Non-contact double-probe square resistance measuring device and method

Abstract

The invention discloses a non-contact double-probe square resistance measuring device and method, and belongs to the technical field of square resistance measurement. A controller, an excitation circuit, an auxiliary circuit, a shielding circuit and an alternating current power supply are arranged in each of the upper probe and the lower probe. When the sheet resistance value of the upper surface film layer of the sample is detected, the excitation circuit of the upper probe and the auxiliary circuit of the lower probe work simultaneously, and when the sheet resistance value of the lower surface film layer of the sample is detected, the auxiliary circuit of the upper probe and the excitation circuit of the lower probe work simultaneously. And controlling on-off of internal circuits of the upper and lower probes according to the set switching frequency, and sequentially measuring sheet resistance values of upper and lower surface film layers of the sample. By adopting the scheme, the square resistance of the same positions of the upper surface and the lower surface of the sample can be simultaneously measured without additionally moving or overturning the sample and the probe, a set of square resistance instrument does not need to be purchased again, and an additional mounting space or a rotating and translation mechanism is not needed, so that the cost is saved, the detection precision is ensured, and the detection efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of square resistance measurement, and in particular to a non-contact double-probe square resistance measurement device and method. Background Art

[0002] In the research and production of thin film materials and new materials, it is often necessary to coat the upper and lower surfaces of the substrate. The substrate is usually made of insulating materials or materials with very high square resistance, and the film materials on the upper and lower surfaces are usually different, for example, one side is a conductor and the other side is a semiconductor. Therefore, there is usually a large difference in the square resistance of the film layers on the upper and lower surfaces. If the thickness of the film layer is not uniform, its conductive properties will be affected. In engineering, the square resistance value is usually measured to determine whether the thickness of the film layer is uniform. Therefore, on the production line, it is necessary to measure the square resistance value of the same position on the upper and lower surfaces of the sample at the same time to quickly evaluate the uniformity of the film layer on the upper and lower surfaces of the sample.

[0003] The existing square resistance measurement technology usually adopts a non-contact dual-probe square resistance measurement device. Figure 1 As shown in the figure, this device includes an upper probe (excitation probe) and a lower probe (auxiliary probe), and the sample is located between the upper and lower probes. Due to space limitations, existing measurement devices cannot simultaneously measure the square resistance values ​​of the upper and lower surfaces of the sample at the same time point. If the square resistance at the same position on the upper and lower surfaces is to be measured, there are usually two methods: flip the sample or probe, or move the sample to the middle of another set of probes. These two methods have the following defects:

[0004] 1. Turn over the sample or probe:

[0005] Actuator: Additional actuator is required to flip the specimen or probe.

[0006] Time consumption: The flipping time is usually long, at least a few seconds. The current production line production cycle is generally 5 pieces / second, or even higher, so it is impossible to achieve real-time online measurement by flipping the sample or probe.

[0007] Accuracy problem: Flipping may cause position deviation or even change the distance between the upper and lower probes and the sample, which will seriously affect the measurement accuracy and even make it impossible to obtain accurate data.

[0008] 2. Move the sample to another set of probes:

[0009] Space requirements: Additional assembly space is required, which is difficult to achieve in some particularly compact production lines.

[0010] Increased costs: Additional probe sets increase acquisition, operation, and maintenance costs.

[0011] Accuracy requirements: A controller needs to be added to ensure that the sample can stay accurately in the same position, which places high demands on the accuracy of the moving device.

[0012] In summary, the existing square resistance measurement methods have many shortcomings in production line applications and cannot meet the measurement requirements of high efficiency and high precision. Therefore, there is an urgent need for a device that can simultaneously measure the square resistance values ​​of the same position on the upper and lower surfaces of the sample on the production line to improve the measurement efficiency and precision. Summary of the invention

[0013] The technical problem to be solved by the present invention is: in view of the above-mentioned defects of the prior art, a non-contact dual-probe square resistance measurement device and method are provided, which can simultaneously measure the square resistance of the same position on the upper and lower surfaces of the sample without additional movement or flipping of the sample and the probe.

