DEVICE INSPECTION APPARATUS AND DEVICE INSPECTION METHOD

Abstract

To provide a technique in which the property of a device to be inspected can be inspected regardless of its state in a short time.SOLUTION: A device inspection apparatus of an embodiment of the present invention comprises: a voltage source for applying a voltage to a device to be inspected; multiple resistors connected in series between the voltage source and the device; a detection unit for detecting a potential difference between both ends of a resistor group including one or more resistors among the multiple resistors; a switching unit for switching the resistor group in which the detection unit detects the potential difference from among the multiple resistors; and a control unit. The control unit is configured so as to control the detection unit and the switching unit so that the potential differences between both ends of the two or more different resistor groups can be detected, and that the potential differences can be detected in ascending order of the combined resistance values between both ends of the resistor groups.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a device inspection apparatus and a device inspection method. [Background technology]

[0002] There is known a device inspection apparatus that applies a voltage to a device to be inspected to inspect the device (see, for example, Patent Document 1). In Patent Document 1, the inspection is performed by switching power supply circuits connected in parallel according to a preset range of the measurement current. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-41997 A Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a technique that can inspect device characteristics in a short time, regardless of the state of the device being inspected. [Means for solving the problem]

[0005] A device testing apparatus according to one embodiment of the present disclosure includes a voltage source that applies a voltage to a device to be tested, a plurality of resistors connected in series between the voltage source and the device, a detection unit that detects a potential difference across a resistor group including one or more of the plurality of resistors, a switching unit that switches the resistor group for which the detection unit detects a potential difference from the plurality of resistors, and a control unit, wherein the control unit is configured to control the detection unit and the switching unit to detect a potential difference across at least two or more different resistor groups, and is configured to control the detection unit and the switching unit to detect the potential difference in order of decreasing combined resistance value across the resistor groups, The control unit controls the voltage source so that a current is supplied to all of the plurality of resistors, and in a state in which a current is supplied to all of the plurality of resistors, The switching unit selects the resistor group having the lowest combined resistance value, and the detection unit No. 1 After a time has elapsed, a potential difference between both ends of the lowest resistor group is detected, and then the switching unit selects a resistor group having a higher combined resistance value than the lowest resistor group, and the detection unit: After the second hour has elapsed Detecting the potential difference across the resistor group death , The start point of the first time period and the start point of the second time period are times when current begins to flow through all of the plurality of resistors. . Effect of the Invention

[0006] According to the present disclosure, device characteristics can be inspected in a short time regardless of the state of the device being inspected. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing an example of an electric circuit of a device inspection apparatus according to a first embodiment; [Diagram 2] A flowchart showing an example of the operation of the device inspection apparatus of FIG. 1. [Diagram 3] 2 is a timing chart showing an example of the operation of the device inspection apparatus of FIG. 1; [Figure 4] FIG. 13 is a diagram showing an example of an electric circuit of a device inspection apparatus according to a second embodiment. [Diagram 5] FIG. 13 is a diagram showing an example of an electric circuit of a device inspection apparatus according to a third embodiment. [Figure 6] FIG. 13 is a diagram showing an example of an electric circuit of a device inspection apparatus according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, non-limiting exemplary embodiments of the present disclosure will be described with reference to the accompanying drawings. In all of the accompanying drawings, the same or corresponding members or parts are designated by the same or corresponding reference numerals, and duplicated descriptions will be omitted.

[0009] [First embodiment] (Device inspection equipment) An example of a device inspection apparatus according to a first embodiment will be described with reference to Fig. 1. The device inspection apparatus according to the first embodiment applies a voltage to a semiconductor device under test (DUT) to inspect various electrical characteristics.

[0010] The device inspection apparatus 10 includes a voltage source 11, resistors 12a1 and 12a2, a detection unit 13, a switching unit 14, a controller 15, and the like.

[0011] Voltage source 11 applies a voltage set by a user (hereinafter referred to as a "set voltage") to DUT 19. Changes to the set voltage and on / off switching of voltage source 11 are controlled by controller 15. Voltage source 11 may be, for example, a programmable DC voltage source.

[0012] Resistors 12a1 and 12a2 are connected in series to DUT 19. That is, resistors 12a1 and 12a2 are connected in series between voltage source 11 and DUT 19. Resistor 12a1 is provided on the voltage source 11 side, and resistor 12a2 is provided on the DUT 19 side. The resistance values ​​of the two resistors 12a1 and 12a2 may be the same or different.

