Measurement system, measurement device and measurement method

Abstract

To provide a technique that is able to measure the temperature or path resistance with a simple configuration.SOLUTION: A measurement system 1 includes: a sensor element D1 that operates according to a diode equation; a current source 10 that supplies three or more currents having different magnitudes to a path P1 including the sensor element D1 and a path resistance Rp1; a voltage measurement device 20 that measures a voltage of the path P1 when each of the three or more currents is supplied from the current source 10 to the path P1, and acquires three or more measurement results of the voltage of the path P1; and an arithmetic device that calculates the temperature of the sensor element D1 or the path resistance Rp1 based on the three or more measurement results.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a measurement system, a measurement device, and a measurement method. [Background technology]

[0002] Conventionally, devices have been used to detect temperature by utilizing the fact that the voltage-current characteristics of a transistor or diode vary with temperature. For example, Patent Document 1 discloses a technology for measuring temperature by utilizing the difference between the emitter-base voltage when a constant current flows through a sense transistor and the emitter-base voltage when a current N times the constant current flows through the sense transistor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-16992

[0004] [overview] However, the inventors have come to recognize the following problem: In the technology described in Patent Document 1, parasitic resistance occurs around the sense transistor due to wiring, etc., and the parasitic resistance affects temperature measurement. For this reason, the technology described in Patent Document 1 cannot measure temperature accurately.

[0005] The present disclosure has been made in light of the above circumstances, and one exemplary purpose thereof is to provide a technique capable of measuring temperature or path resistance with a simple configuration.

[0006] One aspect of the present disclosure is a measurement system that includes a sensor element that operates according to a diode equation, a current source that supplies three or more currents of different magnitudes to a path that includes the sensor element and a path resistance, a voltage measuring device that measures voltages in the path when each of the three or more currents is supplied to the path from the current source to obtain three or more measurement results of the voltages in the path, and a computing device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results.

[0007] Any combination of the above components and conversion of the expressions of the present disclosure into methods, devices, systems, etc. are also valid aspects of the present disclosure. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a measurement system according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing a path voltage curve and its fitting curve. [Figure 3] FIG. 3 is a circuit diagram of a current source according to the first embodiment. [Figure 4] FIG. 4 is a block diagram of a temperature measuring device according to the first comparative technique. [Figure 5] FIG. 5 is a block diagram of a temperature measuring device according to the second comparative technique. [Figure 6] FIG. 6 is a circuit diagram of a current source according to the first modification. [Figure 7] FIG. 7 is a block diagram of a measurement system according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing the relationship between the voltage measured by the voltage measuring instrument and the temperature of the light source. [Figure 9] FIG. 9 is a diagram for explaining problems that occur during wafer testing. [Figure 10] FIG. 10 is a block diagram of a measurement device according to the third embodiment.

[0009] [Detailed explanation] (overview) A summary of some exemplary embodiments of the present disclosure is provided. This summary is intended to provide a simplified overview of some concepts of one or more embodiments in order to provide a basic understanding of the embodiments as a prelude to the more detailed description that follows. It is not intended to limit the scope of the invention or disclosure. This summary is not an exhaustive overview of all possible embodiments, and is not intended to identify key elements of all embodiments or to delineate the scope of some or all aspects. For convenience, the term "one embodiment" may refer to one embodiment (example or variant) or multiple embodiments (examples or variants) disclosed herein.

[0010] A measurement system according to one embodiment includes a sensor element that operates according to a diode equation, a current source that supplies three or more currents of different magnitudes to a path including the sensor element and a path resistance, a voltage measuring device that measures the voltage of the path when each of the three or more currents is supplied to the path from the current source and obtains three or more measurement results of the voltage of the path, and a computing device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results.

[0011] With this configuration, the temperature or path resistance can be measured by applying three or more measurement results to the diode equation. In addition, since there is no need to use multiple sensor elements, the temperature or path resistance can be measured with a simple configuration.

[0012] In one embodiment, the diode equation may be expressed as follows:

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[0013] In one embodiment, the current source may include a reference transistor through which a reference current flows, and three transistors that form current mirror pairs with the reference transistor, each configured to generate the same current in response to the reference current.

[0014] In one embodiment, the current source may include a reference transistor through which a reference current flows, and two transistors that form a current mirror pair with the reference transistor, each configured to generate a different current depending on the reference current.

[0015] In one embodiment, the measurement system may further include a detection device that detects whether or not an abnormality exists in the sensor element. The sensor element may be an LED (Light Emitting Diode). The calculation device may calculate a path resistance based on three or more measurement results. The detection device may detect whether or not an abnormality exists in the sensor element based on the path resistance calculated by the calculation device and the result of measuring the path voltage by the voltage measurement device.

[0016] A measurement device according to one embodiment includes a current source that supplies three or more currents of different magnitudes to a path including a sensor element that operates according to a diode equation and a path resistance; a voltage measuring device that measures the voltage of the path when each of the three or more currents is supplied to the path from the current source, thereby obtaining three or more measurement results of the voltage of the path; and a calculation device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results.

[0017] With this configuration, the temperature or path resistance can be measured by applying three or more measurement results to the diode equation. In addition, since there is no need to use multiple sensor elements, the temperature or path resistance can be measured with a simple configuration.

