JP2017120838A - Junction temperature specification device and junction temperature specification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calculate a failure junction temperature that is a junction temperature at failures.SOLUTION: A junction temperature specification device comprises: an ambient temperature controller 3 that controls an ambient temperature of a semiconductor device having a junction; a local heating controller 4 that gives a heat quantity for the purpose of locally heating the semiconductor device, at the ambient temperature; a measurement unit that measures characteristics of the junction of the semiconductor device; a failure determination unit 15 that determines failures of the semiconductor device from the characteristics of the junction at the plurality of ambient temperatures; and a failure junction temperature specification unit that specifies an ambient temperature at which the heat quantity becomes zero as a failure junction temperature, from a correlation between the heat quantity and the ambient temperature in a case where it is determined that the semiconductor device has failures.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique for obtaining a junction temperature of a semiconductor device.

  When the semiconductor device is operated, a junction (hereinafter referred to as a junction) inside the semiconductor device generates heat and the temperature rises. As semiconductor devices have higher densities and higher powers, the failure of semiconductor devices due to the junction temperature exceeding an allowable value has become a problem. Therefore, as a method of estimating the junction temperature, the relationship between the current flowing through the junction as described in Patent Document 1 and the ambient temperature is obtained, and this corresponds to the junction current when the internal temperature becomes a steady state. A method has been proposed in which the ambient temperature is obtained from the above relationship and is estimated as the junction temperature.

JP 2004-245756 A

  In patent document 1, although the junction temperature at the time of operation | movement can be estimated, the junction temperature at the time of a failure cannot be specified. In general, the maximum operable temperature of a semiconductor device is set by a semiconductor device manufacturer by subtracting a margin from the failure temperature of the most heat-sensitive structure (for example, sealing resin) in the semiconductor device. It does not focus on the temperature of the device, and does not specify the junction temperature at the time of failure. An object of this invention is to obtain | require the failure junction temperature which is the junction temperature at the time of failure.

  In order to solve the above problems, an ambient temperature control unit 3 that controls the ambient temperature of a semiconductor device having a junction, a local heating control unit 4 that applies heat to locally heat the semiconductor device at the ambient temperature, and a semiconductor A measurement unit that measures the junction characteristics of the device, a failure determination unit 15 that determines a failure of the semiconductor device from the junction characteristics at a plurality of ambient temperatures, and an amount of heat and an ambient temperature when the semiconductor device is determined to be failed And a failure junction temperature specifying unit 16 that specifies an ambient temperature at which the amount of heat becomes 0 as a failure junction temperature.

  According to the present invention, a failure junction temperature of a semiconductor device can be obtained.

It is a block diagram which shows the structure of the junction temperature specific device of the semiconductor device by Embodiment 1 of this invention. It is a figure which shows an example of the electrical state supplied to a terminal from the local heating control part in Embodiment 1 of this invention. It is a figure which shows the general voltage-current characteristic of a semiconductor device. It is a figure which shows an example of the electrical property of the semiconductor device of a normal state and a failure state. It is a figure which shows the relationship between the ambient temperature at the time of a failure, and instantaneous input electric power in Embodiment 1 of this invention. It is a block diagram which shows the structure of the junction temperature specific device of the semiconductor device by Embodiment 2 of this invention. It is a figure which shows an example of the electrical state supplied to the terminal from the waveform of the pulse laser beam irradiated to a to-be-measured semiconductor device from the laser control part in Embodiment 2 of this invention to a terminal. It is a figure which shows the relationship between the ambient temperature at the time of a failure, and instantaneous laser beam intensity | strength in Embodiment 2 of this invention. It is a block diagram which shows the structure of the junction temperature of a semiconductor device and failure junction temperature specific | specification apparatus by Embodiment 3 of this invention. It is a figure which shows an example of the scanning of the laser scanning light irradiated to a to-be-measured semiconductor device from the laser scanning part in Embodiment 3 of this invention. It is a figure which shows the relationship between the ambient temperature at the time of a failure, and instantaneous laser scanning light intensity | strength in Embodiment 3 of this invention.