[0013] The detection unit 13 detects a potential difference across the resistor 12a1 and a potential difference across the resistors 12a1 and 12a2. That is, the detection unit 13 detects a potential difference generated when a current supplied to the DUT 19 flows through the resistor 12a1 and a potential difference generated when a current supplied to the DUT 19 flows through the resistors 12a1 and 12a2. The detection unit 13 includes an amplifier 13a, an AD converter 13b, and the like.

[0014] The amplifier 13a is connected between the switching unit 14 and the AD converter 13b. The amplifier 13a amplifies the potential difference between the voltage source 11 side of the resistor 12a1 and the DUT 19 side of the resistor 12a1 and the DUT 19 side of the resistor 12a2, and outputs the amplified potential difference to the AD converter 13b. That is, the amplifier 13a amplifies the potential difference across the resistor 12a1 and the potential difference across the resistors 12a1 and 12a2, and outputs the amplified potential difference to the AD converter 13b. As a result, the minute potential difference generated across the resistor 12a1 and across the resistors 12a1 and 12a2 is amplified and output to the AD converter 13b. As a result, the detection accuracy of the potential difference is improved. The amplifier 13a may be, for example, a current sense amplifier.

[0015] The AD converter 13b is connected between the amplifier 13a and the controller 15. The AD converter 13b converts the potential difference amplified by the amplifier 13a into a digital signal, and outputs the digital signal to the controller 15.

[0016] The switching unit 14 switches between the resistor group (resistor 12a1, resistors 12a1, 12a2) for which the detection unit 13 detects a potential difference from the two resistors 12a1, 12a2. The switching unit 14 includes two switches 14a1, 14a2. The switch 14a1 switches the connection state between the DUT 19 side of the resistor 12a1 and the amplifier 13a. The switch 14a2 switches the connection state between the DUT 19 side of the resistor 12a2 and the amplifier 13a.

[0017] For example, when the current supplied to the DUT 19 is relatively large, the switch 14a1 is switched ON and the switch 14a2 is switched OFF. At this time, the amplifier 13a amplifies the potential difference across the resistor 12a1, that is, the potential difference generated by the current flowing through the resistor 12a1. Also, when the current supplied to the DUT 19 is relatively small, the switch 14a1 is switched OFF and the switch 14a2 is switched ON. At this time, the amplifier 13a amplifies the potential difference across the resistors 12a1 and 12a2, that is, the potential difference generated by the current flowing through the resistors 12a1 and 12a2. The ON / OFF switching of the switches 14a1 and 14a2 is controlled by the controller 15.

[0018] The controller 15 is, for example, a computer, and controls the operation of the voltage source 11, the detection unit 13, the switching unit 14, etc. The controller 15 transmits a control signal for switching ON / OFF of the voltage source 11 and a control signal for changing the set voltage to the voltage source 11. The control signal is generated according to a voltage value previously set by the user. The controller 15 also transmits a control signal for switching ON / OFF of the switches 14a1 and 14a2 to the switching unit 14. The control signal is generated according to a range of a measurement current previously set by the user. The controller 15 also transmits a control signal to the detection unit 13 and the switching unit 14 so as to detect the potential difference of the resistor group (resistor 12a1, resistors 12a1, 12a2) in ascending order of combined resistance value at both ends of the resistor group. That is, the controller 15 transmits a control signal to the detection unit 13 and the switching unit 14 so as to detect the potential difference at both ends of the resistor group 12a1 and then the potential difference at both ends of the resistor group 12a1.

[0019] (Device inspection method) 2 and 3, the device inspection method of the first embodiment will be described by taking as an example a case where the DUT 19 is inspected in the device inspection apparatus 10 of FIG.

[0020] First, in step S1, the controller 15 switches the voltage source 11 ON so that a set voltage is applied to the DUT 19. This causes a current to be supplied to the DUT 19 and the resistors 12a1 and 12a2.

[0021] Next, in step S2, controller 15 controls switching unit 14 to switch the current range to range B. Range B is a range selected when the current supplied to DUT 19 is relatively large. In range B, controller 15 switches switch 14a1 ON and switches 14a2 OFF. As a result, the potentials across resistor 12a1, i.e., the potential on the voltage source 11 side of resistor 12a1 and the potential on the DUT 19 side of resistor 12a1, are input to amplifier 13a.

