JP2010145373A - Resistance measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistance measuring apparatus capable of downsizing and accurately measuring the resistance of an object to be measured. <P>SOLUTION: A resistance measuring apparatus 1 for measuring the resistance of a sample Rt includes: a voltage source Vs; a variable voltage source Vb; and resistors R1 to R3. When the voltage V1 between the resistors R1 and R2 is equal to the voltage V2 between the resistor R3 and the sample Rt, the output voltage V3 of the voltage source Vs and the output voltage V4 of the variable voltage source Vb are in equilibrium with each other. The resistance of the sample Rt can be accurately calculated by measuring any two of the voltages V1 (V2), V3, and V4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a resistance measuring apparatus, and more particularly to a resistance measuring apparatus that can observe a change in resistance value of a sample while applying a constant current to the sample, as represented by an electromigration evaluation test.

  A Wheatstone bridge method has been conventionally known as a method for precisely measuring the resistance value of a sample. First, the principle of the Wheatstone bridge will be described.

FIG. 13 is a circuit diagram showing the Wheatstone bridge circuit 101. The Wheatstone bridge circuit 101 includes a constant voltage source Vs101 and four resistors R101, R102, R103, and R104, and includes a series circuit including two resistors R101 and R102 and a series circuit including two resistors R103 and R104. Are connected in parallel. Here, when the ratio of the resistance value R103 to the resistance value R104 and the ratio of the resistance value R101 to the resistance value R102 are the same, the voltage V102 between the resistance R103 and the resistance R104 is the resistance R101 and the resistance R102. It becomes equal to the voltage V101 between. That is, when V102 = V101,
R101: R102 = R103: R104 (1)
Is established.

When formula (1) is transformed,
R101 × R104 = R103 × R102
And
R103 = R104 × R101 ÷ R102 (2)
It becomes.

  Subsequently, an example of resistance measurement by the Wheatstone bridge method will be described.

  FIG. 14 is a circuit diagram showing a Wheatstone bridge resistance measurement apparatus 201. The resistance measuring device 201 is a circuit that measures the resistance value of the sample Rt, and includes a constant voltage source Vs201 and three resistors R201, R202, and R203. The resistors R201 and R202 are fixed resistors whose resistance values are known, and the resistor R203 is a variable resistor such as a dial / decade resistor. The series circuit composed of the resistors R201 and R202 is connected in parallel to the series circuit composed of the sample Rt and the resistor R203.

Here, the connection relationship between the resistors R201 to R203 and the sample Rt is the same as that of the resistors R101 to R104 shown in FIG. Therefore, when the voltage V202 between the sample Rt and the resistor R203 is equal to the voltage V201 between the resistor R201 and the resistor R202, from the equation (2),
Rt = R203 × R201 ÷ R202 (3)
Holds.

  Here, the variable resistor R203 is adjusted so that V202 = V201. As described above, since the resistance values of the resistors R201 and R202 are known, the resistance value of the sample Rt is calculated from the equation (3). As means for detecting that V202 = V201, an ammeter is provided between the connection point between the resistors R201 and R202 and the connection point between the sample Rt and the resistor R203. When V202 = V201, since the current value of the current I201 flowing through the ammeter is zero, the resistor R203 is adjusted so that I201 = 0.

Here, the detection of whether or not the current I201 is zero can be realized with very high accuracy even with a simple coil-type ammeter. Therefore, the resistance value can be measured by the resistance measuring device 201 more easily than the resistance measuring method such as the Kelvin method. This resistance measurement method is disclosed, for example, in Non-Patent Document 1 below.
Hiroshi Hirayama, Ikuo Otsuki “Electrical Circuit Theory (The Institute of Electrical Engineers of Japan)” IEEJ Publishing 2008

  Since switching means for switching the resistance value is required inside the variable resistor R203 of the resistance measuring device 201, a switch-switching type resistance device that can directly read the resistance value is generally used as the variable resistor R203. However, since the switch-switching type resistance device is large, it is difficult to downsize the resistance measuring device 201. Moreover, since the switch-switching type resistance device uses mechanical parts such as a relay, the performance cannot be maintained for a long time.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to realize a resistance measuring apparatus that can be miniaturized and can accurately measure a resistance value of a measurement target.

  In order to solve the above-described problem, a resistance measurement device according to the present invention is a resistance measurement device for measuring a resistance value of a measurement target, and includes a first voltage source, a second voltage source, and first to first voltage sources. 3 resistors, the second voltage source is a variable voltage source, the first to third resistors are fixed resistors, and the first resistor and the second resistor are connected in series with each other. And the third resistor, the measurement object, and the second voltage source are connected in series to form a second series circuit, and the first series circuit is configured. And one end of the second series circuit are connected to the first voltage source, the other end of the first series circuit and the other end of the second series circuit are grounded, and the first From the voltage source side, the order of the third resistance, the measurement object and the second voltage source, or the measurement object, the third voltage source And the second voltage source is connected in this order, and the first voltage between the first resistor and the second resistor is the first voltage between the third resistor and the measurement object. When the voltage is equal to 2, the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state.

  A resistance measuring device according to the present invention is a resistance measuring device for measuring a resistance value of a measurement object, and includes a first voltage source, a second voltage source, and first to third resistors, The second voltage source is a variable voltage source, the first to third resistors are fixed resistors, and the first resistor and the second resistor are connected in series to form a first series circuit. The third resistor, the measurement object, and the second voltage source are connected in series to form a second series circuit, and one end of the first series circuit and the second series are configured. One end of the circuit is connected to the first voltage source, the other end of the first series circuit and the other end of the second series circuit are grounded, and from the first voltage source side, the first voltage source is connected to the first voltage source. 2 voltage source, the measurement object and the third resistance in this order, or the second voltage source, the third resistance and the measurement object When the first voltage between the first resistor and the second resistor is equal to the second voltage between the third resistor and the measurement object, the first resistor and the second resistor are connected. The voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state.

  A resistance measuring device according to the present invention is a resistance measuring device for measuring a resistance value of a measurement object, and includes a first voltage source, a second voltage source, and first to third resistors, The second voltage source is a variable voltage source, the first to third resistors are fixed resistors, and the first resistor, the second resistor, and the second voltage source are connected in series with each other. The third resistor and the measurement object are connected in series to form a second series circuit, and one end of the first series circuit and the second series circuit are configured. One end of the circuit is connected to the first voltage source, the other end of the first series circuit and the other end of the second series circuit are grounded, and from the first voltage source side, the first voltage source is connected to the first voltage source. 1 resistor, the second resistor, and the second voltage source are connected in this order, and the first resistor between the third resistor and the measurement object When the voltage is equal to the second voltage between the first resistor and the second resistor, the voltage of the first voltage source and the voltage of the second voltage source are in equilibrium. It is characterized by.