[0014] To achieve the above object, the present invention provides a non-contact dual-probe square resistance measuring device, which is used to simultaneously measure the square resistance of the same position on the upper and lower surfaces of a moving sample on a production line, wherein the sample comprises a first film layer, a substrate, and a second film layer, wherein the first film layer and the second film layer are respectively located on the upper and lower surfaces of the substrate, and the non-contact dual-probe square resistance measuring device comprises:

[0015] A first probe, a second probe, a main control unit, a display and an input-output unit;

[0016] The first probe, the second probe, and the display and input-output unit are respectively connected to the main control unit;

[0017] The first probe is vertically arranged above the sample, and the second probe is vertically arranged below the sample, the centers of the first probe and the second probe are in a straight line, and neither the first probe nor the second probe is in contact with the sample;

[0018] The first probe is provided with a first controller, a first excitation circuit, a first auxiliary circuit, a first shielding circuit, and a first AC power supply; the second probe is provided with a second controller, a second excitation circuit, a second auxiliary circuit, a second shielding circuit, and a second AC power supply;

[0019] The first auxiliary circuit and the second auxiliary circuit are both mutual inductance circuits;

[0020] The first shielding circuit and the second shielding circuit are used for electromagnetic field isolation;

[0021] The display and input-output unit is used to set measurement parameters and display measurement results;

[0022] The main control unit receives the measurement parameters set by the display and input-output unit, controls the on-off of the circuits in the first probe and the second probe through the first controller and the second controller, measures the square resistance values ​​of the first film layer and the second film layer in turn, and calculates the square resistance values ​​of the first film layer and the second film layer according to the measurement results of the first probe and the second probe.

[0023] Preferably, the first controller, under the control of the main control unit, controls the on-off connection between the first AC power supply and the first excitation circuit, the on-off connection between the first shielding circuit and the first excitation circuit, and the on-off connection between the first shielding circuit and the first auxiliary circuit;

[0024] Under the control of the main control unit, the second controller controls the on-off connection between the second AC power supply and the second excitation circuit, the on-off connection between the second shielding circuit and the second excitation circuit, and the on-off connection between the second shielding circuit and the second auxiliary circuit.

[0025] Preferably, the first shielding circuit and the second shielding circuit both include an energized shielding shell, a multi-point grounding circuit and a filtering circuit.

[0026] Preferably, the non-contact dual-probe square resistance measuring device further comprises a transmission and support device, and the transmission and support device moves the sample to a detection range of the non-contact dual-probe square resistance measuring device.

[0027] The present invention also provides a non-contact dual-probe square resistance measurement method, which is applied to the non-contact dual-probe square resistance measurement device as described above, and the method comprises the following steps:

[0028] Step S1, adjusting the oscillation frequency of the excitation circuit and the height of the probe so that the penetration depth of the probe covers part of the substrate and does not penetrate into the film layer opposite to the sample;

[0029] Step S2, setting a switching frequency for measuring the square resistance values ​​of the first film layer and the second film layer and a detection frequency of the probe;

[0030] Step S3, controlling the on and off of the circuits in the first probe and the second probe according to the switching frequency, and measuring the square resistance values ​​of the first film layer and the second film layer in sequence;

[0031] Step S4 , calculating the square resistance of the first film layer and the square resistance of the second film layer according to the square resistances measured by the first probe and the second probe and the square resistance of the substrate.

[0032] Preferably, in step S1, the oscillation frequency of the first excitation circuit is the same as the oscillation frequency of the second excitation circuit, and the vertical distance between the first probe and the sample is the same as the vertical distance between the second probe and the sample.

[0033] Preferably, the oscillation frequency of the first excitation circuit and the second excitation circuit is 1-100 MHz.

[0034] Preferably, in step S2, the detection frequency of the first probe is the same as the detection frequency of the second probe, and the detection frequency is an integer multiple of the switching frequency.

[0035] Preferably, the specific method of step S3 is:

[0036] When measuring the square resistance of the first film layer, controlling the first controller to connect the first excitation circuit to the first AC power supply and the first shielding circuit to the first auxiliary circuit, and controlling the second controller to disconnect the second excitation circuit from the second AC power supply and connect the second shielding circuit to the second excitation circuit;

[0037] When measuring the square resistance value of the second film layer, the first controller is controlled to disconnect the first excitation circuit from the first AC power supply and connect the first shielding circuit to the first excitation circuit, and at the same time, the second controller is controlled to connect the second excitation circuit to the second AC power supply and connect the second shielding circuit to the second auxiliary circuit.