[0018] In one embodiment, the sensor element may be a protection diode connected to the input or output terminal of the device under test.

[0019] A measurement method according to one embodiment is a method using the measurement device described above, and includes: a current source supplies three or more currents of different magnitudes to a path including a sensor element operating according to a diode equation and a path resistance; a voltage measuring device measures voltages in the path when each of the three or more currents is supplied to the path from the current source to obtain three or more measurement results of the voltages in the path; and a computing device calculates a temperature of the sensor element or the path resistance based on the three or more measurement results.

[0020] (Embodiment) Preferred embodiments will be described below with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted as appropriate. Furthermore, the embodiments are examples and do not limit the disclosure and invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the disclosure and invention.

[0021] In this specification, "a state in which component A is connected to component B" includes not only a case in which component A and component B are directly physically connected, but also a case in which component A and component B are indirectly connected via other components that do not substantially affect the electrical connection state between them or that do not impair the function or effect achieved by their connection.

[0022] Similarly, "a state in which component C is connected (provided) between component A and component B" includes not only a case in which component A and component C, or component B and component C, are directly connected, but also a case in which they are indirectly connected via other components that do not substantially affect the electrical connection state between them or that do not impair the function or effect achieved by their combination.

[0023] In addition, in this specification, symbols attached to electrical signals such as voltage signals and current signals, or circuit elements such as resistors, capacitors, and inductors, represent the respective voltage values, current values, or circuit constants (resistance values, capacitance values, inductances) as necessary.

[0024] (First embodiment) 1 is a block diagram of a measurement system 1 according to the first embodiment. The measurement system 1 according to the first embodiment mainly includes a current source 10, a voltage measuring device 20, a calculation device 22, and a sensor element D1. The measurement system 1 detects a temperature T1 (specifically, a junction temperature) of the sensor element D1 or a path resistance R included in a path P1. p1 The device is configured to measure

[0025] The sensor element D1 is an element that operates according to a diode equation. The sensor element D1 may be, for example, a diode or a diode-connected transistor. The diode may be, for example, a general-purpose rectifier diode or an LED. The transistor may be, for example, a bipolar transistor or a MOS (Metal Oxide Semiconductor) transistor. In this embodiment, an example will be described in which the sensor element D1 is a general-purpose rectifier diode.

[0026] The current source 10 is connected to the sensor element D1 and the path resistance R p1 Three or more currents I of different magnitudes are flowing through the path P1 including d1 The current source 10 according to this embodiment supplies I 11 ,I 12 ,I 13 (0 11 12 13 ) three currents I d1 supply.

[0027] The path P1 according to this embodiment is formed by a sensor element D1 and a path resistance R p1 The path resistance R p1 includes various resistances in the path P1, such as parasitic resistance caused by wiring, internal resistance of the sensor element D1, and a resistance element (not shown) provided in the path P1. In FIG. 1, these resistances are referred to as the path resistance R p1 The sensor element D1 and the path resistance R p1 In the path P1, a current I d1 flows, the forward voltage V D1 and voltage V R1 (=R p1 ×I d1 ) are generated respectively.

[0028] The voltage measuring device 20 measures the voltage V A1 Measure the voltage V A1 is the voltage at node A1 at the end of path P1. The voltage measuring device 20 is, for example, an A / D converter, and measures the voltage V A1 is converted to a digital signal S V1 Generates a digital signal S V1 is transmitted to the computing device 22.

[0029] In detail, the voltage measuring device 20 measures the voltage V of the path P1 when three or more currents of different magnitudes are supplied to the path P1 from the current source 10. A1 Measure the voltage V of path P1.​​​A1 The voltage measuring device 20 according to this embodiment acquires three or more measurement results of the three currents I 11 ,I 12 ,I 13 When each of these is supplied to path P1, the voltage V A1 (V A11 ,V A12 ,V A13 ) is measured.

[0030] The calculation device 22 calculates the temperature T1 and the path resistance R of the sensor element D1 based on the measurement results of three or more voltage measuring devices 20 (three in this embodiment). p1 The functions of the calculation device 22 are realized by a storage unit 220 and a calculation unit 222. The calculation device 22 may include an MPU (Micro Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory).

[0031] The storage unit 220 stores various information. A1 The data D stored in the storage unit 220 may be stored in the storage unit 220, such as data indicating the measurement results of the above and a program for the calculation unit 222 to execute calculations. 11 is referred to by the calculation unit 222 as necessary.

[0032] The calculation unit 222 calculates the voltage V A1 Based on the three or more measurements, the temperature T1 of the sensor element D1 and the path resistance R p1 The calculation unit 222 according to this embodiment calculates the voltage V A11 ,V A12 ,V A13 Using the measurement results, the temperature T1 and the path resistance R p1 Calculate the result of the calculation. 12 may be stored in the storage unit 220.

[0033] FIG. 2 shows the path voltage curve and its fitting curve. In FIG. 2, the horizontal axis represents the current I d1The vertical axis indicates the voltage V A1 The path voltage curve shows the voltage V of path P1. A1 The fitting curve is a curve obtained by fitting the path voltage curve with quadratic approximation. The path voltage curve is a curve that shows the voltage V of the sensor element D1 regardless of the influence of temperature changes, variations in the sensor element, parasitic resistance, etc. D1 Includes diode curves.

