Charged particle beam device and electrical resistance measurement method

Abstract

To provide a charge particle beam device which allows rapid and reliable acquisition of the electric resistance of a sample.SOLUTION: The present invention relates to a charge particle beam device for measuring the electric resistance of a sample 105 having a laminate structure in at least a part of the sample, the laminate structure being formed of an upper layer conductor 201 and a lower layer conductor 203, and an insulation body 202 in between. The charge particle beam device radiates a charge particle beam on a specified measurement part of the upper layer conductor of the sample by a charge particle beam optical system. A current measurement unit 118 measures a sample current flowing from the upper layer conductor to the lower layer conductor. A detection system measures the energy distribution of secondary electrons discharged from the sample. The control system calculates the electric resistance of a measurement part on the basis of the sample current and the energy distribution of the secondary electrons.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a charged particle beam device and an electrical resistance measurement method using the same. [Background technology]

[0002] In recent years, quantum computers have attracted attention due to their potential for achieving computational speeds exceeding those of conventional computers. Several quantum computer technologies have been proposed, with superconducting elements attracting particular attention. Superconducting elements are composed of Josephson junctions, which are made up of three layers of superconductor, insulator, and superconductor. Superconducting elements utilize the quantum tunneling effect, which allows electrons to pass through the insulating layer due to their wave properties when the insulator is approximately 1 nm thick. The electrical resistance of Josephson junctions is considered an important indicator of device performance. Realizing an error-correcting quantum computer requires one million quantum bits (qubits), and qubit manufacturing technology must be able to minimize the variability of these quantum bits. To achieve this, the electrical characteristics of one million Josephson junctions must be measured quickly and before the process of connecting the Josephson junctions to wiring and other components is completed.

[0003] Techniques for measuring the electrical resistance of elements are widely used in the semiconductor field. A typical example is a device disclosed in Patent Document 1, which measures electrical resistance by contacting a conductive probe with an element of interest under a scanning electron microscope. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-027548 Summary of the Invention [Problem to be solved by the invention]

[0005] The device described in Patent Document 1 has a problem in that the measurement speed is slow because it is necessary to move the conductive probe to the measurement point on the sample. [Means for solving the problem]

[0006] A charged particle beam device according to one embodiment of the present invention includes a stage on which a sample is mounted, the sample having at least a portion thereof formed of a laminated structure in which an insulator is sandwiched between an upper layer conductor and a lower layer conductor; a charged particle beam optical system that focuses a charged particle beam from a charged particle source and irradiates the sample; a detection system that detects secondary electrons emitted as a result of the sample being irradiated with the charged particle beam; and a current measurement unit that measures a sample current that flows from the upper layer conductor to the lower layer conductor as a result of the sample being irradiated with the charged particle beam. a contact pin connected to the current measuring unit and brought into contact with the underlying conductor at the measurement point; and a bias power supply that applies a predetermined bias voltage to the sample via the contact pin. a control system including a recording unit, and the detection system including an energy analyzer that discriminates secondary electrons according to the energy of the secondary electrons and a detector that detects the secondary electrons that have passed through the energy analyzer; the control system records in the recording unit an energy distribution of secondary electrons emitted as a result of the upper conductor of the sample being irradiated with the charged particle beam when no potential difference occurs between the upper conductor and the lower conductor; The control system is located on the upper conductor of the sample. of The measurement point is irradiated with a charged particle beam using a charged particle beam optical system, calculating a potential difference between the upper layer conductor and the lower layer conductor at the measurement point based on the amount of shift in the energy distribution of the secondary electrons measured by the detection system from the energy distribution of the secondary electrons stored in the recording unit; The specimen current measured by the current measurement unit Calculated potential difference Based on this, the electrical resistance at the measurement point is calculated. [Effects of the Invention]

[0007] The present invention provides a charged particle beam device and an electrical resistance measurement method that enable high-speed and reliable acquisition of the electrical resistance of a sample. Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Brief explanation of the drawings]

