JP2014044102A - Four-terminal resistance measuring device, inspection device, four-terminal resistance measuring method and inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make measurement more stable in measurement of values of a measuring object downsized and assembled in high density.SOLUTION: A four-terminal resistance measuring device includes: a pair of contact-type probes 2a, 2b for current supply; an AC current supply section 4 for supplying a current I between solder ball bumps 21, 21 of a measuring object 20 via the pair of contact-type probes 2a, 2b for current supply; a pair of non-contact-type probes 3a, 3b for voltage measurement which are designed to detect voltages at the solder ball bumps 21, 21 by electrostatic capacity coupling; a voltage measurement section 6 for measuring a difference voltage Vd between the voltages at the solder ball bumps 21, 21 of the measuring object 20 detected by the probes 3a, 3b for voltage measurement with an AC current I being supplied to the measuring object 20 via the probes 3a, 3b for current supply; and a resistance value calculation section 7 for calculating a resistance value Rm of the measuring object 20 on the basis of the current value I of the AC current I supplied and the measured difference voltage Vd.

Description

  The present invention relates to a four-terminal resistance measurement device and a four-terminal resistance measurement method for measuring a resistance value of a measurement object, and an inspection device and an inspection method for determining the quality of a measurement object based on the measured resistance value.

  As a device related to this type of four-terminal resistance measuring device and inspection device, a four-terminal resistance measuring device disclosed in Japanese Patent Application Laid-Open No. 2000-111593 is known. This four-terminal resistance measuring device is a pair of contact-type current supply probes that are brought into contact with both ends of a measurement object such as a conductor pattern and resistance, and a constant current between both ends of the measurement object via the current supply probe. A constant current source to be supplied, a pair of contact-type voltage measurement probes for detecting a voltage across the measurement object by supplying a constant current to the measurement object, and both ends via the voltage measurement probe And a measurement unit including a differential amplifier for measuring voltage. In this four-terminal resistance measuring device, a constant current is supplied by contacting a current supply probe to both ends of a measurement target, a voltage measurement probe is contacted to both ends of the measurement target, a voltage at both ends is measured, and the supplied constant current is measured. Based on the current value of the current and the voltage value of the both-ends voltage, the resistance value of the measurement object is measured by the four-terminal method.

Japanese Unexamined Patent Publication No. 2000-111593 (page 1-4, FIG. 1)

  However, the conventional four-terminal resistance measuring device has the following problems to be solved. That is, in the conventional four-terminal resistance measurement device, it is necessary to bring the current supply probe and the voltage measurement probe into contact with both ends of the measurement object one by one. On the other hand, in recent years, electronic components have been miniaturized, and the wiring pattern of a circuit board has also been increased in density in order to mount electronic components at a high density. Therefore, in this conventional four-terminal resistance measurement device, it is extremely difficult to reliably contact the current supply probe and the voltage measurement probe to both ends of the measurement object, and therefore reliable measurement is also difficult. There is a problem.

  The present invention has been made in view of such a problem, and a four-terminal resistance measurement device, an inspection device, and a four-way resistance measurement device that enable reliable measurement in a resistance value measurement for a measurement object that is miniaturized and mounted with high density. An object of the present invention is to provide a terminal resistance measurement method and an inspection method.

  In order to achieve the above object, a four-terminal resistance measuring device according to claim 1 supplies an alternating current between a pair of contact-type current supply probes and both ends of a measurement object via the pair of current supply probes. An alternating current supply unit, a pair of non-contact type voltage measurement probes for detecting each voltage at both ends of the measurement object by capacitive coupling, and the measurement object via the current supply probe A voltage measuring unit for measuring a voltage difference voltage between the both ends of the measurement object detected by the voltage measuring probe in a state in which an alternating current is supplied; and a current value of the supplied alternating current and the measured differential voltage value And a resistance value calculation unit that calculates the resistance value of the measurement object based on the above.