  A resistance measuring device according to the present invention is a resistance measuring device for measuring a resistance value of a measurement object, and includes a first voltage source, a second voltage source, and first to third resistors, The second voltage source is a variable voltage source, the first to third resistors are fixed resistors, and the first resistor, the second resistor, and the second voltage source are connected in series with each other. The third resistor and the measurement object are connected in series to form a second series circuit, and one end of the first series circuit and the second series circuit are configured. One end of the circuit is connected to the first voltage source, the other end of the first series circuit and the other end of the second series circuit are grounded, and from the first voltage source side, the first voltage source is connected to the first voltage source. 2 voltage sources, the first resistor and the second resistor are connected in this order, and a first between the third resistor and the measurement object When the voltage is equal to the second voltage between the first resistor and the second resistor, the voltage of the first voltage source and the voltage of the second voltage source are in equilibrium. It is characterized by.

  In the resistance measuring apparatus according to the present invention, the second voltage source includes a first differential output unit and a first voltage output unit, and the first differential output unit includes the first voltage and the first voltage output unit. A difference from the second voltage is output with a predetermined gain, and the first voltage output means is configured such that the first voltage is greater than the second voltage based on the output voltage of the first difference output means. When the voltage is higher, the output voltage of the first voltage output means is increased, and when the first voltage is lower than the second voltage, the output voltage of the first voltage output means is decreased and the first voltage output means is decreased. The output voltage of the voltage output means is preferably the voltage of the second voltage source.

  In the resistance measuring apparatus according to the present invention, the second voltage source includes a first differential output unit and a first voltage output unit, and the first differential output unit includes the first voltage and the first voltage output unit. A difference from the second voltage is output with a predetermined gain, and the first voltage output means is configured such that the first voltage is greater than the second voltage based on the output voltage of the first difference output means. When the voltage is higher, the output voltage of the first voltage output means is increased, and when the first voltage is lower than the second voltage, the output voltage of the first voltage output means is decreased and the first voltage output means is decreased. A voltage obtained by subtracting the output voltage of the first voltage output means from the voltage of the voltage source is preferably the voltage of the second voltage source.

  According to the above configuration, since the first differential output means and the first voltage output means constituting the second voltage source are both circuits that can be digitized, high integration is possible. Moreover, since a mechanical relay is not required, the lifetime and stability of the resistance measuring device can be improved.

  In the resistance measuring apparatus according to the present invention, the first voltage source is a variable voltage source, and when the potential difference between both ends of the third resistor is a predetermined value, the voltage of the first voltage source is in an equilibrium state. It is preferable to become.

  According to the above configuration, when the potential difference between both ends of the third resistor is a predetermined value, the voltage of the first voltage source is in an equilibrium state. Therefore, in the equilibrium state, the third resistor has a constant current. Flows. In addition, since the third resistor and the measurement target are connected in series with each other, a constant current can flow through the measurement target regardless of the resistance value of the measurement target. Therefore, the resistance measuring device can be applied to an electromigration (EM) tester.

  In the resistance measuring apparatus according to the present invention, the first voltage source includes a third voltage source, a second difference output unit, and a second voltage output unit, and the second difference output unit includes The potential difference between both ends of the third resistor is output with a predetermined gain, and the second voltage output means receives the voltage of the third voltage source and the output voltage of the second difference output means as inputs, and When the voltage of the third voltage source is higher than the output voltage of the second differential output means, the output voltage of the second voltage output means is increased, and the voltage of the third voltage source is the second difference. When the output voltage is lower than the output voltage of the output means, the output voltage of the second voltage output means is preferably lowered, and the output voltage of the second voltage output means becomes the voltage of the first voltage source.

  According to the above configuration, since the third voltage source, the second differential output unit, and the second voltage output unit that constitute the first voltage source are all circuits that can be digitized, High integration is possible.

  In the resistance measuring apparatus according to the present invention, the second series circuit further includes a fourth resistor that is a fixed resistor, and the fourth resistor, the measurement object, and the third resistor are arranged from the first power supply side. Resistance order, the fourth resistance, the third resistance and the order of the measurement object, the measurement object, the third resistance and the fourth resistance, or the third resistance, The measurement object and the fourth resistor are connected in this order, and the first voltage source is a variable voltage source. When the potential difference between both ends of the fourth resistor is a predetermined value, the first voltage is The source voltage is in an equilibrium state, and the fourth resistor preferably has a lower resistance value than the first to third resistors.

  A resistance measuring device according to the present invention is a resistance measuring device for measuring a resistance value of a measurement object, and includes a first voltage source, a second voltage source, and first to fourth resistors, The first voltage source and the second voltage source are variable voltage sources, the first to fourth resistors are fixed resistors, the first resistor, the second resistor, and the second voltage source. Are connected in series to each other to form a first series circuit, and the third resistor, the fourth resistor, and the measurement object are connected to each other in series to form a second series circuit, One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are grounded. In the first series circuit, the first resistor, the second resistor, and the second voltage source are arranged in this order from the first voltage source side. Alternatively, the second voltage source, the first resistor, and the second resistor are connected in this order. In the second series circuit, from the first power supply side, the measurement object, the fourth resistor And the third resistor, or the third resistor, the fourth resistor, and the object to be measured, and connected between the first resistor and the second resistor. When the first voltage is equal to the second voltage between the third resistor and the fourth resistor, and the potential difference between both ends of the fourth resistor is a predetermined value, or the first voltage The first voltage between the resistor and the second resistor is equal to the third voltage between the measurement object and the fourth resistor, and the potential difference between both ends of the fourth resistor is a predetermined value. At some point, the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state, and the fourth resistance is It is characterized in that the resistance value than the first to third low resistance.