Embodiment 1
FIG. 1 is a block diagram showing a configuration of a junction temperature specifying device 1 for a semiconductor device according to Embodiment 1 of the present invention. Referring to FIG. 1, a semiconductor device junction temperature specifying device 1 locally heats an ambient temperature control unit 3 that controls the ambient temperature of a semiconductor device 2 to be measured and an arbitrary region of the semiconductor device 2 to be measured. And a measurement unit 5 that monitors the applied voltage and the applied current for determining the failure of the semiconductor device 2 to be measured and measures the junction characteristics of the semiconductor device. Further, the amount of heat becomes 0 based on the correlation between the failure determination unit 15 that determines whether or not the semiconductor device has failed and the junction characteristics of the semiconductor device and the amount of heat when it is determined that the semiconductor device has failed. A failure junction temperature specifying unit 16 that specifies the ambient temperature as a failure junction temperature that is a failure junction temperature is provided.

  In this embodiment, as an example, the semiconductor device 2 to be measured is a diode, and includes two terminals 201 and 202 respectively connected to PN junctions in the semiconductor device. The terminal 201 is an anode connected to a P-type semiconductor, and the terminal 202 is a cathode connected to an N-type semiconductor. This embodiment can also be applied to an IC that is more complicated than a diode. Here, the junction is not limited to the PN junction, and any semiconductor device having a junction may be used. A PN junction refers to a junction between a P-type semiconductor and an N-type semiconductor, but a junction is not limited to this, and refers to a portion where semiconductors or semiconductors and metals are joined.

  The ambient temperature control unit 3 allows the ambient temperature of the semiconductor device 2 to be measured to be arbitrarily set, and keeps the steady state (including the PN junction portion of the semiconductor device 2 to be measured) at 25 ° C., for example. In the present embodiment, the local heating control unit 4 applies a pulse voltage and current to the terminals 201 and 202 of the semiconductor device 2 to be measured, and changes the pulse width and period, thereby increasing the temperature due to heat generation at the PN junction. A method of changing the area arbitrarily is used.

  The ambient temperature control unit 3 can arbitrarily change the voltage or current supplied to the terminals 201 and 202 of the semiconductor device 2 to be measured, and generally supplies a rectangular wave. A sine wave or a triangular wave may be used. Moreover, although the local heating control part 4 shall apply a pulse-form voltage and a voltage, it is not limited to this, What is necessary is given if it provides calorie | heat amount.

  For example, in the case of a rectangular wave, the voltage and current of the lower terminal and the voltage, current, pulse width, period, and cycle number of the upper terminal can be arbitrarily set. Here, the upper terminal refers to the terminal 201, and the lower terminal refers to the terminal 202. In the present embodiment, the local heating control unit 4 supplies a rectangular wave voltage or current to the terminal 201 and supplies a constant voltage of 0 V to the terminal 202. The voltage or current (first electrical state) of the upper terminal of the rectangular wave is for increasing the junction temperature of the semiconductor device 2 to be measured, and the voltage and current (second electrical state) of the lower terminal is to be measured. This is for determining the failure of the semiconductor device 2. Supply voltage or current to the semiconductor device to heat it, and instantaneously apply the current or voltage for failure determination to check if there is a failure. A heating current or voltage is applied. When failure determination is performed using the voltage and current of the upper terminal, the voltage and current of the lower terminal may be zero.

  FIG. 2 is an example of an electrical state supplied from the local heating control unit 4 to the terminals 201 and 202. In FIG. 2A, the vertical axis represents voltage, and the horizontal axis represents time. In FIG. 2B, the vertical axis represents current, and the horizontal axis represents time. In the present embodiment, the local heating control unit 4 performs measurement with constant current control in FIG. 2A and constant voltage control in FIG. 2B.

  FIG. 3 shows a general voltage-current characteristic of a semiconductor device. The horizontal axis represents voltage and the vertical axis represents current. A semiconductor device having a PN junction has a property that current rapidly increases when an applied voltage exceeds a threshold (Vth). Therefore, in order to raise the temperature of the PN junction, a voltage higher than Vth is applied. However, it is necessary to consume a certain amount of power. Since the slope of the voltage-current characteristic is large in the region exceeding Vth, constant current control is adopted because the amount of increase in the current is larger than that in the voltage and control is easy. In FIG. 3, Ia indicates the amount of increase in current, and Va in FIG. 3 indicates the amount of increase in voltage.

 On the other hand, in the failure determination of the semiconductor device, a voltage equal to or lower than Vth is applied, the voltage is fixed, and the current at that time is measured.