[0008] [Figure 1] 1 shows an example of the configuration of a scanning electron microscope according to a first embodiment. [Figure 2] FIG. 2 is a diagram for explaining the principle of measuring electrical resistance. [Figure 3] 10A and 10B are diagrams for explaining a method for calculating a potential difference in a sample from the energy distribution of secondary electrons. [Figure 4] 1 is an example of a flow for measuring electrical resistance. [Figure 5] 1 is an example of a flow for measuring electrical resistance. [Figure 6] FIG. 10 is a diagram for explaining the measurement timing of the specimen current. [Figure 7] 10 shows an example of the configuration of a scanning electron microscope according to a second embodiment. [Figure 8] 10 is an example of a measurement flow including an electrical resistance adjustment flow. [Figure 9A] 10A and 10B are diagrams for explaining a method of contacting a contact pin with a sample. [Figure 9B] 10A and 10B are diagrams for explaining a method of contacting a contact pin with a sample. [Figure 9C] 10A and 10B are diagrams for explaining a method of contacting a contact pin with a sample. [Figure 10] 1 is a diagram showing an example of a sample configuration; DETAILED DESCRIPTION OF THE INVENTION

[0009] The following describes examples of the present invention. While the drawings shown in the present examples illustrate specific examples based on the principles of the present invention, these are provided for the purpose of understanding the present invention and are not intended to limit the scope of the present invention. The following examples will be described using a scanning electron microscope that uses an electron beam as the charged particle beam irradiated onto a sample, but similar effects can be achieved when various ion beams are used. [Example]

[0010] FIG. 1 shows an example of the configuration of a scanning electron microscope according to a first embodiment. The scanning electron microscope primarily comprises an electron beam optical system that irradiates a sample with an electron beam, a detection system that detects secondary electrons emitted from the sample due to the irradiation of the electron beam, a stage mechanism system arranged in a vacuum chamber (housing) on ​​which the sample is mounted, and a control system that controls the components of the scanning electron microscope and processes various information. The control system may also include an image processing system that performs image restoration and other processes on the formed scanned image. In FIG. 1, the electron source 101, objective lens 103, and deflector 104 are elements that constitute the electron beam optical system. The energy analyzer 111 and detector 112 are elements that constitute the detection system. The detection sampling control unit 113, energy analyzer control unit 122, deflector control unit 109, objective lens control unit 108, stage control unit 107, image formation unit 114, image display unit 115, recording unit 116, and workstation 120 are elements that constitute the control system. These are shown as representative elements, and the present invention is not limited to these.

[0011] Specifically, primary electrons 102 generated by an electron source 101 are deflected by a deflector 104, focused by an objective lens 103, and then irradiated onto a sample 105 mounted on a movable stage 106. The operation of the objective lens 103 is controlled by an objective lens control unit 108, the operation of the deflector 104 by a deflector control unit 109, and the operation of the movable stage 106 by a stage control unit 107.

[0012] Secondary electrons 110 generated by irradiation of the sample 105 with the primary electrons 102 enter the energy analyzer 111, and the secondary electrons 110 that pass through the energy analyzer 111 are detected by the detector 112. The operation of the energy analyzer 111 is controlled by an energy analyzer control unit 122. In FIG. 1, the detector 112 is located closer to the electron source 101 than the deflector 104, but it may be located between the deflector 104 and the objective lens 103 or between the objective lens 103 and the sample 105 as long as it can detect the secondary electrons 110. The detector 112 may be configured as an Everhart-Thornley (ET) detector or a semiconductor detector, which are composed of a scintillator, a light guide, and a photomultiplier tube. However, any detector may be used as long as it has a configuration that can detect electrons. The timing of acquiring a signal from the detector 112 is controlled by a detection sampling control unit 113.

[0013] A contact pin 117 for measuring a specimen current flowing through the specimen 105 due to irradiation of the specimen 105 with the primary electrons 102 is in contact with the specimen 105, and the specimen current is measured by a current measurement unit 118 connected to the contact pin 117. A bias voltage source 121 is connected to the contact pin 117 and the current measurement unit 118, and a negative bias voltage V b (V b <0) is applied to the sample 105 via the contact pin 117.

[0014] The image forming unit 114 forms a scanned image by allocating the signals acquired by the detection sampling control unit 113 to the pixel coordinates of the primary electrons 102 determined by the deflector control unit 109. The generated scanned image is displayed on the image display unit 115 and recorded in the recording unit 116.

[0015] The electron source 101, energy analyzer 111, detector 112, deflector 104, objective lens 103, contact pin 117, and movable stage 106 are housed in a housing 119, and the inside of the housing 119 is maintained in a vacuum state by a vacuum pump (not shown).

