JPH10339756A - Method for inspecting short-circuiting between pins and lsi-testing device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform inspection in a short time by grounding the power supply terminal and the grounding terminal of an LSI (DUT) to be tested, applying each different voltage to each signal pin of the DUT, measuring current that flows to each signal pin of the DUT, and judging whether the signal pin failed or not when a current value indicates an abnormal value. SOLUTION: An LSI-testing device controls voltage source/current measuring circuits 4a-4d according to control signals 101-104 and applies each different voltage to each signal pin of DUT 1 simultaneously. The circuits 4a-4d measure current that flows to each signal pin of the DUT 1. The circuit 4a measures a current value of approximately 100 mA, the circuits 4b and 4c measure -10 mA and 10 mA, and the circuit 4d measures several lens of μA. The voltage source/current measurement circuit measures a current value that is approximately several lens of μA when the signal pin is normal. The power supply terminal and the grounding terminal of the DUT 1 are grounded and at the same time each different voltage is applied to each signal pin and a current value is measured, thus inspecting short-circuiting between pins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LSI under test (hereinafter referred to as a DUT (Device un
der test). In particular, the present invention relates to an inspection method capable of determining which pin is defective in one inspection and an LSI test apparatus using the inspection method.

[0002]

2. Description of the Related Art A short-circuit test between pins performed by a conventional LSI test apparatus is a test for judging whether a signal pin of a DUT is short-circuited with another signal pin, a power supply terminal or the like.

FIG. 2 is a configuration block diagram showing an example of such a conventional method of inspecting for shorts between pins. In FIG. 2, 1 is a DUT, 2a, 2b, 2c and 2d are voltage source / current measurement circuits having both a DC voltage source and a current measurement circuit.
00a, 100b, 100c and 100d are control signals.

The control signals 100a, 100b, 100c and 100d are input to voltage source / current measuring circuits 2a, 2b, 2c and 2d, and are supplied to the voltage source / current measuring circuits 2a, 2b, 2d.
The outputs of 2c and 2d are connected to each signal pin of DUT1. The power terminal and the ground terminal of the DUT 1 are both grounded.

Here, a method of inspecting for short-circuit between pins shown in FIG. 2 will be described. The LSI test equipment has control signals 100 to 10
0d controls the voltage source / current measurement circuits 2a to 2d to simultaneously apply a voltage of about several hundred mV to each signal pin of the DUT 1.

At the same time, a voltage source / current measuring circuit 2a
2d measures the current flowing through each signal pin of the DUT1.

If a certain signal pin is short-circuited with a power supply terminal or a ground terminal, an abnormal current flows.
When an abnormal current flows, the SI test apparatus determines that the corresponding signal pin is defective.

As a result, it is possible to perform a short-circuit test between DUT pins by grounding the power supply terminal and the ground terminal and simultaneously applying a voltage to all signal pins to determine the presence or absence of an abnormal current.

However, in the pin-to-pin short-circuit test shown in FIG. 2, since the same voltage is applied to all the signal pins, if the signal pins are short-circuited, the abnormal current as described above does not flow. Cannot be detected.

FIG. 3 is a block diagram showing another example of a conventional method for inspecting short-circuits between pins which solves such a problem. In FIG. 3, 1, 2a-2d and 100a-1
00d has the same reference numerals as in FIG. 2, and 3a, 3b, 3
c and 3d are switch circuits.

The control signals 100a, 100b, 100c and 100d are input to voltage source / current measuring circuits 2a, 2b, 2c and 2d, and are supplied to the voltage source / current measuring circuits 2a, 2b, 2d.
Outputs of 2c and 2d are connected to one input terminals of switch circuits 3a, 3b, 3c and 3d, respectively.

The output terminals of the switch circuits 3a to 3d are DU
The power supply terminal and the ground terminal of the DUT 1 and the other input terminals of the switch circuits 3a to 3d are connected to the respective signal pins of the T1.

Here, a method of inspecting for a short between pins shown in FIG. 3 will be described. The LSI test apparatus controls the voltage source / current measurement circuit 2a by the control signal 100a to output a voltage of about several hundred mV, and switches the switch circuits 3a, 3b,
3c and 3d are controlled, respectively, as shown in FIG.
The input terminals shown in "b", "c" and "d" are selected.

Since the switch circuit 3a selects the input terminal indicated by "a" in FIG. 3, the output voltage of the voltage source / current measuring circuit 2a is applied to the signal pin indicated by "e" in FIG. .

On the other hand, the switch circuits 3b to 3d are shown in FIG.
Since the input terminals shown in "b" to "d" are selected,
The signal pins other than the signal pin shown in FIG.

The voltage source / current measuring circuit 2a is a DUT
The current flowing through the signal pin indicated by "e" in FIG. 3 is measured.