  The four-terminal resistance measurement device according to claim 2 is the four-terminal resistance measurement device according to claim 1, wherein the voltage measurement unit uses the voltage detected by one of the pair of voltage detection probes as an input signal. A first buffer circuit, a second buffer circuit using the voltage detected by the other of the pair of voltage detection probes as an input signal, and a differential voltage between output voltages of the two buffer circuits as the differential voltage And a differential amplifier circuit for outputting.

  The four-terminal resistance measurement device according to claim 3 is the four-terminal resistance measurement device according to claim 2, wherein the one terminal for voltage measurement excluding a detection surface for detecting the voltage in the one voltage measurement probe. The outer peripheral surface of the probe and the wiring portion connecting the one voltage measuring probe and the input terminal of the first buffer circuit are covered and maintained at the same potential as the output voltage of the first buffer circuit. 1 voltage guard, the outer peripheral surface of the other voltage measurement probe excluding the detection surface for detecting the voltage in the other voltage measurement probe, and the second voltage measurement probe and the second voltage measurement probe. A second voltage guard that covers a wiring portion connecting to the input terminal of the buffer circuit and is maintained at the same potential as the output voltage of the second buffer circuit is provided.

  An inspection apparatus according to a fourth aspect includes a four-terminal resistance measurement apparatus according to any one of the first to third aspects, a resistance value of the measurement target calculated by the four-terminal resistance measurement apparatus, and a predetermined measurement target. And a determination unit that determines the quality of the measurement object by comparing with a defined reference value.

  The four-terminal resistance measurement method according to claim 5 is configured to supply an alternating current between both ends of a measurement target via a pair of current supply probes, and to couple capacitively using a pair of non-contact voltage measurement probes. To detect each voltage at both ends of the measurement object, measure a voltage difference between the voltages at the both ends of the detected measurement object, and determine a current value of the supplied alternating current and the measured difference voltage value. Based on this, the resistance value of the measurement object is calculated.

  The inspection method according to claim 6 is characterized by comparing the resistance value of the measurement object calculated by the four-terminal resistance measurement method according to claim 5 with a reference value defined in advance for the measurement object. Determine.

  In the four-terminal resistance measuring device according to claim 1 and the four-terminal resistance measuring method according to claim 5, an alternating current is supplied by bringing a pair of current supply probes into contact with both ends of the measuring object, and both ends of the measuring object are measured. A pair of voltage measurement probes are brought close to each other, and in this state, each voltage at each end of the measurement object is detected by capacitive coupling by the pair of voltage measurement probes, and the current value of the supplied alternating current is detected. The resistance value of the measurement target is calculated based on the difference voltage between the voltages at each end of the measurement target.

  Therefore, according to the four-terminal resistance measurement device and the four-terminal resistance measurement method, in the conventional four-terminal resistance measurement device, both the pair of current supply probes and the pair of voltage measurement probes are miniaturized and mounted with high density. Although it was difficult to reliably contact the measured object, only a pair of current supply probes were brought into contact with both ends of the measured object, and a pair of voltage measuring probes were placed close to both ends of the measured object. In this state, it is possible to reliably detect the voltage at each end of the measurement object, so that voltage measurement for a measurement object that is miniaturized and mounted with high density, and thus resistance measurement for the measurement object, can be ensured. Can be planned.

  In the four-terminal resistance measuring device according to the second aspect, the voltage at each end of the measurement target is detected by capacitive coupling by each voltage measuring probe. In this case, generally, since the electrostatic capacitance between each voltage measurement probe and the measurement object is small, the coupling impedance becomes large. Therefore, when a voltage detected by each voltage measurement probe is input to an amplifier circuit or the like having a small input impedance, the voltage value of the input voltage decreases. On the other hand, according to this four-terminal resistance measuring device, the input impedance of the buffer circuit is sufficiently larger than the coupling impedance between the voltage measurement probe and the measurement target, and therefore, it occurs at each end of the measurement target. It is possible to reliably detect without reducing the voltage value of each voltage. Therefore, according to this four-terminal resistance measuring device, it is possible to further ensure the resistance value measurement for the measurement object.

