JP2000088912A - Method for measuring thermal characteristics of junction transistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately obtain a junction temperature in a real testing state. SOLUTION: A level of the ambient temperature Ta is deflected at two points or more, and a level of a predetermined power Power to be applied is deflected at least two points or more. A voltage Vbe between a base and an emitter to be applied to a transistor is monitored at the respective levels. A Ta-Vbe graph is drawn, wherein Vbe is an abscissa axis and Ta is an ordinate axis, ΔTa/ΔPower is calculated, and a thermal resistance is obtained. Further, a junction temperature Tj at the time of testing is obtained by a formula of (Tj (tch)) = Ta + thermal resistance × Power) from the temperature Ta at the time of the real testing and the predetermined power Power.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring thermal characteristics of a junction transistor, and more particularly to a method for measuring thermal characteristics of a junction transistor capable of measuring a junction temperature during stress application.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are views for explaining a method for measuring the thermal characteristics of a conventional junction transistor. As shown in FIG. 3, between the gate and source of a junction transistor (junction field effect transistor) 1, a continuous pulse (Ig) of a constant, small current generated by a pulse generator 2 is applied, and The source-to-source voltage (Vgs1 in FIG. 4) is measured.

[0003] While applying a continuous pulse (Ig), a constant power (Vds) from the power supply source 3 for a fixed time.
Is applied between the source and the drain to increase the temperature of the channel and turn off the power (Vds) of the field effect transistor (FET), and then measure the gate-source voltage (Vgs2 in FIG. 4) again. .

Then, a thermal resistance value is calculated from a voltage difference between the gate and the source before and after applying a constant power (Vds) between the source and the drain, and a temperature coefficient of the FET and an applied power determined in advance. .

[0005]

However, in this method, since the channel temperature (Tch) is calculated from the measured values before and after the power is applied, there is a problem that the channel temperature when the power is applied cannot be obtained.

The present invention has been made in view of such a situation. Actually, the ambient temperature (Ta) or the base temperature (Tbase) is set to a predetermined value, and the constant power (Power) is set.
It is intended to determine the thermal resistance and the channel temperature (junction temperature) when r) is applied.

[0007]

According to a first aspect of the present invention, there is provided a method for measuring thermal characteristics of a junction transistor, comprising applying a constant power between a collector and an emitter of the junction transistor to make the ambient temperature or the base temperature constant. A method for measuring the thermal characteristics of a junction transistor, wherein the ambient temperature or the base temperature level is changed by at least two points, the power level is changed by at least two points, and the ambient temperature or the base temperature is changed. Measure the voltage between the base and the emitter under the condition that each power level is combined, calculate the thermal resistance of the junction transistor based on the temperature dependency of the voltage between the base and the emitter when the power is constant, From the thermal resistance, the ambient or base temperature at the time of measurement, and the power value, And calculates the junction temperature of Deployment transistor. According to a second aspect of the present invention, there is provided a method for measuring the thermal characteristics of a junction transistor, wherein a constant power is applied between the collector and the emitter of the junction transistor and the ambient temperature or the base temperature is kept constant to measure the thermal characteristics of the junction transistor. A method for measuring thermal characteristics, wherein the level of the ambient temperature or the base temperature is changed by at least two points, and the level of the collector-emitter voltage is changed by at least two points.
Measure the voltage between the base and the emitter under the condition where each level of the ambient temperature or the base temperature and each level of the voltage between the collector and the emitter are combined, and measure the voltage between the base and the emitter when the power is constant. Based on the temperature dependence of the voltage, the thermal resistance of the junction transistor is calculated, and the junction temperature of the junction transistor is calculated from the thermal resistance, the ambient temperature or base temperature at the time of measurement, and the power value. I do. According to a third aspect of the present invention, there is provided a method for measuring the thermal characteristics of a junction transistor, wherein a constant power is applied between the collector and the emitter of the junction transistor and the ambient temperature or the base temperature is kept constant to measure the thermal characteristics of the junction transistor. A method for measuring thermal characteristics, wherein the level of ambient temperature or base temperature is changed by at least two points, and the level of current between
The voltage between the base and the emitter is measured under the condition where each level of the ambient temperature or the base temperature and each level of the current between the collector and the emitter are combined, and the voltage between the base and the emitter when the power is constant is measured. Based on the temperature dependence of the voltage, the thermal resistance of the junction transistor is calculated, and the junction temperature of the junction transistor is calculated from the thermal resistance, the ambient temperature or base temperature at the time of measurement, and the power value. I do. The power shall be the sum of the product of the collector-emitter voltage value and the current value and the product of the base-emitter voltage value and the current value multiplied. Can be. Further, the thermal resistance can be calculated based on a change in the voltage value corresponding to a change in the ambient temperature. Further, the junction temperature can be calculated by adding the ambient temperature to the product of the value of the thermal resistance and the value of the electric power. In the method for measuring the thermal characteristics of a junction transistor according to the present invention, the ambient temperature or the base temperature level is changed at least two points, the power level is changed at least two points, the ambient temperature or the base temperature and the power are changed. Under the combined conditions, the base-emitter voltage is measured, and the thermal resistance of the junction transistor is calculated based on the temperature dependence of the base-emitter voltage when the power is constant. , The ambient or base temperature at the time of measurement,
From the value of the power, the junction temperature of the junction transistor is calculated.