[0016] The operations of the stage control unit 107, objective lens control unit 108, deflector control unit 109, detection sampling control unit 113, energy analyzer control unit 122, image formation unit 114, image display unit 115, recording unit 116, current measurement unit 118, and bias voltage source 121 are controlled by a workstation 120.

[0017] Next, the principle of measuring the electrical resistance of sample 105 using the scanning electron microscope shown in FIG. 1 will be explained with reference to FIG. 2. Sample 105 has at least a portion of a layered structure of conductor-insulator-conductor. The electrical resistance of conductors 201 and 203 can be considered to be sufficiently small, and the electrical resistance R of sample 105 is determined by the electrical resistance of insulator 202 sandwiched between conductors 201 and 203. Lower conductor 203 is in contact with contact pin 117. In this state, when primary electrons 102 are irradiated onto upper conductor 201, a potential difference ΔV due to the electrical resistance R is generated between upper conductor 201 and lower conductor 203, and a sample current I S For example, when the insulator 202 is made of alumina with a thickness of several nanometers, which can be formed as a Josephson junction, the electrical resistance R is on the order of GΩ, and the sample current I S In this embodiment, as will be described later, a current of the order of nA flows through the specimen. S is measured, and the potential difference ΔV is measured from the energy distribution of the secondary electrons 110. R=ΔV / I S ...(Formula 1) From these values, the electrical resistance R is calculated according to Ohm's law shown as (Equation 1).

[0018] Next, a method for determining the potential difference ΔV from the energy distribution of the secondary electrons 110 will be described with reference to FIG. 3. First, the energy distribution of the secondary electrons 110 can be obtained by the energy analyzer 111 and the detector 112 in the scanning electron microscope of FIG. 1. The configuration of the energy analyzer 111 is not particularly limited. For example, in the case of a deceleration field type energy analyzer, the energy analyzer 111 is composed of one or more grids, and the energy analyzer control unit 122 applies a negative voltage to the grids while sweeping the voltage value. The secondary electrons 110 that pass through the energy analyzer 111 are detected by the detector 112, so that the secondary electrons 110 can be discriminated and detected by their energy. Alternatively, in the case of a deflection type energy analyzer, the energy analyzer 111 is composed of two cylindrical or hemispherical electrodes. The energy analyzer control unit 122 applies a voltage between the electrodes, and the secondary electrons 110 that pass between the electrodes are detected by the detector 112. Since secondary electrons 110 with different energies pass through the electrodes in different trajectories, the secondary electrons 110 can be detected by distinguishing them by their energy by detecting the secondary electrons 110 for each trajectory with a detector 112.

[0019] When no potential difference occurs in the sample 105, the bias voltage V applied to the sample 105 b The secondary electrons 110 accelerated at the potential difference θ are incident on the energy analyzer 111. Therefore, when no potential difference is generated in the sample 105, the energy distribution 302 of the secondary electrons is b ), a detection signal rises from the potential difference ΔV. Here, e is the elementary charge. On the other hand, when a potential difference ΔV is generated in the sample 105, the energy distribution 301 of the secondary electrons 110 emitted from the sample 105 is shifted by the potential difference ΔV from the energy distribution 302 of the secondary electrons 110 when no potential difference is generated. Therefore, the potential difference ΔV of the sample 105 can be obtained by analyzing the amount of shift in the energy distribution of the secondary electrons 110. Here, the potential difference ΔV can be calculated by comparing the peak positions or the rising positions of the energy distribution of the secondary electrons, but the calculation method is not limited to a specific one as long as it can calculate the amount of shift in the energy distribution.

[0020] Methods for acquiring energy distribution 302 of secondary electrons 110 when no potential difference is generated include acquiring it at a location where only a conductor is present on sample 105, or acquiring it on a conductor reference sample (not shown) mounted separately from sample 105 on movable stage 106. The acquired energy distribution 302 of secondary electrons when no potential difference is generated is recorded in recording unit 116. The acquired energy distribution 302 of secondary electrons when no potential difference is generated can be registered by the device user himself, or can be registered in advance by the device manufacturer when the device is shipped.