If the signal pin indicated by "e" in FIG. 3 is short-circuited to the power supply terminal, the ground terminal or another signal pin, an abnormal current flows. The signal pin indicated by "e" in 3 is determined to be defective.

Similarly, each of the other signal pins has a good
The defect of the DUT 1 is determined by sequentially inspecting the defects.

As a result, the signal pins other than the signal pin to be inspected, the power supply terminal and the ground terminal are grounded, and a voltage is applied to the signal pin to be inspected to determine whether there is an abnormal current. It is possible to perform a pin-to-pin short-circuit inspection including

[0020]

However, in the pin-to-pin short test shown in FIG. 3, a short circuit between signal pins can be detected, but the test must be performed by the number of signal pins of the DUT 1, so that the test time becomes long. Sisters,
There is a problem that the throughput of the whole inspection is deteriorated. Therefore, the problem to be solved by the present invention is:
An object of the present invention is to realize an inspection method capable of performing a short-circuit inspection between pins in a short time and an LSI test apparatus using the inspection method.

[0021]

According to a first aspect of the present invention, a power supply terminal and a ground terminal of a DUT are grounded, and different signal voltages are applied to signal pins of the DUT. And measuring a current value flowing through each signal pin of the DUT, and determining that the signal pin is defective when the current value indicates an abnormal value.

According to a second aspect of the present invention, there is provided a second aspect of the present invention wherein, when there are two signal pins through which a current having the same absolute value of the abnormal value flows, the second signal pin has the same absolute value. This is characterized in that it is determined that two signal pins are short-circuited.

In order to achieve the above object, according to a third aspect of the present invention, there is provided an LSI for inspecting a short circuit between pins of a DUT.
In the test apparatus, a voltage is applied to each signal pin of the DUT whose power supply terminal and ground terminal are grounded, and
A voltage source / current measuring circuit for measuring a current value flowing through each signal pin of the UT, wherein different voltages are applied to each signal pin of the DUT, and the signal indicates an abnormal value when the current value indicates an abnormal value; It is characterized by judging a defective pin.

According to a fourth aspect of the present invention, in the fourth aspect of the present invention, when there are two signal pins through which currents having the same absolute value of the abnormal value flow, there is provided a second aspect. It is characterized in that it is determined that two signal pins are short-circuited.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a configuration of an embodiment of a method for inspecting short-circuits between pins according to the present invention.

In FIG. 1, reference numeral 1 denotes the same reference numeral as in FIG. 2, and reference numerals 4a, 4b, 4c and 4d denote voltage source / current measuring circuits having both a DC voltage source and a current measuring circuit;
2, 103 and 104 are control signals, 5a, 5b, 5c,
5d, 5e, 5f, 5g and 5h are protection diodes inside the DUT 1.

Control signals 101, 102, 103 and 10
4 is input to voltage source / current measuring circuits 4a, 4b, 4c and 4d.

The output of the voltage source / current measuring circuit 4a is a DUT
1 and connected to the anode of the protection diode 5a and the cathode of the protection diode 5b.

Similarly, the output of the voltage source / current measurement circuit 4b is connected to the signal pin of the DUT 1 and connected to the anode of the protection diode 5c and the cathode of the protection diode 5d.
The voltage source / current measurement circuit 4c is connected to the signal pin of the DUT 1 and connected to the anode of the protection diode 5e and the cathode of the protection diode 5f by the voltage source / current measurement circuit 4d.
Are connected to the signal pin of the DUT 1 and to the anode of the protection diode 5g and the cathode of the protection diode 5h, respectively.

The cathodes of the protection diodes 5a, 5c, 5e and 5g are connected to a power supply terminal, and the power supply and ground terminals of the DUT 1 and the protection diodes 5b, 5d, 5f.
And 5h anodes are grounded.

Here, the method of inspecting for a short between pins shown in FIG. 1 will be described. The LSI test equipment controls the control signals 101 to 10
4 controls the voltage source / current measuring circuits 4a to 4d to
A voltage of a different value is simultaneously applied to each signal pin of the UT1.

At the same time, the voltage source / current measuring circuit 4a
4d measure the current flowing through each signal pin of the DUT1.

For example, the voltages applied to "A", "B", "C" and "D" in FIG.
2 "," Vf3 ", and" Vfn ", and the respective voltage values are Vf1 = 0.10V (1) Vf2 = 0.11V (2) Vf3 = 0.12V (3): Vfn = 0.50V (4 ).

If the signal pin indicated by "d" in FIG. 1 is normal, a current of about several tens of .mu.A flows through the power supply terminal via the protection diode 5g as indicated by "e" in FIG.

On the other hand, the signal pin indicated by "A" in FIG.
Assuming that the power supply terminal or the ground terminal of T1 is short-circuited, the voltage applied to the signal pin "A" in FIG.
Since the power supply terminal of the UT 1 is grounded through the power supply terminal, an abnormal current flows as indicated by "f" in FIG.