  According to the four-terminal resistance measuring device of claim 3, both voltage guards cover and shield the outer peripheral surface of the voltage measuring probe and both wiring parts, thereby shielding disturbance noise that causes measurement errors. Therefore, it is possible to measure the resistance value with high accuracy. In this case, when the potential of both voltage guards is another potential different from the output voltage of each buffer circuit, a current path is formed through which current flows from each wiring section to another potential via both voltage guards. Thus, the voltage value of the voltage input to the input portion of the voltage buffer decreases. On the other hand, according to this four-terminal resistance measuring device, since both voltage guards and the output part of each buffer circuit are maintained at the same potential, the current path is not formed, and as a result, the input voltage of the voltage buffer Can be avoided, and thus the resistance value of the measurement object can be measured more reliably.

  Further, according to the inspection apparatus according to claim 4 and the inspection method according to claim 6, the resistance value of the measurement target calculated by the four-terminal resistance measurement is compared with a reference value preliminarily defined for the measurement target. Thus, the quality of the measurement target can be reliably determined.

1 is a configuration diagram showing a configuration of an inspection apparatus 1. FIG.

  Hereinafter, embodiments of a four-terminal resistance measurement device, an inspection device, a four-terminal resistance measurement method, and an inspection method will be described with reference to the accompanying drawings.

  Initially, the structure of the test | inspection apparatus 1 as an example of a 4-terminal resistance measuring apparatus and a test | inspection apparatus is demonstrated.

  The inspection apparatus 1 is, for example, a circuit board inspection apparatus for inspecting a circuit board. As shown in FIG. 1, a pair of current supply probes 2a and 2b (hereinafter also referred to as “probe 2” when not distinguished). , A pair of voltage measurement probes 3a and 3b (hereinafter also referred to as “probe 3” when not distinguished), an alternating current supply unit 4, a current detection unit 5, a voltage measurement unit 6, a resistance value calculation unit 7, and a determination unit 8 The storage unit 9 and the output unit 10 are configured so that the resistance value Rm of the measurement target 20 can be measured. In this case, for example, the inspection apparatus 1 performs a continuity inspection using the conductor pattern formed on the circuit board (bare board) 100 on which no component is mounted as the measurement target 20. Specifically, the inspection apparatus 1 measures the resistance value (that is, the resistance value Rm) between the solder ball bumps 21 and 21 formed at both ends of the measurement target 20, and the measurement target 20 is defined in advance. Compared with the reference value Rr, when the resistance value Rm is equal to or less than the reference value Rr, the continuity of the measurement target 20 is good, and when the resistance value Rm exceeds the reference value Rr, the measurement target 20 is subjected to pattern cutting. It is determined (inspected) that there is a continuity failure.

  Each of the current supply probes 2a and 2b is a contact type probe, and is used to supply an AC measurement current to the measurement object 20. In this case, the current supply probe 2 a has a base end connected to the alternating current supply unit 4, and a tip is brought into contact with one of the pair of solder ball bumps 21 during measurement. The current supply probe 2b has a base end connected to a reference potential, and a tip is brought into contact with the other solder ball bump 21 during measurement.

  The voltage measuring probes 3a and 3b are non-contact type probes, and are used to measure the voltage generated in each solder ball bump 21. In this case, the voltage measuring probe 3a has a base end connected to a non-inverting input terminal of a first buffer circuit 61a described later. In the voltage measurement probe 3a, at the time of measurement, the detection surface Sd at the tip for detecting the voltage is brought close to the solder ball bump 21 of the measurement target 20 and is brought close to the capacitance Ca via the capacitance Ca. Capacitance coupling is individually performed with each solder ball bump 21, and a voltage generated in each solder ball bump 21 is detected as a detection voltage Va. The voltage measuring probe 3b has a base end connected to a non-inverting input terminal of a second buffer circuit 61b described later. In the voltage measurement probe 3b, at the time of measurement, the detection surface Sd at the tip for detecting the voltage is brought close to the solder ball bump 21 of the measurement target 20 and is brought close to the voltage Cb via the capacitance Cb. Each of the solder ball bumps 21 is individually capacitively coupled, and a voltage generated in each solder ball bump 21 is detected as a detection voltage Vb. Hereinafter, when the capacitances Ca and Cb are not distinguished, they are also referred to as “capacitance C”.

