Test device

Abstract

The invention provides a test device capable of automatically switching and efficiently performing a high-voltage test and a current-voltage characteristic measurement on a plurality of test objects while avoiding damage to the test objects caused by an operator's carelessness and an extension of the time required for the high-voltage test. The test device includes a first circuit for performing a high-voltage test, a second circuit for performing current-voltage characteristic measurement, and a control unit for controlling the first circuit and the second circuit. The first circuit includes a first power source that outputs a first voltage applied to the plurality of test objects in the high voltage test, and a plurality of first switching circuits that electrically connect or disconnect the first power source and the plurality of test objects. The second circuit includes a second power source that outputs a second voltage to be applied to the plurality of test objects during current-voltage characteristic measurement, and a plurality of second switching circuits that electrically connect or disconnect the second power source and the plurality of test objects.

Description

Technical Field

[0001] The present invention relates to a test device. Background Art

[0002] In a high temperature reverse bias test using a power MOSFET or the like as a test object, a high temperature and high voltage stress is applied to the test object, and the time until insulation breakdown occurs in the test object is measured.

[0003] Patent Document 1 discloses a withstand voltage test apparatus that applies a high voltage to a plurality of samples simultaneously, detects the state of each sample by a breakdown detection circuit, and controls the applied voltage and application time.

[0004] Prior art literature

[0005] Patent Literature

[0006] [Patent Document 1] Japanese Utility Model Publication No. 48-84275 Summary of the invention

[0007] Problems to be solved by the invention

[0008] In the high temperature reverse bias test related to the background art, in order to measure the degree of degradation of the test object during the test, it is necessary to interrupt the test, remove the test object from the test tank, and measure the current-voltage characteristics of the test object using a measuring instrument such as a curve tracer.

[0009] However, when taking the test object out of the test tank, it is necessary to wait until the temperature of the test tank drops from high temperature to normal temperature. In addition, when starting the high temperature reverse bias test again after measuring the current-voltage characteristics, it is also necessary to wait until the temperature of the test tank rises from normal temperature to high temperature and stabilizes. As a result, useless waiting time is generated, and the time required for the test is prolonged.

[0010] In addition, when removing the test object from the test tank or connecting the removed test object to the measuring instrument, there is a possibility that the test object may be damaged due to the operator's carelessness. In addition, since multiple test objects of the same type are tested simultaneously in the high-temperature reverse bias test, it is extremely inefficient to perform these operations manually. As a result, the time required for the test is further prolonged.

[0011] The present invention is made to solve the above-mentioned problems, and its object is to obtain a test device that can automatically switch and efficiently implement high voltage tests and current-voltage characteristic measurements on multiple test objects while avoiding damage to the test object caused by the operator's carelessness and the prolonged time required for high voltage tests.

[0012] Means for solving problems

[0013] A test device according to a first aspect of the present invention comprises: a first circuit for performing a high voltage test on a plurality of test objects; a second circuit for performing a current-voltage characteristic measurement on the plurality of test objects; and a control unit for controlling the first circuit and the second circuit, wherein the first circuit comprises: a first power supply for outputting a first voltage applied to the plurality of test objects during the high voltage test; and a plurality of first switching circuits for electrically connecting or disconnecting the first power supply and the plurality of test objects, and the second circuit comprises: a second power supply for outputting a second voltage applied to the plurality of test objects during the current-voltage characteristic measurement; and a plurality of second switching circuits for electrically connecting or disconnecting the second power supply and the plurality of test objects, wherein the first circuit and the second circuit comprise a plurality of channels, each of the plurality of channels corresponding to each of the plurality of test objects, and each of the channels comprises a first switching circuit among the plurality of first switching circuits and a second switching circuit among the plurality of second switching circuits.

[0014] According to the first embodiment, a high voltage test can be performed on a plurality of test objects through the first circuit, and a current-voltage characteristic measurement can be performed through the second circuit, so that it is not necessary to remove the test object from the test device for the current-voltage characteristic measurement, and to connect the removed test object to the measurement device. As a result, it is possible to automatically switch and efficiently perform the high voltage test and the current-voltage characteristic measurement on a plurality of test objects while avoiding damage to the test object due to the operator's carelessness and a prolonged time required for the high voltage test.

[0015] The test device according to the second aspect of the present invention may be configured such that, in the first aspect, the second circuit further includes a protection circuit connected between the second power supply and the plurality of second switching circuits to protect the second power supply from the first voltage.

[0016] According to the second aspect, the protection circuit can prevent the high first voltage from being applied to the second power supply via the test object and causing the second power supply to fail.

[0017] The test device involved in the third embodiment of the present invention may be a test device in the first or second embodiment, wherein the control unit controls the multiple first switching circuits to electrically connect the first power supply and the multiple test objects, and controls the multiple second switching circuits to electrically disconnect the second power supply and the multiple test objects when implementing the high voltage test; and controls the multiple first switching circuits to electrically disconnect the first power supply and the multiple test objects, and controls the multiple second switching circuits to electrically connect the second power supply and the multiple test objects when implementing the current-voltage characteristic measurement.

[0018] According to the third embodiment, by controlling the plurality of first switching circuits and the plurality of second switching circuits, the high voltage test and the current-voltage characteristic measurement can be appropriately implemented respectively. In addition, by controlling the plurality of first switching circuits and the plurality of second switching circuits, it is possible to appropriately prevent the second power supply from failing due to the implementation of the high voltage test and the first power supply from failing due to the implementation of the current-voltage characteristic measurement.