[0034] Although the details will be described later, the calculation unit 222 according to this embodiment calculates (I 11 ,V A11 ), (I 12 ,V A12 ), (I 13 ,V A13 ) The temperature T1 of the sensor element D1 and the path resistance R p1 Calculate.

[0035] In addition, the current I d1 The flow of current through the sensor element D1 causes the sensor element D1 to generate heat. Therefore, the calculation unit 222 may correct the calculated temperature T1 in consideration of the heat generated by the sensor element D1.

[0036] 3 is a circuit diagram of the current source 10 according to this embodiment. 11 (=I1), I 12 (=2×I1) and I 13 (=3×I1) d1 3, the current source 10 according to this embodiment includes a current mirror circuit 100, a switch unit 102, and a resistor R1.

[0037] The current mirror circuit 100 outputs a reference current I ref1The reference transistor M1 has a current flowing through it, and three transistors M2 to M4 that form current mirror pairs with the transistor M1. In this embodiment, an example is described in which the number of transistors that form current mirror pairs with the transistor M1 is three, but the number of transistors that form current mirror pairs with the transistor M1 may be four or more.

[0038] The transistors M1 to M4 are each configured as a P-channel MOS (Metal Oxide Semiconductor) transistor. A power supply voltage VDD is supplied to the source of each of the transistors M1 to M4. The gate of the transistor M1 is connected to the drain of the transistor M1 in common with the gates of the transistors M2 to M4. A resistor R1 is connected to the drain of the transistor M1, and a reference current I ref1 is playing.

[0039] The transistors M2 to M4 each generate a reference current I ref1 The current I1 is configured to generate the same current I1 according to the reference current I ref1 The transistors M2 to M4 are configured with the same parameters (for example, size parameters).

[0040] The switch unit 102 selects the current I1 generated by each of the transistors M2 to M4. d1 The switch unit 102 includes switches SW1 to SW3, which may be controlled to be turned on and off by receiving a control signal from a control circuit (not shown).

[0041] When switch SW1 is on, the current I1 generated by transistor M2 is equal to the current I d1 and the current I1 generated by transistor M2 when it is off contributes to the current I d1 The switch SW2 is provided so that when it is on, the current I1 generated by the transistor M3 does not contribute to the current I d1and the current I1 generated by transistor M3 when it is off contributes to the current I d1 When the switch SW3 is turned on, the current I1 generated by the transistor M4 is reduced to the current I d1 and the current I1 generated by transistor M4 when it is off contributes to the current I d1 It is provided so as not to contribute to

[0042] By controlling the on / off of the switches SW1 to SW3, the current I d1 For example, by turning on switch SW1 and turning off switches SW2 and SW3, the magnitude of the current I d1 I1(=I 11 ) can be obtained. In addition, by turning on the switches SW1 and SW2 and turning off the switch SW3, the current I d1 2×I1(=I 12 ) can be obtained. Furthermore, by turning on all of the switches SW1, SW2, and SW3, the current I d1 3×I1(=I 13 ) in this way. The current source 10 generates three currents I d1 can be generated.

[0043] In this embodiment, an example has been described in which the switch unit 102 includes three switches SW1 to SW3. However, the present invention is not limited to this. For example, the switch SW1 may be short-circuited, and the switch unit 102 may include only two switches SW2 and SW3. In this case, too, the three currents I having different magnitudes as described above can be controlled by controlling the on / off of the switches SW2 and SW3. d1 In this case, the current I d1 If .gtoreq.0, the current source 10 may be disabled.

[0044] Hereinafter, the temperature T1 and the path resistance R p1 The method for calculating the diode equation of the sensor element D1 is expressed by the following equation (1).

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[0045] Equation (3) is applied to a current I b By quadratic approximation, the following equation (4) is obtained.

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[0046] Equation (4) is I b >>I S Under these conditions, it is expressed by the following equation (5).

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[0047] where V A1 =V R1 +V D1 Therefore, the voltage V A1 is expressed by the following equation (6) from equation (5).

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[0048] where V A1 V A1 =aI d1 2 +bI d1 +c. V A1 Is any I d1 (>0) also V A1> 0. Therefore, the coefficients a, b, and c are all positive values. Therefore, the coefficient a is I d1 2 It is appropriate to use the absolute values ​​of the coefficients a, b, and c, and the coefficients a, b, and c can be expressed by the following equations (7) to (9).

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[0049] where V A11 ,V A12 ,V A13 teeth, V A11 =aI 11 2 +bI 11 +c V A12 =aI 12 2 +bI 12 +c V A13 =aI 13 2 +bI 13 +c By solving this simultaneous equation, the values ​​of the coefficients a, b, and c can be found.

[0050] Here, from equation (7),

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[0051] From equation (12), the path resistance R p1 Here, in equations (10) to (12), I d1 For example, I 12 The path resistance R p1 Once this is determined, it becomes possible to calculate the temperature T1 with high accuracy as follows:

[0052] In equation (7), I b =I 12 Then, the following equation (13) is obtained.

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[0053] Furthermore, according to the measurement method of this embodiment, the voltage V A1 The offset error of is a function of the temperature T1 and the path resistance R p1 The above simultaneous equations can be expressed as the following equation (15) by matrix transformation.