[0022] Next, in step S3, the controller 15 determines whether the current is supplied to the resistor 12a1 for a predetermined time T B Here, since a current starts to flow through the resistor 12a1 from the time when the voltage source 11 is switched ON in step S1, the time when the current starts to flow through the resistor 12a1 is the time when the voltage source 11 is switched ON in step S1. B is the time from when a current starts to flow through resistor 12a1 until the potential difference across resistor 12a1 stabilizes. This time depends on the resistance value of resistor 12a1, and is longer the higher the resistance value of resistor 12a1 is, and shorter the lower the resistance value of resistor 12a1 is. This is because the DUT 19 and the wiring connecting voltage source 11 and DUT 19 have a certain amount of capacitance, and the electric circuit included in device testing apparatus 10 can be regarded as an RC circuit. The time constant τ of an RC circuit is calculated as τ=RC (where R is the resistance value of the electric circuit, and C is the capacitance value of the electric circuit). When the resistance value of resistor 12a1 is high, the value of R in the above formula becomes large, and the time constant τ becomes large. Note that, when the predetermined time T B may be a time longer than the time from when a current starts to flow through resistor 12a1 to when the potential difference across resistor 12a1 becomes stable.

[0023] Next, in step S4, the controller 15 controls the detection unit 13 so that the amplifier 13a amplifies the potential difference across the resistor 12a1, and the AD converter 13b converts the potential difference amplified by the amplifier 13a into a digital signal. The controller 15 also calculates the value of the current supplied to the DUT 19 based on the digital signal converted by the AD converter 13b.

[0024] Next, in step S5, controller 15 controls switching unit 14 to switch the current range from range B to range A. Range A is a range selected when the current supplied to DUT 19 is relatively small. In range A, controller 15 switches switch 14a1 to OFF and switches 14a2 to ON. As a result, the potentials across resistors 12a1 and 12a2, i.e., the potential on the voltage source 11 side of resistor 12a1 and the potential on the DUT 19 side of resistor 12a2, are input to amplifier 13a.

[0025] Next, in step S6, the controller 15 determines whether the current flows through the resistors 12a1 and 12a2 for a predetermined time T A Here, since current has been flowing through resistors 12a1 and 12a2 since voltage source 11 was switched ON in step S1, the time when current started to flow through resistors 12a1 and 12a2 is the time when voltage source 11 was switched ON in step S1. In step S6, a predetermined time T B Therefore, in step S6, the controller 15 A -T B Wait until a given time T Ais the time from when current starts to flow through resistors 12a1 and 12a2 until the potential difference across resistors 12a1 and 12a2 stabilizes. This time depends on the combined resistance of resistors 12a1 and 12a2, and is longer the higher the combined resistance of resistors 12a1 and 12a2 is, and shorter the lower the combined resistance of resistors 12a1 and 12a2 is. The combined resistance of resistors 12a1 and 12a2 is higher than the resistance of resistor 12a1. Therefore, the predetermined time T A is a given time T B It will be longer than.

[0026] Next, in step S7, the controller 15 controls the detection unit 13 so that the amplifier 13a amplifies the potential difference across the resistors 12a1 and 12a2, and the AD converter 13b converts the potential difference amplified by the amplifier 13a into a digital signal. The controller 15 also calculates the value of the current supplied to the DUT 19 based on the digital signal converted by the AD converter 13b.

[0027] Next, in step S8, the controller 15 selects the measurement result to be output based on the measurement value measured in step S4 and the measurement value measured in step S7. The measurement value measured in step S4 may be, for example, a digital signal obtained by amplifying and converting the potential difference between both ends of the resistor 12a1, or a current value calculated based on the digital signal. The measurement value measured in step S7 may be, for example, a digital signal obtained by amplifying and converting the potential difference between both ends of the resistors 12a1 and 12a2, or a current value calculated based on the digital signal. For example, the controller 15 outputs the measurement result in the A range when the measurement value in the A range is within the measurable range, and outputs the measurement result in the B range when the measurement value in the A range is not within the measurable range. As a result, even if a large current flows through the DUT 19 due to the state of the DUT 19 and the measurement value in the A range is not within the measurable range, an accurate measurement value can be output because the measurement value in the B range, which is selected when the current supplied to the DUT 19 is relatively large, has already been obtained. The measurement results are preferably output in a manner that allows the user to check them, and may be displayed on the display screen of the device inspection apparatus 10, for example.