[0021] 9A to 9C show methods for contacting the contact pin 117 with the sample 105. When the underside of the sample 105 is a conductor, as shown in FIG. 9A, it is effective to bring the contact pin 117 into contact with the underside of the sample 105. In contrast, FIGS. 9B and 9C show an example in which the underside of the sample 105 is covered with an insulator 204. In this case, it is effective to bring the contact pin 117 into contact with the side of the sample 105, as shown in FIG. 9B. Alternatively, when the underside of the sample 105 is covered with an insulator but the upper surface of the sample 105 is only partially covered with an insulator 202, as shown in FIG. 9C, it is effective to bring the contact pin 117 into contact with a region where the conductor 203 is exposed from the upper surface of the sample 105. In this way, in order to change the contact position of the contact pin 117 depending on the film structure of the sample 105, it is desirable to install a position control mechanism (probing mechanism) for the contact pin 117, although this is not shown in FIG. 1.

[0022] The flow of measuring the electrical resistance is shown in Figure 4. The sample 105 is placed on the movable stage 106 inside the housing 119 (S401), a scanned image of the sample 105 is acquired, and the acquired scanned image is displayed on the image display unit 115 (S402). Next, the user of the apparatus designates a location on the scanned image displayed on the image display unit 115 where the electrical resistance of the sample 105 is to be measured (S403). The workstation 120 controls the movable stage 106 and / or the deflector 104 by the stage control unit 107 and / or the deflector control unit 109 to irradiate the electron beam onto the location designated in step S403 (S404), and the workstation 120 calculates the sample current I that flows when the electron beam is irradiated onto the designated location. S The energy distribution of the secondary electrons 110 emitted by irradiating the specified location with the electron beam is acquired and recorded in the recording unit 116 (S405). Furthermore, the workstation 120 calculates the potential difference ΔV by comparing the secondary electron energy distribution in the case where no potential difference occurs, which has been previously recorded in the recording unit 116, with the secondary electron energy distribution acquired in step S405 (S406). Finally, the specimen current I acquired in step S406 is S The electric resistance R is calculated by substituting the potential difference ΔV calculated in step S407 into (Equation 1), and is displayed on the image display unit 115 (S407).

[0023] A method for measuring the steady-state electrical resistance R in step S407 will be described with reference to FIG. 6. FIG. 6 shows the sample current I measured by the current measurement unit 118. S As shown in Figure 2, the sample 105 is a capacitor made up of layers of conductors, insulators, and conductors. When irradiated with an electron beam, the potential difference ΔV gradually changes, and after a certain time has passed, the capacitor is charged and the potential difference ΔV reaches a steady state. Therefore, when irradiated with an electron beam, the sample current I S The sample current I S The steady-state electrical resistance R can be calculated using the potential difference ΔV. A typical value is the specimen current I 1 millisecond after electron beam irradiation. Sand the potential difference ΔV, the steady-state electrical resistance R can be obtained.

[0024] In the measurement flow of FIG. 4, the measurement location for electrical resistance is specified on the scanned image. In contrast, FIG. 5 shows a measurement flow for electrical resistance in which the measurement location for electrical resistance is specified in advance and the specified measurement location is recorded in the recording unit 116. In the measurement flow of FIG. 5, the same steps as those in the measurement flow of FIG. 4 are assigned the same reference numerals, and redundant explanations will be omitted. In the measurement flow of FIG. 5, the following processing is performed to irradiate the specified location recorded in advance in the recording unit 116 with an electron beam. The coordinates of the movable stage 106 on which the sample 105 is mounted are matched with the layout information of the sample 105 recorded in the recording unit 116 (S501). This can be achieved by acquiring a scanned image of an alignment pattern on the sample 105. In step S501, the layout information of the sample 105 is associated with the coordinates of the movable stage 106. As a result, the workstation 120 controls the movable stage 106 via the stage control unit 107 to move the movable stage 106 so that the specified location stored in the recording unit 116 comes into the field of view of the scanning electron microscope (S502).

[0025] In the above explanation, for the sake of simplicity, an example is shown in which upper layer conductor 201 and lower layer conductor 203 are stacked one-to-one as sample 105, but when integrating elements, a configuration is generally used in which multiple upper layer conductors 201 separated from each other are provided for lower layer conductor 203, as shown in Fig. 10. In such a case, even when measurement points are designated for each of upper layer conductor 201a, upper layer conductor 201b, and upper layer conductor 201c, there is no need to move contact pin 117. This allows electrical resistance to be measured at multiple measurement points at high speed. [Example]

[0026] In the second embodiment, a scanning electron microscope is disclosed that is provided with a mechanism for adjusting the electrical resistance of a sample if the measured electrical resistance is not a desired value after measuring the electrical resistance of the sample.