[0019] The test device involved in the fourth aspect of the present invention can be any one of the first to third aspects, wherein the control unit controls the first power supply to output the first voltage and controls the second power supply to not output the second voltage when implementing the high voltage test, and controls the first power supply to not output the first voltage and controls the second power supply to output the second voltage when implementing the current-voltage characteristic measurement.

[0020] According to the fourth aspect, by controlling the first power supply and the second power supply, it is possible to more reliably prevent the second power supply from failing due to the high voltage test and the first power supply from failing due to the current-voltage characteristic measurement.

[0021] The test device involved in the fifth embodiment of the present invention may be that in the third or fourth embodiment, the second power supply includes a second power supply shared by the multiple channels, and when implementing the current-voltage characteristic measurement, the control unit controls the multiple second switching circuits to electrically connect the multiple test objects to the one second power supply in sequence.

[0022] According to the fifth aspect, it is sufficient to install only one second power supply, so that the cost can be reduced.

[0023] The test device involved in the sixth aspect of the present invention may be in the third or fourth aspect, wherein the second power supply includes multiple second power supplies, and each channel also includes a second power supply among the multiple second power supplies. When implementing the current-voltage characteristic measurement, the control unit controls the multiple second switching circuits to electrically connect the multiple second power supplies and the multiple test objects in parallel.

[0024] According to the sixth aspect, the current-voltage characteristic measurement can be performed on a plurality of test objects in parallel, and thus the time required for the current-voltage characteristic measurement can be shortened.

[0025] The test device involved in the seventh embodiment of the present invention can be any one of the first to sixth embodiments, wherein each test object has a control electrode, and the first circuit also has: a third power supply, which outputs a third voltage applied to each of the control electrodes of the multiple test objects in the high voltage test; and a plurality of third switching circuits, which electrically connect or disconnect the third power supply and the control electrodes of the multiple test objects, and the second circuit also has: a fourth power supply, which outputs a fourth voltage applied to each of the control electrodes of the multiple test objects in the current-voltage characteristic measurement; and a plurality of fourth switching circuits, which electrically connect or disconnect the fourth power supply and the control electrodes of the multiple test objects, and each channel also includes a third switching circuit among the multiple third switching circuits and a fourth switching circuit among the multiple fourth switching circuits.

[0026] According to the seventh aspect, a semiconductor element having a control electrode such as a power transistor can be used as a test object. In addition, by controlling a plurality of third switching circuits and a plurality of fourth switching circuits, it is possible to appropriately prevent the fourth power supply from failing due to the implementation of the high voltage test and the third power supply from failing due to the implementation of the current-voltage characteristic measurement.

[0027] The test device involved in the eighth embodiment of the present invention may be that in the seventh embodiment, the third power supply includes multiple third power supplies, and each channel also includes a third power supply among the multiple third power supplies. When implementing the high voltage test, the control unit controls the multiple third switching circuits to electrically connect the multiple third power supplies and the control electrodes of the multiple test objects in parallel.

[0028] According to the eighth mode, a high voltage test can be performed on a plurality of test objects in parallel, thereby shortening the time required for the high voltage test. In addition, each channel includes a third power supply, so even if insulation breakdown occurs in a test object of a certain channel, a desired voltage can be reliably applied to the control electrode of the test object of another channel from the third power supply.

[0029] The test device involved in the ninth aspect of the present invention may be that in the seventh or eighth aspect, the fourth power supply includes a fourth power supply shared by the multiple channels, and when implementing the current-voltage characteristic measurement, the control unit controls the multiple fourth switching circuits to electrically connect the control electrodes of the multiple test objects in turn to the one fourth power supply.

[0030] According to the ninth aspect, it is sufficient to install only one fourth power supply, so the cost can be reduced.

[0031] The test device involved in the tenth aspect of the present invention may be in the seventh or eighth aspect, wherein the fourth power supply includes multiple fourth power supplies, and each channel also includes a fourth power supply among the multiple fourth power supplies. When implementing the current-voltage characteristic measurement, the control unit controls the multiple fourth switching circuits to electrically connect the multiple fourth power supplies and the control electrodes of the multiple test objects in parallel.

[0032] According to the tenth aspect, the current-voltage characteristic measurement can be performed on a plurality of test objects in parallel, and thus the time required for the current-voltage characteristic measurement can be shortened.

[0033] The test device according to the eleventh aspect of the present invention may be any one of the first to tenth aspects, further comprising: a test tank having an internal space in which the plurality of test objects are arranged, and controlling an environment of the internal space.

[0034] According to the eleventh aspect, by placing the test object in the test tank, environmental stress such as temperature stress can be applied to the test object. As a result, a high temperature reverse bias test can be performed using a power transistor or the like as the test object.

[0035] Effects of the Invention

[0036] According to the present invention, high voltage tests and current-voltage characteristic measurements on a plurality of test objects can be automatically switched and efficiently performed while avoiding damage to the test object due to operator's carelessness and prolonged time required for the high voltage test. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a diagram that simply shows the configuration of a test device according to an embodiment of the present invention.

[0038] Figure 2 This is a diagram that simply shows the configuration of a test device according to an embodiment of the present invention.

[0039] Figure 3This is a diagram that simply shows the configuration of a test device according to an embodiment of the present invention.

[0040] Figure 4 This is a diagram that simply shows the configuration of a test device according to an embodiment of the present invention.

[0041] Figure 5 This is a timing chart showing the relationship between the execution timing of the high voltage test or the current-voltage characteristic measurement and the temperature control of the internal space of the test tank.

[0042] Figure 6 This is a diagram showing in simplified form the configuration of a test device according to a modified example.