  A resistance measuring device according to the present invention is a resistance measuring device for measuring a resistance value of a measurement object, and includes a first voltage source, a second voltage source, and first to fourth resistors, The first voltage source and the second voltage source are variable voltage sources, the first to fourth resistors are fixed resistors, the first resistor, the second resistor, and the second voltage source. Are connected in series to each other to form a first series circuit, and the third resistor, the fourth resistor, and the measurement object are connected to each other in series to form a second series circuit, One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are grounded. In the first series circuit, the second voltage source, the first resistor, and the second resistor are arranged in this order from the first voltage source side. In the second series circuit, from the first power supply side, the fourth resistor, the measurement object and the third resistance, or the third resistance and the measurement object And the fourth resistor is connected in this order, and a first voltage between the first resistor and the second resistor is a second voltage between the third resistor and the measurement object. When the potential difference between the both ends of the fourth resistor is equal to a predetermined value, or the first voltage between the first resistor and the second resistor is equal to the voltage, the measurement object and the fourth resistor When the potential difference between both ends of the fourth resistor is equal to a predetermined value, the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state. Thus, the fourth resistor has a lower resistance value than the first to third resistors.

  In the resistance measurement apparatus according to the present invention, the first voltage source includes a third voltage source, a first differential output unit, and a first voltage output unit, and the first differential output unit includes the above-described first differential output unit. The potential difference between both ends of the fourth resistor is output with a predetermined gain, and the first voltage output means receives the voltage of the third voltage source and the output voltage of the first difference output means as inputs, and When the voltage of the third voltage source is higher than the output voltage of the first differential output means, the output voltage of the first voltage output means is increased, and the voltage of the third voltage source is the first difference. When the output voltage is lower than the output voltage of the output means, the output voltage of the first voltage output means is preferably lowered, and the output voltage of the first voltage output means becomes the voltage of the first voltage source.

  According to the above configuration, since the third voltage source, the second differential output unit, and the second voltage output unit that constitute the first voltage source are all circuits that can be digitized, High integration is possible.

  As described above, the resistance measuring apparatus according to the present invention is a resistance measuring apparatus for measuring a resistance value of a measurement target, and includes a first voltage source, a second voltage source, and first to third resistors. The second voltage source is a variable voltage source, the first to third resistors are fixed resistors, and the first resistor and the second resistor are connected in series to each other. 1 series circuit, the third resistor, the measurement object and the second voltage source are connected in series to form a second series circuit, and one end of the first series circuit One end of the second series circuit is connected to the first voltage source, the other end of the first series circuit and the other end of the second series circuit are grounded, and the first voltage source From the side, in order of the third resistance, the measurement object and the second voltage source, or the measurement object, the third resistance and the top A second voltage source is connected in this order, and a first voltage between the first resistor and the second resistor is a second voltage between the third resistor and the measurement object. Since the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state, a resistance measuring device that can be miniaturized and can accurately measure the resistance value of the measurement target is provided. There is an effect that it can be realized.

[Embodiment 1]
The first embodiment of the present invention will be described below with reference to FIGS. First, the principle of the resistance measuring apparatus according to the present embodiment will be described with reference to FIG.

  FIG. 1 is a circuit diagram showing a schematic configuration of a resistance measuring apparatus 1 according to the present embodiment. The resistance measuring apparatus 1 is a circuit that measures the resistance value of the sample Rt, and includes a voltage source Vs, a variable voltage source Vb, and three resistors R1, R2, and R3.

  The voltage source Vs is composed of a DA converter, for example, and outputs a constant voltage V3. Each of the resistors R1, R2, and R3 is a fixed resistor having a known resistance value. The resistor R1 and the resistor R2 are connected in series, and the sample Rt, the resistor R3, and the variable voltage source Vb are connected in series. More specifically, one end of the resistor R1 and one end of the sample Rt are both connected to the voltage source Vs. The other end of the resistor R1 is connected to one end of the resistor R2, and the other end of the resistor R2 is grounded. The other end of the sample Rt is connected to one end of the resistor R3, the other end of the resistor R3 is connected to one end of the variable voltage source Vb, and the other end of the variable voltage source Vb is grounded.

  The variable voltage source Vb is a voltage source that can output not only a positive voltage but also a negative voltage, and is composed of several operational amplifiers as will be described later. Further, the voltage of the variable voltage source Vb is balanced at the voltage V4 when the voltage V1 between the resistor R1 and the resistor R2 is equal to the voltage V2 between the sample Rt and the resistor R3.

At this time, the voltage V1 is obtained by dividing the voltage V3 by the resistor R1 and the resistor R2.
(V3-V1): V1 = R1: R2
V1 = V3 × R2 / (R1 + R2) Formula (4)
It becomes. On the other hand, the voltage V2 is obtained by dividing the potential difference between the voltage V3 and the voltage V4 by the sample Rt and the resistor R3.
(V3-V2) :( V2-V4) = Rt: R3
V2 = (R3 × V3 + Rt × V4) / (R3 + Rt) (5)
It becomes. Here, since V1 = V2, from Equation (4) and Equation (5),
V3 × R2 / (R1 + R2) = (R3 × V3 + Rt × V4) / (R3 + Rt)
Rt = R1 * R3 * V3 / (V3 * R2- (R1 + R2) * V4) (6)
Holds. Since the resistors R1 to R3 and the voltage V3 are known, the resistance value of the sample Rt can be calculated by measuring the voltage V4.

  The measurement of the voltage V4 can be easily realized by an AD converter as will be described later. The variable voltage source Vb can be easily configured with several operational amplifiers. Next, the variable voltage source Vb will be described with reference to FIG.

  FIG. 2 is a circuit diagram showing a specific configuration of the resistance measuring apparatus 1. In the figure, as a specific configuration of the variable voltage source Vb shown in FIG. 1, an instrumentation amplifier Amp1, a sample and hold circuit 2, an AD conversion circuit 3, a CPU 4, a DA conversion circuit 5, and an operational amplifier MOD1 are illustrated. . In the same figure, an AD conversion circuit 6 is also shown as a specific configuration for measuring the voltage V4.

  The instrumentation amplifier Amp1 has two input terminals + IN and −IN. The voltage V1 is input to the input terminal + IN, and the voltage V2 is input to the input terminal −IN. The instrumentation amplifier Amp1 outputs a difference obtained by subtracting the potential of the input terminal −IN from the potential of the input terminal + IN, that is, a voltage of (V1−V2).

  The output voltage of the instrumentation amplifier Amp1 is temporarily held by the sample and hold circuit 2 and input to the AD conversion circuit 3. Thereby, the output voltage of the instrumentation amplifier Amp1 is converted into a digital signal by the AD conversion circuit 3 and monitored by the CPU 4. The digital signal from the AD conversion circuit 3 is converted again into an analog voltage in the DA conversion circuit 5 via the CPU 4.