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[0054] Voltage V A1 If there is an offset error ΔV1 in the measurement result, the coefficient a is

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[0055] Now, extracting the error term from the right-hand side of equation (17), we get

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[0056] 4 is a block diagram of a temperature measuring device 8 according to the comparative technique 1. The temperature measuring device 8 according to the comparative technique 1 includes a current source 80, an A / D converter 82, a computing device 84, and a diode D8.

[0057] The current source 80 supplies a current I d8 is supplied to the diode D8. The current I that can be supplied by the current source 80 according to the comparative technique is d8 The A / D converter 82 detects the voltage V across the diode D8. D8 and path resistance R p8 Voltage V R8 The voltage V is the sum of A8 is converted into a digital signal S V8 The arithmetic unit 84 converts the digital signal S V8 Based on this, the temperature T8 of the diode D8 is calculated.

[0058] The diode equation for diode D8 is given by n8, where n is the diode coefficient of diode D8, and I is the reverse saturation current of diode D8. S8 Then, it is expressed by the following equation (19).

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[0059] However, in reality, the path resistance R p8 is not 0, V A8 =V R8 +V D8 =R p8 I d8 +V D8 Therefore, the voltage V A8 The measurement result is the path resistance R p8 As a result, the temperature measuring device 8 according to the comparative technique 1 cannot measure the temperature T8 with high accuracy. Furthermore, if there is variation in the diodes, the influence of the error also occurs.

[0060] Furthermore, in the temperature measuring device 8 according to the comparative technique 1, unlike the measuring system 1 according to the above embodiment, the temperature is measured using the current I d8 and an offset error ΔV8 of the measurement voltage. Specifically, when there are offset errors ΔI8 and ΔV8, in comparative technique 1, the temperature T8 is T=α{V D2 (I8+ΔI8)+ΔV8} Therefore, the temperature measuring device 8 according to the first comparative technique is affected by the offset error ΔI8 and the offset error ΔV8.

[0061] 5 is a block diagram of a temperature measuring device 9 according to comparative technique 2. The temperature measuring device 9 according to comparative technique 2 includes current sources 90 and 92, an A / D converter 94, a computing device 96, and diodes D91 and D92.

[0062] Current source 90 supplies a current I to diode D91. d91 The current source 92 supplies a current I d91 p(>1) times the current I d92 Here, the forward voltage of diodes D91 and D92 is V D9 This is represented as (I).

[0063] The A / D converter 94 is connected to the diode D91 and the path resistor R p91 The voltage V of the path P91 including A91 , diode D92 and path resistance R p92 The voltage V of the path P92 including A92 and is converted to a digital signal S V9 The arithmetic unit 96 generates the digital signal S V9 Based on this, the temperature T9 of the diodes D91 and D92 is calculated.

[0064] Here, the voltage V A91 and voltage V A92 are expressed by the following equations, respectively. V A91 =R p91 ×I d91 +V D9 (I d91 ) V A92 =R p92 ×p×I d91 +V D9 (p×I d91 ) The difference between these voltages, ΔV A9 teeth, ΔV A9 =V A92 -V A91 =(R p92 ×pR p91 )I d91 +V D9 (p×I d91 )-V D9 (I d91 ) Here, V A91 +βΔV A9 =V ref where Vref is a constant. From this equation, the path resistance R p91 ,R p92 can be canceled out, and the relational expression for the temperature T9 can be expressed by the following equation (20).

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[0065] According to the temperature measuring device 9 of the comparative technique 2, the path resistance R including the parasitic resistance is smaller than that of the temperature measuring device 8 of the comparative technique 1. p91 ,R p92 This has the advantage that the influence of the temperature on the temperature measurement can be suppressed, and the influence of variations in the sensor elements can be suppressed.

[0066] However, the temperature measuring device 9 according to the comparative technique 2 has the following disadvantages. (1) The above parameters β, A, B, and V ref Temperature calibration to obtain this requires measurements under two temperature conditions, which increases the cost of temperature measurement. (2) The temperature measuring device 9 in the comparative technique 2 requires two sensor elements (diodes D91 and D92), which increases the circuit area. (3) Route resistance R p91 ,R p92 The effect of is compensated for by temperature calibration, so after compensation, the path resistance R p91 ,R p92 If the temperature fluctuates, the temperature measurement will be affected by the fluctuation.

[0067] Furthermore, in the temperature measuring device 9 according to the comparative technique 2, unlike the measuring system 1 according to the above embodiment, the temperature is measured using the current I d91and an offset error ΔV9 of the measured voltage. Specifically, when there are offset errors ΔI9 and ΔV9, in comparative technique 2, the temperature T9 is expressed by the following equation (21).

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[0068] Furthermore, the temperature measuring devices 8 and 9 according to the first and second comparative techniques cannot measure the path resistance itself.