  FIG. 4 shows an example of electrical characteristics of a semiconductor device in a normal state and a failed state. The vertical axis represents the logarithm of current, and the horizontal axis represents voltage. When the junction of the semiconductor device is in a normal state, almost no current flows in a region below Vth, but when there is a failure, current flows even when it is below Vth, so it can be determined whether or not it is broken. Since a slight current flows even in a normal state, the failure determination unit 15 sets a reference value in advance, and determines that a failure occurs when the current at a predetermined voltage exceeds the reference value. Such a failure determination method is general.

  When the junction structure in the semiconductor device fails, the current flowing in the region below Vth increases. Therefore, in this embodiment, measurement is performed in a region below Vth. However, since the amount of current flowing through the semiconductor device is small in this region, constant voltage control that is easy to control is employed.

  The pulse width of the current or voltage for heating the semiconductor device is the voltage and current application time in the semiconductor device 2 to be measured and the heat supply time from the PN junction of the semiconductor device 2 to be measured. The temperature rise region can be arbitrarily set according to the width. By sufficiently shortening the pulse width, it is possible to heat only a minute region such as a PN junction having only a minute heat capacity, which cannot be measured by the method described in Patent Document 1. The period of the pulse is defined as a time required for the region where the temperature of the semiconductor device 2 to be measured to rise due to the application of the rectangular wave upper voltage and current to return to the temperature state before the application of the upper voltage and current. The number of cycles is set to the number of cycles in which the repetition of the temperature change of the semiconductor device 2 is stable, and can be arbitrarily set.

  When the voltage and current changes of the semiconductor device 2 to be measured by the local heating control unit 4 are monitored by the measurement unit 5 and the amount of current measured in the constant voltage control reaches the reference value for failure determination, the failure determination unit 15 The semiconductor device 2 is determined to be faulty, and the measurement unit 5 ends the measurement of the semiconductor current amount. Alternatively, when the constant current control voltage reaches the failure determination voltage, the semiconductor device 2 to be measured is determined to be failed, and the measurement is terminated. Since the electrical failure of the semiconductor device 2 to be measured has two types of failure, that is, an open failure and a short (including a small current) failure, the failure determination unit 15 needs to set two types of failure determination voltage and current. It can be arbitrarily set according to the electrical characteristics of the measurement semiconductor device 2.

  A heavy failure such as an open failure can be determined by constant current control. It is desirable to perform constant voltage control because it is necessary to measure the current with high accuracy when the degree of leakage failure such that current leaks below Vth is light. In the case of an open failure, the voltage rises to the limit voltage value set in advance in the local heating control unit 4 or the power supply device 8 in the constant current control, and the current becomes almost zero in the constant voltage control. In the case of a short-circuit failure, the voltage decreases with constant current control, and the voltage value is determined by the resistance at the short-circuit location. In the constant voltage control, the current rises to a limit current value set in advance in the local heating control unit 4 or the power supply device 8.

  When failure determination does not occur within an arbitrary number of cycles, failure determination unit 15 increases instantaneous input power that is the product of the upper voltage and current of semiconductor device 2 to be measured by increasing the current in the first electrical state. The above-described failure determination is performed again. The increase width of the current can be arbitrarily set. The current increase in the first electrical state is performed until the failure determination unit 15 of the semiconductor device 2 to be measured determines failure, and the current in the first electrical state at the time of failure determination (hereinafter referred to as failure current) is recorded. .

  The above fault current measurement is performed under different temperature conditions, for example, 50 ° C., 75 ° C., and 100 ° C. When the ambient temperature rises, the temperature reached in the temperature rise region due to the applied current also rises, so that the relationship between the ambient temperature and the instantaneous input power at the time of failure as shown in FIG. 5 is obtained. Assuming that the ambient temperature is the Y-axis and the instantaneous input power at the time of failure is the X-axis, the failure junction temperature in an arbitrary region can be obtained by obtaining the intercept of the Y-axis by extrapolation approximation when the instantaneous input power at the time of failure is zero. Can be calculated. Here, the relationship between the input power and the ambient temperature is seen, but this may be the relationship between the amount of heat given to the semiconductor and the ambient temperature.

  Further, as shown in FIG. 5, the amount obtained by subtracting the ambient temperature from the failure junction temperature corresponds to the junction temperature increase amount due to the instantaneous input power at the time of failure, which is the power given from the local control heating unit at the time of failure. That is, since the correlation between the instantaneous input power and the increase in junction temperature is obtained from the relationship between the multiple ambient temperatures and the instantaneous input power at the time of failure, the junction temperature due to the instantaneous input power applied during operation to the ambient temperature during operation The junction temperature during operation can be calculated by adding the increments. When the instantaneous input power, that is, the amount of heat applied to the junction increases, the junction temperature as a whole increases even if the ambient temperature is low, and the junction fails. By checking how much heat is applied to the junction and how much the ambient temperature is at the semiconductor device, the ambient temperature at which the instantaneous input power is 0, that is, when the heat is 0, A fault junction temperature can be identified.

