Resistivity testing device and method for low-resistivity material

Abstract

The invention provides a resistivity testing device and a resistivity testing method for a low-resistivity material, and belongs to the technical field of resistivity detection. The resistivity testing device for the low-resistivity material comprises four probes, a pulse power supply, an oscilloscope and a standard resistor, the four probes comprise a first probe, a second probe, a third probe and a fourth probe, the four probes are sequentially arranged in a row at equal intervals, and the pulse power supply and the standard resistor are connected with the first probe and the fourth probe in series; during testing, a to-be-tested sample is pressed below the four probes, and the oscilloscope is connected with the to-be-tested sample in parallel through the second probe and the third probe and used for measuring pulse voltage waveforms and readings at the two ends of the to-be-tested sample when pulse current is loaded. According to the invention, the high-voltage pulse current is utilized, the transient high current passes through the to-be-measured sample, so that the voltage at the two ends of the to-be-measured sample is relatively high, and the resistivity of the low-resistivity material can be accurately measured by adopting a voltmeter and an oscilloscope with general sensitivity.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of resistivity detection technology, and particularly relates to a resistivity testing device and testing method for low resistivity materials. BACKGROUND

[0002] The four-probe measuring instrument is a special instrument for measuring the resistivity of semiconductor materials and the square resistance, and is used for measuring the resistivity of rod-shaped and block-shaped semiconductor materials (including thick and thin sheets) and the square resistance of diffusion layers, ion implantation layers and anti-new epitaxial layers on silicon sheets. The instrument has the characteristics of high measurement precision, high sensitivity, good stability, wide measurement range and compact structure, and the measurement result is directly displayed by numbers, and the instrument is convenient to use.

[0003] However, the four-probe measuring instrument is limited by the testing principle, so that the testing result is extremely dependent on the voltmeter testing module. For low resistivity materials, the voltage reading is often small under the constant current mode, to the micro-volt or even nano-volt level. Therefore, the low resistivity material testing requires a voltage measurement module with extremely high sensitivity, but such a voltage module is too sensitive and is easily affected by environmental static electricity and even internal circuit board signals during the testing process, resulting in inaccurate testing results. The equipment capable of accurately testing low resistivity often has problems such as bulky size, high equipment cost and difficult maintenance.

[0004] Therefore, it is urgent to develop a new resistivity testing method for low resistivity materials, which can not only accurately measure the resistivity, but also has the characteristics of low cost and easy maintenance. SUMMARY

[0005] In view of the above problems of the prior art, the present application provides a resistivity testing device and testing method for low resistivity materials based on pulse current.

[0006] To achieve the above purpose, the specific technical solutions of the present application are as follows:

[0007] In a first aspect, the present application provides a resistivity testing device for low resistivity materials, comprising four probes, a pulse power supply, an oscilloscope and a standard resistance; the four probes are provided with first, second, third and fourth probes, and the four probes are arranged in a row in equal intervals; the pulse power supply and the standard resistance are connected in series with the first and fourth probes; during testing, the sample is pressed under the four probes, and the oscilloscope is connected in parallel with the sample to be tested through the second and third probes, and is used to measure the pulse voltage waveform and the reading of the sample to be tested at both ends under the load of pulse current.

[0008] Further, the voltage of the pulse power supply is 0.1-50 V, the on-time is 0.1-500 ms, and the off-time is 0.1-2 s.

[0009] Further, the standard resistance is in series with the sample to be measured, and the standard resistance is a combined standard resistance box or an independent standard resistance, which can be selected according to the resistivity of the sample to be measured.

[0010] Further, the oscilloscope can be any commercially available brand, and the oscilloscope has functions of waveform tracking, square wave triggering, signal amplitude adjustment, waveform recording, waveform playback, and waveform peak measurement.

[0011] Further, the oscilloscope is a machine with double channels, which can measure the pulse voltage waveform and the reading of the standard resistance on both sides when the pulse current is loaded, while measuring the voltage on both ends of the sample to be measured.

[0012] Further, the resistivity testing device for low resistivity material further comprises a signal amplifier, the input end of the signal amplifier is connected in parallel with the sample to be measured through the second and third probes, and the output end is connected with channel one of the oscilloscope, for amplifying and transmitting the collected voltage to the oscilloscope. The standard resistance is connected with positive and negative leads on both sides, and is connected with channel two of the oscilloscope.