  The alternating current supply unit 4 is composed of an alternating constant current source or an alternating current source (in this example, an alternating current source) and is connected between the probe 2a and a reference potential, and a current I as a measurement current. Is supplied between the solder ball bumps 21 and 21 of the measuring object 20 via the probes 2a and 2b.

  The current detection unit 5 is composed of, for example, a shunt resistor, detects a voltage generated at both ends of the shunt resistor when the current I output from the alternating current supply unit 4 flows, and detects the detected voltage Vi as A described later. / D converter 72 to output.

  The voltage measuring unit 6 includes a first buffer circuit 61a, a second buffer circuit 61b (hereinafter also referred to as “buffer circuit 61” when the buffer circuits 61a and 61b are not distinguished from each other), and a differential amplifier circuit 62. ing.

  As an example, the first buffer circuit 61a is composed of an amplifier circuit using an operational amplifier. The non-inverting input terminal is connected to the base end of the voltage measuring probe 3a, and the inverting input terminal is connected to the output terminal. Has been. The buffer circuit 61a receives the detection voltage Va detected by the voltage measurement probe 3a and buffers and amplifies it to output the detection voltage Va as an output voltage.

  The second buffer circuit 61b is constituted by an amplifier circuit using an operational amplifier as an example, the non-inverting input terminal is connected to the base end of the voltage measuring probe 3b, and the inverting input terminal is the output terminal. It is connected to the. The buffer circuit 61b receives the detection voltage Vb detected by the voltage measurement probe 3b and buffers and amplifies it to output the detection voltage Vb as an output voltage.

  The differential amplifier circuit 62 has one input terminal connected to the output terminal of the buffer circuit 61a and the other input terminal connected to the output terminal of the buffer circuit 61b. The differential amplifier circuit 62 receives the detection voltages Va and Vb output from the buffer circuits 61a and 61b, respectively, and amplifies the difference voltage between the input detection voltages Va and Vb with a predetermined amplification factor. It outputs as the difference voltage Vd of each voltage in the both ends of the object 20.

  Further, the inspection device 1 is provided with a first voltage guard Ga and a second voltage guard Gb (hereinafter also referred to as “voltage guard G” when the voltage guards Ga and Gb are not distinguished from each other).

  The first voltage guard Ga is made of a conductor such as a mesh wire, and includes an outer peripheral surface excluding the detection surface Sd (that is, a distal end surface) of the voltage measurement probe 3a, a proximal end portion of the voltage measurement probe 3a, and a buffer. The wiring portion W connecting the non-inverting input terminal of the circuit 61a is covered. The first voltage guard Ga is connected to the output terminal of the first buffer circuit 61a and is maintained at the same potential as the detection voltage Va of the first buffer circuit 61a.

  The second voltage guard Gb is made of a conductor such as a mesh wire, and has an outer peripheral surface excluding the detection surface Sd (that is, a distal end surface) in the voltage measurement probe 3b and a proximal end portion of the voltage measurement probe 3b. And a wiring portion W connecting the non-inverting input terminal of the second buffer circuit 61b. The second voltage guard Gb is connected to the output terminal of the second buffer circuit 61b and is maintained at the same potential as the detection voltage Vb of the second buffer circuit 61b.

  The resistance value calculation unit 7 includes A / D converters 71 and 72 and an arithmetic circuit 73. In this case, the A / D converter 71 samples the difference voltage Vd output from the differential amplifier circuit 62 at a predetermined sampling rate and converts it into digital data (waveform data) Dv indicating the voltage waveform of the difference voltage Vd. Convert and output. In addition, the A / D converter 72 samples the detection voltage Vi output from the current detection unit 5 at the same rate as the sampling rate of the A / D converter 71, so that the AC current supply unit 4 supplies the measurement target 20. It is converted into digital data (waveform data) Di indicating the current waveform of the supplied current I (the current value is referred to as “current value I”) and output. The arithmetic circuit 73 inputs the digital data Dv and Di, and based on the digital data Dv and Di (that is, the difference voltage Vd and the current value I), the measurement object 20 (that is, between the solder ball bumps 21 and 21). The resistance value Rm is calculated.