[0008]

1 and 2 are diagrams for explaining a method for measuring the thermal characteristics of a junction transistor according to the present invention. As shown in FIG. 1, a constant current from the power supply 13 flows between the collector and the emitter of the junction transistor 11, and a constant power (Power) (= V
ce × Ice + Vbe × Ibe ≒ Vce × Ice, and the ambient temperature (Ta) or the base temperature (Tbas)
e) in a test conducted at a constant value, Ta (Tbas
The level of e) is assigned at least two points, and the level of Power is assigned at least two points. Here, the ambient temperature (T
a) will be used. The base-emitter voltage (Vb) applied to the junction transistor 11
e) is monitored at each level.

As shown in FIG. 2, the vertical axis is Vb
e, Ta is plotted on the horizontal axis, a Ta (Tbase) -Vbe graph is drawn, and the thermal resistance is calculated from the following equation.

Thermal resistance = ΔTa / △ Power

Further, a junction temperature (Tj) (or a channel temperature (Tch)) at the time of the test is obtained from Ta at the time of the test and Power.

That is, when the Ta-Vbe graph is drawn, it becomes a straight line as shown in FIG. 2, and from the difference between Power and the temperature difference between Ta, Tj (Tc
h) can be calculated.

Thermal resistance (σ) = (Ta2-Ta1) / (P
power2-Power1), T is given by the following equation.
j (Tch) can be obtained.

Tj (Tch) = Ta + σ × Power

Here, Ta is the ambient temperature during the test,
Power is the power applied between the collector and the emitter during the test.

Hereinafter, a method for measuring the thermal characteristics of a junction transistor according to the present invention will be described in detail with reference to FIGS.

(Embodiment 1) As described above, between the collector and the emitter of the junction transistor 11,
A constant current is passed, and a constant power (Power) (= Vce
× Ice + Vbe × Ibe ≒ Vce × Ice), and the ambient temperature (Ta) or the base temperature (Tbase)
In a test performed with the temperature constant, the ambient temperature Ta (Tba
se) at least two points, and Po
Change the level of wer at least 2 points. Here, the ambient temperature (Ta) is used.

Therefore, the level is determined by the ambient temperature Ta and Powe.
r for each level. At each level, the base-emitter voltage (Vbe) applied to the junction transistor 11 is monitored.

FIG. 2 is a graph showing the relationship between Ta and Vbe obtained as described above. From FIG. 2, the ambient temperature is Ta1, and the value of Power is Power1.
And the value of the voltage Vbe between the base and the emitter at the time of
An ambient temperature Ta2 when the Power is Power2 is read such that the value of the voltage Vbe between the base and the emitter when the value of the Power is Power2 becomes the same. Here, the thermal resistance and Tj (T
ch) is calculated. That is, the fact that Vbe is the same means that Tj (Tch) is the same, and the difference between the ambient temperatures Ta1 and Ta2 is the temperature increased by the difference in Power. Therefore, V
The ambient temperatures Ta1 and Ta2 are determined so that the values of be are the same. From this value Ta2, PKG thermal resistance (σ) can be obtained from the following equation.

PKG thermal resistance (σ) = (Ta2-Ta1)
/ (Power2-Power1)

Tj (Tch) at the time of stress application can be calculated from the thermal resistance (σ) of PKG, Power at the time of actual stress application (at the time of test) and ambient temperature Ta from the following equation.

Tj (Tch) = Ta + σ × Power

In this manner, the base-emitter voltage (Vbe) applied to the junction transistor 11 is monitored while the ambient temperature (Ta) is actually set to a predetermined value and a predetermined constant power (Power) is applied. I do. Since the base-emitter voltage (Vbe) has temperature dependency (has linearity), the actual temperature, that is, the ambient temperature (Ta) is set to a predetermined value, and a predetermined constant power (Powe) is set.
The thermal resistance and the junction temperature (channel temperature) with r) applied can be determined.