As shown in equation (1), since the voltage of "Vf1 = 0.10 V" is applied to the signal pin shown by "A" in FIG. 1, the signal pin shown by "A" in FIG. Assuming that the resistance value between them is about 1 Ω, the abnormal current “Ierr1” indicated by “f” in FIG. 1 becomes Ierr1 = 0.10V / 1Ω = 100 mA (5).

Further, when the signal pins indicated by "b" and "c" in FIG. 1 are short-circuited, an abnormal current flows as indicated by "g" in FIG. 1 because a potential difference exists between the signal pins.

As shown in equations (2) and (3), FIG.
The signal pins shown in the middle “b” and “c” have “Vf2 = 0.
Since the voltages of 11 V "and" Vf3 = 0.12 V "are applied, if the resistance value between each signal pin is set to about" 1Ω ", the abnormal current" Ierr2 "shown by" G "in FIG. (0.12V-0.11V) / 1Ω = 10mA (6)

That is, the voltage source / current measuring circuit 4a is set to "10
A current value of about 0 mA "is measured, the voltage source / current measurement circuits 4b and 4c measure current values of about" -10 mA "and" 10 mA ", and the voltage source / current measurement circuit 4d measures" number 10 ".
A current value of about μA ″ will be measured.

Therefore, when the signal pin is normal, the voltage source / current measuring circuit measures a current value of about “several tens μA”, and when the signal pin is short-circuited to the power terminal or the ground terminal of the DUT 1, A current value of about “100 mA” is measured by the voltage source / current measurement circuit.

When the signal pins are short-circuited, a positive current value is measured by the voltage source / current measuring circuit on the signal pin side where the applied voltage is high, and the applied voltage is low on the signal pin side. A negative current value will be measured by the source / current measurement circuit.

That is, if an abnormal current value exceeding about several tens of μA is measured in the voltage source / current measuring circuit, it is understood that the signal pin is abnormal, and if an abnormal current having the same absolute value is detected. If measured, the corresponding signal pins are short-circuited.

As a result, the power supply terminal and the ground terminal of the DUT 1 are grounded, and a voltage source / current measuring circuit simultaneously applies different voltages to each signal pin to measure the current value flowing through each signal pin. Thereby, it is possible to perform a short-circuit inspection between pins.

Further, when signal pins are short-circuited in one inspection, it is possible to specify which signal pin is short-circuited.

Furthermore, unlike the conventional example shown in FIG. 3, there is no need to sequentially select signal pins to be measured by a switch circuit, so that a short-circuit inspection between pins can be performed in a short time.

In the embodiment shown in FIG. 1, voltages of "0.10 V" to "0.01 V" are sequentially applied to each signal pin of the DUT 1. However, the present invention is not limited to this. What is necessary is just to select suitably according to the number of signal pins, the maximum rating of signal pins, etc.

[0047]

As is apparent from the above description,
According to the present invention, the following effects can be obtained. By grounding the power supply terminal and the ground terminal of the DUT and simultaneously applying different voltages to each signal pin by a voltage source / current measuring circuit and measuring the current value flowing through each signal pin, the pins can be quickly connected. An inspection method capable of performing an inter-short inspection and an LSI test apparatus using the inspection method can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a short-circuit inspection method between pins according to the present invention.

FIG. 2 is a configuration block diagram showing an example of a conventional method of inspecting for shorts between pins.

FIG. 3 is a configuration block diagram showing another example of the conventional method of inspecting for shorts between pins.

[Explanation of symbols]

1 DUT 2a, 2b, 2c, 2d, 4a, 4b, 4c, 4d Voltage source / current measurement circuit 3a, 3b, 3c, 3d Switch circuit 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h Protection diode 100a , 100b, 100c, 100d, 101, 1
02, 103, 104 control signal

Claims (4)

[Claims] 1. A power supply terminal and a ground terminal of a DUT are grounded, voltages of different values are applied to respective signal pins of the DUT, and a current value flowing through each signal pin of the DUT is measured. A short-circuit inspection method between pins for determining a failure of the signal pin when the signal indicates an abnormal value. 2. The pin according to claim 1, wherein when there are two signal pins through which a current having the same absolute value of the abnormal value flows, it is determined that the two signal pins are short-circuited. Short circuit inspection method. 3. An LSI for inspecting a short circuit between pins of a DUT.
A test apparatus, comprising: a voltage source / current measurement circuit that applies a voltage to each signal pin of the DUT to which a power terminal and a ground terminal are grounded and measures a current value flowing to each signal pin of the DUT. An LSI test apparatus, wherein different voltage values are applied to respective signal pins, and when the current value indicates an abnormal value, a defect of the signal pin is determined. 4. When there are two signal pins through which a current having the same absolute value of the abnormal value flows, it is determined that the two signal pins are short-circuited. Item 3. An LSI test apparatus according to Item 3.