[0013] Further, the low resistivity material includes but is not limited to pure aluminum material or pure copper material.

[0014] In the second aspect, the application provides a resistivity testing method for low resistivity material, which is detected by using the resistivity testing device for low resistivity material, and comprises the following steps:

[0015] The pulse voltage of the sample to be measured between the standard resistance on both sides and the second and third probes is measured, and the resistivity of the low resistivity material is calculated by combining the four-probe standard calculation formula.

[0016] Further, the calculation formula is as follows:

[0017]

[0018] Wherein, ρ represents the resistivity, the unit is Ω·cm; V x represents the voltage measured between the second and third probes, the unit is mV; V R represents the voltage measured on both sides of the standard resistance, the unit is mV; R0 represents the resistance value of the standard resistance, the unit is Ω; D represents the diameter of the sample to be measured, the unit is cm; W represents the thickness of the sample to be measured, the unit is cm; S represents the average distance of the four probes, the unit is cm; F sp represents the four-probe distance correction factor; F2(S / D) represents the sample diameter correction factor, and F(W / S) represents the sample thickness correction factor, wherein F2(S / D) and F(W / S) are measured through experiments according to the size and thickness of the sample to be measured.

[0019] The present application is based on the principle of testing the resistivity of low resistivity material by pulse current as follows:

[0020] By using high-voltage pulse current, high current is realized through the sample to be tested in a moment, so that the voltage across the sample to be tested is high, and the resistivity of low resistivity material can be accurately measured by using a voltage table and an oscilloscope with general sensitivity; compared with direct current, pulse current has the characteristics of instantaneity and small heat, which reduces the resistivity fluctuation of low resistivity material caused by heat in the circuit test process.

[0021] Compared with the prior art, the present application has the advantages of:

[0022] (1) The method for testing the resistivity of low resistivity material based on pulse current in the present application does not depend on high sensitivity and high resolution voltage table, and can realize the analysis and test of the resistivity of low resistivity material (such as pure copper), has the advantages of simple device structure, simple operation, low cost and accurate measurement result.

[0023] (2) Compared with ordinary direct current test power supply, the pulse power supply used in the present application can apply pulse high voltage, and the voltage value across the material in the measurement circuit can reach the range that can be tested by voltage table and oscilloscope with ordinary sensitivity and accuracy.

[0024] (3) The pulse power supply used in the present application can reduce the heating of the sample in the measurement process and improve the accuracy of the resistivity test. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The present application provides a resistivity testing device for low resistivity material, as shown in the figure, 1 represents a sample to be tested, 2 represents four probes, and 3 represents a standard resistance.

[0026] Figure 2 The present application provides a flowchart of the resistivity testing method of low resistivity material. DETAILED DESCRIPTION

[0027] The technical solutions of the present application will be described below. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] It should be understood that the schematic drawings in the present application are not drawn to scale, and the flowcharts show operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowcharts can be implemented in sequence, and steps without logical context relationship can be reversed in sequence or implemented simultaneously. In addition, one or more other operations can be added to the flowcharts or one or more operations can be removed from the flowcharts under the guidance of the content of the present application.

[0029] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive or alternative embodiments. It is explicitly and implicitly understood that the embodiments described herein can be combined.

[0030] The present application provides a resistivity testing device for low resistivity material, comprising four probes, a pulse power supply, an oscilloscope and a standard resistance; the four probes are provided with first, second, third and fourth probes, and the four probes are arranged in a row in equal intervals; the pulse power supply and the standard resistance are connected in series with the first and fourth probes; during testing, the sample is pressed under the four probes, and the oscilloscope is connected in parallel with the sample through the second and third probes, and is used to measure the pulse voltage waveform and the reading of the sample at both ends when a pulse current is loaded.

[0031] The standard resistance and the sample to be tested are in series, and the standard resistance is a combined standard resistance box or an independent standard resistance, and the appropriate resistance value of the standard resistance can be selected according to the resistivity of the sample to be tested. The oscilloscope can be any commercially available brand, and the oscilloscope has functions such as waveform tracking, square wave triggering, signal amplitude adjustment, waveform recording, waveform playback, and waveform peak measurement. The oscilloscope is a machine with two channels, which can measure the pulse voltage waveform and the reading of the standard resistance at both ends when a pulse current is loaded, while measuring the voltage at both ends of the sample to be tested.