[0043] Figure 7 This is a diagram showing in simplified form the configuration of a test device according to another modified example. DETAILED DESCRIPTION

[0044] Hereinafter, the embodiments of the present invention will be described in detail using the drawings. In addition, elements denoted by the same reference numerals in different drawings represent the same or corresponding elements.

[0045] Figures 1 to 4 The test device is a simplified diagram showing the structure of a test device according to an embodiment of the present invention. The test device includes a first circuit 1 for performing a high voltage test on a test object SA, SB, a second circuit 2 for measuring current-voltage characteristics of the test object SA, SB, and a control unit 3 for controlling the first circuit 1 and the second circuit 2.

[0046] The control unit 3 is a microcontroller, a programmable logic controller, a general-purpose personal computer, or the like.

[0047] In the example of the present embodiment, only two test objects SA and SB are shown for simplicity of explanation, but the number of test objects SA and SB may be three or more.

[0048] The test objects SA and SB are, for example, semiconductor elements of the same type. The semiconductor element may also be a power transistor with three electrodes such as a power MOSFET, a bipolar transistor, or an IGBT. In the example of the present embodiment, the test objects SA and SB are N-channel power MOSFETs having three electrodes of a gate G, a source S, and a drain D. In addition, the semiconductor element may also be a thyristor with three electrodes. In addition, the semiconductor element may also be a high-voltage diode with two electrodes. In addition, the test objects SA and SB are not limited to semiconductor elements, but may also be coatings for vehicle-mounted equipment with insulating coatings applied on the metal surface, or ceramic joints, etc.

[0049] The high voltage test implemented by the first circuit 1 is a test for evaluating the durability or performance of the test object SA, SB by applying a high voltage to the test object SA, SB. The high voltage test includes a high temperature reverse bias test or a withstand voltage test. For example, in the high temperature reverse bias test, the time until the test object SA, SB breaks down is measured and recorded by continuously applying high temperature and high voltage stress to the test object SA, SB for a long time.

[0050] The current-voltage characteristic measurement implemented by the second circuit 2 includes a threshold voltage measurement, an on-resistance measurement, or an insulation breakdown voltage measurement, etc., for measuring the degree of degradation of the test objects SA and SB during the high voltage test. In the threshold voltage measurement, the drain voltage is fixed to a certain value, the gate voltage is scanned, and the drain current is measured, thereby measuring the threshold voltage. In the on-resistance measurement, the gate voltage is fixed to a certain value of the on-voltage, the drain current is scanned, the drain voltage is measured, and the on-resistance is measured. In the insulation breakdown voltage measurement, the gate voltage is fixed to a certain value of the off-voltage, the drain voltage is scanned, and the drain current is measured, thereby measuring the insulation breakdown voltage.

[0051] like Figure 4 As shown, the test apparatus includes a test tank 80. The test tank 80 has an internal space in which a plurality of test objects including test objects SA and SB are arranged. The plurality of test objects are accommodated in the internal space of the test tank 80, for example, in a state where they are fixed by a clamp (not shown) and the clamp is mounted on a rack (not shown). The control unit 3 controls the temperature of the internal space of the test tank 80 by configuring a heater 90 in the test tank 80. The heater 90 can control the temperature of the internal space of the test tank 80 to a high temperature of, for example, about 200 to 300°C. In addition, in addition to the heater 90, a cooler for cooling can also be configured in the internal space of the test tank 80. In addition, by configuring a humidifier and a dehumidifier in the internal space of the test tank 80, the humidity can be controlled in addition to the temperature.

[0052] like Figures 1 to 3 As shown, the first circuit 1 has a first power supply 11 and first switching circuits 21A, 21B. The first power supply 11 outputs a first voltage V1 which is a high voltage applied to the drain D of the test object SA, SB in a high voltage test. The first switching circuit 21A electrically connects or disconnects the positive electrode of the first power supply 11 and the drain D of the test object SA, and the first switching circuit 21B electrically connects or disconnects the positive electrode of the first power supply 11 and the drain D of the test object SB. The first switching circuits 21A, 21B are configured using mechanical relays or semiconductor relays.

[0053] The second circuit 2 includes a second power supply 12 and second switching circuits 22A and 22B. The second power supply 12 outputs a second voltage V2 applied to the drain D of the test object SA and SB during the current-voltage characteristic measurement. The second switching circuit 22A electrically connects or disconnects the positive electrode of the second power supply 12 and the drain D of the test object SA, and the second switching circuit 22B electrically connects or disconnects the positive electrode of the second power supply 12 and the drain D of the test object SB. The second switching circuits 22A and 22B are configured using mechanical relays or semiconductor relays.

[0054] In addition, the first circuit 1 has third power supplies 13A, 13B and third switching circuits 23A, 23B. The third power supply 13A outputs a third voltage V3 applied to the gate G of the test object SA in the high voltage test, and the third power supply 13B outputs a third voltage V3 applied to the gate G of the test object SB in the high voltage test. The third switching circuit 23A electrically connects or disconnects the negative electrode of the third power supply 13A and the gate G of the test object SA, and the third switching circuit 23B electrically connects or disconnects the negative electrode of the third power supply 13B and the gate G of the test object SB. The third switching circuits 23A, 23B are configured using mechanical relays, semiconductor relays, or the like.

[0055] In addition, the second circuit 2 has a fourth power supply 14 and fourth switching circuits 24A and 24B. The fourth power supply 14 outputs a fourth voltage V4 to be applied to the gate G of the test object SA and SB in the current-voltage characteristic measurement. The fourth switching circuit 24A electrically connects or disconnects the positive electrode of the fourth power supply 14 and the gate G of the test object SA, and the fourth switching circuit 24B electrically connects or disconnects the positive electrode of the fourth power supply 14 and the gate G of the test object SB. The fourth switching circuits 24A and 24B are configured using mechanical relays or semiconductor relays.