[0069] According to the measurement system 1 of this embodiment, the voltage measuring device 20 measures three or more (three in this embodiment) currents I with different magnitudes from the current source 10. d1 When each of these is supplied to path P1, the voltage V of path P1 A1 Measure the voltage V of path P1. A1 The calculation device 22 calculates the temperature T1 of the sensor element D1 or the path resistance R based on the three or more measurement results. p1 With this configuration, the temperature T1 or the path resistance R can be calculated by applying the results of three or more measurements to the diode equation. p1 In addition, since there is no need to use multiple sensor elements, it is possible to measure the temperature T1 or the path resistance R p1 can be measured.

[0070] According to the measurement system 1 of this embodiment, temperature calibration can be performed under one temperature condition, making it possible to perform measurements at low cost. In addition, since only one sensor element (sensor element D1) is required, the circuit area can be reduced. Furthermore, the current I d1 offset error and voltage V A1 Since there is no influence of offset error in the measurement, high-precision measurement is possible.

[0071] The inventors performed a virtual temperature calibration at 25°C and performed a simulation of temperature measurement in the range of -25 to 150°C, and confirmed that the measurement system 1 according to this embodiment can measure temperature with high accuracy.

[0072] (Variation 1) 6 is a circuit diagram of a current source 12 according to Modification 1. The current source 12 according to Modification 1 may be provided in place of the current source 10 in the measurement system 1 according to the above embodiment. The current source 12 according to Modification 1 has a current mirror circuit 120, a switch section 122, and a resistor R2. The current source 12 according to Modification 1 has a current mirror circuit 120, a switch section 122, and a resistor R2. 21 (=I2), I 22 (=I3) and I 23 (=I2+I3) Three currents I d2 where 0 <I2<I3であるものとする。

[0073] The current mirror circuit 120 generates a reference current I ref2 6 illustrates an example in which two transistors form a current mirror pair with the transistor M5, but the number of transistors that form a current mirror pair with the transistor M5 may be three or more.

[0074] The transistors M5 to M7 are each configured as a P-channel MOS transistor. A power supply voltage VDD is supplied to the source of each of the transistors M5 to M7. The gate of the transistor M5 is connected to the drain of the transistor M5 in common with the gates of the transistors M6 and M7. A resistor R2 is connected to the drain of the transistor M5, and a reference current I ref2 is playing.

[0075] The two transistors M6 and M7 each have a reference current I ref2Specifically, transistor M6 is configured to generate a different current depending on the reference current I ref2 The transistor M7 generates a current I2 according to the reference current I ref2 The current I3 is generated in response to the

[0076] The switch unit 122 selects the current I2 generated by the transistor M6 and the current I3 generated by the transistor M7. d2 The switch unit 122 is configured to select a current that contributes to the power supply voltage Vcc. The switch unit 122 includes switches SW4 and SW5. The switches SW4 and SW5 may be controlled to be turned on and off by receiving a control signal from a control circuit (not shown).

[0077] When switch SW4 is on, the current I2 generated by transistor M6 is equal to the current I d2 and the current I2 generated by transistor M6 when it is off contributes to the current I d2 The switch SW5 is provided so that when it is on, the current I3 generated by the transistor M7 does not contribute to the current I d2 and the current I3 generated by transistor M7 when it is off contributes to the current I d2 It is provided so as not to contribute to

[0078] By controlling the on / off of the switches SW4 and SW5, the current I d2 For example, by turning on switch SW4 and turning off switch SW5, the magnitude of the current I d2 I2(=I 21 ) can be set. Also, by turning on the switch SW5 and turning off the switch SW4, the current I d2 to I3(=I 22 ) can be obtained. Furthermore, by turning on both the switches SW4 and SW5, the current I d2 I2+I3(=I 23 In this way, the current source 12 can generate three currents I d2 can be generated.

[0079] By forming a current mirror pair using transistors M6 and M7 that generate different currents, as in the current source 12 of Modification 1, it is possible to reduce the number of transistors and form the current source 12 with a simpler configuration than the current source 10 of the above embodiment.

[0080] (Variation 2) In the above embodiment, an example in which the current sources 10 and 12 generate three currents with different magnitudes has been described. However, the current sources may generate four or more currents with different magnitudes. In this case, the voltage measuring device 20 measures the voltage V when each of the four or more currents is supplied to the path P1. A1 The computing device 22 may measure the four or more voltages V A1 Based on the measurement results, the temperature T1 and the path resistance R p1 You can calculate four or more voltages V A1 By using the measurement results, the temperature T1 and the path resistance R p1 It is possible to calculate

[0081] (Variation 3) In the above embodiment, the diode equation of the sensor element D1 is expressed as the current I b The example of quadratic approximation is explained. D1 can be approximated by third or higher orders. D1 When approximating by a third or higher order, different currents corresponding to the order (four or more) are supplied to the sensor element D1. A1 By using the measurement results, the temperature T1 and the path resistance R p1 By increasing the order of approximation of the diode equation, the temperature T1 and the path resistance R can be calculated more accurately. p1 It is possible to calculate

[0082] The inventors have confirmed that although the higher the order, the greater the degree of conformity between the path voltage curve and the fitting curve, a second-order approximation can achieve sufficient accuracy in temperature measurement.

[0083] (Second embodiment) 7 is a block diagram of a measurement system 2 according to the second embodiment. The measurement system 2 according to the second embodiment includes a semiconductor device 30 and a light source D2.