  The operational amplifier MOD1 has two input terminals + IN and −IN. The output voltage of the DA converter circuit 5 is input to the input terminal + IN, and the input terminal −IN is grounded. The operational amplifier MOD1 increases the output voltage when (input terminal + IN potential)> (input terminal-IN potential), and (input terminal + IN potential) <(input terminal-IN potential). Lowers the output voltage. In other words, the output voltage of the operational amplifier MOD1 is stabilized when (input terminal + IN potential) = (input terminal−IN potential).

  Since the output voltage of the DA converter circuit 5 is equal to the output voltage (V1-V2) of the instrumentation amplifier Amp1, the operational amplifier MOD1 changes the output voltage until V1-V2 = 0, and V1 = V2. At this time, the output voltage V4 is in an equilibrium state. Specifically, when V1> V2 when the voltage source Vs starts applying the voltage V3, V1−V2> 0, so the operational amplifier MOD1 increases the output voltage. In this case, the output voltage V4 in the equilibrium state is a positive voltage. On the other hand, when V1 <V2 when the voltage source Vs starts applying the voltage V3, V1−V2 <0, so the operational amplifier MOD1 reduces the output voltage. In this case, the output voltage V4 in the equilibrium state is a negative voltage.

  The voltage V4 is converted into a digital value by the AD conversion circuit 6 and monitored by the CPU 4. Thereby, the voltage V4 is measured, and the resistance value of the sample Rt is calculated by the above equation (6). Note that the output voltage of the instrumentation amplifier Amp1 may be directly input to the input terminal + IN of the operational amplifier MOD1. Further, although the calculation formula of the sample Rt is different, in the resistance measuring apparatus 1, the positions of the sample Rt and the resistor R3 may be interchanged.

  As described above, the resistance measuring apparatus 1 does not use a variable resistor that requires a mechanical relay or a switch, unlike the conventional resistance measuring apparatus, and therefore can improve the life, stability, and reliability of the circuit. . In addition, since the circuit constituting the resistance measuring apparatus 1 can be completely digitized, the resistance measuring apparatus 1 can be miniaturized and highly integrated.

  Then, the modification of this embodiment is demonstrated.

  FIG. 3 is a circuit diagram illustrating a schematic configuration of the resistance measuring apparatus 11 according to a modification of the present embodiment. The resistance measuring device 11 is a circuit for measuring the resistance value of the sample Rt, similarly to the resistance measuring device 1 shown in FIG. 1, and includes a voltage source Vs, a variable voltage source Vb, and three resistors R1, R2, and R3. . Each element constituting the resistance measuring device 11 is substantially the same as that in the resistance measuring device 1.

  On the other hand, in the resistance measuring apparatus 11, the resistor R1, the resistor R2, and the variable voltage source Vb are connected in series, and the sample Rt and the resistor R3 are connected in series. That is, in the resistance measuring device 1, the variable voltage source Vb is connected in series with the sample Rt and the resistor R3, whereas in the resistance measuring device 11, the variable voltage source Vb is connected in series with the resistors R1 and R2. Yes. More specifically, one end of the resistor R1 and one end of the sample Rt are both connected to the voltage source Vs. The other end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the variable voltage source Vb, and the other end of the variable voltage source Vb is grounded. The other end of the sample Rt is connected to one end of the resistor R3, and the other end of the resistor R3 is grounded.

The voltage of the variable voltage source Vb is balanced at the voltage V4 when the voltage V1 between the sample Rt and the resistor R3 is equal to the voltage V2 between the resistor R1 and the resistor R2. At this time, the voltage V1 is obtained by dividing the voltage V3 by the sample Rt and the resistor R3.
(V3-V1): V1 = Rt: R3
V1 = V3 × R3 / (Rt + R3) (7)
It becomes. On the other hand, the voltage V2 is obtained by dividing the potential difference between the voltage V3 and the voltage V4 by the resistor R1 and the resistor R2.
(V3-V2) :( V2-V4) = R1: R2
V2 = (R2 × V3 + R1 × V4) / (R1 + R2) (8)
It becomes. As described above, since V1 = V2 and the resistors R1 to R3 and the voltage V3 are known, the resistance value of the sample Rt can be calculated from the equations (7) and (8) by measuring the voltage V4. . The specific configuration of the variable voltage source Vb is substantially the same as that shown in FIG.

  Although the calculation formula of the sample Rt is different, the positions of the sample Rt and the resistor R3 may be interchanged in the resistance measuring device 11. In the resistance measuring apparatuses 1 and 11, the variable voltage source Vb is provided on the ground side, but the invention is not limited to this. For example, the variable voltage source Vb may be provided between the resistors constituting the bridge or between the resistor and the sample.

  Next, another modification of the present embodiment will be described with reference to FIG.

  FIGS. 4A to 4B are circuit diagrams each showing a schematic configuration of resistance measuring devices 21 and 31 according to still another modification of the present embodiment.

  The resistance measuring device 21 shown in FIG. 4A has a configuration in which a variable voltage source Vb is connected to one end of the sample Rt on the voltage source Vs side, and the voltage V1 between the resistors R1 and R2 is the variable voltage source. When equal to the voltage V2 between Vb and the resistor R3, the voltage of the variable voltage source Vb is in an equilibrium state.

At this time, if the output voltage of the variable voltage source Vb is V4,
V1 = V3 × R2 / (R1 + R2) (9)
V2 = (V3-V4) * R3 / (Rt + R3) (10)
It becomes. Here, since V1 = V2 and the resistors R1 to R3 and the voltage V3 are known, the resistance value of the sample Rt can be calculated from the equations (9) and (10) by measuring the voltage V4.

  In the resistance measuring device 21, the positions of the sample Rt and the resistor R3 may be interchanged.

The resistance measuring device 31 shown in FIG. 4B has a configuration in which the variable voltage source Vb is connected to one end of the resistor R1 on the voltage source Vs side, and the voltage V1 between the resistor R1 and the resistor R2 is the sample Rt. When it becomes equal to the voltage V2 between the resistor R3, the voltage of the variable voltage source Vb is in an equilibrium state. At this time, the voltage V2 is obtained by dividing the voltage V3 by the sample Rt and the resistor R3.
(V3-V2): V2 = Rt: R3
V2 = V3 × R3 / (Rt + R3) (11)
It becomes. On the other hand, when the output voltage of the variable voltage source Vb is V4, the voltage V1 is
V1 = (V3-V4) × R2 / (R1 + R2) (12)
It becomes. Since V1 = V2 and the resistors R1 to R3 and the voltage V3 are known, the resistance value of the sample Rt can be calculated from the equations (11) and (12) by measuring the voltage V4.