[0056] In addition, the first circuit 1 has ammeters 41A, 41B, 43A, 43B, and the second circuit 2 has an ammeter 44. The ammeter 41A is connected between the first power supply 11 and the first switching circuit 21A. The ammeter 41B is connected between the first power supply 11 and the first switching circuit 21B. The ammeter 43A is connected between the third power supply 13A and the third switching circuit 23A. The ammeter 43B is connected between the third power supply 13B and the third switching circuit 23B. The ammeter 44 is connected between the fourth power supply 14 and the fourth switching circuits 24A, 24B.

[0057] In addition, the second circuit 2 has protection circuits 31A and 31B. The protection circuit 31A is connected between the gate G of the test object SA and the third switching circuit 23A and the fourth switching circuit 24A. The protection circuit 31B is connected between the gate G of the test object SB and the third switching circuit 23B and the fourth switching circuit 24B.

[0058] In addition, the second circuit 2 includes fifth switching circuits 25A, 25B, sixth switching circuits 26A, 26B, protection circuits 32, 33, an ammeter 42, and a voltmeter 51. The fifth switching circuit 25A is connected between the drain D of the test object SA and the protection circuit 33, and the fifth switching circuit 25B is connected between the drain D of the test object SB and the protection circuit 33. The sixth switching circuit 26A is connected between the source S of the test object SA and the voltmeter 51, and the sixth switching circuit 26B is connected between the source S of the test object SB and the voltmeter 51. The protection circuit 32 is connected between the second switching circuits 22A, 22B and the ammeter 42, and the protection circuit 33 is connected between the fifth switching circuits 25A, 25B and the voltmeter 51. The ammeter 42 is connected between the protection circuit 32 and the positive electrode of the second power supply 12. The voltmeter 51 is connected between the protection circuit 33 and the sixth switching circuits 26A, 26B. The fifth switching circuits 25A and 25B and the sixth switching circuits 26A and 26B are configured using mechanical relays, semiconductor relays, or the like.

[0059] The protection circuits 31A, 31B, 32, and 33 have an overcurrent limiting function and an overvoltage limiting function, and protect the circuit elements from sudden surge currents and surge voltages. The protection circuit 32 protects the second power supply 12 and the ammeter 42 from surge currents and surge voltages caused by the first voltage V1 of the high voltage, and the protection circuit 33 protects the voltmeter 51 from surge currents and surge voltages caused by the first voltage V1 of the high voltage. The protection circuit 31A protects the fourth power supply 14 and the ammeter 44 from surge currents and surge voltages caused by the first voltage V1, and protects the third power supply 13A and the ammeter 43A from surge currents and surge voltages caused by the second voltage V2. The protection circuit 31B protects the fourth power supply 14 and the ammeter 44 from surge currents and surge voltages caused by the first voltage V1, and protects the third power supply 13B and the ammeter 43B from surge currents and surge voltages caused by the second voltage V2.

[0060] The test device is connected to the test objects SA and SB, and has a plurality of channels CH for performing high voltage tests and current-voltage characteristic measurements on the test objects SA and SB. Specifically, the first circuit 1 and the second circuit 2 have a plurality of channels CHA and CHB, and each channel CH of the plurality of channels CHA and CHB corresponds to each of the plurality of test objects SA and SB.

[0061] The channel CHA corresponding to the test object SA includes the first switching circuit 21A, the second switching circuit 22A, the third switching circuit 23A, the fourth switching circuit 24A, the fifth switching circuit 25A, the sixth switching circuit 26A, the ammeters 41A and 43A, the protection circuit 31A, and the third power supply 13A. The channel CHB corresponding to the test object SB includes the first switching circuit 21B, the second switching circuit 22B, the third switching circuit 23B, the fourth switching circuit 24B, the fifth switching circuit 25B, the sixth switching circuit 26B, the ammeters 41B and 43B, the protection circuit 31B, and the third power supply 13B.

[0062] The control unit 3 controls the first power supply 11, the second power supply 12, the third power supply 13A, 13B, the fourth power supply 14, the first switching circuit 21A, 21B, the second switching circuit 22A, 22B, the third switching circuit 23A, 23B, the fourth switching circuit 24A, 24B, the fifth switching circuit 25A, 25B and the sixth switching circuit 26A, 26B.

[0063] Figure 1 , a control example for the case of implementing a high voltage test on the test objects SA and SB is shown. Figure 2 , a control example of the case where the current-voltage characteristic measurement of the test object SA is performed is shown. Figure 3 , a control example is shown when the current-voltage characteristic measurement of the test object SB is performed.

[0064] like Figure 1 As shown, when implementing a high voltage test on the test objects SA, SB, the control unit 3 connects the first power supply 11, disconnects the second power supply 12, connects the third power supplies 13A, 13B, disconnects the fourth power supply 14, connects the first switching circuit 21A, 21B, disconnects the second switching circuit 22A, 22B, connects the third switching circuit 23A, 23B, disconnects the fourth switching circuit 24A, 24B, disconnects the fifth switching circuit 25A, 25B, and disconnects the sixth switching circuit 26A, 26B.