This makes it possible to accurately determine the junction temperature in the actual test state. Further, by performing a life test using this value, the reliability of the measurement can be increased and the accuracy can be improved.

Next, another embodiment of the method for measuring the thermal characteristics of a junction transistor according to the present invention will be described.

(Embodiment 2) When shaking the Power, V
Focusing only on ce, consider that Vce is shifted by two or more points. A constant current is passed between the collector and the emitter of the junction transistor 11 so that a constant power (Power = V
ce × Ice + Vbe × Ibe ≒ Vce × Ice, and the ambient temperature (Ta) or the base temperature (Tbas)
e) in a test conducted at a constant value, Ta (Tbas
e) is shaken at least two points, and Vce is shaken at least two points. The base-emitter voltage (Vb) applied to the junction transistor 11 at each level
e) is monitored. Here, the ambient temperature (Ta) is used.

The relationship between Ta and Vbe obtained as described above is graphed, and the collector-emitter voltage becomes Vce2 such that the ambient temperature becomes the same as the Vbe value when Ta1 and the collector-emitter voltage becomes Vce1. By reading the temperature at the time of, Ta2 is obtained. From this value, the PKG thermal resistance can be obtained from the following equation.

Thermal resistance = (Ta2-Ta1) / ((Vce
2 × Ice + Vbe × Ibe2) − (Vce1 × Ice
+ Vbe × Ibe1))

Tj (Tch) at the time of stress application can be calculated from the PKG thermal resistance and Power at the time of actual stress application (at the time of test) in the same manner as in the first embodiment.

(Embodiment 3) When shaking the Power,
Focusing only on ce, consider giving Ice two or more points. A constant current is passed between the collector and the emitter of the junction transistor 11 so that a constant power (Power = V
ce × Ice + Vbe × Ibe ≒ Vce × Ice, and the ambient temperature (Ta) or the base temperature (Tbas)
e) in a test conducted at a constant value, Ta (Tbas
e) Swing at least two points, and swing Ice at least two points. Hereinafter, the ambient temperature Ta will be used.

At each level, the base-emitter voltage (Vbe) applied to the junction transistor 11
Monitor The relationship between Ta and Vbe obtained as described above is graphed, and the value of the current Ice between the collector and the emitter is set so that the ambient temperature is equal to the Vbe value when the current between the collector and the emitter is Ice1. Is Ic
By reading the temperature at e2, Ta2 is obtained. From this value Ta2, the PKG thermal resistance can be calculated from the following equation.

Thermal resistance = (Ta2-Ta1) / ((Vce
× Ice2 + Vbe × Ibe2) − (Vce × Ice1
+ Vbe × Ibe1))

Based on the thermal resistance of the PKG and the power and the ambient temperature Ta when the stress is actually applied (during the test), the Tj at the time when the stress is
(Tch) can be calculated.

(Embodiment 4) As a reverse method, a PKG thermal resistance can be obtained as follows. That is, first, the actual stress application state (Ta (Tbas
e), Vce, Ice) at each level, the base-emitter voltage (Vb
e) is monitored.

Next, Ta (Tbase) and Ice are changed, and Ta (Tbase) is set so that Vbe after stabilization becomes the same as Vbe in the actual stress applied state previously taken.
, And in the same manner as in the first embodiment,
Tj (Tch) can be calculated.

(Embodiment 5) As shown in Embodiment 4, instead of changing Ta (Tbase) and Ice, it is also possible to change Ta (Tbase) and Vce. First, the actual stress application state (T
At each level of a (Tbase), Vce, Ice), the base-emitter voltage (Vbe) applied to the junction transistor 11 is monitored. Next, Ta (Tbas
e) and Vce are changed so that Vbe after stabilization becomes the same as Vbe in the actual stress applied state previously taken.
Ta (Tbase) can be found, and Tj (Tch) can be calculated in the same manner as in the first embodiment.

(Embodiment 6) Embodiments 4 and 5 above
And Ta (Tbase) and Ice, or Ta (Tb)
ase) and Vce, without changing Ta (Tbas
e) and both Ice and Vce can be changed. First, the actual stress application state (Ta (T
The base-emitter voltage (Vbe) applied to the junction transistor 11 is monitored at each level of (base), Vce, Ice).

Next, stress (Ta (Tbase), V
ce, Ice) so that Vbe after stabilization becomes the same as Vbe in the actual stress applied state previously taken.
Ta (Tbase) can be found out, and Tj (Tch) can be calculated in the same manner as in the first embodiment.

