JP2000065890A - Lsi test system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LSI test system capable of shortening the measurement time. SOLUTION: An LIS test system 2 is provided with a power supply circuit 9 to supply the power to a device 1 to be measured, a test signal generating circuit 4 to transmit the test signal to the device 1 to be measured, a power supply current measurement circuit 10 to measure the waveform of the power supply current to be supplied from the power supply circuit 9, a signal conversion circuit 11 to convert the measured waveform of the power supply current into the spectrum data, and a signal analysis circuit 12 to analyze a failure of the device 1 to be measured based on the converted spectrum data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an LSI test system used for detecting and analyzing an LSI failure.

[0002]

2. Description of the Related Art Conventionally, there has been an apparatus which applies a test pattern to a device under test such as an LSI, measures a static power supply current for each test pattern, and determines whether or not the device under test has a failure. In this device, as the operation speed of the device under test increases, the speed of the test pattern generated by the device can be increased.

[0003]

However, in this device, it takes time to measure the quiescent power supply current for each test pattern. This is because the performance is limited by the performance of components used in the circuit for measuring the quiescent power supply current. For this reason, in the measurement, the generation speed of the test pattern is reduced to a speed at which the measurement circuit of the quiescent power supply current can operate. Therefore, it takes a considerable amount of time to measure all the quiescent power supply currents of a series of test patterns.
In particular, a series of test patterns may be composed of tens of thousands to hundreds of thousands of patterns, and in such a case, the measurement requires an enormous amount of time.

The present invention has been made in order to solve the above-mentioned problem, and provides an LSI test system capable of shortening a measurement time.

[0005]

According to a first aspect of the present invention, there is provided a power supply circuit for supplying power to a device under test, a test signal generating circuit for transmitting a test signal to the device under test, and a power supply circuit for supplying power from the power supply circuit. Power supply current measurement circuit for measuring a power supply current waveform to be measured, a signal conversion circuit for converting the measured power supply current waveform to spectrum data, and a signal analysis for performing a failure analysis of the device under test based on the converted spectrum data This is an LSI test system having a circuit.

According to a second aspect of the present invention, there is further provided a memory for storing spectrum data obtained from a normally operating device under test, a spectrum data stored in the memory, and a spectrum obtained from the device under test. A comparison circuit for comparing data with the data, the signal analysis circuit,
The L according to claim 1, wherein failure analysis of the device under test is performed based on a comparison result by the comparison circuit.
This is an SI test system.

According to a third aspect of the present invention, there are provided at least a plurality of the power supply circuits, a power supply current measurement circuit, and a signal conversion circuit, and the connection between the plurality of power supply current measurement circuits and the plurality of signal conversion circuits is freely switched. 3. The LSI test system according to claim 1, further comprising a switching unit capable of performing the following.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of the present invention.
Shown in Reference numeral 1 in the figure denotes an LSI to be measured. An LSI test system 2 that tests the LSI 1 to be measured includes a timing generation unit 3, a control unit 4, a power supply unit 5 for a sample, a connection switch 6, a spectrum analysis unit 7, and a memory 8. Although not shown, the sample power supply unit 5 and the spectrum analysis unit 7
A plurality is provided.

The sample power supply unit 5 includes a sample power supply 9,
A power supply current measuring circuit 10 and a power supply voltage measuring circuit 14 are provided. Further, the spectrum analysis unit 7 includes a signal conversion circuit 11, a signal analysis circuit 12, and a comparison determination circuit 13.

The timing generating unit 3 is connected to the control unit 4. The control unit 4 is connected to the sample power supply unit 5 and to each input terminal of the LSI 1 to be measured by a connection line (not shown).

The control unit 4 includes a sample power supply unit 5
Is connected to a sample power supply 9 built in the. The output of the sample power supply 9 is connected to the power supply terminal of the LSI 1 to be measured via the power supply current measurement circuit 10. This power supply terminal is also connected to the input of the power supply voltage measurement circuit 14. The output of the power supply current measurement circuit 10 is connected to one end of the connection switch 6. The outputs of the power supply current measurement circuits incorporated in a plurality of power supply units for samples (not shown) are also connected to one end of the connection switch 6.

The other end of the connection changeover switch 6 is connected to a signal conversion circuit 11 built in the spectrum analysis unit 7, but the same applies to a plurality of spectrum analysis units not shown. The output of the signal conversion circuit 11 is connected to a signal analysis circuit 12, and the output of the signal analysis circuit 12 is connected to a comparison / determination circuit 13. Further, the comparison determination circuit 13 is also connected to the memory 8.