[0027] The configuration of the scanning electron microscope of Example 2 is shown in Figure 7. Components that are the same as those in the scanning electron microscope shown in Figure 1 are assigned the same reference numerals, and duplicate explanations will be omitted. Compared to the configuration in Figure 1, the scanning electron microscope shown in Figure 7 additionally includes a laser light source 701, a viewport 703, and a laser control unit 704. The operation of the laser control unit 704 is controlled by the workstation 120.

[0028] A laser light source 701 is disposed outside the housing 119 and is capable of generating a laser beam 702. The laser beam 702 generated by the laser light source 701 is introduced into the housing 119 through a viewport 703 attached to the housing 119 and is irradiated onto the sample 105. Here, the irradiation position of the laser beam 702 on the sample 105 coincides with the irradiation position of the primary electrons 102 on the sample 105. The irradiation of the laser beam 702 on the sample 105 is controlled by a laser control unit 704.

[0029] FIG. 8 shows a flow chart for adjusting the electrical resistance of a sample if the measured electrical resistance is not the desired value. The flow for measuring the electrical resistance at a specified location on the sample is the same as the measurement flow chart in FIG. 4, and the same reference numerals are used to designate the same steps, and redundant explanations will be omitted. After calculating the electrical resistance R (S407), it is determined whether the measured electrical resistance is within a predetermined range (S801). This predetermined range can be recorded in advance in the recording unit 116 by the device user as an acceptable range for the electrical resistance R. If the electrical resistance R is within the predetermined range, the flow ends. On the other hand, if the electrical resistance R does not satisfy the predetermined range, the workstation 120 controls the laser control unit 704 to emit laser light 702 from the laser light source 701, and the laser light 702 is irradiated onto the measurement location specified in S403 (S802). When the laser light 702 is irradiated onto the sample, the temperature of the irradiated location rises, and the crystallinity of the insulator 202 changes, resulting in a change in electrical resistance. Thereafter, the electron beam is irradiated again to the designated location (S404), and the electrical resistance R is measured (S405 to S407). The intensity and wavelength of the laser light 702 irradiated in step S802 can be registered in advance in the recording unit 116 by the device user.

[0030] Figure 8 shows an example of applying the measurement flow of Figure 4, but even when applying the measurement flow shown in Figure 5 in which the measurement points for electrical resistance are recorded in advance in recording unit 116, by determining the electrical resistance value and irradiating laser light after measuring the electrical resistance, it is possible to adjust the electrical resistance if the measured electrical resistance is not the desired value.

[0031] The present disclosure is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0032] 101: electron source, 102: primary electrons, 103: objective lens, 104: deflector, 105: sample, 106: movable stage, 107: stage control unit, 108: objective lens control unit, 109: deflector control unit, 110: secondary electrons, 111: energy analyzer, 112: detector, 113: detection sampling control unit, 114: image formation unit, 115: image display unit, 116: recording unit, 117: contact pin, 118: current measurement unit, 119: housing, 120: workstation, 121: bias voltage source, 122: energy analyzer control unit, 201: upper layer conductor, 202: insulator, 203: lower layer conductor, 204: insulator, 301, 302: energy distribution of secondary electrons, 701: laser light source, 702: laser light, 703: viewport, 704: laser control unit.

Claims

1. a stage on which a sample is mounted, the sample having at least a layered structure in which an insulator is sandwiched between an upper layer conductor and a lower layer conductor; a charged particle beam optical system that focuses a charged particle beam from a charged particle source and irradiates the sample with the focused beam; a detection system for detecting secondary electrons emitted as a result of irradiation of the sample with a charged particle beam; a current measuring unit that measures a specimen current that flows from the upper layer conductor to the lower layer conductor due to irradiation of the upper layer conductor of the specimen with a charged particle beam; a contact pin connected to the current measuring unit and brought into contact with the underlying conductor at a measurement point; a bias power supply that applies a predetermined bias voltage to the sample via the contact pin; a control system including a recording unit; the detection system includes an energy analyzer that discriminates secondary electrons according to their energy, and a detector that detects secondary electrons that have passed through the energy analyzer; the control system records, in the recording unit, an energy distribution of secondary electrons emitted as a result of the upper layer conductor of the sample being irradiated with a charged particle beam when no potential difference occurs between the upper layer conductor and the lower layer conductor; the control system irradiates the measurement location on the upper conductor of the sample with a charged particle beam using the charged particle beam optical system, calculates a potential difference between the upper conductor and the lower conductor at the measurement location based on an amount of shift in the secondary electron energy distribution measured by the detection system from the secondary electron energy distribution stored in the recording unit, and calculates the electrical resistance of the measurement location based on the sample current measured by the current measurement unit and the calculated potential difference.