[0032] In some examples, the resistivity testing device for low resistivity material further comprises a signal amplifier, the input end of the signal amplifier is connected in parallel with the sample to be tested through the second and third probes, and the output end is connected with channel one of the oscilloscope, for amplifying and transmitting the collected voltage to the oscilloscope. The standard resistance is connected with positive and negative leads respectively, and is connected with channel two of the oscilloscope.

[0033] In some examples, the voltage of the pulse power supply is 0.1-50 V, the on time is 0.1-500 ms, and the off time is 0.1-2 s.

[0034] The method for detecting the resistivity of low resistivity material by using the resistivity testing device for low resistivity material comprises the following steps as shown in the drawings: Figure 2 The method comprises the following steps: measuring the pulse voltage of the sample to be measured between the standard resistance and the second and third probes, and calculating the resistivity of the low resistivity material by combining the four-probe standard calculation formula, wherein the calculation formula is as follows:

[0035]

[0036] Wherein, ρ represents the resistivity, and the unit is Ω·cm; V x represents the voltage measured between the second and third probes, and the unit is mV; V R represents the voltage measured on both sides of the standard resistance, and the unit is mV; R0 represents the resistance value of the standard resistance, and the unit is Ω; D represents the diameter of the sample to be measured, and the unit is cm; W represents the thickness of the sample to be measured, and the unit is cm; S represents the average distance between the four probes, and the unit is cm; F sp represents the four-probe distance correction factor; F2(S / D) represents the sample diameter correction factor, and F(W / S) represents the sample thickness correction factor, and the values can be found in the national standard.

[0037] Embodiment 1

[0038] A resistivity testing device for low resistivity material comprises four probes, a pulse power supply, an oscilloscope, a standard resistance, and a signal amplifier as shown in the drawings. Figure 1 The four probes are provided with a first probe, a second probe, a third probe, and a fourth probe, and the four probes are arranged in a row with equal distances. The pulse power supply and the standard resistance are connected in series with the first probe and the fourth probe. During testing, the sample to be measured is pressed under the four probes, and the bottom of the sample to be measured is provided with an insulating pad. The oscilloscope is connected in parallel with the sample to be measured through the second probe and the third probe, and is used to measure the pulse voltage waveform and the reading of the sample to be measured at both ends when a pulse current is loaded.

[0039] The standard resistance and the sample to be measured are in series, and the standard resistance is a combined standard resistance box or an independent standard resistance. The resistance value of the standard resistance can be selected according to the resistivity of the sample to be measured. The oscilloscope can be any commercially available brand, and the oscilloscope has the functions of waveform tracking, square wave triggering, signal amplitude adjustment, waveform recording, waveform playback, and waveform peak measurement. The oscilloscope is a one-machine dual-channel device, which can measure the voltage at both ends of the sample to be measured and the pulse voltage waveform and the reading of the standard resistance at both sides when a pulse current is loaded. The input end of the signal amplifier is connected in parallel with the sample to be measured through the second probe and the third probe, the output end is connected with channel one of the oscilloscope, and is used to amplify and transmit the collected voltage to the oscilloscope. The positive and negative leads of the standard resistance are connected with channel two of the oscilloscope.

[0040] The resistivity of low resistivity material (pure aluminum material) is tested by using the resistivity testing device for low resistivity material, including the following steps:

[0041] (1) Measure the thickness and diameter of the sample to be tested, and press it under the four-probe device;

[0042] (2) Use different pulse voltages 5 V, 15 V, 25 V, 35 V, 45 V, on for 10 ms, off for 1 s. Test respectively;

[0043] (3) Read the voltage values of the standard resistor (the resistance value of the standard resistor is 110 mΩ) under different pulse voltages, which are 980 mV, 1117 mV, 1264 mV, 1378 mV, and 1500 mV respectively;

[0044] (4) Read the voltage values of the sample to be tested between the second and third probes under different pulse voltages (after 1000 times amplification), which are 79 mV, 90 mV, 102 mV, 111 mV, and 121 mV respectively;

[0045] (5) The sample diameter is 30 mm, the probe spacing is 1 mm, the sample thickness is 0.4 mm, the probe calibration coefficient F SP =0.0176, and the table lookup value F2(S / D)=4.49 and F(W / S)=0.993;

[0046] (6) According to the formula, the average resistivity value is calculated multiple times, which is 2.78×10 -8 Ω·cm, which is basically consistent with the standard resistivity 2.8×10 -8 Ω·cm.