  In the resistance measuring device 31, the positions of the sample Rt and the resistor R3 may be interchanged.

  Next, a specific example of a configuration in which the variable voltage source Vb is connected to the voltage source Vs will be described with reference to FIG.

  FIG. 5 is a circuit diagram showing a specific configuration of the resistance measuring device 21 shown in FIG. In the figure, the variable voltage source Vb includes an instrumentation amplifier Amp1, a sample and hold circuit 2, an AD conversion circuit 3, a CPU 14, a DA conversion circuit 5, an operational amplifier MOD1, and an AD conversion circuit 7. That is, the elements constituting the variable voltage source Vb of the resistance measuring device 21 are the same as the elements constituting the variable voltage source Vb of the resistance measuring apparatus 1 shown in FIG. 2 except for the CPU 14 and the AD conversion circuit 7.

  The instrumentation amplifier Amp1 has two input terminals + IN and −IN. The voltage V1 is input to the input terminal + IN, and the voltage V2 is input to the input terminal −IN. The instrumentation amplifier Amp1 outputs a difference obtained by subtracting the potential of the input terminal −IN from the potential of the input terminal + IN, that is, a voltage of (V1−V2).

  The output voltage of the instrumentation amplifier Amp1 is temporarily held by the sample and hold circuit 2 and input to the AD conversion circuit 3. Thereby, the output voltage of the instrumentation amplifier Amp1 is converted into a digital signal by the AD conversion circuit 3 and monitored by the CPU. The voltage V3 from the voltage source Vs is also converted into a digital signal by the AD conversion circuit 7 and monitored by the CPU.

  The CPU 14 adds the digital signal from the AD conversion circuit 7 to the digital signal from the AD conversion circuit 3, and outputs the added signal to the DA conversion circuit 5. Thereby, the DA conversion circuit 5 outputs an analog voltage of (V1−V2 + V3).

  The operational amplifier MOD1 has two input terminals + IN and −IN. The output voltage of the DA converter circuit 5 is input to the input terminal + IN, and the voltage V3 is input to the input terminal −IN. The operational amplifier MOD1 increases the output voltage when (input terminal + IN potential)> (input terminal-IN potential), and (input terminal + IN potential) <(input terminal-IN potential). Lowers the output voltage. In other words, the output voltage of the operational amplifier MOD1 is stabilized when (input terminal + IN potential) = (input terminal−IN potential).

  Here, since (potential of input terminal + IN) = V1−V2 + V3 and (potential of input terminal −IN) = V3, the operational amplifier MOD1 changes the output voltage until V1−V2 = 0, When V1 = V2, the output voltage V4a is in an equilibrium state. Specifically, when V1> V2 when the voltage source Vs starts to apply the voltage V3, V1−V2 + V3> V3 is satisfied, so that the operational amplifier MOD1 increases the output voltage. On the other hand, when V1 <V2 when the voltage source Vs starts to apply the voltage V3, V1−V2 + V3 <V3, and the operational amplifier MOD1 lowers the output voltage.

  In the resistance measuring device 21, the output voltage V4a of the operational amplifier MOD1 is different from the voltage V4 of the variable voltage source Vb shown in FIG. 4A, and the voltage V4 of the variable voltage source Vb is the voltage V3. The output voltage V4a is subtracted from the output voltage. That is, when V1> V2, the voltage V4 of the variable voltage source Vb decreases, and when V1 <V2, the voltage V4 of the variable voltage source Vb increases.

  The voltage V4a is converted into a digital value by the AD conversion circuit 6 and monitored by the CPU 4. Since the voltage V4 of the variable voltage source Vb is V3-V4a as described above, the CPU 4 determines the voltage V4 based on the digital value from the AD conversion circuit 6 and the digital value from the AD conversion circuit 7. Calculate the value. Thereby, the resistance value of the sample Rt is calculated from the above formulas (9) and (10). Although the calculation formula of the sample Rt is different, the positions of the sample Rt and the resistor R3 may be interchanged in the resistance measuring device 21.

[Embodiment 2]
A second embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a resistance measuring apparatus applicable to an electromigration (EM) test that requires a predetermined constant current to flow through a sample will be described.

  FIG. 6 is a circuit diagram illustrating a schematic configuration of the resistance measuring device 41 according to the present embodiment. The resistance measuring device 41 has a configuration in which a variable voltage source Vv that outputs a voltage V5 is provided instead of the voltage source Vs in the resistance measuring device 1 shown in FIG. The variable voltage source Vv is in an equilibrium state at the voltage V5 when the potential difference between both ends of the resistor R3 connected in series with the sample Rt is a predetermined value.

  That is, when the variable voltage source Vv is in an equilibrium state, the constant current Ir3 flows through the resistor R3 because the potential difference between both ends of the resistor R3 is equal regardless of the resistance value of the sample Rt. Since the current flowing through the sample Rt is also the constant current Ir3, the current flowing through the sample Rt is constant even if the resistance value of the sample Rt is different.

Thus, in the resistance measuring device 41, when V1 = V2 and the potential difference between both ends of the resistor R3 is a predetermined value, the variable voltage source Vb and the variable voltage source Vv are the voltage V4 and the voltage V5, respectively. It becomes an equilibrium state. At this time, the series circuit of the resistor R3 and the variable voltage source Vb can be regarded as a resistor of (V2 ÷ Ir3) Ω. Therefore, according to the Wheatstone bridge principle,
Rt = (V2 / Ir3) × R1 ÷ R2 (13)
It becomes. Here, since the potential difference between both ends of the resistor R3 in the equilibrium state is a known voltage, the constant current Ir3 is also known. Therefore, the resistance value of the sample Rt can be calculated by measuring the voltage V2 (or voltage V1).

  As will be described later, since the circuit elements constituting the variable voltage source Vv can be highly integrated similarly to the variable voltage source Vb, the resistance measuring device 41 can be downsized. Next, the variable voltage source Vv will be described with reference to FIG.

  FIG. 7 is a circuit diagram showing a specific configuration of the resistance measuring device 41. The variable voltage source Vv includes a voltage source Vss, an instrumentation amplifier Amp2, and an operational amplifier MOD2. The voltage source Vss is a voltage source that outputs a predetermined constant voltage, and includes, for example, a DA converter circuit.

  The instrumentation amplifier Amp2 has two input terminals + IN and −IN, and amplifies and outputs a potential difference between the input terminal + IN and the input terminal −IN with a predetermined gain. The voltage (voltage V2) at one end of the resistor R3 on the sample Rt side is input to the input terminal + IN of the instrumentation amplifier Amp2, and the voltage (voltage) at the other end of the resistor R3 is input to the input terminal -IN of the instrumentation amplifier Amp2. V4) is input.