[0084] The light source D2 according to this embodiment is an LED that functions as a sensor element. A power supply voltage VDD is supplied to the anode of the light source D2, and the cathode of the light source D2 is connected to the semiconductor device 30. The light emission of the light source D2 is controlled by the semiconductor device 30.

[0085] The semiconductor device 30 controls the operation of the light source D2 and measures the path resistance R of the path P2 including the light source D2. p2 and can detect the presence or absence of an abnormality in the light source D2. The semiconductor device 30 may be configured as a single IC (Integrated Circuit) chip. The semiconductor device 30 may also include an MPU, ROM, RAM, etc. as necessary. The semiconductor device 30 according to this embodiment includes a driver 32, a voltage measuring device 34, a storage device 36, a processing device 38, and an output terminal OUT.

[0086] The driver 32 is configured to control the operation of the light source D2. Specifically, the driver 32 functions as a current source and outputs a drive current I DRV The driver 32 according to this embodiment can generate three or more drive currents I with different magnitudes by sinking the drive current I from the light source D2. DRV can be supplied to path P2.

[0087] The path P2 is connected to the light source D2 and the path resistance R p2 Specifically, the path P2 is a path from the power supply voltage node to the output terminal OUT of the semiconductor device 30. p2 includes various resistances in the path P2, such as parasitic resistance caused by wiring, internal resistance of the light source D2, and a resistance element (not shown) provided in the path P2. In FIG. 7, these resistances are referred to as the path resistance R p2 A current I DRVflows, the light source D2 and the path resistance R p2 are the forward voltage V D2 and voltage V R2 (=R p2 ×I DRV ) occurs.

[0088] The voltage measuring instrument 34 measures the voltage V at the output terminal OUT. A2 Specifically, the voltage measuring device 34 measures three or more drive currents I DRV When each of these is supplied to path P2, the voltage V A2 Measure the voltage V A2 is V A2 =VDD-V D2 -V R2 Also, the voltage V of the path P2 P2 is V P2 =V D2 +V R2 Therefore, the voltage V A2 Measuring the voltage V P2 The voltage measuring device 34 according to this embodiment is configured as an A / D converter and measures the voltage V A2 is converted to a digital signal S V2 Generates a digital signal S V2 is transmitted to the storage device 36, and the storage device 36 stores the voltage V A2 The measurement results are stored.

[0089] The storage device 36 stores various information. A2 The data D stored in the storage device 36 may be stored in the processing device 38. 21 is referred to by the processing unit 38 as needed.

[0090] The processing device 38 functions as a control device, a calculation device, and a detection device for the driver 32. Specifically, the processing device 38 executes various processes, for example, controls the operation of the driver 32, and calculates the path resistance R p2The data D obtained by the processing device 38 performing various processes can be used to calculate the 22 may be stored in the storage device 36. The functions of the processing device 38 are realized by a control unit 380, a calculation unit 382, ​​and a detection unit 384.

[0091] The control unit 380 outputs the control signal S DR to the driver 32 to control the operation of the driver 32. In this embodiment, the control unit 380 controls three or more drive currents with different magnitudes. DRV is supplied to path P2.

[0092] The calculation unit 382 calculates three or more voltages V A2 Based on the measurement results, the path resistance R p2 The calculation unit 382 calculates the path resistance R in the same manner as the calculation unit 222 according to the first embodiment. p2 can be calculated.

[0093] The detection unit 384 detects the path resistance R p2 and the voltage measuring instrument 34 measures the voltage V A2 The detection unit 384 detects whether or not there is an abnormality in the light source D2 based on the result of measuring the voltage V A2 If the measurement result of the voltage V exceeds a predetermined threshold voltage, the detection unit 384 may detect that there is an abnormality in the light source D2. A2 If the measurement result is equal to or less than a predetermined threshold voltage, it may be determined that there is no abnormality in the state of the light source D2.

[0094] For example, when light source D2 heats up, the forward voltage V D2 decreases, so the voltage V A2 rises, and it can be detected that there is an abnormality in the light source D2. Also, if both terminals of the light source D2 are short-circuited, it can be detected that there is an abnormality in the light source D2.

[0095] In this embodiment, an example will be described in which all of the functions of the memory device 36 and the processing device 38 are realized by the semiconductor device 30, but some or all of the functions of the memory device 36 and the processing device 38 may be realized by a device provided outside the semiconductor device 30. In this case, the semiconductor device 30 and the external device may communicate with each other, and various processes may be performed as necessary.

[0096] 8 is a diagram showing the relationship between the measured voltage V of the voltage measuring instrument 34 and the temperature T2 of the light source D2. In FIG. 8, the horizontal axis represents the temperature T2, and the vertical axis represents the measured voltage V. In FIG. 8, the path resistance R p2 If there is no (R p2 The line L1 indicates the measured voltage V (=0) and the path resistance R p2 If there is (R p2 The line L2 shows the measured voltage V (>0). The measured voltage V is proportional to the path resistance R p2 If there is a line (line L2), the path resistance R p2 When there is no line (line L1), the path resistance R p2 Voltage V R2 It is lower because of this.