[0065] As a result, the first power supply 11 outputs the first voltage V1, the second power supply 12 does not output the second voltage V2, the third power supplies 13A and 13B output the third voltage V3, and the fourth power supply 14 does not output the fourth voltage V4. In addition, the first switching circuits 21A and 21B are in an electrically connected state, the second switching circuits 22A and 22B are in an electrically disconnected state, the third switching circuits 23A and 23B are in an electrically connected state, the fourth switching circuits 24A and 24B are in an electrically disconnected state, the fifth switching circuits 25A and 25B are in an electrically disconnected state, and the sixth switching circuits 26A and 26B are in an electrically disconnected state.

[0066] A high voltage test is performed on the test objects SA and SB by applying the high voltage first voltage V1 to the drain D in a state where the gate G is reverse biased by the third voltage V3 .

[0067] like Figure 2 As shown, when implementing the current-voltage characteristic measurement of the test object SA, the control unit 3 disconnects the first power supply 11, connects the second power supply 12, disconnects the third power supplies 13A, 13B, connects the fourth power supply 14, disconnects the first switching circuit 21A, 21B, connects the second switching circuit 22A, disconnects the second switching circuit 22B, disconnects the third switching circuit 23A, 23B, connects the fourth switching circuit 24A, disconnects the fourth switching circuit 24B, connects the fifth switching circuit 25A, disconnects the fifth switching circuit 25B, connects the sixth switching circuit 26A, and disconnects the sixth switching circuit 26B.

[0068] As a result, the first power supply 11 does not output the first voltage V1, the second power supply 12 outputs the second voltage V2, the third power supplies 13A and 13B do not output the third voltage V3, and the fourth power supply 14 outputs the fourth voltage V4. In addition, the first switching circuits 21A and 21B are in an electrically disconnected state, the second switching circuit 22A is in an electrically connected state, the second switching circuit 22B is in an electrically disconnected state, the third switching circuits 23A and 23B are in an electrically disconnected state, the fourth switching circuit 24A is in an electrically connected state, the fourth switching circuit 24B is in an electrically disconnected state, the fifth switching circuit 25A is in an electrically connected state, the fifth switching circuit 25B is in an electrically disconnected state, the sixth switching circuit 26A is in an electrically connected state, and the sixth switching circuit 26B is in an electrically disconnected state.

[0069] For example, in the threshold voltage measurement, a voltage of a certain value is applied to the drain D of the test object SA through the second voltage V2, and the voltage of the gate G of the test object SA is scanned by the fourth voltage V4. The current of the drain D of the test object SA is measured by the ammeter 42, thereby measuring the threshold voltage of the test object SA.

[0070] In addition, the sixth switching circuit 26B is disconnected in order to disconnect three of the four terminals of the test object SB in the four-terminal method when switching to the test object SA. The path including the voltmeter 51 has a smaller current value than the path including the second power supply 12. Therefore, by configuring the sixth switching circuit 26B in the path including the voltmeter 51, the degree of freedom of selecting elements related to the sixth switching circuit 26B is increased compared to the case where the sixth switching circuit 26B is configured in the path including the voltmeter 51.

[0071] like Figure 3 As shown, when implementing the current-voltage characteristic measurement of the test object SB, the control unit 3 disconnects the first power supply 11, connects the second power supply 12, disconnects the third power supplies 13A, 13B, connects the fourth power supply 14, disconnects the first switching circuit 21A, 21B, disconnects the second switching circuit 22A, connects the second switching circuit 22B, disconnects the third switching circuit 23A, 23B, disconnects the fourth switching circuit 24A, connects the fourth switching circuit 24B, disconnects the fifth switching circuit 25A, connects the fifth switching circuit 25B, disconnects the sixth switching circuit 26A, and connects the sixth switching circuit 26B.

[0072] As a result, the first power supply 11 does not output the first voltage V1, the second power supply 12 outputs the second voltage V2, the third power supplies 13A and 13B do not output the third voltage V3, and the fourth power supply 14 outputs the fourth voltage V4. In addition, the first switching circuits 21A and 21B are in an electrically disconnected state, the second switching circuit 22A is in an electrically disconnected state, the second switching circuit 22B is in an electrically connected state, the third switching circuits 23A and 23B are in an electrically disconnected state, the fourth switching circuit 24A is in an electrically disconnected state, the fourth switching circuit 24B is in an electrically connected state, the fifth switching circuit 25A is in an electrically disconnected state, the fifth switching circuit 25B is in an electrically connected state, the sixth switching circuit 26A is in an electrically disconnected state, and the sixth switching circuit 26B is in an electrically connected state.

[0073] For example, in the threshold voltage measurement, a voltage of a certain value is applied to the drain D of the test object SB through the second voltage V2, and the voltage of the gate G of the test object SB is scanned by the fourth voltage V4. The current of the drain D of the test object SB is measured by the ammeter 42, thereby measuring the threshold voltage of the test object SB.

[0074] In addition, the sixth switching circuit 26A is disconnected in order to disconnect three of the four terminals of the test object SA in the four-terminal method when switching to the test object SB. The path including the voltmeter 51 has a smaller current value than the path including the second power supply 12. Therefore, by configuring the sixth switching circuit 26A in the path including the voltmeter 51, the degree of freedom of selecting elements related to the sixth switching circuit 26A is increased compared to the case where the sixth switching circuit 26A is configured in the path including the voltmeter 51.

[0075] Figure 5 This is a timing chart showing the relationship between the execution timing of the high voltage test or the current-voltage characteristic measurement and the temperature control of the internal space of the test tank 80 .

[0076] At time T0, the control unit 3 performs the first current-voltage characteristic measurement X0. At time T0, the temperature of the internal space of the test tank 80 is a normal temperature K0. In the current-voltage characteristic measurement X0, the control unit 3 sequentially performs the current-voltage characteristic measurement on the test objects SA and SB.