  The operational amplifier MOD2 has two input terminals + IN and −IN. The output voltage V6 from the voltage source Vss is input to the input terminal + IN, and the input terminal −IN is supplied from the instrumentation amplifier Amp2. Output voltage is input. The operational amplifier MOD2 increases the output voltage when (input terminal + IN potential)> (input terminal-IN potential), and (input terminal + IN potential) <(input terminal-IN potential). Decreases the output voltage, and when (input terminal + IN potential) = (input terminal -IN potential), the output voltage becomes stable.

If the gain of Amp2 is g, the potential difference between both ends of the resistor R3 is V2-V4.
(V2-V4) × g = V6
In this case, the output voltage of the operational amplifier MOD2 is in a balanced state. At this time, the current Ir3 flowing through the resistor R3 is
Ir3 = (V2−V4) / R3 = V6 × R3 / g (14)
It becomes constant at. Since R3 is known in Expression (14), the constant current value desired to flow through the sample Rt can be controlled by setting the voltage V6 and the gain g of the instrumentation amplifier Amp2 to desired values.

  In parallel with the transition of the output voltage of the operational amplifier MOD2 to the balanced state, the output voltage of the operational amplifier MOD1 is balanced at the voltage V4 so that V1 = V2. As described above, in the resistance measurement device 41, the AD conversion circuit 6 is configured to measure the voltage V2 in order to calculate the resistance value of the sample Rt based on the equation (13). The specific operation of the variable voltage source Vb including the instrumentation amplifier Amp1, the sample-and-hold circuit 2, the AD conversion circuit 3, the CPU 4, the DA conversion circuit 5, and the operational amplifier MOD1 is the resistance measuring device shown in FIG. 1 is substantially the same as that in FIG.

  Then, the modification of this embodiment is demonstrated.

  FIG. 8 is a circuit diagram showing a schematic configuration of a resistance measuring device 51 according to a modification of the present embodiment. The resistance measuring device 51 has a configuration in which a variable voltage source Vv is provided instead of the voltage source Vs in the resistance measuring device 11 shown in FIG. Similar to the variable voltage source Vv of the resistance measuring device 41 shown in FIG. 6, the variable voltage source Vv is in an equilibrium state at the voltage V5 when the potential difference between both ends of the resistor R3 connected in series with the sample Rt is a predetermined value. .

FIG. 9 is a circuit diagram showing a specific configuration of a resistance measuring device 51 according to a modification of the present embodiment. In the resistance measuring device 51, similarly to the resistance measuring device 41, the variable voltage source Vv includes a voltage source Vss, an instrumentation amplifier Amp2, and an operational amplifier MOD2, and the two input terminals + IN and −IN of the instrumentation amplifier Amp2 Is inputted with the voltage across the resistor R3. As a result, the output voltage of the operational amplifier MOD2 is balanced at the voltage V5 when the potential difference between both ends of the resistor R3 is a predetermined value. Further, the output voltage of the operational amplifier MOD1 is balanced at the voltage V4 when V1 = V2. At this time,
V1 = V5 × R3 / (Rt + R3) (15)
V2 = (R2 × V5 + R1 × V4) / (R1 + R2) (16)
Therefore, the resistance value of the sample Rt can be calculated from the equations (15) and (16) by measuring the voltage V4 and the voltage V5.

  When the voltages V4 and V5 are in an equilibrium state, the current flowing through the resistor R3 is constant because the potential difference between both ends of the resistor R3 is constant at a predetermined value regardless of the resistance value of the sample Rt. Therefore, even if the sample Rt is different, the current flowing through the sample Rt is constant.

  The resistance measuring devices 41 and 51 according to the present embodiment are examples, and the resistors R1 to R3 and the variable voltage source Vb constituting the Wheatstone bridge are the same as the configuration shown in FIG. 4 as in the first embodiment. Can be arranged.

[Embodiment 3]
A third embodiment of the present invention will be described below with reference to FIGS. When the sample Rt is a conductor component that should be 0Ω originally, such as a contact point of an optical MOSFET relay or an electrical wiring inside the LSI, but in reality has a slight resistance value (about 1 to 10Ω). In order to measure the resistance value of Rt, it is necessary to pass a relatively large current through the sample Rt. In the present embodiment, a resistance measuring apparatus capable of flowing a large current through the sample Rt will be described.

  FIG. 10 is a circuit diagram showing a schematic configuration of the resistance measuring device 61 according to the present embodiment. The resistance measuring device 61 is further provided with a resistor R4 in the resistance measuring device 51 shown in FIG. 8, and the output voltage of the variable voltage source Vv is balanced with the voltage V7 when the potential difference between both ends of the resistor R4 becomes a predetermined value. It is comprised so that it may become. Specifically, a series circuit of a resistor R1, a resistor R2, and a variable voltage source Vb and a series circuit of a resistor R4, a sample Rt, and a resistor R3 are connected in parallel to each other. Further, when the voltage V1 between the sample Rt and the resistor R3 becomes equal to the voltage V2 between the resistor R1 and the resistor R2, the output voltage of the variable voltage source Vb is in an equilibrium state at the voltage V4. The resistor R4 is a fixed resistor. When the output voltage of the variable voltage source Vv is in an equilibrium state, a constant current Ir4 flows through the resistor R4 regardless of the resistance value of the sample Rt.

  FIG. 11 is a circuit diagram showing a specific configuration of the resistance measuring device 61. In the resistance measuring device 61, the variable voltage source Vv includes a voltage source Vss, an instrumentation amplifier Amp2, and an operational amplifier MOD2. The two input terminals + IN and −IN of the instrumentation amplifier Amp2 are connected to both ends of the resistor R4. A voltage is input. Thereby, the output voltage of the operational amplifier MOD2 is balanced at the voltage V7 when the potential difference between both ends of the resistor R4 is a predetermined value. Further, the output voltage of the operational amplifier MOD1 is balanced at the voltage V4 when V1 = V2.

At this time, assuming that the current flowing through the resistor R2 is Ir2, the series circuit of the resistor R2 and the variable voltage source Vb can be regarded as a resistor of (V2 ÷ Ir2) Ω. From the Wheatstone bridge principle,
Rt + R4 = R3 × R1 ÷ (V2 ÷ Ir2)
Rt = R3 × R1 ÷ (V2 ÷ Ir2) −R4
Here, since the resistance values of R1 to R4 are known and Ir2 = (V2−V4) ÷ R2, the resistance value of the sample Rt is measured by measuring the voltage V2 and the voltage V4 using an AD converter (not shown). Can be calculated.