2. In claim 1, the control system uses the specimen current measured by the current measurement unit after a predetermined time has elapsed since the charged particle beam optical system started irradiating the measurement point of the specimen with the charged particle beam, to calculate the electrical resistance of the measurement point; A charged particle beam device, wherein the predetermined time is set based on the time it takes for the specimen current to transition to a steady state.

3. In claim 1, The energy distribution of secondary electrons stored in the recording unit is the energy distribution of secondary electrons measured by the detection system when a charged particle beam is irradiated onto a portion of the sample where only a conductor is present, or is the energy distribution of secondary electrons measured by the detection system when a charged particle beam is irradiated onto a standard sample of a conductor mounted on the stage.

4. In claim 1, A charged particle beam device having a position control mechanism for changing the contact position of the contact pin with the sample.

5. In claim 1, The energy analyzer is a charged particle beam device that is a deceleration field type energy analyzer or a deflection type energy analyzer.

6. In claim 1, the control system includes an image forming unit, the control system causes the sample to be scanned with the charged particle beam by the charged particle beam optical system, and causes the scanned image formed by the image forming unit to be displayed on the image display unit; The measurement location is designated in the scanned image displayed on the image display unit.

7. In claim 1, the control system includes an image forming unit, The recording unit records layout information of the sample and the measurement points designated in advance, the control system scans the sample with a charged particle beam using the charged particle beam optical system, and aligns the scanned image formed by the image forming unit with the layout information of the sample, thereby associating the layout information of the sample with coordinates of the stage; The control system controls the stage so that the measurement location recorded in the recording unit is within the field of view of the charged particle beam device.

8. In claim 1, a laser light source that irradiates the sample with laser light; The control system is a charged particle beam device that causes the laser light source to irradiate the measurement location with laser light when the electrical resistance of the measurement location does not satisfy a predetermined range.

9. In claim 8, the laser light source is disposed outside a housing that houses the charged particle beam optical system; The laser light source is a charged particle beam device that irradiates the sample with laser light through a viewport provided in the housing.

10. In claim 1, A charged particle beam device in which a Josephson junction is formed in the layered structure of the sample.

11. 1. An electrical resistance measurement method for measuring the electrical resistance of a sample having, at least in part, a layered structure in which an insulator is sandwiched between an upper layer conductor and a lower layer conductor, using a charged particle beam device, the method comprising: the charged particle beam device comprises: a stage on which the sample is mounted; a charged particle beam optical system that focuses a charged particle beam from a charged particle source and irradiates the sample with the beam; a detection system that detects secondary electrons emitted as a result of the sample being irradiated with the charged particle beam; a current measurement unit that measures a sample current that flows from the upper layer conductor to the lower layer conductor as a result of the upper layer conductor of the sample being irradiated with the charged particle beam; contact pins that are connected to the current measurement unit and that come into contact with the lower layer conductor at a measurement point; a bias power supply that applies a predetermined bias voltage to the sample via the contact pin; and a control system that includes a recording unit; the detection system includes an energy analyzer that discriminates secondary electrons according to their energy, and a detector that detects secondary electrons that have passed through the energy analyzer; the control system records, in the recording unit, an energy distribution of secondary electrons emitted as a result of the upper layer conductor of the sample being irradiated with a charged particle beam when no potential difference occurs between the upper layer conductor and the lower layer conductor; the charged particle beam optical system irradiates the measurement location on the upper layer conductor of the sample with a charged particle beam by the charged particle beam optical system; The control system calculates the potential difference between the upper conductor and the lower conductor at the measurement point based on the amount of shift in the secondary electron energy distribution measured by the detection system from the secondary electron energy distribution stored in the recording unit, and calculates the electrical resistance of the measurement point based on the sample current measured by the current measurement unit and the calculated potential difference.

12. In claim 11, the control system uses the specimen current measured by the current measurement unit after a predetermined time has elapsed since the charged particle beam optical system started irradiating the measurement point of the specimen with the charged particle beam, to calculate the electrical resistance of the measurement point; The electrical resistance measuring method, wherein the predetermined time is set based on the time it takes for the sample current to transition to a steady state.

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