[0028] As described above, according to the first embodiment, the controller 15 controls the detection unit 13 and the switching unit 14 to detect the potential difference between both ends of the resistor group in ascending order of combined resistance value between both ends of the resistor group. That is, the controller 15 controls the detection unit 13 and the switching unit 14 to detect the potential difference between both ends of the resistors 12a1 and 12a2 after detecting the potential difference between both ends of the resistor 12a1. This makes it possible to perform measurement in the B range, which is selected when the current supplied to the DUT 19 is relatively large, within the measurement time in the A range, which is selected when the current supplied to the DUT 19 is relatively small. Therefore, it is possible to obtain measurement results in two current ranges (the A range and the B range) within the measurement time in the A range. As a result, it is possible to inspect the device characteristics in a short time regardless of the state of the DUT 19.

[0029] Second Embodiment (Device inspection equipment) An example of a device inspection apparatus according to the second embodiment will be described with reference to Fig. 4. The device inspection apparatus according to the second embodiment differs from the device inspection apparatus 10 according to the first embodiment in that the number of resistor groups is n (n is an integer equal to or greater than 3). The following description will focus on the differences from the device inspection apparatus 10 according to the first embodiment.

[0030] The device inspection apparatus 20 includes a voltage source 21, resistors 22a1 to 22a n , a detection unit 23, a switching unit 24, a controller 25, etc.

[0031] Voltage source 21 may have a similar configuration to voltage source 11 .

[0032] Resistor 22a1~22a n are connected in series to the DUT 29. n are connected in series between the voltage source 21 and the DUT 29. n From the voltage source 21 side, resistors 22a1, 22a2, . . . , resistors 22a n The resistors 22a1 to 22a n The resistance values ​​may be the same or different.

[0033] The detector 23 may have the same configuration as the detector 13, and includes an amplifier 23a, an AD converter 23b, and the like.

[0034] The switching unit 24 includes n resistors 22a1 to 22a n The resistor group (resistor 22a1, resistors 22a1, 22a2, . . . , resistors 22a1, 22a2, . . . , 22a n The switching unit 24 has n switches 24a1 to 24a n Including switches 24a1 to 24a n are resistors 22a1, 22a2, . . . , 22a n The connection state between the DUT 29 side and the amplifier 23a is switched.

[0035] The controller 25 may have the same configuration as the controller 15, and controls the operations of the voltage source 21, the detection unit 23, the switching unit 24, etc. The controller 25 controls the resistor group (resistor 22a1, resistors 22a1, 22a2, . . . , resistors 22a1, 22a2, . . . , 22a n The control signal is sent to the detection unit 23 and the switching unit 24 so that the potential differences across the resistor groups are detected in ascending order of combined resistance values ​​across the resistor groups.

[0036] (Device inspection method) The device inspection method of the second embodiment may be the same as the device inspection method of the first embodiment. In the device inspection method of the second embodiment, the controller 25 controls the detection unit 23 and the switching unit 24 to detect the potential difference between both ends of at least two or more different resistor groups among the multiple resistor groups. The controller 25 also controls the detection unit 23 and the switching unit 24 to detect the potential difference between both ends of the resistor groups in ascending order of combined resistance value at both ends of the resistor groups.

[0037] As described above, according to the second embodiment, the controller 25 controls the detection unit 23 and the switching unit 24 to detect the potential difference between both ends of the resistor group in ascending order of combined resistance value between both ends of the resistor group. This makes it possible to perform measurements in a plurality of current ranges in a short time. As a result, the device characteristics can be inspected in a short time regardless of the state of the DUT 29.

[0038] Third embodiment (Device inspection equipment) An example of a device inspection apparatus according to the third embodiment will be described with reference to FIG. n The present embodiment differs from the device inspection apparatus 20 of the second embodiment in that it has switching units 34a, 34b that switch the connection states between the DUT 39 side and the voltage source 31 side and the amplifier 33a. The following mainly describes the differences from the device inspection apparatus 20 of the second embodiment.

[0039] The device inspection apparatus 30 includes a voltage source 31, resistors 32a1 to 32a nThe device includes a detection unit 33, switching units 34a and 34b, a controller 35, etc.

[0040] Voltage source 31 may have a similar configuration to voltage source 21 .

[0041] Resistor 32a1~32a n The resistors 22a1 to 22a n It may have a similar configuration.