[0097] The detector 384 detects that there is an abnormality in the light source D2 when the measured voltage V exceeds the threshold voltage Ve. 21 If the resistance exceeds the value, it is assumed that there is an abnormality in the light source D2. p2 If there is no line (line L1), when the measurement voltage V becomes the threshold voltage Ve, the temperature T2 becomes T 21 In this case, it is possible to appropriately detect that there is an abnormality in the light source D2 in response to the measured voltage V exceeding the threshold voltage Ve.

[0098] However, the path resistance R p2 If there is a line L2, when the measurement voltage V is the threshold voltage Ve, the temperature T2 is T 22 (>T 21 ) Therefore, the presence or absence of an abnormality in the light source D2 cannot be accurately detected by simply comparing the measured voltage V with the threshold voltage Ve. p2 and drive current IDRV Using the measured voltage V, the path resistance R p2 Voltage V R2 The detection unit 384 compares this added voltage with the threshold voltage Ve, thereby being able to accurately detect an abnormality in the light source D2.

[0099] (Third embodiment) 9 is a diagram for explaining the problems that may occur during wafer testing. During wafer testing, probes 42 of a testing device are placed in contact with the terminals (input terminals and output terminals) of an IC chip (device under test) on a wafer 40. At this time, contact resistance occurs at the contact surface C between the probes 42 and the IC chip terminals, and this contact resistance affects the test.

[0100] In the third embodiment, a measuring device for measuring this contact resistance will be described. A protective diode for preventing electrostatic breakdown is generally connected to the terminal of the IC chip on the wafer. In this embodiment, an example will be described in which the contact resistance is measured using this protective diode as a sensor element.

[0101] 10 is a block diagram of a measurement device 50 according to the third embodiment. The measurement device 50 is connected to a protection diode D3 via a probe 42 (not shown in FIG. 10). The measurement device 50 uses the protection diode D3 of the IC chip to measure the contact resistance R p3 The measuring device 50 according to this embodiment includes a current source 52, a voltage measuring device 54, a storage device 56, and an arithmetic unit 58. The measuring device 50 may include an MPU, a RAM, and a ROM.

[0102] The current source 52 has a contact resistance R p3 Three or more currents I of different magnitudes flow through path P3, which includes protection diode D3. d3 A current I d3 The flow of p3 and protection diode D3 are connected to the voltage V R3 (=R p3 ×I d3 ) and forward voltage V D3occurs.

[0103] The path P3 is formed by the sensor element D1 and the path resistance R p1 The node A3 may be a portion of the probe that comes into contact with a terminal of the IC chip.

[0104] The voltage measuring device 54 measures the voltage V A3 Specifically, the voltage measuring device 54 measures three or more currents I from the current source 52. d3 When each of these is supplied to path P3, the voltage V A3 Measure the voltage V of path P3. A3 Obtain three or more measurements of the voltage V A3 is V A3 =V R3 +V D3 The voltage measuring device 54 is, for example, an A / D converter, and measures the voltage V A3 is converted to a digital signal S V3 Generates a digital signal S V3 is transmitted to the storage device 56, which stores the voltage V A3 The measurement results are stored.

[0105] The storage device 56 stores various information. A3 The data D stored in the storage device 56 may include data indicating the measurement results of the wafer test, data indicating the measurement results for the wafer test, and programs for the arithmetic device 58 to execute various calculations. 31 is referred to by the calculation device 58 as necessary.

[0106] The calculation device 58 calculates the contact resistance R based on the measurement result of the voltage measuring device 54. p3 The calculation device 58 calculates the data D 32 may be stored in the storage device 56. The arithmetic unit 58 may include an MPU, a RAM, a ROM, etc. as necessary. The functions of the arithmetic unit 58 are realized by a calculation unit 580 and a correction unit 582.

[0107] The calculation unit 580 calculates the voltage V A3 Based on the results of three or more measurements, the temperature T3 or contact resistance R of the protection diode D3 p3 The calculation unit 580 calculates the temperature T3 and contact resistance R of the protection diode D3 in the same manner as the calculation unit 222 according to the first embodiment. p3 can be calculated.

[0108] The correction unit 582 corrects the contact resistance R calculated by the calculation unit 580. p3 Based on this, the measurement results for the wafer test can be corrected. p3 This reduces the influence of the noise on the wafer test, making it possible to perform the wafer test with higher accuracy.

[0109] (supplement) Although the embodiments according to the present disclosure have been described using specific terms, this description is merely an example to facilitate understanding and does not limit the scope of the present disclosure or the claims, and the scope of the present invention is defined by the claims. Furthermore, not only the embodiments but also embodiments, examples, and modifications not described herein are included in the scope of the present invention. For example, one or more elements of one embodiment can be combined with one or more elements of another embodiment.

[0110] (Addendum) One aspect of the technology disclosed in this specification can be understood as follows.

[0111] (Item 1) a sensor element operating according to a diode equation; a current source that supplies three or more currents of different magnitudes to a path including the sensor element and a path resistance; a voltage measuring device that measures voltages of the paths when the three or more currents are supplied to the paths from the current sources, and obtains three or more measurement results of the voltages of the paths; and a calculation device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measurement system.

[0112] (Item 2) The diode equation is expressed by the following equation (22):

number

number

[0113] (Item 3) the current source includes a reference transistor through which a reference current flows, and three transistors each forming a current mirror pair with the reference transistor; each of the three transistors is configured to generate the same current in response to the reference current; 3. The measuring system according to item 1 or 2.