  The failure determination unit 15 determines a failure of the semiconductor device from the junction characteristics of the semiconductor device measured by the measurement unit 5 at a plurality of ambient temperatures. In the present embodiment, whether or not the current at the predetermined voltage exceeds or does not exceed the threshold is measured based on the current-voltage characteristics, and if it exceeds, the failure is determined.

  The failure junction temperature specifying unit 16 stores the relationship between the amount of heat or power and the ambient temperature when it is determined that the semiconductor device has failed. When the semiconductor device fails, the failure junction temperature specifying unit 16 Specify the correlation of the temperature. In the specified correlation, the ambient temperature when the amount of heat or power becomes 0 is identified, and the ambient temperature is identified as the failure junction temperature.

  If you try to identify the temperature at which the PN junction (junction) fails, and if you raise the temperature to the temperature at which the PN junction actually fails, it will be measured by the failure before it becomes thermally stable and accurate. There is a problem that it becomes impossible. Further, in the method as described in Patent Document 1, since the heat is saturated in the entire semiconductor device, the temperature at which the heat-sensitive portion such as the package resin fails first and the PN junction in the arbitrary region fails is measured. The problem of not being able to do it also occurs.

  According to the first embodiment, the junction of the semiconductor device is heated until it actually fails, and the local heating is repeatedly repeated in a thermally stable state so that the relationship between the current or voltage and the junction failure can be accurately performed. Thus, there is an effect that a failure junction temperature, which is a temperature at which a failure occurs in a junction of a semiconductor device, can be specified.

Embodiment 2
In the first embodiment, a method of applying a pulse voltage and current is used as a method of locally heating the semiconductor device 2 to be measured. However, in the second embodiment, the method of locally heating is pulsed laser light irradiation. Thus, it is not limited to the place where the power is consumed most like the PN junction portion, and it is possible to locally heat an arbitrary place where it is desired to obtain the junction temperature and the failure junction temperature during operation. Further, the temperature rise region can be arbitrarily changed by changing the wavelength, irradiation area, and irradiation time.

  FIG. 6 is a block diagram showing a configuration of the junction temperature specifying device 6 of the semiconductor device according to the second embodiment of the present invention. Referring to FIG. 6, the junction temperature specifying device 6 of the semiconductor device locally heats the ambient temperature control unit 3 that controls the ambient temperature of the semiconductor device 2 to be measured and an arbitrary region of the semiconductor device 2 to be measured. A laser control unit 7 for controlling the pulse laser beam 701, a power supply device 8 for applying a voltage for determining a failure of the semiconductor device 2 to be measured, and a measuring unit 5 for monitoring the applied voltage and applied current.

  The ambient temperature of the semiconductor device 2 to be measured can be arbitrarily set by the ambient temperature control unit 3, and is kept at a steady state (including the PN junction portion of the semiconductor device 2 to be measured) at 25 ° C., for example. In the present embodiment, a method of arbitrarily changing the temperature rise region of the semiconductor device 2 to be measured by changing the wavelength, irradiation area, and irradiation time of the pulsed laser light 701 emitted from the laser control unit 7 is used. The wavelength, irradiation area, and irradiation time of the pulse laser beam 701 can be arbitrarily set.

  FIG. 7 shows an example of the waveform of the pulse laser beam 701 irradiated from the laser control unit 7 to the semiconductor device 2 to be measured and the electrical state supplied from the power supply device 8 to the terminal 201. In order to perform a failure determination of the semiconductor device 2 to be measured by local heating by irradiation with the pulse laser beam 701, the power supply device 8 supplies the terminals 201 to 202 of the semiconductor device 2 to be measured while the pulse laser beam 701 is OFF. A voltage and current that do not increase the junction temperature of the semiconductor device 2 to be measured (for example, less than the threshold voltage of the diode) are applied, and changes in the voltage and current are monitored by the measuring unit 5. When the monitored voltage and current amount reach the failure determination voltage and current, the semiconductor device 2 to be measured is determined to be faulty, and the measurement of the semiconductor device to be measured is terminated. Since there are two types of electrical failure of the semiconductor device 2 to be measured, an open failure and a short failure (including a small current), it is necessary to set two types of failure determination voltages and currents. It can be set arbitrarily depending on the characteristics.

