JP2002189054A - Reliability test device of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliability test device, capable of efficiently and safely specifying a failure device, even when certain constant current or more is made to flow for failure, such as voltage resistant deterioration of a device to be tested. SOLUTION: The reliability test device for performing the life time test for the semiconductor device is provided with LED emission resistance (first resistance) 6 connected to a power source line supplying test voltage to each test device 4 to be tested, current limiting resistance (second resistance) 7 inserted and connected between the resistance 6 and the power source input terminal of the device 4 to be tested, and LED 8 connected in parallel with the resistance 6. When a current value, flowing in the resistance 6 at the value of the resistance 6, exceeds a set value, it is set at a value in which LED 8 emits by the voltage drop of both the ends of the resistance 6, and even if the device 4 to be tested is short-circuited at the value of the resistance 7, it is set at a value which does not exceed a prescribed current value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device reliability test apparatus.

[0002]

2. Description of the Related Art Generally, in a reliability test of a semiconductor device, a life test in which a reverse bias voltage is applied for a predetermined time (several hundred to several thousand hours) in a high-temperature or high-humidity atmosphere is performed.

In this type of test, a plurality of devices under test are mounted on a single test board and inserted into a test chamber (a constant temperature chamber or a constant temperature / humidity chamber). Power is supplied to each test board via a card edge connector, and power is supplied to each device under test by wiring on the test board.

As shown in FIG. 3, a test tank 1 is provided with a protective resistor circuit board 5 ′ and a device under test 4.
Power is supplied from an external power supply to the card edge connector 3 via a protection resistor circuit.

In an actual life test, in order to prevent an overcurrent from flowing to the device under test 4 in the event of a short-mode failure or the like, a protective resistance 7 ″ of several tens kΩ to several hundreds kΩ is connected to a power supply and a test target. In general, it is connected between the devices 4. Here, the value of the protection resistor 7 ″ is
Although it is desirable that the overcurrent value be as small as possible, it is desirable that the overcurrent value be as small as possible. However, as the resistance value increases, the voltage drop due to leak current or the like increases and the applied voltage to the device under test 4 decreases. Often chosen as a value.

[0006]

However, when a life test is performed by the test apparatus as described above, when a failure such as deterioration of the withstand voltage of the device under test 4 occurs, the current limited by the protection resistor 7 ″ at the maximum. However, if the overcurrent value cannot be suppressed to a sufficiently low value by the protection resistor 7 "for the above-described reason, the protection resistor 7" becomes red-hot due to the flowing current, or a plurality of If a failure occurs in the devices under test 4, there is a problem that the current exceeds the current limit, so it is necessary to detect and remove the failure of the device under test 4 at an early stage.

In the conventional apparatus, it is only necessary to monitor the voltage at one point at any time. However, it is inefficient because manual measurement of the number of devices to be measured is required using a voltmeter and a probe. For a withstand voltage device, etc., the applied voltage is several hundred.
Care must be taken in the measurement because the voltage is reduced to several hundreds of volts, and there is a problem that sufficient measures are required for that.

The present invention has been made in view of the above-mentioned problem, and its object is to solve the problem even when a certain amount of current or more flows due to a failure such as deterioration of withstand voltage of a device under test. It is an object of the present invention to provide a semiconductor device reliability test apparatus capable of efficiently and safely specifying a failed device.

[0009]

According to a first aspect of the present invention, there is provided a reliability test apparatus for performing a life test of a semiconductor device, wherein a power supply line for supplying a test voltage to each device under test is provided. A first resistor connected to the first resistor;
And a second resistor inserted and connected between the first resistor and a power input terminal of the device under test, and an LED connected in parallel to the first resistor. The value of the first resistor is set to the first resistor. When the value of the current flowing through the resistor exceeds the set value, the LED is set to a value at which the LED emits light due to the voltage drop across the resistor, and the value of the second resistor is set to the predetermined current value even when the device under test is short-circuited. The value is set so as not to exceed.

A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the first and second resistors are constituted by variable resistors.

Therefore, according to the first aspect of the present invention, when the current increases due to deterioration of the device under test or the like, if the current value exceeds a certain set value, the voltage across the first resistor is increased. When the LED emits light by exceeding the ON voltage of the LED, and when a larger current flows due to a short mode failure of the device under test, the current becomes almost the second.
Is limited to the value determined by the resistance value of
In addition, a faulty device can be specified safely.

According to the second aspect of the present invention, the value of the first resistor and the value of the second resistor can be changed arbitrarily to make L
The current value at which the ED emits light and the current limit value of the device under test can be changed.