[0114] (Item 4) the current source includes a reference transistor through which a reference current flows, and two transistors each forming a current mirror pair with the reference transistor; the two transistors are configured to generate different currents responsive to the reference current; 3. The measuring system according to item 1 or 2.

[0115] (Item 5) a detection device for detecting whether or not there is an abnormality in the sensor element; the sensor element is an LED (Light Emitting Diode), the calculation device calculates the path resistance based on the three or more measurement results; the detection device detects whether or not there is an abnormality in the sensor element based on the path resistance calculated by the arithmetic device and the result of measuring the voltage of the path by the voltage measuring device. 5. The measurement system according to any one of items 1 to 4.

[0116] (Item 6) a current source that supplies three or more currents of different magnitudes to a path including a sensor element that operates according to a diode equation and a path resistance; a voltage measuring device that measures voltages of the paths when the three or more currents are supplied to the paths from the current sources, and obtains three or more measurement results of the voltages of the paths; and a calculation device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measuring equipment.

[0117] (Item 7) the sensor element is a protection diode connected to an input or output terminal of a device under test; Item 6. The measuring device according to item 6.

[0118] (Item 8) A measurement method using the measurement device according to item 6 or 7, the current source supplies three or more currents of different magnitudes to a path including a sensor element and a path resistance that operates according to a diode equation; the voltage measurement device measures a voltage of the path when each of the three or more currents is supplied to the path from the current source, thereby obtaining three or more measurement results of the voltage of the path; The calculation device calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measurement method. [Explanation of symbols]

[0119] 1, 2 Measurement system, 8, 9 Temperature measuring device, 10, 12, 52, 80, 90, 92 Current source, 20, 34, 54 Voltage measuring device, 22, 58, 84, 96 Arithmetic unit, 30 Semiconductor device, 32 Driver, 36, 56 Memory device, 38 Processing device, 40 Wafer, 42 Probe, 50 Measuring device, 82, 94 A / D converter, 100, 120 Current mirror circuit, 102, 122 Switch unit, 220 Memory unit, 222, 382, ​​580 Calculation unit, 380 Control unit, 384 Detection unit, 582 Correction unit, D1 Sensor element, D8, D91, D92 Diode, D2 Light source, D3 Protection diode, P1 to P3 Path, R1, R2 Resistor, SW1 to SW5 Switch, M1 to M7 Transistor, Rp1, Rp2, Rp3, Rp8, Rp91, Rp92 path resistance.

Claims

1. a sensor element operating according to a diode equation; a current source that supplies three or more currents of different magnitudes to a path including the sensor element and a path resistance; a voltage measuring device that measures voltages of the paths when the three or more currents are supplied to the paths from the current sources, and obtains three or more measurement results of the voltages of the paths; and a calculation device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measurement system.

2. The diode equation is expressed by the following equation (1): [Equation 1] In the formula (1), V Ｄ is the forward voltage of the sensor element, I is the current flowing through the sensor element, Is is the reverse saturation current of the sensor element, T is the temperature of the sensor element, n is the diode coefficient of the sensor element, k is the Boltzmann constant, and q is the elementary charge, The above equation (1) is the current I ｂ In I ｂ >>I Ｓ When a quadratic approximation is performed under the above conditions, it is expressed by the following equation (2): [Equation 2] The voltage V of the path Ａ is the path resistance R ｐ As, V Ａ =R ｐ I+V Ｄ ・・・(3) is expressed as The calculation device calculates the temperature or the path resistance based on the formula (2) and the formula (3). The measurement system of claim 1 .

3. the current source includes a reference transistor through which a reference current flows, and three transistors each forming a current mirror pair with the reference transistor; the three transistors are each configured to generate the same current in response to the reference current; The measurement system of claim 1 .

4. the current source includes a reference transistor through which a reference current flows, and two transistors each forming a current mirror pair with the reference transistor; the two transistors are configured to generate different currents in response to the reference current; The measurement system of claim 1 .

5. a detection device for detecting whether or not there is an abnormality in the sensor element; the sensor element is an LED (Light Emitting Diode), the calculation device calculates the path resistance based on the three or more measurement results; the detection device detects whether or not there is an abnormality in the sensor element based on the path resistance calculated by the arithmetic device and the result of measuring the voltage of the path by the voltage measuring device.

5. A measurement system according to any one of claims 1 to 4.

6. a current source that supplies three or more currents of different magnitudes to a path including a sensor element that operates according to a diode equation and a path resistance; a voltage measuring device that measures voltages of the paths when the three or more currents are supplied to the paths from the current sources, and obtains three or more measurement results of the voltages of the paths; and a calculation device that calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measuring device.

7. the sensor element is a protection diode connected to an input or output terminal of a device under test; The measuring device according to claim 6.

8. A measurement method using the measurement device according to claim 6 or 7, the current source supplies three or more currents of different magnitudes to a path including a sensor element and a path resistance that operates according to a diode equation; the voltage measuring device measures a voltage of the path when each of the three or more currents is supplied to the path from the current source, thereby obtaining three or more measurement results of the voltage of the path; The calculation device calculates the temperature of the sensor element or the path resistance based on the three or more measurement results. Measurement method.

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