Next, the operation of this embodiment will be described. The timing generation unit 3 outputs a timing signal, and this timing signal is input to the control unit 4. The control unit 4 operates in accordance with the timing signal, and controls the sample power supply 9 built in the sample power supply unit 5. Further, the control unit 4 sends the measured LSI 1 via a connection line (not shown) according to the timing signal.
The test pattern is transmitted to each input terminal of.

The power output from the sample power supply 9 built in the sample power supply unit 5 is supplied to the power supply terminal of the LSI 1 to be measured via the power supply current measurement circuit 10. A power supply voltage measuring circuit 14 is also connected to the power supply terminal, and the applied power supply voltage is detected, and the sample power supply 9 is controlled so as to have a preset power supply voltage. Since a plurality of power supply units for the sample are provided, even if an LSI requires a plurality of power supply voltages, for example, an LSI in which a circuit driven by +5 V and a circuit driven by +3.3 V are mixed, the LSI is required Power can be supplied.

The power supply current measuring circuit 10 measures the power supply current waveform in synchronization with the test pattern output from the control unit 4 and connects the measured current waveform to the connection switch 6.
To the signal conversion circuit 11 via A plurality of power supply current measurement circuits and signal conversion circuits are connected to the connection changeover switch 6, and current waveforms output by the plurality of power supply current measurement circuits can be sent to the plurality of signal conversion circuits, respectively.

The signal conversion circuit 11 converts the sent current waveform into a signal for each frequency component and outputs spectrum data. The output spectrum data is stored in the signal analysis circuit 1
2 is input.

The spectrum data input to the signal analysis circuit 12 is sent to a comparison judgment circuit 13. On the other hand, the spectrum data of the normal LSI is stored in the memory 8 in advance, and the spectrum data of the normal LSI is also sent to the comparison determination circuit 13. The comparison determination circuit 13 compares the two transmitted spectrum data, and returns the comparison result to the signal analysis circuit 12. The signal analysis circuit 12 performs a failure analysis of the measured LSI 1 based on the returned comparison result.

If any failure occurs in the LSI 1 to be measured, for example, if the wiring of the internal circuit is short-circuited or disconnected,
An abnormal power supply current waveform not observed in a normal LSI is observed. As a result, the spectrum data obtained by converting the power supply current waveform also includes the normal LSI and the faulty LSI.
The difference comes out with. Based on this difference, the LSI under test 1
It is determined whether or not there is a failure, and if there is a failure, this failure is analyzed.

Since the static current flowing when the test pattern is applied and caused by the failure of the LSI under test 1 flows repeatedly when the test pattern is repeatedly applied, the power supply current waveform is converted into a frequency component. A component corresponding to the application period appears in the spectrum. on the other hand,
Since the switching current of the internal transistor, which also exists in a normal LSI, has a frequency component different from the static current resulting from the above-described fault, the fault can be detected by distinguishing these components.

In this embodiment, since a plurality of sample power supply units 5 and a plurality of spectrum analysis units 7 are mounted, a plurality of LSIs can be tested at the same time.

[0021]

According to the present invention, a fault can be detected by observing a spectrum, and it is not necessary to take a long time to measure a quiescent power supply current, and a fault can be detected in a short time. Further, since the failure can be detected in a short time, the cost of the LSI test can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of an LSI test system according to the present invention.

[Explanation of symbols]

1 LSI under test (device under test) 2 LSI
Test system 3 Timing generation unit 4 Control unit 5 Power supply unit for sample 6 Connection changeover switch 7 Spectrum analysis unit 8 Memory 9 Power supply for sample 10 Power supply current measurement circuit 11 Signal conversion circuit 12 Signal analysis circuit 13 Comparison judgment circuit

Claims (3)

[Claims] 1. A power supply circuit for supplying power to a device under test, a test signal generation circuit for transmitting a test signal to the device under test, and a power supply current measurement circuit for measuring a power supply current waveform supplied from the power supply circuit An LSI test system comprising: a signal conversion circuit that converts a measured power supply current waveform into spectrum data; and a signal analysis circuit that performs a failure analysis of the device under test based on the converted spectrum data. 2. A memory for storing spectrum data obtained from a normally operating device under test, and a comparing circuit for comparing the spectrum data stored in the memory with the spectrum data obtained from the device under test. 2. The LSI test system according to claim 1, wherein the signal analysis circuit performs a failure analysis on the device under test based on a comparison result obtained by the comparison circuit. 3. 3. A switching means having at least a plurality of the power supply circuits, a power supply current measurement circuit, and a signal conversion circuit, and having a switching means capable of freely switching connections between the plurality of power supply current measurement circuits and the plurality of signal conversion circuits. 3. The LSI test system according to claim 1, wherein: