JPH0648703B2 - Electronic device testing method and testing apparatus therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a test method and a test apparatus for performing non-contact characteristic evaluation or failure detection of an electronic device such as VLSI by a charged beam. Especially MO
The present invention relates to a test method and a test apparatus for measuring the gate leak value of an S capacitor, the junction leak value of a pn junction, the capacitance of a MOS capacitor, and the like.

[Conventional technology]

In order to realize a fine electronic device such as VLSI, it is indispensable to develop a test apparatus and a test method for testing an electronic device during each manufacturing stage. A contact-type test device using a mechanical probe method or the like has been used for the electrical characteristic test of a conventional electronic device (wafer or the like). This type of test apparatus cannot be adapted to the submicron region, particularly in terms of spatial resolution. In order to cope with this, electron beam testers using an electron beam have come to be used. As the electron beam tester, for example, "I
Electron Beam Testing Technology for C ", Scanning Electron Microscopy, 1981, Volume 1, 305 (" ELECT
RON BEAM TEST TECHNIQUES FOR INTEGRATED CIRCUIT
S ", Scanning Electron Microscopy, 1981, vol.1, p.30
Some are listed in 5). FIG. 9 (a) is a diagram showing a device configuration for measuring a potential contrast, and FIG. 9 (b) is a diagram showing a device configuration for measuring a potential signal waveform.

In FIG. 9 (a), 1 is an electron gun, 2 is a lens, 3 is a scan coil for determining an irradiation point of an electron beam, 4 is a scan generator for supplying a current to the scan coil 3, and 5 is a two. Detector for detecting secondary electron SE,
6 is an amplifier for amplifying the output signal of the detector 5, 7 is an IC drive unit for driving the IC to be tested, and 8 is a monitor TV.

Further, in FIG. 9 (b), 9 is a chopper, 10 is a pulse generator for supplying a pulse to the chopper 9, 11 is a phase shifter for performing signal phase shift, 12 is a delay unit for delaying a signal, and 13 is a dual unit. Secondary electron spectrometer, 14 is a linearization unit, and 15 is an oscilloscope plotter. In FIG. 9 (b), the same or corresponding parts as those in FIG. 9 (a) are designated by the same reference numerals.

[Problems to be solved by the invention]

The apparatus shown in FIGS. 9 (a) and 9 (b) inputs a test signal from an external terminal to an electronic device enclosed in an IC package by a contact type means, and uses an electron beam only as a detecting means. Is. Therefore, it has been used for functional inspection of finished products and not for tests in the middle of manufacturing. Further, the electron beam is used as a probe for displaying an image of voltage contrast or observing the time change of the potential at a certain point, and the electron beam has not been used as a voltage supply source.

Also, JP-A-57-196540 or JP-B-4
As disclosed in Japanese Patent Laid-Open No. 5-8820, a part of an electronic device is irradiated with an electron beam, and secondary electrons at that location or at another location are measured by using an energy analyzer or the like to detect gate leakage and disconnection of metal wiring. A test device and method for evaluating the presence / absence have been proposed. However, this method has a problem in that the potential at the irradiation position of the charged beam increases or decreases with time and cannot be kept constant, so that a quantitative characteristic test cannot be performed.

[Means for solving problems]

In order to solve such a problem, the present invention provides an irradiation unit that irradiates a predetermined position of an electronic device with a primary charged beam, a detection unit that detects secondary electrons generated from an irradiated portion, and Control means for controlling the primary charged beam so that the detected amount of secondary electrons is constant, potential measuring means for measuring the potential at the irradiation point of the electronic device, and current measuring means for measuring the substrate current flowing through the substrate of the electronic device. In a test method of an electronic device using a test apparatus equipped with,
The quality of the electronic device is determined based on the relationship between the potential of the irradiation point of the electronic device and the substrate current.

[Action]

In the test apparatus according to the present invention, in addition to the irradiation means for irradiating the predetermined position of the electronic device with the primary charged beam,
Conventionally, an external terminal is provided by having control means for controlling the beam current of the primary charged beam or the on / off ratio of the primary pulsed beam so that the detected amount of secondary electrons generated from the irradiation point of the electronic device becomes constant. The voltage supply, which has been performed from the above, can be performed without contact. Furthermore, the substrate current can be measured simultaneously with the potential at this irradiation point.

Further, in the test method according to the present invention, the substrate current is measured at the same time as the potential, and the device is tested from the substrate current-potential characteristic. Therefore, the gate leak and the junction leak are obtained by using both the values of the substrate current and the potential. Quantitative measurement of devices such as capacitance measurement can be performed.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of an electronic device testing apparatus according to the present invention. The charged beam 22 generated by the charged beam generating source 21 is accelerated by the accelerating source 23 so that the sample stage 35
Is illuminated on the electronic device 34 above. 24 is an aligner, 25
Is an aligner power supply, 26 is a lens, 27 is a lens power supply as control means, 28 is a blanker, 29 is a blanking power supply, 30 is a deflector as irradiation means, 31 is a deflection power supply, 32 is an objective lens, 33 is an objective lens Power. The primary charged beam is deflected by the deflector 30 so as to be irradiated on a predetermined position of the electronic device 34, and the focus is adjusted by the objective lens 32. 36 is an energy analyzer for measuring the potential of the electronic device 34, 37 is a secondary electron detection as a detection means for detecting the secondary electrons emitted from the electronic device 34 and determining the irradiation position of the charged beam 22. It is a vessel. Reference numeral 38 is a potential measuring circuit as a potential measuring means for measuring the potential of the electronic device 34, and its output corresponds to the potential. 39 is an ammeter as a current measuring means for measuring the substrate current. Regarding the energy analyzer 36 and the potential measuring circuit 38, for example, “Secondary electron detection system for quantitative potential measurement”, Scanning, 1983, Vol. 5, p. 151 (“Seconda
ry Electron Detection Systems for Quantitative Vol
"Tage Measurements", SCANNING, 1983, vol, 5.p.151). The output of the potential measuring circuit 38 and the output of the ammeter 39 are input to the display device 40, and the display device 40 displays the substrate current-potential characteristic. Further, the output of the potential measuring circuit 38 is input to the lens power supply 27 that controls the beam current of the primary charged beam in order to fix the potential to a certain value. Here, when the potential is fixed to a negative value, a charged beam (electron beam) that is negatively charged with an acceleration voltage whose secondary electron emission ratio δ is smaller than 1 is used, and when the potential is fixed to a positive value, An electron beam having an accelerating voltage whose secondary electron emission ratio δ is larger than 1 or a charged beam positively charged may be used.
In this apparatus, the beam current is changed by adjusting the lens power supply 27 so that the secondary electron emission amount becomes constant, that is, the electric potential becomes constant. When positively charged, the potential increases as the charged beam 22 is irradiated. Here, the beam current is reduced when the potential has risen to a desired level, and the potential is adjusted to be constant.
Gate leak and junction leak can be measured by measuring the substrate current or the beam current while the potential is fixed. The beam current can be measured using a Faraday cup. Alternatively, Japanese Patent Application Sho 60
As shown by -48069, a secondary electron detection electrode and a secondary electron suppression electrode are provided, and it can be obtained from the sum of both of them and the substrate current flowing through the sample table 35. The latter is more convenient because it is not necessary to align the sample table 35 each time when measuring the beam current.

FIG. 2 is a block diagram showing the second embodiment. Reference numeral 41 is a differentiating circuit for obtaining the time derivative of the substrate current, and 42 is a differentiating circuit for obtaining the time derivative of the potential. In this second embodiment, the ammeter 39
The ratio of the time derivative of the substrate current output from or the substrate current output from the differentiating circuit 41 and the time derivative of the potential output from the potential measuring circuit 38 or the potential output from the differentiating circuit 42 is obtained by the divider 43. It is configured to be displayed on the display device 40. The configuration is the same as that of FIG. 1 except for the configuration for displaying the test results. In the configuration of FIG. 2, the time variation of the substrate current and the potential is detected by the differentiating circuits 41 and 42, and the substrate current or the differential signal thereof and the potential or the time differential thereof are selected by the switches S1 and S2, and the ratio thereof is selected. Is calculated by the divider 43. The quality of the electronic device 34 is determined according to the magnitude of the output of the divider 43. Place a differential amplifier after the divider 43
It is also possible to judge whether the electronic device 34 is good or bad by comparing the output of the above with the reference value and whether it is larger than the reference value. The switching of the switches S1 and S2 is selected according to the measurement item.For example, in the case of leak measurement, the ratio of the potential and the substrate current or the ratio of the differential between the two, and further, the leak when the potential is fixed, The quality of the electronic device 34 can be determined based on the ratio of the potential to the substrate current or the derivative thereof. When the capacitance is measured, the ratio between the substrate current and the time derivative of the potential may be obtained. It is also possible to measure the time change of these values and the potential dependence. Although the differentiation circuits 41 and 42 are used, the potential measurement circuit 38,
The configuration may be such that the output of the ammeter 39 is input to the computer and differential calculation is performed.

Next, the operating principle of this test apparatus will be described. The secondary electron emission ratio δ when an electron beam is irradiated as the primary charged beam has a peak at any accelerating voltage from several hundred volts to about 3,000 volts depending on the material of the sample, and in the region above that, the accelerating voltage is higher. Decreases with increasing. At this time, the secondary electron emission ratio δ becomes larger or smaller than 1 depending on the magnitude of the acceleration voltage. This electron beam is M
When the metal electrode of the OS capacitor is irradiated, the electrode of the electronic device is positively charged if the acceleration voltage is δ> 1, and is negatively charged if δ <1. Therefore, when the electrode is not connected to the external wiring, the potential of the electrode changes with time.

FIG. 3 shows an example of actual measurement of changes in potential and substrate current with time when the MOS capacitor is irradiated with an electron beam at a constant beam current. The semiconductor substrate is silicon, the insulating film is a 1200 Å thick silicon oxide film, and the electrodes are 500 μm square polysilicon. The acceleration voltage is 3 kV, and the case where δ <1 is negatively charged is shown. The potential changes to the negative side with time. The way of the change is exponential, and the change amount is large at first, and gradually decreases and is saturated. On the other hand, the amount of change in the substrate current decreases greatly at first, but the substrate current itself decreases to zero after reaching a certain peak value in a normal MOS capacitor. The substrate current does not decrease to zero in a MOS capacitor with many gate leaks. In order to positively charge the electrode of the MOS capacitor, the electron beam may be irradiated with an acceleration voltage such that δ> 1, or the positively charged ion beam may be irradiated.

FIG. 4 is a characteristic diagram showing an actual measurement example of the relationship between the junction voltage and the substrate current when the pn junction in the well (we11) region formed in the semiconductor substrate is irradiated with an electron beam. Here, the semiconductor substrate is n-type silicon and the well region is p-type. The acceleration voltage is 4 kV and the beam current is 200 pA.
The voltage across the junction and the substrate current increase and saturate over time. The solid line is the substrate current measured by electron beam −
It is the measurement result of the voltage between the junctions, and the broken line is the measurement result using the usual mechanical probe method. In the case of the solid line, the current value of the electron beam is kept constant, whereas in the case of the broken line, the voltage applied to the electrodes is kept constant. For this reason, the substrate current is larger measured in the test apparatus that supplies the current, depending on whether the voltage is supplied or the current is supplied. However, also in the mechanical probe method, when a current source is connected and the same measurement is performed, a substrate current-voltage characteristic as indicated by the solid line can be obtained. In FIG. 4, 47
Is a substrate current of an electronic device with a large leak and defective −
Voltage characteristic curves, and 48 and 49 are substrate current-voltage characteristic curves of non-defective electronic devices. In a defective electronic device, the substrate current rises rapidly with almost no increase in potential from the middle. On the other hand, in a good electronic device, the substrate current saturates or peaks and then decreases.

Next, one embodiment of a method for testing an electronic device according to the present invention will be described with reference to FIGS. The electron beam 22 is applied to a predetermined position on the electronic device 34. Electron beam 22
The potential of the electronic device 34 and the substrate current change with the irradiation of. This change in energy analyzer
36 and potential measuring circuit 38 to measure the potential and ammeter 39
The substrate current is measured in accordance with, and the substrate current-potential characteristic is displayed on the display device 40. Alternatively, the beam current is controlled so that the potential is fixed at a certain value, and the substrate current at that time is measured. This fixed potential is changed and the measurement is repeated, and the result is displayed on the display device 40 as the substrate current-potential characteristic. When determining only the quality of the electronic device 34, one fixed potential may be measured. That is, the fourth
As shown in the figure, the substrate current differs depending on the size of the leak even if the potential is the same. As described above, the solid line in FIG. 4 is the measurement result of the substrate current-junction voltage by the measurement using the electron beam, and the broken line is the measurement result using the ordinary mechanical probe method. For example, the substrate current at a potential of 2 V is 60 to 80 pA in the good device curves 48 and 49, whereas it is 200 pA in the bad device curve 47, which is almost the same as the beam current. This figure shows the measurement when the beam current is kept constant.However, when the potential is fixed, the substrate current is almost the same as in the mechanical probe method indicated by the broken line. Below 20 pA, the curve 47 of the defective device is about 200 pA, which is almost the same as the beam device. Attempting to increase the fixed potential will prevent the potential from rising to that point in the bad device curve 47. This also makes it possible to test the electronic device.

As is clear from FIGS. 3 and 4, the smaller the substrate current, the smaller the leak. Therefore, when determining the quality of the electronic device based on the size of the leak, it is sufficient to measure the time change of the substrate current or its time derivative, but it takes time to know whether the substrate current is saturated.
Therefore, it is faster to measure the potential and test it using the potential or the ratio to the time derivative, and the difference due to the size of the beam current is reflected, and the quality of the electronic device is accurately determined. be able to. When the beam current is kept constant, the ratio dI / dV or I / V of the time derivative (dI / dt) of the substrate current I to the time derivative of the potential (dV / dt) is larger or smaller than a certain value. The quality can be determined by.
That is, in a normal pn junction or MOS capacitor, the substrate current saturates with time, and these values become smaller. However, if the leak is large, the substrate current is not saturated, and these values become large. When the potential is fixed to a certain value, the substrate current or its time derivative and the ratio of the potential, the value of I / V or (dI / dt) / V are small if normal, and these values are large if the leak is large. Grows. Therefore, it is possible to judge the quality of the leak based on the size of these. Fourth
As shown in the figure, the measurement result using the solid line electron beam is asymptotic to the measurement result in which the voltage is supplied using the mechanical probe method of the broken line as the potential increases, that is, as the irradiation time elapses. There is. Therefore, not only the magnitude of the junction leak but also the value of the junction leak can be quantitatively measured from the substrate current-potential characteristic. For example, if the beam current is changed and the substrate current and the potential at the time of saturation are measured, the substrate current-voltage characteristics similar to those of the mechanical probe method can be obtained. When measuring the gate leak and junction leak, the substrate current-voltage characteristics are measured with the same beam current, but by measuring the time derivative of the potential (dV / dt) or the time derivative of the substrate current (dI / dt). Alternatively, it is also possible to quantitatively perform comparison between wafers and chips by measuring a beam current required to fix a certain electric potential.

FIG. 5 is a third diagram of the electronic device testing apparatus according to the present invention.
It is a block diagram which shows the Example of. The primary charged beam 22 is chopped into a pulse beam using a blanker 28, a blanking power source 29, and a blanking aperture 44 by a signal from a pulse control circuit 45. In this device, signals of the same phase for each pulse of the secondary electron signal amount are compared, and the output of the potential measurement circuit 38 is feed-packed to the pulse control circuit 45 so that this value becomes constant, and the pulse beam It is configured to change the on / off ratio of. Other device configurations are the same as those shown in FIG. 1 or 2. There are two methods for changing the on / off ratio: a method of changing the pulse frequency by keeping the pulse width of the pulse beam in the on state constant and a method of changing the pulse width of the on state by keeping the frequency constant. May be used. With this configuration, the potential can be kept constant even in the case of a pulse beam.

FIG. 6 is a waveform diagram showing that the potential of the device having the configuration of FIG. 5 can be kept constant. Fig. 6 (a) ~
(c) shows the change in the potential when the pulse width of the ON state of the pulse beam is changed while keeping the frequency constant. Waveforms 52, 54, 56 and 58 show the time change of the beam current, and 51, 53, 55 and 57 show the time change of the electric potential. Here, the case of being positively charged is taken as an example. That is, as the primary charged beam, a negatively charged beam is irradiated with an accelerating voltage having a secondary electron emission ratio δ of greater than 1, or a positively charged beam. When the electronic device 34 is irradiated with the pulse beam 22, the potential rises when the pulse beam 22 is in the on state and falls when the pulse beam 22 is in the off state. When the OFF state is short, the next pulse is emitted before the electric charge of the previously emitted pulse is sufficiently discharged, so that the potential rises for each pulse as shown in FIG. 6 (a). On the other hand, if the OFF state is long, the electric charge of the previously irradiated pulse is discharged, and the change in the electric potential decreases as shown in FIG. 6 (b), and the electric potential decreases with each pulse or becomes zero. become. However, since the on / off ratio of the pulse beam 22 that keeps this potential constant changes depending on the capacity of the irradiated portion and the magnitude of gate leakage, the on / off ratio cannot be set in advance. To this end, the potential is detected from the secondary electron emission amount δ to adjust the on / off ratio of the pulse beam 22.
As shown in (c), the potential can have a triangular waveform with a constant peak. When the frequency is high, the potential becomes almost constant as shown in Fig. 6 (d). In this device configuration, when the potential is fixed, if the gate leak is large, charges are not accumulated. Therefore, it is necessary to lengthen the ON state of the pulse beam 22 as compared with an electronic device having a small gate leak. Therefore, the size of the gate leak can be identified by monitoring the on / off ratio of the pulse beam that fixes the potential to a certain value.

FIG. 7 is a flow chart for explaining an embodiment of the electronic device testing method according to the present invention. Here, the substrate current and the potential are measured, the above measurement data is input to a computer, and the quality of the electronic device is determined and the capacitance is measured by calculation processing.

First, in step 61, beam alignment is performed. Then, as shown in step 62, start beam irradiation,
The timer is started together with this.

Next, at step 63, the time, substrate current, and potential are measured at certain time intervals shown at step 64 and stored in the memory of the computer. The time interval at this time may be constant, but as shown in FIG. 3, since the time change of the potential / substrate current is large immediately after the irradiation of the charged beam, the time interval is shortened at first, and the time interval is set when the potential becomes saturated. It is more efficient to make it longer.

When the potential becomes saturated in step 65, the process proceeds to step 66. In step 66, it is determined whether or not the substrate current I is saturated. If saturated, the process proceeds to step 67, and if not saturated, the process proceeds to step 71.

In step 67, the irradiation of the primary charged beam and the timer are stopped, and the process proceeds to step 68.

If the substrate current I is not saturated even if the potential is saturated, it means that there is a large amount of leakage. Therefore, in step 71, the irradiation of the primary charged beam and the timer operation are stopped, and then, as shown in step 72, the capacitance is measured. It is determined that the gate leak is large without performing.

When measuring the capacitance, first, the time change of the potential and the substrate current as shown in FIG. 3 is measured, and in step 68, the time change of the charge amount Q is obtained from the time integration of the substrate current I by the following equation. .

Next, as shown in step 69, the capacitance C is changed to C (t) = (dQ / dt)
It is calculated from / (dV / dt) or C (t) = dQ / dV. Here, when the beam current is constant, the capacitance may be calculated by C (t) = I / (dV / dt).

Next, as shown in step 70, this capacitance C or C-
V plot is displayed and these values are
The data is stored in a disk (FD) (not shown).

FIG. 8 is an example of a CV plot measured by this method. The electronic device used for the measurement is a polysilicon gate MOS capacitor formed on a 1200 Å oxide film on an n-type silicon substrate, and the gate metal is 500μ.
It is m square. The solid line 80 is the result of electron beam measurement using this method, and the broken line 90 is the result of qusi-static CV measurement using the mechanical probe method. This measurement is obtained from the changes over time in the potential and the substrate current as shown in FIG. In this case, the potential shifts from zero with the irradiation time. Therefore, the C-V plot of the solid line 80 is also plotted so that the gate voltage deviates from zero as the irradiation time increases. Immediately after the beam irradiation, the capacity using the electron beam method changed more rapidly,
The two experimental results do not match well, but the absolute values of both match well in the region where the potential is saturated. Therefore, the absolute value of the capacitance can be measured in the region where the potential is saturated. Further, in the region where the potential is not saturated, an abnormality in the flat band voltage (V _FB ) of the MOS capacitor can be detected from the rate of increase in capacity and the rise.

Here, the capacity is calculated by measuring the time change of the potential and the substrate current after the start of beam irradiation, but the time change of the potential and the substrate current is measured by changing the beam irradiation condition after fixing the potential to a certain value. Then, the capacity may be obtained.

〔The invention's effect〕

As described above, according to the present invention, the irradiation unit that irradiates the predetermined position of the electronic device with the primary charged beam, the detection unit that detects the secondary electrons generated from the irradiated portion, and the detection amount of the secondary electrons. A test including a control means for controlling the primary charged beam so that the voltage becomes constant, a potential measuring means for measuring the potential at the irradiation point of the electronic device, and a current measuring means for measuring the substrate current flowing through the substrate of the electronic device. In the test method of the electronic device using the apparatus, since the quality of the electronic device is determined by the relationship between the potential at the irradiation point of the electronic device and the substrate current, the potential at a predetermined position on the non-contact fine electronic device is determined. It is possible to set the leak value, capacity and its voltage dependence, quantitative measurement of the threshold voltage of the transistor, etc. That.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an electronic device testing apparatus according to the present invention, FIG. 2 is a block diagram showing a second embodiment, and FIG. 3 is a case where a MOS beam is irradiated with a charged beam. FIG. 4 is a characteristic diagram showing an example of actual measurement of changes in electrode potential and substrate current with time. FIG. 4 shows changes in electrode potential and substrate current with time when a pn junction in a well region formed in a semiconductor substrate is irradiated with a charged beam. 5 is a characteristic diagram showing an actual measurement example, FIG. 5 is a configuration diagram showing a third embodiment of an electronic device testing apparatus according to the present invention, and FIG. 6 explains the principle of fixing a potential by the apparatus of FIG. FIG. 7 is a flow chart for explaining an embodiment of an electronic device testing method according to the present invention, and FIG. 8 is a measurement example of a capacitance of a MOS capacitor measured by this method (CV plot). ) Is a characteristic diagram showing It is a block diagram showing a test device of the child device. 21 …… Charged beam generator, 22 …… Charged beam, 23 …… Acceleration source, 24 …… Aligner, 25 …… Aligner power supply, 26 …… Lens, 27 …… Lens power supply, 28 …… Blanker, 29 …… Blanking power supply, 30 …… deflector, 31 …… deflection power supply, 32 ……
Objective lens, 33 ... Objective lens power supply, 34 ... Electronic device, 35 ... Sample stage, 36 ... Energy analyzer, 37 ... Secondary electron detector, 38 ... Potential measuring circuit, 39 ... Ammeter , 40
...... Display device.

Front page continued (72) Inventor Meihei Fujinami 3-1, Morinosato Wakamiya, Atsugi City, Kanagawa Prefecture At Nippon Telegraph and Telephone Corporation Atsugi R & D Laboratories (72) Inventor Nobuo Shimazu 3-1, Morinosato Wakamiya, Atsugi City, Kanagawa Japan Telegraph Telephone Atsugi Research Institute of Electrical Communication

Claims (5)

[Claims] 1. An irradiation means for irradiating a predetermined position of an electronic device with a primary charged beam, a detection means for detecting secondary electrons generated from an irradiated portion, and a detection amount of the secondary electrons becomes constant. As described above, a test apparatus including a control unit that controls the primary charged beam, a potential measuring unit that measures the potential of the irradiation point of the electronic device, and a current measuring unit that measures the substrate current flowing through the substrate of the electronic device. A test method for an electronic device to be used, wherein the quality of the electronic device is determined based on a relationship between a potential of an irradiation point of the electronic device and a substrate current. 2. The test method for an electronic device according to claim 1, wherein the relationship between the potential at the irradiation point of the electronic device and the substrate current is a change in the substrate current with respect to the potential at the irradiation point. . 3. The relationship between the electric potential at the irradiation point of the electronic device and the substrate current is calculated by differentiating the electric charge amount obtained from the integral of the substrate current with respect to the electric potential at the irradiation point, that is, the time derivative of the electric charge amount and the time derivative of the electric potential. The method for testing an electronic device according to claim 1, wherein the ratio is a ratio. 4. The test method for an electronic device according to claim 1, wherein the relationship between the potential at the irradiation point of the electronic device and the substrate current is a ratio of the time derivative of the substrate current and the potential. . 5. An irradiation unit that irradiates a predetermined position of an electronic device with a primary charged beam, a detection unit that detects secondary electrons generated from an irradiated portion, and a detection amount of the secondary electrons becomes constant. As described above, the control means for controlling the primary charged beam, the potential measuring means for measuring the potential of the irradiation point of the electronic device, and the current measuring means for measuring the substrate current flowing in the substrate of the electronic device are provided. Test equipment for electronic devices.