test,
A power cycle test method, wherein a power application timing is adjusted such that a start temperature, which is a temperature at which power application to the device under test is started, changes with repetition of the test cycle.   The power cycle test method according to claim 6, wherein the timing of power application is adjusted so that the start temperature for each test cycle changes along a preset profile.   The start temperature for each test cycle is changed along the profile including a temperature increasing step for increasing the start temperature for each test cycle and a temperature decrease step for decreasing the start temperature for each test cycle. The power cycle test method according to claim 7, wherein the timing of power application is adjusted.   The power application timing is adjusted such that the start temperature for each test cycle varies along the profile further including a temperature maintenance step in which the start temperature is maintained for each test cycle. Power cycle test method.   The power cycle test method according to claim 8 or 9, wherein the start temperature for each test cycle in the temperature raising step is calculated, and the start temperature for each test cycle in the temperature drop step is calculated.

Images