[0038] Preferably, the specific method of step S4 is:

[0039] Assuming that the square resistance of the substrate is R0, when measuring the square resistance of the first film layer, the square resistance measured by the first probe is R1. If R0>R1, the square resistance of the first film layer RA=R1*R0 / (R0-R1); if R0<=R1, the square resistance of the first film layer RA=R1; when measuring the square resistance of the second film layer, the square resistance measured by the second probe is R2. If R0>R2, the square resistance of the second film layer RB=R2*R0 / (R0-R2); if R0<=R2, the square resistance of the second film layer RB=R2.

[0040] The present invention has the following beneficial effects: In this solution, a controller, an excitation circuit, an auxiliary circuit, a shielding circuit, and an AC power supply are arranged in the upper and lower probes, and the controller is used to control the on and off of the excitation circuit and the AC power supply, the on and off of the auxiliary circuit and the shielding circuit, and the on and off of the excitation circuit and the shielding circuit. When the shielding circuit and the auxiliary circuit are connected, only the excitation circuit works, and when the shielding circuit and the excitation circuit are connected, only the auxiliary circuit works. When detecting the square resistance value of the film layer on the upper surface of the sample, the excitation circuit of the upper probe and the auxiliary circuit of the lower probe work simultaneously, and when detecting the square resistance value of the film layer on the lower surface of the sample, the auxiliary circuit of the upper probe and the excitation circuit of the lower probe work simultaneously. The on and off of the internal circuits of the upper and lower probes are controlled according to the set switching frequency, and the square resistance values ​​of the film layers on the upper and lower surfaces of the sample are measured in turn. By adopting the solution of the present invention, the square resistance of the same position on the upper and lower surfaces of the sample can be measured simultaneously without additionally moving or flipping the sample and the probe, and there is no need to re-purchase a set of square resistance meter, and no additional installation space or rotation and translation mechanism is required, which not only saves costs, but also ensures detection accuracy and improves detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 The figure is a schematic diagram of an existing non-contact dual-probe square resistance measurement device and a double-sided coated sample measurement.

[0043] Figure 2 A schematic diagram of a non-contact dual-probe square resistance measurement device and a double-sided coated sample measurement provided by an embodiment of the present invention.

[0044] Figure 3 A schematic diagram of the internal circuit connections of the probes when the non-contact dual-probe square resistance measurement device provided by an embodiment of the present invention measures the first film layer.

[0045] Figure 4 A schematic diagram of the internal circuit connections of the probes when the non-contact dual-probe square resistance measurement device provided by an embodiment of the present invention measures the second film layer.

[0046] Figure 5 A schematic diagram of the structure of an excitation circuit provided by a non-contact dual-probe square resistance measurement device provided in an embodiment of the present invention.

[0047] Figure 6 A schematic diagram of the auxiliary circuit structure provided by the non-contact dual-probe square resistance measurement device provided in an embodiment of the present invention.

[0048] Figure 7 A schematic diagram of the steps of a non-contact dual-probe square resistance measurement method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The sample described in the present invention refers to the product produced in batches by an automated production line, and its structure is as follows Figure 1 As shown, it includes a substrate, a first film layer plated on the upper surface of the substrate, and a second film layer plated on the lower surface of the substrate. The square resistance of the substrate is a nominal value, and the square resistance of the first film layer and the second film layer also have corresponding nominal values. However, due to process and other reasons, the square resistance of the first film layer and the second film layer may still be significantly different from the nominal specifications. If the thickness of the first film layer and the second film layer is not uniform, their conductive properties will be affected. Therefore, under the production line beat, it is very important to quickly measure the square resistance of the first film layer and the second film layer to determine the thickness uniformity of the first film layer and the second film layer.

