JP2000121692A - Test device for semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect deterioration status of heat resistance without removing a semiconductor element to be tested from a test device. SOLUTION: A very small constant current source 2 for always applying such a very small d.c. constant current IM that heat eneration is ignored to a semiconductor element 4 to be tested is connected to the element 4. Variable resistors 5 are respectively connected in series to the semiconductor elements 4 to be tested. An input terminal of a sample hold circuit 6 for sample holding the voltage VM2 of the semiconductor element 4 to be tested in response to a timing signal immediately after the end of application of the current IT is connected to both ends of each semiconductor element 4 including the variable resistors 5. The output terminal of the sample hold circuit 6 is connected to the input terminal of a comparator 7, the comparator 7 outputs when the voltage VM2 of the semiconductor element 4 is lower than the reference voltage Vref to turn on a thyristor 9, thereby causing a light emitting diode 10 to emit light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device test apparatus and a test method capable of simultaneously performing a thermal fatigue test for evaluating a structural resistance of a semiconductor having a PN junction on a plurality of semiconductor devices. is there.

[0002]

2. Description of the Related Art Conventionally, a test apparatus for performing a thermal fatigue test on a semiconductor device having a PN junction has a current I as shown in FIG.
A constant current source 1 for supplying T, a relay circuit 3, and a plurality of semiconductor devices under test 4 are connected in series, and the relay circuit 3 is controlled by a timing controller 11 to connect a plurality of serially connected devices 4 to FIG. Is generated by applying an intermittent current IF shown in FIG.

[0003]

However, the conventional test apparatus removes the semiconductor device under test 4 from the device when a predetermined number of times of energization has been performed, and measures the thermal resistance of the device to perform a deterioration diagnosis. Therefore, there are the following disadvantages. That is, since the deterioration diagnosis of the semiconductor device under test 4 is performed only at a predetermined number of times of energization, deterioration occurring during the test cannot be determined, and it is difficult to accurately grasp the deterioration time of each device.

In addition, the element must be removed every time the thermal resistance is measured, which is troublesome, and causes problems such as erroneous connection at the time of attachment and detachment, stress at the time of attachment, and the like. When testing a plurality of devices at the same time, it takes a lot of trouble and requires careful handling.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to determine deterioration of thermal resistance during a test without removing a plurality of semiconductor devices under test simultaneously from the device. It is an object of the present invention to provide a semiconductor device test device capable of accurately diagnosing deterioration of a semiconductor device.

[0006]

In order to solve the above-mentioned problems and achieve the object, a semiconductor device test apparatus according to the present invention provides a semiconductor device under test connected in series with a preset current. In a semiconductor test apparatus for simultaneously testing the resistance of the element by intermittently supplying current, an intermittent current source for intermittently supplying a DC current sufficient to cause the element to generate heat with the element. A constant current source for constantly supplying a sufficiently small DC current to the element that can neglect the heat generation of the element, a variable resistor connected in series for each element, and the variable resistor. A comparison circuit that compares a voltage between both ends of the element with a reference voltage, wherein the comparison circuit determines the magnitude of the voltage between both ends immediately after energization by the intermittent current source.

[0007] Preferably, the intermittent current source is PN.
Electric current is supplied in the forward direction of the semiconductor element having the junction.

Preferably, the apparatus further includes a determination circuit for determining that the element has deteriorated when a voltage across the element immediately after the application of the current by the intermittent current source falls below the reference voltage.

[0009]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a circuit block diagram of a semiconductor test apparatus according to an embodiment of the present invention.

In the following, PN is used as a semiconductor device under test.
An example using a junction diode will be described.

Diagnosis of deterioration of a semiconductor device having a PN junction in a thermal fatigue test is performed by thermal resistance. For this thermal resistance, a small DC constant current IM is applied in advance in the forward direction of the PN junction of the semiconductor device under test, and a sufficient current is applied for a predetermined time to generate heat due to power loss of the semiconductor device under test itself. The PN junction voltage VM1 of the semiconductor device under test before application of this current and the PN junction voltage V
It is calculated from the voltage difference ΔVF of M2 = VM1-VM2.