  However, since the resistance measuring device 61 further includes the resistor R4 as compared with the resistance measuring device according to the second embodiment, the resistor R4 is an extra loss. When the voltage drop at the resistor R4 is large, the circuit scale of the operational amplifier MOD2 needs to be increased so that the output voltage V7 can be increased, and accordingly, the voltage supplied to the operational amplifier MOD2 needs to be increased. .

  Therefore, in the resistance measuring device 61, the resistance value of the resistor R4 is set lower than the resistance values of the resistors R1 to R3. For example, the resistance values of the resistors R1 to R3 are set to 100 to 1 kΩ, whereas the resistance value of the resistor R4 is set to about 100 mΩ. For this reason, even when the constant current Ir4 is large, the potential difference between both ends of the resistor R4 is relatively small, so that the circuit scales of the instrumentation amplifier Amp2 and the operational amplifier MOD2 need not be increased. Therefore, a large current can be passed through the sample, and the circuit scale can be reduced.

  In the resistance measuring device 61, the positions of the resistors R4 and R3 may be interchanged. Furthermore, the arrangement of the resistance, the variable voltage source, and the sample constituting the bridge of the resistance measurement device is not limited to the arrangement in the resistance measurement device 61. However, the resistor R4 having a small resistance value is provided to flow a large constant current through the sample Rt, and thus is connected in series with the sample Rt and the resistor R3. When the resistor R4 is connected in series with the variable voltage source Vb, the variable voltage source Vb needs to be resistant to a large current. In this case, since the circuit scale of the variable voltage source Vb is increased, it is difficult to reduce the size of the resistance measuring device. Hereinafter, a modified example of the resistance measuring device according to the present embodiment will be described with reference to FIG.

  FIGS. 12A to 12B are circuit diagrams showing schematic configurations of resistance measuring apparatuses 71 and 81 according to the modified example of the present embodiment, respectively. In each of the resistance measuring devices 71 and 81, when the potential difference between both ends of the resistor R4 becomes a predetermined value, the output voltage of the variable voltage source Vv is in an equilibrium state with the voltage V7, and a constant current Ir4 is passed through the resistor R4 and the sample Rt. .

  A resistance measuring device 71 shown in FIG. 12A has a configuration in which the variable voltage source Vb is connected to one end of the resistor R1 on the variable voltage source Vv side in the resistance measuring device 61 shown in FIG. The voltage of the variable voltage source Vb is in an equilibrium state when the voltage V1 between the sample Rt and the resistor R3 becomes equal to the voltage V2 between the resistor R1 and the resistor R2. In the resistance measuring device 71, the positions of the resistors R4 and R3 may be interchanged.

  The resistance measuring device 81 shown in FIG. 12B has a configuration in which the positions of the sample Rt and the resistor R4 are exchanged in the resistance measuring device 61 shown in FIG. The resistance measuring device 81 is variable when the voltage V1a between the sample Rt and the resistor R4 or the voltage V1b between the resistor R4 and the resistor R3 becomes equal to the voltage V2 between the resistor R1 and the resistor R2. The voltage of the voltage source Vb is in an equilibrium state. In the resistance measuring device 81, the positions of the sample Rt and the resistor R3 may be interchanged.

[Summary of Embodiment]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be suitably applied to a technique for measuring a resistance value of a sample by a Wheatstone bridge.

It is a circuit diagram showing a schematic structure of a resistance measuring device concerning a 1st embodiment of the present invention. It is a circuit diagram which shows the specific structure of the resistance measuring apparatus shown in FIG. It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the modification of the 1st Embodiment of this invention. It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the further another modification of the 1st Embodiment of this invention. It is a circuit diagram which shows the specific structure of the resistance measuring apparatus shown to Fig.4 (a). It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the 2nd Embodiment of this invention. It is a circuit diagram which shows the specific structure of the resistance measuring apparatus shown in FIG. It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the modification of the 2nd Embodiment of this invention. It is a circuit diagram which shows the specific structure of the resistance measuring apparatus shown in FIG. It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the 3rd Embodiment of this invention. It is a circuit diagram which shows the specific structure of the resistance measuring apparatus shown in FIG. It is a circuit diagram which shows schematic structure of the resistance measuring apparatus which concerns on the modification of the 3rd Embodiment of this invention. It is a circuit diagram which shows a Wheatstone bridge circuit. It is a circuit diagram which shows the resistance measuring apparatus of the conventional Wheatstone bridge.

Explanation of symbols

1.11.21.31.41.51.61.71.81 Resistance measuring device R1 Resistance (first resistance)
R2 resistance (second resistance)
R3 resistance (third resistance)
R4 resistance (fourth resistance)
Rt sample (measuring object)
Vs voltage source (first voltage source)
Vv variable voltage source (first voltage source)
Vb variable voltage source (second voltage source)
Amp1 Instrumentation amplifier (first differential output means)
Amp2 Instrumentation amplifier (second differential output means)
MOD1 operational amplifier (first voltage output means)
MOD2 operational amplifier (second voltage output means)
V1 ・ V1a ・ V1b Voltage (first voltage)
V2 ・ V2a ・ V2b Voltage (second voltage)

Claims (12)