  The determination unit 8 includes a digital circuit including a CPU and a memory (both not shown). The resistance value Rm of the measurement target 20 calculated by the arithmetic circuit 73 and the measurement target 20 are defined in advance. Based on the reference value Rr stored in the storage unit 9, a determination process for determining pass / fail of the measurement target 20 and an output process for outputting the determination result of the determination process to the output unit 10 are executed. In this case, when the measured resistance value Rm is less than or equal to the reference value Rr in the determination process, the determination unit 8 has good conduction of the measurement target 20 and the measured resistance value Rm exceeds the reference value Rr. Then, it is determined that there is a conduction failure such as pattern cutting in the measurement object 20.

  The storage unit 9 is configured by a semiconductor memory as an example, and stores a reference value Rr defined in advance for each measurement target 20.

  As an example, the output unit 10 is configured using a display device such as a display, and displays the determination result output in the output process by the determination unit 8 on the display.

  Next, a four-terminal resistance measurement method for measuring the resistance value of the measurement object 20, an inspection method for determining pass / fail based on the measurement value, and the operation of the inspection apparatus 1 at that time will be described with reference to the drawings. .

First, the current supply probes 2a and 2b are brought into contact with the solder ball bumps 21 and 21 of the measurement target 20, respectively. Next, a current I is supplied between the solder ball bumps 21 and 21 of the measurement target 20 from an AC constant current source. At this time, the current detection unit 5 detects a voltage generated at both ends of the shunt resistor when the current I output from the alternating current supply unit 4 flows, and outputs the detection voltage Vi to the A / D converter 72. To do. Next, the voltage measurement probes 3a and 3b are respectively provided in the vicinity of the solder ball bumps 21 and 21 so that the detection surfaces Sd of the voltage measurement probes 3a and 3b face the surfaces (upper surfaces) of the solder ball bumps 21 and 21, respectively. Deploy. At this time, each probe 3 is electrostatically coupled to each solder ball bump 21 via the electrostatic capacitance C between each solder ball bump 21, and each voltage generated in the corresponding solder ball bump 21. Are detected as detection voltages Va and Vb, respectively. In this case, when the frequency of the alternating current to be supplied is f, the coupling impedance Z between the probe 3 and the measurement target 20 is expressed as the following formula (1).
Z = j × 1 / 2πfC (1) (j is an imaginary unit)

Next, the detection voltages Va and Vb detected by the probe 3 are input to the buffer circuits 61a and 61b, respectively. At this time, the buffer circuits 61a and 61b buffer and amplify the detection voltages Va and Vb, respectively, and output them. In this case, generally, since the capacitance C between the probe 3 and the measurement target 20 is small, the coupling impedance Z is large according to the above equation (1). Therefore, when the detection voltages Va and Vb from the probe 3 are input to an amplifier circuit having a small input impedance, the voltage values of the detection voltages Va and Vb are lowered. On the other hand, in this example, since the input impedance of the buffer circuit 61 is sufficiently larger than the coupling impedance Z, the voltage values of the voltages generated on the solder ball bumps 21 and 21 (that is, the detection voltages Va and Vb). Can be reliably detected without lowering. Here, for example, when it is desired to measure the detection voltages Va and Vb with an accuracy of 1%, when the input impedance of the buffer circuit 61 is Zi, the input impedance Zi needs to satisfy the following expression (2). It becomes.
Zi> Z / 0.01 (2)
Therefore, in this example, the input impedance Zi of the buffer circuit 61 is designed to be 100 times or more the coupling impedance Z.