In FIG. 1, reference numeral 4 denotes a semiconductor device under test, which is connected in series so that a plurality of devices 4 can be tested at the same time, and has a constant current source 1 for heating the semiconductor device 4 under test. It is connected via a relay circuit 3.

The semiconductor device under test 4 is connected to a minute constant current source 2 for constantly supplying a minute DC constant current IM such that the heat generation of the device can be ignored.
By controlling the relay circuit 3 by the timing controller 11, the current I shown in FIG.
F is flowing.

Variable resistances 5 are connected in series to the semiconductor element 4 to be tested, and the respective resistance values are adjusted by passing a DC constant current IM before the test. The voltage VM1 applied to 4 is adjusted to be the same for all elements.

In addition, in order to cause the semiconductor device under test 4 to generate heat, the timing controller 11 controls a current IT supplied to each semiconductor device under test 4 including the variable resistor 5, and controls a current IT including the variable resistor 5. An input terminal of a sample and hold circuit 6 for receiving a timing signal and sampling and holding the voltage VM2 of the semiconductor element under test 4 immediately after the end of the supply of the current IT is connected to both ends of the semiconductor element 4.

Further, the output terminal of the sample and hold circuit 6 is connected to the input terminal of a comparator 7, and the comparator 7 compares the sampled and held voltage VM2 with a reference voltage Vref provided by a voltage source 8. The voltage VM2 is
It is calculated by subtracting the thermal resistance determination value ΔVFL from the previously determined VM1 (VM1−ΔVFL). Comparator 7
Means that the voltage VM2 of the semiconductor element 4 under test is equal to the reference voltage V
An output is generated when the voltage falls below ref, and the thyristor 9 is turned on to cause the light emitting diode 10 to emit light.
This makes it possible to detect the deterioration of the thermal resistance during the test without removing the semiconductor device under test 4 from the test apparatus.

The present invention can be applied to a modified or modified embodiment without departing from the spirit of the invention.

[0019]

As described above, according to the present invention, it is possible to determine the deterioration state of the thermal resistance during the test without removing the semiconductor device under test from the test apparatus. In the case of carrying out, it is not necessary to remove it for the measurement of thermal resistance, the efficiency of the test man-hour can be improved, the timing of deterioration can be accurately grasped, and an appropriate diagnosis can be performed.

[0020]

[Brief description of the drawings]

FIG. 1 is a circuit block diagram of a semiconductor device test apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a current applied to a semiconductor device under test in the present embodiment.

FIG. 3 is a circuit block diagram of a conventional semiconductor test apparatus.

FIG. 4 is a diagram showing a current applied to a semiconductor device under test in the related art.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 constant current source 2 minute constant current source 3 relay circuit 4 semiconductor device under test 5 variable resistor 6 sample and hold circuit 7 comparator 8 voltage source 9 thyristor 10 light emitting diode 11 timing controller

Claims (3)

[Claims] 1. A semiconductor device test apparatus for intermittently applying a preset current to a series-connected semiconductor device under test to test the durability of the device, wherein the device has An intermittent current source for intermittently applying a direct current sufficient to cause the element to generate heat; and an intermittent current source for constantly applying a sufficiently small direct current to the element so that the heat generation of the element can be ignored. A constant current source; a variable resistor connected in series for each element; and a comparison circuit for comparing a voltage across the element including the variable resistance with a reference voltage, wherein the comparison circuit is energized by the intermittent current source. A test apparatus for a semiconductor device, which determines the magnitude of the voltage between both ends immediately after the test. 2. The semiconductor device test apparatus according to claim 1, wherein the intermittent current source supplies current in a forward direction of the semiconductor device having a PN junction. 3. The apparatus according to claim 2, further comprising a determination circuit for determining that the element has deteriorated when a voltage across the element immediately after the application of the current by the intermittent current source falls below the reference voltage. 2. The apparatus for testing a semiconductor device according to claim 1.