In the above embodiment, the ambient temperature (Ta) is used, but the base temperature (Tba) is used.
It is also possible to use se).

Although the description has been given of the junction type transistor, the present invention can be applied to a junction type field effect transistor.

[0041]

As described above, according to the method for measuring the thermal characteristics of a junction transistor according to the present invention, the ambient temperature or the base temperature is changed at least two points, the power level is changed at least two points, and the ambient temperature is changed. Alternatively, measure the voltage between the base and emitter under the condition that each level of the base temperature and each level of the power are combined, and determine the junction transistor based on the temperature dependence of the voltage between the base and the emitter when the power is constant. The thermal resistance of the junction transistor is calculated from the thermal resistance, the ambient temperature or base temperature at the time of measurement, and the power value. Or, set the base temperature and adjust the thermal resistance and the junction temperature or channel temperature with a constant voltage applied to it. It is possible to measure.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a method for measuring the thermal characteristics of a junction transistor according to the present invention.

FIG. 2 is a graph showing a relationship between a base-emitter voltage Vbe and an ambient temperature Ta in FIG.

FIG. 3 is a diagram for explaining a conventional method for measuring the thermal characteristics of a junction transistor.

4 is a diagram showing a pulse Ig, a power between a source and a drain, and a voltage between a gate and a source Vgs in FIG.
6 is a timing chart showing a change in the state.

[Explanation of symbols]

 1,11 junction transistor 2 pulse generator 3,13 power supply source 12 voltage source

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) H01L 21/337 29/808

Claims (6)

[Claims] 1. A method for measuring thermal characteristics of a junction transistor, comprising applying a constant power between a collector and an emitter of the junction transistor and keeping an ambient temperature or a base temperature constant and measuring the thermal characteristics of the junction transistor. At least two points of the ambient temperature or the base temperature level are changed and at least two points of the power level are changed. Under the condition that the respective levels of the ambient temperature or the base temperature are combined with the respective levels of the power, And measuring the thermal resistance of the junction transistor based on the temperature dependency of the voltage between the base and the emitter when the power is constant, and calculating the thermal resistance and the ambient temperature during the measurement. Alternatively, the junction temperature of the junction transistor is determined from the base temperature and the value of the power. A method for measuring thermal characteristics of a junction transistor, comprising calculating a junction temperature. 2. A method for measuring thermal characteristics of a junction transistor, comprising applying a constant power between a collector and an emitter of the junction transistor and keeping an ambient temperature or a base temperature constant and measuring the thermal characteristics of the junction transistor. The ambient temperature or the base temperature level is changed at least two points, the collector-emitter voltage level is changed at least two points, and the ambient temperature or the base temperature and the collector-emitter voltage are changed. Under combined conditions,
A voltage between the base and the emitter is measured, and a thermal resistance of the junction transistor is calculated based on a temperature dependency of the voltage between the base and the emitter when the power is constant. A method for measuring a thermal characteristic of a junction transistor, comprising calculating a junction temperature of the junction transistor from the ambient temperature or the base temperature and the value of the power. 3. A method for measuring thermal characteristics of a junction transistor, comprising applying a constant power between a collector and an emitter of the junction transistor and keeping an ambient temperature or a base temperature constant and measuring the thermal characteristics of the junction transistor. The ambient temperature or the base temperature level is changed at least two points, the collector-emitter current level is changed at least two points, and the ambient temperature or the base temperature and the collector-emitter current are changed. Under combined conditions,
A voltage between the base and the emitter is measured, and a thermal resistance of the junction transistor is calculated based on a temperature dependency of the voltage between the base and the emitter when the power is constant. A method for measuring a thermal characteristic of a junction transistor, comprising calculating a junction temperature of the junction transistor from the ambient temperature or the base temperature and the value of the power. 4. The power is obtained by adding a value obtained by multiplying a value of a voltage between a collector and an emitter by a value of a current and a value obtained by multiplying a value of a voltage between a base and an emitter and a value of a current. 4. The method for measuring thermal characteristics of a junction transistor according to claim 1, wherein: 5. The heat of a junction transistor according to claim 1, wherein the thermal resistance is calculated based on a change in the value of the voltage corresponding to a change in the ambient temperature. Characteristics measurement method. 6. The method according to claim 1, wherein the junction temperature is calculated by adding the ambient temperature to a value obtained by multiplying the value of the thermal resistance by the value of the power. 4. The method for measuring thermal characteristics of a junction transistor according to claim 1.