JPH0894719A - Diagnostic device for analog integrated circuit - Google Patents

Abstract

PURPOSE: To specify the failed part of an analog integrated circuit without physically contacting it. CONSTITUTION: An energy beam generator 1 and an energy beam scanner 2 are used to scan a chip of a device 7 to be measured. A constant voltage generated by a constant voltage source 5 is supplied to the device 7 through a fluctuation current detection/amplifier 6. The fluctuation value of the supply current is observed and amplified by the fluctuation current detection/amplifier 6. A test signal generated by a signal generator 10 is applied to the device 7. The data of current fluctuation value observed and processed by the fluctuation current detection/amplifier 6 are sent to a system control/signal processing unit 4 and are converted to brightness. Further, energy beam application position information from an energy beam generator 1 and an energy beam scanner 2 is received and is sent to a CRT 3 along with the brightness information. The CRT 3 configures and displays an image from the sent brightness information and the energy beam application position information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for diagnosing a fault in an analog integrated circuit, and more particularly to a device for diagnosing a fault in an analog integrated circuit by observing a current flowing through a wiring.

[0002]

2. Description of the Related Art A conventional analog integrated circuit fault diagnosis apparatus is used for the purpose of pursuing the cause of an analog integrated circuit manufactured when the analog integrated circuit does not operate as designed, and making an improvement. FIG. 5 is a diagram illustrating an example of a conventional analog integrated circuit failure diagnosis apparatus. The probe 104 is physically brought into contact with an appropriate portion of the integrated circuit chip 103 of the analog integrated circuit device 105 to be measured. The measuring device 101 is connected to the probe 104, and can measure a voltage of a portion where the probe 104 is in contact. The device drive system 102 generates voltages, currents, and signals for operating and testing the integrated circuit device 105.

Next, the operation will be described. The device driving system 102 is operated under the condition of testing the function of the integrated circuit device 105. At this time, the voltage at the portion where the probe 104 is brought into contact is observed by the measuring instrument 101. Based on this data, the state of the current flowing through each wiring inside the circuit is known. Failure diagnosis is performed by comparing this state with design data or with a normally operating equivalent integrated circuit.

[0004]

In this conventional analog integrated circuit failure diagnosing device, it is necessary to physically contact the probe with the circuit to be measured. It's getting harder to raise a needle. In addition, the probe itself acts as a load on the circuit to be measured and may affect the operation of the circuit. Further, there is a problem that the circuit to be measured itself is destroyed by standing the probe.

In order to solve the above problems, it is an object of the present invention to perform fault diagnosis by measuring the current of each part of the circuit under test without physically contacting the circuit under test.

[0006]

The first invention of the present invention is as follows:
An energy beam generator for generating an energy beam, an energy beam scanner for receiving and scanning the energy beam from the energy beam generator, a data base for stably loading the device under test, and generating a constant voltage. A constant voltage source, receives the constant voltage, supplies a constant voltage to the device under test, observes the supplied current at this time,
Receiving a fluctuating current detection / amplifier for amplifying the fluctuating value, energy beam generation information from the energy beam generator, and energy beam irradiation position information from the energy beam scanner; A system control / signal processing unit that uses the fluctuation value of the supply current to the energy beam irradiation position for each energy beam irradiation position, and a CRT that displays an image based on the energy beam irradiation position information and the luminance information from the system control / signal processing unit. And a signal generator for applying a test signal to the device under test.

According to a second aspect of the present invention, in the first aspect, a temperature control unit for keeping the temperature of the device to be measured constant is provided.

According to a third aspect of the present invention, in the first aspect, a layout information storage means for storing layout information of a chip of a device under test, and a gate for generating a gate signal for controlling an energy beam from the layout information It has a signal generator, an energy beam generator that receives the gate signal and controls generation of an energy beam, and an energy beam scanner.

According to a fourth aspect of the present invention, in the first aspect, layout information storage means for storing layout information of a chip of a device under test;
A gate signal generator for generating a gate signal indicating that the beam irradiation position is in the wiring area on the chip of the device under test from the beam irradiation position information from the energy beam scanner, and receiving the gate signal and receiving the energy beam. Has a system control / signal processing unit that processes a signal from a fluctuating current detection / amplifier only when the wiring area is irradiated.

[0010]

The fault diagnosis apparatus for an analog integrated circuit according to the present invention detects and specifies a fault location by observing a static current value flowing through each wiring in a circuit under test by a physically touching method. Is possible. Normally, it is difficult to observe the current of each part of the circuit without changing the circuit, but in the present invention, the temperature rise of the irradiation part caused by the irradiation of the energy beam is utilized to make the wiring in the integrated circuit The electric resistance value of is locally changed minutely,
The current flowing through the wiring in the circuit is observed by detecting the fluctuation of the supplied current caused by this. Further, by scanning the portion where the electric resistance value of the wiring is locally changed, it is possible to obtain an image of the state of the current flowing in the circuit. The current image thus obtained is compared with the current image in a normal circuit, or the design value is referred to identify the failure location.