[0013]

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

<Embodiment 1> FIG. 1 is a block diagram of a semiconductor device reliability test apparatus according to the present invention. In FIG. 1, 1 is a test tank, 2 is a test board, 3 is a test board 2 and an external Card edge connector for connecting the power line from
Is a device to be tested, 5 is a protection resistor circuit board provided outside the test tank 1, 6 is a resistor for emitting LED, 7 is a resistor for limiting current, 8 is an LED, Vs is a power supply terminal, and GND is a ground terminal. It is.

In the above configuration, the operation of the reliability test apparatus will be described using an actual numerical example.

The test voltage applied to the device under test 4 is 1
At 000 V, a reverse bias is applied to the device under test (the NPN transistor in the present embodiment) 4, and if the leakage current is such that the voltage drop caused by flowing through the resistors 6 and 7 is negligible, Vs , A voltage of 1000 V may be applied.

Here, when the device under test 4 is deteriorated and the leak current increases, if the current becomes, for example, about 1 mA or more, the LED 8 emits light to identify the failed device. Is about 2 V, the value of the resistor 6 may be set to 2 (V) / 1 (mA) = 2 (kΩ).

Next, in order to prevent the LED 8 from being destroyed by an overcurrent due to the failure of the device under test 4, for example, if the maximum rated current of the LED 8 is 20 mA, the value of the resistor 7 is set to about 1000 (V). / 20 (mA) = 50 (k
Ω) or more.

In the above configuration by setting the resistance value,
When the leakage increases due to the deterioration of the device under test 4 during the reliability test, when the current exceeds 1 mA, the voltage drop of the resistor 6 exceeds 2 V, and the LED 8 emits light. In the worst case where the device under test 4 has almost failed in a short-circuit state, the maximum value of the current is almost 1000 (V) / 50 (kΩ).
= 20 (mA).

As described above, in this embodiment, the LED 8 emits light when the leak current exceeds about 1 mA due to the deterioration of the device under test 4, so that the deteriorated device can be easily specified, and Even in the case of a state failure, the current flowing through the LED 8 does not exceed the maximum rating of the LED 8, so that the LED 8 is not destroyed.

<Embodiment 2> Next, Embodiment 2 of the present invention will be described with reference to FIG.

FIG. 2 is a block diagram of a semiconductor device reliability test apparatus according to this embodiment. The difference from the first embodiment is that the LED light emitting resistor 6 'and the current limiting resistor 7' are variable resistors. In that it is made up of containers.

In the reliability test according to the present invention, since conditions such as a device under test, a test temperature, and a test voltage change depending on the test, it may be necessary to change a current value for causing the LED 8 to emit light. Further, when the test voltage changes, it is necessary to change the current limiting resistance value.

Thus, in the present embodiment, each resistor 6 ',
Since 7 'is composed of a variable resistor, these resistors 6',
It is easily possible to change the resistance value of 7 'to a value suitable for the test as required.

[0025]

As apparent from the above description, according to the present invention, in a reliability test apparatus for performing a life test of a semiconductor element, a reliability test apparatus connected to a power supply line for supplying a test voltage to each device under test is provided. A first resistor, a second resistor inserted and connected between the first resistor and a power supply input terminal of the device under test, and an LED connected in parallel to the first resistor. Is set to a value at which the LED emits light due to a voltage drop across the resistor when the value of the current flowing through the first resistor exceeds a set value, and the value of the second resistor is set to the value when the device under test is short-circuited. Since the current value is set to a value that does not exceed the predetermined current value even if a certain amount of current or more flows due to a failure such as deterioration of the withstand voltage of the device under test, failure occurs efficiently and safely. The effect is that the device can be identified. That.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a semiconductor device reliability test apparatus according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a semiconductor device reliability test apparatus according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a conventional semiconductor device reliability test apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Test tank 2 Test board 3 Card edge connector part 4 Device under test 5 Protective resistor circuit board 6, 6 'LED light emitting resistor (first resistor) 7, 7' Current limiting resistor (second resistor) 8 LED

Claims (2)

[Claims] In a reliability test apparatus for performing a life test of a semiconductor element, a first resistor connected to a power supply line for supplying a test voltage to each device under test; A second resistor inserted and connected between the power input terminals, and an LE connected in parallel with the first resistor;
D, and when the value of the current flowing through the first resistor exceeds a set value, a voltage drop across the resistor causes the L to decrease.
A reliability test apparatus for a semiconductor device, wherein the value of the second resistor is set to a value that does not exceed a predetermined current value even when the device under test is short-circuited. 2. The reliability test apparatus for a semiconductor device according to claim 1, wherein said first and second resistors are constituted by variable resistors.