  Next, the detection voltages Va and Vb respectively output from the buffer circuit 61 are input to the input terminals of the differential amplifier circuit 62. At this time, the differential amplifier circuit 62 amplifies the difference voltage between the input detection voltages Va and Vb with a predetermined amplification factor and outputs the amplified voltage as the difference voltage Vd of the measurement target 20.

  Next, in the resistance value calculation unit 7, the A / D converter 71 outputs the digital data Dv of the difference voltage Vd output from the differential amplifier circuit 62, and the A / D converter 72 is used for the current detection unit 5. Is output as digital data Di (ie, current value I of current I output from AC current supply unit 4). In addition, the arithmetic circuit 73 calculates the resistance value Rm of the measurement target 20 based on the input digital data Dv and Di.

  Next, the determination unit 8 performs a determination process for determining the quality of the measurement target 20 based on the resistance value Rm of the measurement target 20 calculated by the arithmetic circuit 73 and the reference value Rr stored in the storage unit 9. In this determination process, the determination unit 8 compares the calculated resistance value Rm with the reference value Rr, and determines that the continuity of the measurement target 20 is good when the resistance value Rm is determined to be equal to or less than the reference value Rr. To do. On the other hand, when the resistance value Rm is larger than the reference value Rr, the determination unit 8 determines that there is a continuity failure in the measurement target 20. The determination unit 8 outputs the determination result to the output unit 10.

  At this time, the output unit 10 displays the determination result output from the determination unit 8 on the display. Thereby, the result of the inspection is visually recognized by the operator.

  As described above, in this inspection apparatus 1 and the four-terminal resistance measurement method, the probe 2 is brought into contact with the solder ball bump 21 to supply the current I to the measurement target 20 and the probe 3 is brought close to the solder ball bump 21 to obtain the state. , The voltage generated in each solder ball bump 21 of the measuring object 20 by the capacitive coupling using the electrostatic capacitance C between the probe 3 and the solder ball bump 21 is detected by the probe 3, and the detected voltage Va , Vb, the voltage (difference voltage value Vd) between the solder ball bumps 21 and 21 in the measuring object 20 is measured. Further, in the inspection device 1 and the four-terminal resistance measurement method, the resistance value Rm of the measurement target 20 is calculated based on the difference voltage value Vd and the current value I of the supplied current I. Therefore, according to the inspection apparatus 1 and the four-terminal resistance measurement method, it is possible to ensure the voltage measurement for the measurement target 20 that is miniaturized and mounted with high density, and thus the value measurement for the measurement target 20.

  Further, according to the inspection apparatus 1, since the input impedance of the buffer circuit 61 is sufficiently larger than the coupling impedance Z between the probe 3 and the measurement target 20, the voltage generated at the solder ball bump 21 of the measurement target 20. In other words, the detection can be performed reliably without lowering the voltage value of the detection voltages Va and Vb. Therefore, according to this inspection apparatus 1, it is possible to further ensure the resistance value measurement for the measurement object 20.

  Further, according to the inspection device 1, the voltage guard G includes the wiring portion W that connects the outer peripheral surface excluding the detection surface Sd of the probe 3 and the base end portion of the probe 3 and the non-inverting input terminal of the buffer circuit 61. By covering and shielding, the voltage guard G shields disturbance noise that causes measurement errors, so that the resistance value can be accurately measured. In this case, when the potentials of the voltage guards G are different from the detection voltages Va and Vb, which are output voltages of the buffer circuits 61, currents are passed from the wiring portions W to other potentials via the voltage guards 61. Due to the formation of the flowing current path, the voltage values of the detection voltages Va and Vb input to the non-inverting input terminal of the voltage buffer 61 are lowered. On the other hand, according to this inspection apparatus 1, since both voltage guards 61 and the output portions of the buffer circuits 61 are maintained at the same potential, the current path is not formed, and as a result, the input of the voltage buffer 61 It is possible to avoid a decrease in the voltage value of the voltage (that is, the detection voltages Va and Vb), thereby further ensuring the resistance value measurement for the measurement target 20.