[0011]

The present invention will be described below with reference to the drawings.

FIG. 1 is an apparatus configuration diagram showing an embodiment of the first invention.

In FIG. 1, an energy beam scanner 2 receives an energy beam from an energy beam generator 1 and irradiates a device under test 7 with the energy beam. The system control / signal processing unit 4 receives the beam irradiation position information from the energy beam scanner 2, the energy beam generation information from the energy beam generator 1, and also the data from the variable current detection / amplifier 6. Then, the result of the signal processing is displayed on the CRT 3. The device under test 7 is placed on the data base 8 and held stably. The fluctuating current detection / amplifier 6 receives a constant voltage from the constant voltage source 5 and supplies it to the device under test 7. Further, it receives the fluctuation information of the supply current to the device under test 7 and sends it to the system control / signal processing unit 4. The signal generator 10 generates a test signal and applies it to the device under test.

Next, the operation of the circuit shown in FIG. 1 will be described.
The energy beam generated by the energy beam generator 1 is introduced into an energy beam scanner 2. The energy beam scanner 2 irradiates the beam while narrowing it down (for example, with a diameter of 1 μm or less) onto a chip to be measured of the device to be measured 7. The constant voltage generated by the constant voltage source 5 passes through the variable current detection / amplifier 6 and the device under test 7
Is supplied to. The signal generator 10 generates a test signal for the device under test 7 and applies it to the device under test 7.
When the energy beam is irradiated on the chip to be measured, the temperature of the irradiated portion rises. However, when the irradiated portion is a wiring region, the electric resistance of the irradiated portion increases with a local temperature rise. The increase in the electric resistance of the wiring changes the current supplied from the constant voltage source 5 when a current flows through the wiring. This fluctuating current is observed by the fluctuating current detection / amplifier 6 and the information is transmitted to the system control / signal processing unit 4.
Send to Further, the system control / signal processing unit 4 includes the energy beam generator 1 and the energy beam scanner 2
The irradiation information of the energy beam is received from and the magnitude of the fluctuating current is displayed as brightness on the CRT 3 for each irradiation position of the beam. The supply current to the device under test 7 fluctuates when the energy beam is applied to the wiring area where the current flows, and the supply current to the device 7 when the energy beam is applied to the wiring area where no current flows. Does not change, the current-carrying wiring is displayed as an image on the CRT 3.

A method of diagnosing a device under test using the analog integrated circuit fault diagnosing apparatus according to the present invention includes the following steps. By using the present invention, it is possible to observe which current is flowing through which wiring in the device under test, and by comparing the two, it is possible to diagnose a fault location in the device under test. Become. Alternatively, it is possible to diagnose a failure location by observing the same device that is operating normally under the same conditions and comparing it with the observation result of the failure device. Since this diagnosis is a simple comparison between the design value and the observed value, or the current value of a normal device and the current value of an abnormal device, it is possible to diagnose a failure in a short time. Further, a failure location is often directly linked to a wiring through which an abnormal current flows, and accurate diagnosis can be made by comparing these current values. Furthermore, because of the simple configuration of observing the current value while irradiating and scanning the energy beam, a simple failure diagnosis device can be realized.

FIG. 2 shows an embodiment of the second invention.

In FIG. 2, a temperature control unit 9 is connected to the material table 8. The temperature of the chip of the device under test 7 is kept constant by the temperature control unit 9. In the present invention, a change in the temperature of the irradiation part due to the irradiation of the energy beam is reflected on a change in the supply current, and the change is measured and used. Therefore, by maintaining the chip surface temperature constant, high-precision measurement with little noise can be performed.

FIG. 3 shows an embodiment of the third invention.

In FIG. 3, the layout information storage means 13 of the device under test 7 is connected to a gate signal generator 14, and the gate signal generator 14 is connected to the energy beam generator 1.
It is connected to the. It is also connected to the energy beam scanner 2. The gate signal generator 14 extracts information on the wiring region on the chip of the device under test 7 from the layout information storage unit 13 and obtains position information of the energy beam irradiation unit from the energy beam scanner 2.
Then, the energy beam is turned on so that only the wiring part is irradiated with the energy beam on the chip of the device under test.
-Off or a gate signal for controlling the intensity of the beam power is generated and sent to the energy beam generator 1.
By irradiating the energy beam only to the wiring region on the chip of the device under test 7, the measurement of the fluctuation value of the supply current can prevent noise caused by irradiating the energy beam outside the wiring region. Measurement of a fluctuating current having a high / N ratio can be realized.

FIG. 4 shows an embodiment of the fourth invention. Figure 4
The gate signal generator 14 is then connected to the energy beam scanner 2 and the system control / signal processing unit 4. From the layout information storage means 13 to the device under test 7
And information on the irradiation position of the energy beam from the energy beam scanner 2 is obtained.
Then, the gate signal generator 14 performs signal processing on the fluctuation value of the supply current only when the energy beam irradiates the wiring area on the chip of the device under test 7 with the system control / signal processing unit 4, and the energy other than the wiring area is subjected to energy processing. The fluctuation value of the supply current when the beam irradiates generates a gate signal which is not processed. With this configuration, when the fluctuation value of the supply current is measured, noise caused by the fluctuation of the supply current is removed when the energy beam is irradiated to a region other than the wiring region, so that observation with less noise can be realized.

[0021]

As described above, in the fault diagnosing apparatus for an analog integrated circuit according to the present invention, the electric resistance of the wiring changes due to the local temperature change of the irradiation part due to the irradiation of the energy beam onto the chip of the device under test. Is regarded as a change in the supply current, and is physically non-contact with the device under test. Therefore, compared with the measurement of the voltage, current, etc. inside the circuit of the device under measurement due to the physical contact of the probe, there is no adverse effect on the circuit and there is no danger of physically destroying the circuit. Further, since the current of the wiring of the chip of the device to be measured is observed by scanning with the energy beam, one measurement time can be extremely short, and the measurement can be speeded up.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing an embodiment of a first invention.

FIG. 2 is a device configuration diagram showing an embodiment of a second invention.

FIG. 3 is an apparatus configuration diagram showing an embodiment of the third invention.

FIG. 4 is a device configuration diagram showing an embodiment of a fourth invention.

FIG. 5 is a device configuration diagram showing an embodiment of a conventional failure diagnosis device.

[Explanation of symbols]

 Reference Signs List 1 energy beam generator 2 energy beam scanner 3 CRT 4 system control / signal processing unit 5 constant voltage source 6 fluctuating current detection / amplifier 7 device under test 8 reference table 9 temperature control unit 10 signal generator 13 layout information storage means 14 Gate signal generator 101 Measuring device 102 Device driving system 103 Chip to be measured 104 Probe 105 Analog integrated circuit device to be measured

Claims (8)

[Claims] An apparatus for diagnosing a failure of an integrated circuit by observing a wiring current of an analog integrated circuit, comprising: an energy beam generator for generating an energy beam; and an energy beam for receiving the energy beam from the energy beam generator and scanning the beam. A beam scanner, a data base for stably loading the device under test, a constant voltage source for generating a constant voltage, receiving the constant voltage, supplying a constant voltage to the device under test, and observing a supply current at this time. ,
Receiving a fluctuating current detection / amplifier for amplifying the fluctuating value, energy beam generation information from the energy beam generator, and energy beam irradiation position information from the energy beam scanner; A system control / signal processing unit that uses the fluctuation value of the supply current to the measuring device as luminance information for each energy beam irradiation position, and displays an image based on the energy beam irradiation position information and luminance information from the system control / signal processing unit. A fault diagnosis apparatus for an analog integrated circuit, comprising: a CRT; and a signal generator for applying a test signal to a device under test. 2. A fault diagnosis apparatus for an analog integrated circuit according to claim 1, further comprising a temperature control unit for keeping the temperature of the device under test constant. 3. A layout information storage means for storing layout information of a chip of a device to be measured, an energy beam generator for receiving the layout information to turn on / off an energy beam or to control the intensity of the power, and an energy beam scan. 2. The apparatus according to claim 1, further comprising a vessel.
A fault diagnosis device for an analog integrated circuit according to the above. 4. The beam irradiation position on the chip of the device under test is determined based on the layout information storage means storing the layout information of the chip of the device under test and the beam irradiation position information from the layout information and the energy beam scanner. A gate signal generator for generating a gate signal notifying that the wiring area is present, and a system control / processing for processing the signal from the variable current detection / amplifier only when the energy beam irradiates the wiring area with the gate signal. The fault diagnosis device for an analog integrated circuit according to claim 1, further comprising a signal processing unit. 5. The method according to claim 1, wherein a laser beam generator is used as said energy beam generator.
3. A fault diagnostic device for an analog integrated circuit according to 3 or 4. 6. An electron beam generator is used as the energy beam generator.
Alternatively, the fault diagnosing device for an analog integrated circuit as described in 4 above. 7. The energy beam generator according to claim 1, wherein a particle beam generator is used.
Alternatively, the fault diagnosing device for an analog integrated circuit as described in 4 above. 8. The fault diagnosis apparatus for an analog integrated circuit according to claim 7, wherein an ion beam generator is used as said particle beam generator.