  When failure determination is not made within an arbitrary number of cycles, the laser beam intensity of the pulsed laser beam 701 is increased to increase the thermal load on the semiconductor device 2 to be measured, and the above measurement is performed again. The increase width of the laser light intensity can be set arbitrarily. The laser light intensity is increased until the semiconductor device 2 to be measured becomes a failure determination, and the laser light intensity at the time of the failure determination (hereinafter referred to as failure laser light intensity) is recorded.

  The above fault current measurement is performed under different ambient temperature conditions, for example, 50 ° C., 75 ° C., and 100 ° C. When the ambient temperature rises, the temperature reached in the temperature rise region due to the pulse laser irradiation also rises, so that the relationship between the ambient temperature and the failure laser light intensity as shown in FIG. 8 is obtained. If the ambient temperature is the Y axis and the failure laser light intensity is the X axis, the failure junction temperature in an arbitrary region is estimated by obtaining the ambient temperature when the failure laser light intensity is 0, that is, the intercept of the Y axis by extrapolation approximation. can do.

  Further, as shown in FIG. 8, one failure condition (ambient temperature and instantaneous laser light intensity at the time of failure) is measured at one point in an operating state in which a current flows through the semiconductor device 2 to be measured, and the ambient temperature and the failure laser light intensity are measured. When the graph of the relationship is plotted, at the same instantaneous laser beam intensity, the ambient temperature decreases in the operating state by the amount of heat generated by the input power. The amount of decrease corresponds to the amount of increase in junction temperature due to heat generation during operation. The junction temperature during operation can be estimated by adding the increase in junction temperature due to heat generation during operation to the ambient temperature during operation.

  In the present embodiment, the parts different from the first embodiment have been described. The other parts are the same as those in the first embodiment.

Embodiment 3
In the second embodiment, as a method for locally heating the semiconductor device 2 to be measured, a failure is determined by voltage and current using a method in which the local heating method is pulsed laser light irradiation. However, in the third embodiment, By using laser beam scanning as the local heating method, it is possible to perform local heating over a certain range in which the junction temperature and failure junction temperature during operation are desired. In addition, by detecting the laser reflected light intensity at the same time as the laser beam scanning and determining the failure from the intensity change, it is possible to determine the junction temperature and the failure junction temperature at the time of operation at the location that was irradiated at that moment. It is also possible to image the acquired junction temperature and failure junction temperature of each laser irradiation location. Furthermore, the temperature rise region range can be arbitrarily changed by changing the wavelength, irradiation range, and scanning speed.

  FIG. 9 is a block diagram showing a configuration of the junction temperature specifying device 9 for a semiconductor device according to the third embodiment of the present invention. Referring to FIG. 9, the junction temperature specifying device 9 of the semiconductor device locally heats the ambient temperature control unit 3 that controls the ambient temperature of the semiconductor device 2 to be measured and an arbitrary region of the semiconductor device 2 to be measured. A laser scanning section 12 that scans the laser scanning light 1201, a laser reflected light detection device 13 for determining a failure of the semiconductor device 2 to be measured, and an imaging that maps the acquired junction temperature and failure junction temperature during operation A processing device 14 is provided.

  The ambient temperature of the semiconductor device 2 to be measured can be arbitrarily set by the ambient temperature control unit 3, and is kept at a steady state (including the PN junction portion of the semiconductor device 2 to be measured) at 25 ° C., for example. In the present embodiment, a method of arbitrarily changing the temperature rise region of the semiconductor device 2 to be measured by changing the wavelength, irradiation range, and scanning speed of the laser scanning light 1201 scanned by the laser scanning unit 12 is used. The wavelength, irradiation area, and irradiation time of the laser scanning light 1201 can be arbitrarily set.

  The failure determination of the semiconductor device 2 to be measured due to local heating by irradiation with the laser scanning light 1201 is performed by the failure determination unit 15 by detecting the intensity change of the laser reflected light by the laser reflected light detection device 13. When a semiconductor device fails due to local overheating of laser light irradiation, the light absorption characteristics at the laser irradiation location change, so that it is possible to determine the failure of the semiconductor device by detecting a change in the intensity of laser reflected light.