  Moreover, according to this inspection method, the quality of the measuring object 20 can be determined by comparing the resistance value Rm of the measuring object 20 calculated by the four-terminal resistance measurement with the reference value Rr previously defined for the measuring object 20. It can be determined with certainty.

  In addition, although the example which comprised the alternating current supply part 4 with the alternating current source was demonstrated, it replaced with an alternating current source and an alternating current source can also be employ | adopted. In this configuration, the arithmetic circuit 73 is based on the digital data Dv (detection voltage Vd) output from the A / D converter 71 and the known current value output from the AC constant current source, and the resistance value of the measurement target 20. Since Rm can be calculated, the current detector 5 and the A / D converter 71 can be omitted, and the inspection apparatus 1 can be configured simply.

  Moreover, although the example which makes the measuring object 20 a conductor pattern was demonstrated, in the test | inspection apparatus 1, the resistance mounted in the circuit board 100, the unmounted resistance, etc. can also be made into the measuring object 20. FIG. Furthermore, in this example, the application to the inspection apparatus 1 has been described, but the present invention can also be applied to a resistance measurement apparatus that measures the resistance value of the measurement object 20 without having an inspection function.

DESCRIPTION OF SYMBOLS 1 Four terminal resistance measuring apparatus and inspection apparatus 2a, 2b Current supply probe 3a, 3b Voltage measurement probe 4 AC current supply part 5 Current detection part 6 Voltage measurement part 7 Resistance value calculation part 8 Judgment part 20 Measurement object 61a, 61b First and second buffer circuits 62 Differential amplifier circuits Ca and Cb Capacitance Ga and Gb First and second voltage guards I Current W Wiring section

Claims (6)

  A pair of contact-type current supply probes, an alternating current supply unit for supplying an alternating current between both ends of the measurement object via the pair of current supply probes, and at both ends of the measurement object by capacitive coupling A pair of non-contact type voltage measurement probes for detecting each voltage, and the measurement detected by the voltage measurement probe in a state where the alternating current is supplied to the measurement object via the current supply probe A voltage measuring unit that measures a voltage difference voltage between the both ends of the object, a resistance value calculating unit that calculates a resistance value of the measurement object based on the current value of the supplied alternating current and the measured difference voltage value; A four-terminal resistance measuring device.   The voltage measuring unit inputs a first buffer circuit having the voltage detected by one of the pair of voltage detection probes as an input signal and the voltage detected by the other of the pair of voltage detection probes. The four-terminal resistance measuring device according to claim 1, further comprising: a second buffer circuit that serves as a signal; and a differential amplifier circuit that outputs a differential voltage between the output voltages of the two buffer circuits as the differential voltage.   An outer peripheral surface of the one voltage measurement probe excluding a detection surface for detecting the voltage in the one voltage measurement probe, and an input terminal of the one voltage measurement probe and the first buffer circuit And a detection surface for detecting the voltage in the other voltage measuring probe, and a first voltage guard that is maintained at the same potential as the output voltage of the first buffer circuit. The removed outer peripheral surface of the other voltage measuring probe and the wiring portion connecting the other voltage measuring probe and the input terminal of the second buffer circuit are covered and the output voltage of the second buffer circuit is The four-terminal resistance measuring device according to claim 2, further comprising a second voltage guard maintained at the same potential.   The four-terminal resistance measurement device according to claim 1, the resistance value of the measurement object calculated by the four-terminal resistance measurement device, and a reference value defined in advance for the measurement object are compared. And a determination unit that determines whether the measurement target is good or bad.   An alternating current is supplied to both ends of the measurement target via a pair of current supply probes, and each voltage at the both ends of the measurement target is detected by capacitive coupling using a pair of non-contact type voltage measurement probes. Measuring the difference voltage of the voltage at the both ends of the detected measurement object, and calculating the resistance value of the measurement object based on the current value of the supplied alternating current and the measured difference voltage value Resistance measurement method.   An inspection method for determining pass / fail of a measurement object by comparing the resistance value of the measurement object calculated by the four-terminal resistance measurement method according to claim 5 and a reference value defined in advance for the measurement object.

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