A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to third resistors;
The second voltage source is a variable voltage source, the first to third resistors are fixed resistors,
The first resistor and the second resistor are connected in series to form a first series circuit,
The third resistor, the measurement object, and the second voltage source are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
From the first voltage source side, the third resistor, the measurement object, and the second voltage source are connected in this order, or the measurement object, the third resistor, and the second voltage source are connected in this order. And
When the first voltage between the first resistor and the second resistor is equal to the second voltage between the third resistor and the measurement object, the voltage of the first voltage source And the voltage of the second voltage source are in an equilibrium state. A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to third resistors;
The second voltage source is a variable voltage source, the first to third resistors are fixed resistors,
The first resistor and the second resistor are connected in series to form a first series circuit,
The third resistor, the measurement object, and the second voltage source are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
From the first voltage source side, the second voltage source, the measurement object, and the third resistance are connected in this order, or the second voltage source, the third resistance, and the measurement object are connected in this order. And
When the first voltage between the first resistor and the second resistor is equal to the second voltage between the third resistor and the measurement object, the voltage of the first voltage source And the voltage of the second voltage source are in an equilibrium state. A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to third resistors;
The second voltage source is a variable voltage source, the first to third resistors are fixed resistors,
The first resistor, the second resistor, and the second voltage source are connected in series to form a first series circuit,
The third resistor and the measurement object are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
The first resistor, the second resistor, and the second voltage source are connected in this order from the first voltage source side,
When the first voltage between the third resistor and the measurement object is equal to the second voltage between the first resistor and the second resistor, the voltage of the first voltage source And the voltage of the second voltage source are in an equilibrium state. A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to third resistors;
The second voltage source is a variable voltage source, the first to third resistors are fixed resistors,
The first resistor, the second resistor, and the second voltage source are connected in series to form a first series circuit,
The third resistor and the measurement object are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
From the first voltage source side, the second voltage source, the first resistor, and the second resistor are connected in this order,
When the first voltage between the third resistor and the measurement object is equal to the second voltage between the first resistor and the second resistor, the voltage of the first voltage source And the voltage of the second voltage source are in an equilibrium state. The second voltage source includes first differential output means and first voltage output means,
The first difference output means outputs a difference between the first voltage and the second voltage with a predetermined gain,
The first voltage output means increases the output voltage of the first voltage output means when the first voltage is higher than the second voltage based on the output voltage of the first differential output means. When the first voltage is lower than the second voltage, the output voltage of the first voltage output means is reduced,
4. The resistance measuring apparatus according to claim 1, wherein an output voltage of the first voltage output means is a voltage of the second voltage source. The second voltage source includes first differential output means and first voltage output means,
The first difference output means outputs a difference between the first voltage and the second voltage with a predetermined gain,
The first voltage output means increases the output voltage of the first voltage output means when the first voltage is higher than the second voltage based on the output voltage of the first differential output means. When the first voltage is lower than the second voltage, the output voltage of the first voltage output means is reduced,
5. The resistance measurement according to claim 2, wherein a voltage obtained by subtracting an output voltage of the first voltage output means from a voltage of the first voltage source becomes a voltage of the second voltage source. apparatus. The first voltage source is a variable voltage source,
The resistance measuring apparatus according to claim 1, wherein when the potential difference between both ends of the third resistor is a predetermined value, the voltage of the first voltage source is in an equilibrium state. . The first voltage source includes a third voltage source, second differential output means, and second voltage output means,
The second difference output means outputs a potential difference between both ends of the third resistor with a predetermined gain,
The second voltage output means receives the voltage of the third voltage source and the output voltage of the second differential output means as inputs, and the voltage of the third voltage source is the output of the second differential output means. When the output voltage is higher than the output voltage, the output voltage of the second voltage output means is increased, and when the voltage of the third voltage source is lower than the output voltage of the second differential output means, the second voltage output means Reduce the output voltage of
8. The resistance measuring apparatus according to claim 7, wherein the output voltage of the second voltage output means is the voltage of the first voltage source. The second series circuit further includes a fourth resistor that is a fixed resistor,
From the first power supply side, the fourth resistance, the measurement target and the third resistance in this order, the fourth resistance, the third resistance and the measurement target in this order, the measurement target, the first 3 and the fourth resistor in this order, or the third resistor, the measurement object, and the fourth resistor in this order,
The first voltage source is a variable voltage source,
When the potential difference between both ends of the fourth resistor is a predetermined value, the voltage of the first voltage source is in an equilibrium state,
The resistance measurement apparatus according to claim 7, wherein the fourth resistor has a lower resistance value than the first to third resistors. A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to fourth resistors;
The first voltage source and the second voltage source are variable voltage sources, the first to fourth resistors are fixed resistors,
The first resistor, the second resistor, and the second voltage source are connected in series to form a first series circuit,
The third resistor, the fourth resistor, and the measurement target are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
In the first series circuit, in order from the first voltage source side, the first resistor, the second resistor, and the second voltage source, or the second voltage source, the first voltage source, And the second resistor in this order,
In the second series circuit, from the first power supply side, the measurement object, the fourth resistor and the third resistor in this order, or the third resistor, the fourth resistor and the measurement. Connected in the order of the target,
A first voltage between the first resistor and the second resistor is equal to a second voltage between the third resistor and the fourth resistor, and both ends of the fourth resistor. The first voltage between the first resistor and the second resistor is equal to the third voltage between the measurement object and the fourth resistor. Equally, when the potential difference between both ends of the fourth resistor is a predetermined value, the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state,
The resistance measurement device according to claim 4, wherein the fourth resistor has a lower resistance value than the first to third resistors. A resistance measuring device for measuring a resistance value of a measurement object,
A first voltage source, a second voltage source, and first to fourth resistors;
The first voltage source and the second voltage source are variable voltage sources, the first to fourth resistors are fixed resistors,
The first resistor, the second resistor, and the second voltage source are connected in series to form a first series circuit,
The third resistor, the fourth resistor, and the measurement target are connected in series to form a second series circuit,
One end of the first series circuit and one end of the second series circuit are connected to the first voltage source, and the other end of the first series circuit and the other end of the second series circuit are Grounded,
In the first series circuit, the second voltage source, the first resistor, and the second resistor are connected in this order from the first voltage source side,
In the second series circuit, from the first power supply side, the fourth resistor, the measurement target, and the third resistance are arranged in this order, or the third resistance, the measurement target, and the fourth resistance. Connected in the order of resistance,
The first voltage between the first resistor and the second resistor is equal to the second voltage between the third resistor and the measurement object, and the potential difference between both ends of the fourth resistor. Is a predetermined value, or the first voltage between the first resistor and the second resistor is equal to the third voltage between the measurement object and the fourth resistor, When the potential difference between both ends of the fourth resistor is a predetermined value, the voltage of the first voltage source and the voltage of the second voltage source are in an equilibrium state,
The resistance measurement device according to claim 4, wherein the fourth resistor has a lower resistance value than the first to third resistors. The first voltage source includes a third voltage source, first difference output means, and first voltage output means,
The first difference output means outputs a potential difference between both ends of the fourth resistor with a predetermined gain,
The first voltage output means receives the voltage of the third voltage source and the output voltage of the first differential output means, and the voltage of the third voltage source is the output of the first differential output means. When higher than the output voltage, the output voltage of the first voltage output means is increased, and when the voltage of the third voltage source is lower than the output voltage of the first differential output means, the first voltage output means Reduce the output voltage of
12. The resistance measuring apparatus according to claim 10, wherein an output voltage of the first voltage output means is a voltage of the first voltage source.

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