  FIG. 10 shows an example of scanning with the laser scanning light 1201 irradiated from the laser scanning unit 12 to the semiconductor device 2 to be measured. The semiconductor device 2 to be measured is scanned while detecting the reflected light intensity from the laser irradiation spot for each irradiation point. When scanning within a certain range in which the junction temperature during operation and the failure junction temperature are to be obtained is completed and failure is not determined at all irradiation points, the laser light intensity of the laser light 1201 is increased, thereby increasing the semiconductor device 2 to be measured. The above-mentioned measurement is performed again by increasing the heat load on the. The increase width of the laser light intensity can be set arbitrarily. The laser light intensity is increased until all the laser light irradiation points of the semiconductor device 2 to be measured are determined to be faulty, and the laser light intensity at the time of the fault judgment at each point (hereinafter referred to as fault laser light intensity) is recorded. To do.

  The above failure determination is performed under different ambient temperature conditions, for example, 50 ° C., 75 ° C., and 100 ° C. When the ambient temperature rises, the temperature reached in the temperature rise region due to laser irradiation also rises, so that the relationship between the ambient temperature and the instantaneous laser scanning light intensity at the time of failure as shown in FIG. 11 is obtained. If the ambient temperature is the Y axis and the instantaneous laser scanning light intensity at the time of failure is the X axis, the ambient temperature when the instantaneous laser scanning light intensity at the time of failure is 0, that is, the intercept of the Y axis is obtained by extrapolation approximation, The failure junction temperature in an arbitrary region can be calculated at each laser light irradiation location, and the failure junction temperature can be mapped.

  In addition, as shown in FIG. 11, with the semiconductor device 2 to be measured operating, failure conditions (ambient temperature at the time of failure and instantaneous laser light intensity) are measured and plotted on a graph of the relationship between the ambient temperature and the failure laser light intensity. Then, at the same ambient temperature, the failure laser light intensity decreases in the operating state by the amount of heat generated by the input power. The amount of decrease corresponds to the amount of increase in junction temperature due to heat generation during operation. The junction temperature during operation can be calculated by adding the increase in junction temperature due to heat generation during operation to the ambient temperature during operation. Furthermore, since the junction temperature during operation can be calculated at each laser beam irradiation point, mapping of the junction temperature during operation is also possible.

  In the present embodiment, the parts different from the first or second embodiment have been described. The other parts are the same as those in the first or second embodiment.

  1, 6, 9 Junction temperature specifying device of semiconductor device, 2 semiconductor device to be measured, 201 terminal 1, 202 terminal 2, 3 ambient temperature control unit, 4 local heating control unit, 5 measurement unit, 7 laser control unit, 8 power supply Apparatus, 12 laser scanning section, 15 failure determination section, 1201 laser scanning light, 13 laser reflected light detection apparatus, 14 imaging processing apparatus

Claims (7)

An ambient temperature controller that controls the ambient temperature of the semiconductor device having the junction;
At the ambient temperature, a local heating control unit that applies heat to locally heat the semiconductor device; and
A measurement unit for measuring the characteristics of the junction of the semiconductor device;
From a plurality of characteristics of the junction at the ambient temperature, a failure determination unit that determines a failure of the semiconductor device,
A junction temperature specifying unit including a failure junction temperature specifying unit for specifying the ambient temperature at which the amount of heat becomes 0 as a failure junction temperature based on a correlation between the amount of heat and the ambient temperature when the semiconductor device is determined to be in failure; apparatus. The junction temperature specifying device according to claim 1, wherein the amount of heat is given by an electric current. The junction temperature specifying device according to claim 1, wherein the amount of heat is given by laser light. The junction temperature specifying device according to any one of claims 1 to 3, wherein the junction characteristic is a current-voltage characteristic. The junction temperature specifying device according to claim 3, wherein the characteristic of the junction is a reflection intensity of laser light. The junction temperature specifying device according to claim 4, wherein the failure determination unit determines that a failure occurs when a current at a predetermined voltage exceeds a threshold in the current-voltage characteristics. Controlling the ambient temperature of the semiconductor device having a junction;
Applying an amount of heat to heat the semiconductor device at the ambient temperature;
Measuring the junction characteristics of the semiconductor device;
Determining a failure of the semiconductor device from a plurality of characteristics of the junction at the ambient temperature;
A step of identifying the ambient temperature at which the amount of heat is 0 as a failure junction temperature from the correlation between the amount of heat and each ambient temperature when it is determined that the semiconductor device has failed.

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