[0077] At time T1 , the control unit 3 controls the heater 90 to start raising the temperature of the internal space of the test tank 80 .

[0078] At time T2, the temperature of the internal space of the test tank 80 rises to the target temperature K1.

[0079] At time T3 , when a predetermined time has passed since time T2 and the temperature of the internal space of the test tank 80 has stabilized at the target temperature K1 , the control unit 3 causes the first power supply 11 to start increasing the output voltage.

[0080] At time T4, when the output voltage of the first power supply 11 rises to the first voltage V1, the control unit 3 starts the implementation of the high voltage test and starts the accumulation of the test time.

[0081] If the timing for the current-voltage characteristic measurement is reached, at time T5, the control unit 3 stops accumulating the test time of the high voltage test while disconnecting the first power supply 11. The control unit 3 stores the cumulative value P1 of the test time from time T4 to time T5. In addition, the timing for the current-voltage characteristic measurement may be a fixed time interval or a time interval that varies according to the degree of degradation of the test objects SA and SB.

[0082] At time T6, the control unit 3 performs the second current-voltage characteristic measurement X1. At time T6, the temperature of the internal space of the test tank 80 is maintained at the target temperature K1. In the current-voltage characteristic measurement X1, the control unit 3 sequentially performs the current-voltage characteristic measurement on the test objects SA and SB.

[0083] When the second current-voltage characteristic measurement X1 is completed, at time T7 , the control unit 3 causes the first power supply 11 to start increasing the output voltage again.

[0084] At time T8, when the output voltage of the first power supply 11 rises to the first voltage V1 again, the control unit 3 starts accumulating the test time of the high voltage test again.

[0085] When the next execution timing of the current-voltage characteristic measurement comes, the control unit 3 turns off the first power supply 11 at time T9 and stops the accumulation of the test time of the high voltage test. The control unit 3 stores the accumulated value P2 of the test time from time T8 to time T9.

[0086] At time T10, the control unit 3 performs the third current-voltage characteristic measurement X2. At time T10, the temperature of the internal space of the test tank 80 is maintained at the target temperature K1. In the current-voltage characteristic measurement X20, the control unit 3 sequentially performs the current-voltage characteristic measurement on the test objects SA and SB.

[0087] The control unit 3 repeatedly executes the same processing as described above until the total of the integrated values ​​P1, P2, . . . , Pn of the test time of the high voltage test reaches the target test time.

[0088] At time T14 , the control unit 3 stops driving the heater 90 to start lowering the temperature of the internal space of the test tank 80 .

[0089] At time T15, the temperature of the internal space of the test tank 80 drops to room temperature K0.

[0090] At time T16, when a predetermined waiting time has elapsed since time T15, the control unit 3 performs the final current-voltage characteristic measurement Xn+1. In the current-voltage characteristic measurement Xn+1, the control unit 3 sequentially performs the current-voltage characteristic measurement on the test objects SA and SB.

[0091] in addition, Figure 5 The timing chart shown is an example, and the timing of measuring the current-voltage characteristics is not limited to Figure 5 For example, the current-voltage characteristic measurement may be added between time T2 and time T3.

[0092] According to the test device according to the present embodiment, a high voltage test can be performed on a plurality of test objects SA, SB through the first circuit 1, and a current-voltage characteristic measurement can be performed through the second circuit 2, so that it is not necessary to remove the test objects SA, SB from the test device for the current-voltage characteristic measurement, and to connect the removed test objects SA, SB to the measuring device. As a result, it is possible to automatically switch and efficiently perform the high voltage test and the current-voltage characteristic measurement on a plurality of test objects SA, SB while avoiding damage to the test objects SA, SB due to the operator's carelessness and a prolonged time required for the high voltage test.

[0093] Furthermore, according to the test apparatus according to the present embodiment, the protection circuit 32 can prevent the high first voltage V1 from being applied to the second power supply 12 via the test objects SA and SB, thereby preventing the second power supply 12 from malfunctioning.

[0094] Furthermore, according to the test device involved in this embodiment, by controlling the plurality of first switching circuits 21A, 21B and the plurality of second switching circuits 22A, 22B, it is possible to appropriately implement the high voltage test and the current-voltage characteristic measurement, respectively. Furthermore, by controlling the plurality of first switching circuits 21A, 21B and the plurality of second switching circuits 22A, 22B, it is possible to appropriately prevent the second power supply 12 from malfunctioning due to the implementation of the high voltage test and the first power supply 11 from malfunctioning due to the implementation of the current-voltage characteristic measurement.

[0095] Furthermore, according to the test apparatus of this embodiment, by controlling the first power supply 11 and the second power supply 12, it is possible to more reliably prevent the second power supply 12 from failing due to the high voltage test and the first power supply 11 from failing due to the current-voltage characteristic measurement.

[0096] Furthermore, according to the test apparatus according to the present embodiment, when the current-voltage characteristic measurement is performed, the control unit 3 controls the plurality of second switching circuits 22A and 22B to sequentially electrically connect the plurality of test objects SA and SB to the one second power supply 12. Thus, it is sufficient to install only one second power supply 12, and thus it is possible to reduce costs.

[0097] Furthermore, according to the test device according to the present embodiment, a semiconductor element having a gate G (control electrode) such as a power transistor can be used as the test object SA, SB. Furthermore, by controlling the plurality of third switching circuits 23A, 23B and the plurality of fourth switching circuits 24A, 24B, it is possible to appropriately prevent the fourth power supply 14 from malfunctioning due to the implementation of the high voltage test and the third power supply 13A, 13B from malfunctioning due to the implementation of the current-voltage characteristic measurement.