[0042] The detector 33 may have the same configuration as the detector 23, and includes an amplifier 33a, an AD converter 33b, and the like.

[0043] The switching unit 34a may have the same configuration as the switching unit 24, and includes n switches 34a1 to 34a n Switches 34a1 to 34a n are resistors 32a1, 32a2, . . . , 32a n The connection state between the DUT 39 side and the amplifier 33a is switched.

[0044] The switching unit 34b includes n switches 34b1 to 34b n Including switches 34b1 to 34b n are resistors 32a1, 32a2, . . . , 32a n The connection state between the voltage source 31 side and the amplifier 33a is switched.

[0045] The controller 35 may have the same configuration as the controller 25, and controls the operations of the voltage source 31, the detection unit 33, the switching units 34a, 34b, etc. The controller 35 transmits a control signal to the detection unit 33 and the switching units 34a, 34b so as to detect the potential differences across the resistor groups in ascending order of combined resistance values ​​across the resistor groups.

[0046] (Device inspection method) The device inspection method of the third embodiment may be the same as the device inspection method of the second embodiment. In the device inspection method of the third embodiment, the controller 35 controls the detection unit 33 and the switching units 34a and 34b to detect the potential difference between both ends of at least two or more different resistor groups among the multiple resistor groups. The controller 35 also controls the detection unit 33 and the switching units 34a and 34b to detect the potential difference between both ends of the resistor groups in ascending order of combined resistance value at both ends of the resistor groups.

[0047] As described above, according to the third embodiment, the controller 35 controls the detection unit 33 and the switching units 34a and 34b to detect the potential difference between both ends of the resistor group in ascending order of combined resistance value between both ends of the resistor group. This makes it possible to perform measurements in a plurality of current ranges in a short time. As a result, the device characteristics can be inspected in a short time regardless of the state of the DUT 39.

[0048] Furthermore, according to the third embodiment, the switches 34a1 to 34a n and switches 34b1 to 34b n By switching ON / OFF of the resistors 32a1 to 32a n The connection state between the DUT 39 side and the voltage source 31 side and the amplifier 33a is switched. n As a result, a large number of resistor groups are selected, making it possible to measure a wide range of currents with a small number of components.

[0049] [Fourth embodiment] (Device inspection equipment) An example of a device inspection apparatus according to the fourth embodiment will be described with reference to FIG. n and the switching unit 44. n The following description will focus on the differences from the device inspection apparatus 20 of the second embodiment.

[0050] The device inspection apparatus 40 includes a voltage source 41, resistors 42a1 to 42a n , a detection unit 43, a switching unit 44, a controller 45, etc.

[0051] Voltage source 41 may have a similar configuration to voltage source 21 .

[0052] Resistor 42a1~42a n The resistors 22a1 to 22a n It may have a similar configuration.

[0053] The detection unit 43 includes amplifiers 43a1 to 43a n , AD converter 43b, etc.

[0054] Amplifiers 43a1 to 43a n The switching unit 44 and the resistor group (resistor 42a1, resistors 42a1, 42a2, . . . , resistors 42a1, 42a2, . . . , 42a n ) are connected between the amplifiers 43a1 to 43a n are the voltage source 41 side of the resistor 42a1 and the resistors 42a1 to 42a n The potential difference between the DUT 49 side and the resistor group (resistor 42a1, resistors 42a1, 42a2, . . . , resistors 42a1, 42a2, . . . , 42a n A small potential difference occurring between both ends of the amplifier 43a1 to 43a is amplified and output to the AD converter 43b. As a result, the detection accuracy of the potential difference is improved. n may be, for example, a current sense amplifier.

[0055] The AD converter 43b may have the same configuration as the AD converter 23b.

[0056] The switching unit 44 includes n resistors 42a1 to 42a n The detection unit 43 detects a potential difference between the resistor group (resistor 42a1, resistors 42a1, 42a2, . . . , resistors 42a1, 42a2, . . . , 42a nThe switching unit 44 has n switches 44a1 to 44a n The switches 44a1 to 44a n are amplifiers 43a1 to 43a n and the AD converter 43b.

[0057] The controller 45 may have the same configuration as the controller 25, and controls the operations of the voltage source 41, the detection unit 43, the switching unit 44, etc. The controller 45 controls the resistor group (resistor 42a1, resistors 42a1, 42a2, . . . , resistors 42a1, 42a2, . . . , 42a n The control signal is sent to the detection unit 43 and the switching unit 44 so that the potential differences across the resistor groups are detected in ascending order of combined resistance value across the resistor groups.