[0047] Example 2

[0048] The resistivity of low resistivity material (pure copper material) is tested by using the resistivity testing device for low resistivity material described in Example 1, including the following steps:

[0049] (1) Measure the thickness and diameter of the sample to be tested, and press it under the four-probe device;

[0050] (2) Use different pulse voltages 5 V, 15 V, 25 V, 35 V, 45 V, on for 10 ms, off for 1 s. Test respectively;

[0051] (3) Read the voltage values of the standard resistor (the resistance value of the standard resistor is 110 mΩ) under different pulse voltages, which are 54.88 mV, 63 mV, 68 mV, 75.9 mV, and 81 mV respectively;

[0052] (4) Read the voltage value of the sample to be measured between the second and third probes under different pulse voltages (1000 times amplification), which are 15.8 mV, 18 mV, 19.6 mV, 22 mV and 23.4 mV, respectively;

[0053] (5) The sample diameter is 30 mm, the probe spacing is 1 mm, the sample thickness is 0.07 mm, the probe calibration coefficient F SP =0.0176, and the table lookup gives F2(S / D)=4.49 and F(W / S)=1;

[0054] (6) According to the formula, the average resistivity value is 1.75×10 -8 Ω·cm, which is basically consistent with the standard resistivity 1.72×10 -8 Ω·cm.

[0055] The above specific embodiments describe the implementation of the application in detail, but the application is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concepts of the application, the technical solutions of the application can be modified and changed in many simple ways, and these simple modifications all belong to the protection scope of the application.

Claims

1. A resistivity testing device for low resistivity materials, characterized in that, The device includes a four-probe array, a pulse power supply, an oscilloscope, and a standard resistor. The four-probe array consists of a first, second, third, and fourth probe, arranged in a row with equal spacing. The pulse power supply and the standard resistor are connected in series with the first and fourth probes. During testing, the sample is pressed under the four probes. The oscilloscope is connected in parallel with the sample through the second and third probes to measure the pulse voltage waveform and reading across the sample when a pulse current is applied.

2. The resistivity testing apparatus for low resistivity materials according to claim 1, characterized in that, The pulse power supply has a voltage of 0.1-50 V, a conduction time of 0.1-500 ms, and a turn-off time of 0.1-2 s.

3. The resistivity testing apparatus for low resistivity materials according to claim 1, characterized in that, The standard resistor is either a combined standard resistor box or an independent standard resistor.

4. The resistivity testing apparatus for low resistivity materials according to claim 1, characterized in that, The oscilloscope is a dual-channel device, which can measure the voltage across the sample under test while simultaneously measuring the pulse voltage waveform and reading across a standard resistor when a pulse current is applied.

5. The resistivity testing apparatus for low resistivity materials according to claim 1, characterized in that, The resistivity testing device for low resistivity materials also includes a signal amplifier for amplifying the acquired voltage and transmitting it to an oscilloscope.

6. The resistivity testing apparatus for low resistivity materials according to claim 1, characterized in that, The low resistivity material includes, but is not limited to, pure aluminum or pure copper.

7. A method for testing the resistivity of a low resistivity material, characterized in that, The resistivity testing apparatus for low resistivity materials according to any one of claims 1-6 is used for detection, comprising the following steps: The pulse voltage of the sample under test is measured on both sides of the standard resistor and between the second and third probes. The resistivity of the low resistivity material is calculated by combining the standard four-probe calculation formula.

8. The resistivity testing method for low resistivity materials according to claim 1, characterized in that, The calculation formula is as follows: ; Where ρ represents resistivity, with units of Ω·cm; V x This represents the voltage measured between the second and third probes, in mV; V R R0 represents the voltage measured across the standard resistor, in mV; R0 represents the resistance value of the standard resistor, in Ω; D represents the diameter of the sample to be tested, in cm; W represents the thickness of the sample to be tested, in cm; S represents the average spacing between the four probes, in cm; F sp F represents the correction factor for the spacing between the four probes; F2(S / D) represents the correction factor for the diameter of the sample to be tested, and F(W / S) represents the correction factor for the thickness of the sample to be tested.

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