[0098] Furthermore, according to the test device according to the present embodiment, when a high voltage test is performed, the control unit 3 controls the plurality of third switching circuits 23A, 23B to electrically connect the plurality of third power supplies 13A, 13B and the gates G of the plurality of test objects SA, SB simultaneously and in parallel. Thus, the high voltage test can be performed on the plurality of test objects SA, SB simultaneously and in parallel, and thus the time required for the high voltage test can be shortened. Furthermore, since each channel CH includes the third power supplies 13A, 13B, even when the test object SA of a certain channel CHA has insulation breakdown, the desired voltage can be reliably applied from the third power supply 13B to the gate G of the test object SB of the other channel CHB.

[0099] Furthermore, according to the test apparatus according to the present embodiment, when the current-voltage characteristic measurement is performed, the control unit 3 controls the plurality of fourth switching circuits 24A and 24B to sequentially electrically connect the gates G of the plurality of test objects SA and SB to one fourth power supply 14. Thus, it is sufficient to install only one fourth power supply 14, and thus it is possible to reduce costs.

[0100] Furthermore, according to the test apparatus of this embodiment, environmental stress such as temperature stress can be applied to the test objects SA and SB by placing the test objects SA and SB in the test tank 80. As a result, a high temperature reverse bias test can be performed using power transistors and the like as the test objects SA and SB.

[0101] <Modification>

[0102] Figure 6: is a diagram showing a simplified structure of a test device according to a modification. In this modification, the test objects SA and SB are high voltage diodes having two electrodes, an anode A and a cathode K. When a high voltage test is performed on the test objects SA and SB, the control unit 3 turns on the first power supply 11, turns off the second power supply 12, turns on the first switching circuit 21A and 21B, turns off the second switching circuit 22A and 22B, turns off the fifth switching circuit 25A and 25B, and turns off the sixth switching circuit 26A and 26B. When a current-voltage characteristic measurement is performed on the test object SA, the control unit 3 turns off the first power supply 11, turns on the second power supply 12, turns off the first switching circuit 21A and 21B, turns on the second switching circuit 22A, turns off the second switching circuit 22B, turns on the fifth switching circuit 25A, turns off the fifth switching circuit 25B, turns on the sixth switching circuit 26A, and turns off the sixth switching circuit 26B. When the current-voltage characteristic measurement is performed on the test object SB, the control unit 3 disconnects the first power supply 11, connects the second power supply 12, disconnects the first switching circuit 21A, 21B, disconnects the second switching circuit 22A, connects the second switching circuit 22B, disconnects the fifth switching circuit 25A, connects the fifth switching circuit 25B, disconnects the sixth switching circuit 26A, and connects the sixth switching circuit 26B. In this way, even for the test objects SA and SB having two electrodes, the high voltage test and the current-voltage characteristic measurement can be switched. The same is true for the case of more than three channels.

[0103] Figure 7 2 is a simplified diagram showing the structure of a test device according to another modified example. In the above embodiment, the test objects SA and SB are connected to the ammeter 42 and the voltmeter 51 by a four-terminal method, but the present invention is not limited to this example. Figure 7 As shown, the following structure can also be set: the protection circuit 32 and the second switching circuit 22A, 22B are omitted from the structure of the embodiment, and the ammeter 42 and the second power supply 12 are connected between the protection circuit 33 and the sixth switching circuit 26A, 26B, thereby connecting each test object SA, SB and the ammeter 42 and the voltmeter 51 through a two-terminal method.

[0104] In addition, in the above-mentioned embodiment, only one second power supply 12 is installed for the two channels CHA and CHB, but two second power supplies 12 may be installed to correspond to the two channels CHA and CHB. In this case, each channel CHA and CHB includes an independent second power supply 12, and when the current-voltage characteristic measurement is performed, the control unit 3 controls the plurality of second switching circuits 22A and 22B to electrically connect the plurality of second power supplies 12 and the plurality of test objects SA and SB in parallel at the same time. Thus, the current-voltage characteristic measurement can be performed on the plurality of test objects SA and SB in parallel at the same time, so that the time required for the current-voltage characteristic measurement can be shortened. The same is true for the case of three or more channels.

[0105] Similarly, in the above-mentioned embodiment, only one fourth power supply 14 is installed for the two channels CHA and CHB, but two fourth power supplies 14 may be installed to correspond to the two channels CHA and CHB. In this case, each channel CHA and CHB includes an independent fourth power supply 14, and when the current-voltage characteristic measurement is performed, the control unit 3 controls the plurality of fourth switching circuits 24A and 24B to electrically connect the plurality of fourth power supplies 14 and the plurality of test objects SA and SB in parallel at the same time. Thus, the current-voltage characteristic measurement can be performed on the plurality of test objects SA and SB in parallel at the same time, so that the time required for the current-voltage characteristic measurement can be shortened. The same is true for the case of more than three channels.