[0058] (Device inspection method) The device inspection method of the fourth embodiment may be the same as the device inspection method of the second embodiment. In the device inspection method of the fourth embodiment, the controller 45 controls the detection unit 43 and the switching unit 44 to detect the potential difference between both ends of at least two or more different resistor groups among the multiple resistor groups. The controller 45 also controls the detection unit 43 and the switching unit 44 to detect the potential difference between both ends of the resistor groups in ascending order of combined resistance value at both ends of the resistor groups.

[0059] As described above, according to the fourth embodiment, the controller 45 controls the detection unit 43 and the switching unit 44 to detect the potential difference between both ends of the resistor group in ascending order of combined resistance value between both ends of the resistor group. This makes it possible to perform measurements in a plurality of current ranges in a short time. As a result, the device characteristics can be inspected in a short time regardless of the state of the DUT 49.

[0060] In the above-described embodiments, the controllers 15, 25, 35, and 45 are examples of the control unit.

[0061] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The above-described embodiments may be omitted, substituted, or modified in various forms without departing from the scope and spirit of the appended claims.

[0062] In the above embodiment, the switching unit includes a plurality of switches, but the present disclosure is not limited to this. For example, the switching unit may include a multiplexer. [Explanation of symbols]

[0063] 10,20,30,40 Device inspection equipment 11,21,31,41 Voltage Source 12a1~12a2,22a1~22a n ,32a1~32a n ,42a1~42a n resistor 14, 24, 34a, 34b, 44 Switching section 15,25,35,45 Controller

Claims

1. a voltage source for applying a voltage to the device under test; a plurality of resistors connected in series between the voltage source and the device; a detection unit that detects a potential difference between both ends of a resistor group including one or more resistors among the plurality of resistors; a switching unit that switches the resistor group among the plurality of resistors for which the detection unit detects a potential difference; A control unit; Equipped with the control unit is configured to control the detection unit and the switching unit to detect a potential difference across at least two or more different resistor groups, and is configured to control the detection unit and the switching unit to detect the potential difference in ascending order of combined resistance values ​​across the resistor groups; the control unit controls the voltage source so that a current is supplied to all of the plurality of resistors, and in a state in which a current is supplied to all of the plurality of resistors, the switching unit selects a resistor group having the lowest combined resistance value, the detection unit detects a potential difference between both ends of the resistor group having the lowest combined resistance value after a first time has elapsed, next, the switching unit selects a resistor group having a combined resistance value higher than that of the resistor group having the lowest combined resistance value, and the detection unit detects a potential difference between both ends of the resistor group after a second time has elapsed; The start point of the first time period and the start point of the second time period are times when current begins to flow through all of the plurality of resistors. Device inspection equipment.

2. The detection unit includes an amplifier provided between the switching unit and the control unit or the resistor group. The device inspection apparatus according to claim 1 .

3. The switching unit is configured to switch only the side of the device of the resistor group.

3. The device inspection apparatus according to claim 1 or 2.

4. The switching unit is configured to switch the resistor group between the voltage source side and the device side.

3. The device inspection apparatus according to claim 1 or 2.

5. the control unit is configured to output a value corresponding to one potential difference selected from the plurality of potential differences detected by the detection unit. The device inspection apparatus according to any one of claims 1 to 4.

6. The control unit is configured to calculate a current supplied to the device based on the potential difference detected by the detection unit. The device inspection apparatus according to any one of claims 1 to 5.

7. 1. A device inspection method for inspecting a device to be inspected by applying a voltage to the device through a plurality of resistors connected in series, comprising: detecting a potential difference across a plurality of resistor groups including one or more resistors among the plurality of resistors in ascending order of combined resistance value across the plurality of resistor groups; detecting the potential difference includes selecting a resistor group having the lowest combined resistance value while current is being supplied to all of the plurality of resistors, detecting a potential difference across the resistor group having the lowest combined resistance value after a first time has elapsed, and then selecting a resistor group having a combined resistance value higher than that of the resistor group having the lowest combined resistance value, and detecting a potential difference across the resistor group after a second time has elapsed; The start point of the first time period and the start point of the second time period are times when current begins to flow through all of the plurality of resistors. Device inspection methods.

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