[0106] In addition, in the above-mentioned embodiment, for example, for the test object SA, when a high voltage test is performed, the first power supply 11 and the first switching circuit 21A are turned on, and the second power supply 12 and the second switching circuit 22A are turned off. When the current-voltage characteristic measurement is performed, the first power supply 11 and the first switching circuit 21A are turned off, and the second power supply 12 and the second switching circuit 22A are turned on. As a first modification, when a high voltage test is performed, the first power supply 11 and the first switching circuit 21A are turned on, the second power supply 12 is turned off, and the second switching circuit 22A is turned on. When the current-voltage characteristic measurement is performed, the first power supply 11 is turned off, the first switching circuit 21A is turned on, and the second power supply 12 and the second switching circuit 22A are turned on. As a second modification, when a high voltage test is performed, the first power supply 11 and the first switching circuit 21A are turned on, the second power supply 12 is turned off, and the second switching circuit 22A is turned on. When the current-voltage characteristic measurement is performed, the first power supply 11 and the first switching circuit 21A are turned off, and the second power supply 12 and the second switching circuit 22A are turned on. As a third modified example, when a high voltage test is performed, the first power supply 11 and the first switching circuit 21A are turned on, and the second power supply 12 and the second switching circuit 22A are turned off, and when a current-voltage characteristic measurement is performed, the first power supply 11 is turned off, the first switching circuit 21A is turned on, and the second power supply 12 and the second switching circuit 22A are turned on. The same is true for other test objects SB and the like.

[0107] [Explanation of symbols]

[0108] 1 first circuit; 2 second circuit; 3 control unit; 11 first power supply; 12 second power supply; 13A, 13B third power supply; 14 fourth power supply; 21A, 21B first switching circuit; 22A, 22B second switching circuit; 23A, 23B third switching circuit; 24A, 24B fourth switching circuit; 32 protection circuit; 80 test slot.

Claims

1. A test device comprising: A first circuit performs a high voltage test on a plurality of test objects; a second circuit for measuring current-voltage characteristics of the plurality of test objects; and a control unit, controlling the first circuit and the second circuit, The first circuit has: a first power supply that outputs a first voltage to be applied to the plurality of test objects in the high voltage test; as well as a plurality of first switching circuits for electrically connecting or disconnecting the first power source and the plurality of test objects; The second circuit has: a second power supply that outputs a second voltage to be applied to the plurality of test objects during the current-voltage characteristic measurement; as well as a plurality of second switching circuits for electrically connecting or disconnecting the second power source and the plurality of test objects; The first circuit and the second circuit have a plurality of channels, each of the plurality of channels corresponds to each of the plurality of test objects. Each channel includes a first switching circuit among the plurality of first switching circuits and a second switching circuit among the plurality of second switching circuits.

2. The test device according to claim 1, wherein: The second circuit also has: A protection circuit is connected between the second power supply and the plurality of second switching circuits, and protects the second power supply from being affected by the first voltage.

3. The test device according to claim 1, wherein: When implementing the high voltage test, The control unit controls the plurality of first switching circuits to electrically connect the first power source and the plurality of test objects. The control unit controls the plurality of second switching circuits to electrically disconnect the second power source from the plurality of test objects. When the current-voltage characteristic measurement is performed, The control unit controls the plurality of first switching circuits to electrically disconnect the first power source from the plurality of test objects. The control unit controls the plurality of second switching circuits to electrically connect the second power source and the plurality of test objects.

4. The test device according to claim 1, wherein: When implementing the high voltage test, The control unit controls the first power supply to output the first voltage, The control unit controls the second power supply so as not to output the second voltage, When the current-voltage characteristic measurement is performed, The control unit controls the first power supply so as not to output the first voltage, The control unit controls the second power supply to output the second voltage.

5. The test device according to claim 3, wherein: The second power supply includes a second power supply shared by the plurality of channels. When the current-voltage characteristic measurement is performed, the control unit controls the plurality of second switching circuits so as to electrically connect the plurality of test objects to the one second power supply in sequence.

6. The test device according to claim 3, wherein: The second power source includes a plurality of second power sources, Each channel further comprises a second power source among the plurality of second power sources, When the current-voltage characteristic measurement is performed, the control unit controls the plurality of second switching circuits so as to electrically connect the plurality of second power supplies and the plurality of test objects in parallel.

7. The test device according to claim 1, wherein: Each of the test objects has a control electrode, The first circuit also has: a third power supply that outputs a third voltage to be applied to each of the control electrodes of the plurality of test objects in the high voltage test; as well as a plurality of third switching circuits for electrically connecting or disconnecting the third power supply and the control electrodes of the plurality of test objects; The second circuit also has: a fourth power supply that outputs a fourth voltage to be applied to each of the control electrodes of the plurality of test objects during the current-voltage characteristic measurement; as well as a plurality of fourth switching circuits for electrically connecting or disconnecting the fourth power supply and the control electrodes of the plurality of test objects; Each channel further includes a third switching circuit among the plurality of third switching circuits and a fourth switching circuit among the plurality of fourth switching circuits.

8. The test device according to claim 7, wherein: The third power source includes a plurality of third power sources, Each channel further comprises a third power source among the plurality of third power sources, When the high voltage test is performed, the control unit controls the plurality of third switching circuits so as to electrically connect the plurality of third power supplies and the respective control electrodes of the plurality of test objects in parallel.

9. The test device according to claim 7, wherein: The fourth power supply includes a fourth power supply shared by the plurality of channels, When the current-voltage characteristic measurement is performed, the control unit controls the plurality of fourth switching circuits so as to electrically connect the control electrodes of the plurality of test objects to the one fourth power supply in sequence.

10. The test device according to claim 7, wherein: The fourth power source includes a plurality of fourth power sources, Each channel further comprises a fourth power source among the plurality of fourth power sources, When the current-voltage characteristic measurement is performed, the control unit controls the plurality of fourth switching circuits so as to electrically connect the plurality of fourth power supplies and the respective control electrodes of the plurality of test objects in parallel.

11. The test device according to any one of claims 1 to 10, wherein: The test device also has: The test tank has an internal space in which the plurality of test objects are arranged, and controls the environment of the internal space.

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