[0051] The general idea of ​​the present invention is: a controller, an excitation circuit, an auxiliary circuit, a shielding circuit, and an AC power supply are set in the upper and lower probes. The controller is used to control the on and off of the excitation circuit and the AC power supply, the on and off of the auxiliary circuit and the shielding circuit, and the on and off of the excitation circuit and the shielding circuit. When the shielding circuit and the auxiliary circuit are connected, only the excitation circuit works, and when the shielding circuit and the excitation circuit are connected, only the auxiliary circuit works. When detecting the square resistance value of the first film layer, the excitation circuit of the upper probe and the auxiliary circuit of the lower probe work simultaneously, and when detecting the square resistance value of the second film layer, the auxiliary circuit of the upper probe and the excitation circuit of the lower probe work simultaneously. By setting the switching frequency, the square resistance values ​​of the first film layer and the second film layer are measured in turn.

[0052] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings of the specification. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0053] like Figure 2-4 As shown, an embodiment of the present invention provides a non-contact dual-probe square resistance measuring device, which is used to simultaneously measure the square resistance of the same position on the upper and lower surfaces of a moving sample on a production line, wherein the sample includes a first film layer, a substrate, and a second film layer, and the first film layer and the second film layer are respectively located on the upper and lower surfaces of the substrate. The non-contact dual-probe square resistance measuring device includes:

[0054] The first probe, the second probe, the main control unit, the display and the input-output unit.

[0055] The first probe, the second probe, and the display and input-output unit are all connected to the main control unit respectively.

[0056] The first probe is vertically arranged above the sample, and the second probe is vertically arranged below the sample. The centers of the first probe and the second probe are in a straight line, and neither the first probe nor the second probe contacts the sample.

[0057] In an embodiment of the present invention, the first probe and the second probe are cylindrical in shape with a diameter of 20 mm. The first probe and the second probe are coaxially arranged in a direction perpendicular to the sample, so that the first probe and the second probe can be aligned with the same position on the upper and lower surfaces of the sample.

[0058] The first probe is provided with a first controller, a first excitation circuit, a first auxiliary circuit, a first shielding circuit, and a first AC power supply. The second probe is provided with a second controller, a second excitation circuit, a second auxiliary circuit, a second shielding circuit, and a second AC power supply.

[0059] The first auxiliary circuit and the second auxiliary circuit are both mutual inductance circuits.

[0060] The first shielding circuit and the second shielding circuit are used for electromagnetic field isolation.

[0061] The embodiment of the present invention has no special restrictions on the layout of the circuits in the probe.

[0062] like Figure 5 The figure shows a circuit structure diagram of the excitation circuit provided by some embodiments of the present invention. The first excitation circuit and the second excitation circuit can both adopt Figure 5 The circuit structure shown. Specifically, the excitation circuit is an RLC parallel resonant circuit composed of an AC power supply U1, a first capacitor C1, a first resistor R2, and a first inductor L1, U1 is a high-frequency AC current source, U2 is its equivalent DC voltage, and L2, R3 and L3, R4 are equivalent circuits of wires respectively. The shielding circuit is connected to the excitation circuit, specifically, the shielding circuit is connected in parallel to both ends of the first capacitor C1 to form a closed loop.

[0063] like Figure 6 FIG. 1 is a schematic diagram of a circuit structure of an auxiliary circuit provided in some embodiments of the present invention. The first auxiliary circuit and the second auxiliary circuit can both adopt Figure 6 The circuit structure is shown. Figure 6 for Figure 5The mutual inductance circuit of the circuit shown is driven by the excitation circuit through mutual inductance, and its main components are the second capacitor C3 and the second inductor L4. R1 is a parasitic resistor, C2 is a parasitic capacitor, D1 is a diode, and C4 is a picofarad capacitor, which is grounded to shield high-frequency interference. In the setting of circuit parameters, C3=C1 and L4=L1 can usually be selected. The shielding circuit is connected to the auxiliary circuit, specifically, the shielding circuit is connected in parallel to the two ends of the second capacitor C3 to form a closed loop.

[0064] In an embodiment of the present invention, the first shielding circuit and the second shielding circuit both include an energized shielding shell, a multi-point grounding circuit and a filtering circuit. When the energized shielding shell is energized, it can reflect and absorb external electromagnetic interference, such as conductive polymer materials (such as polyacetylene, polyaniline, etc.), oxide semiconductor materials (such as titanium dioxide, zinc oxide, etc.) and some composite materials (such as carbon nanotube / polymer composites, metal / insulator composites, etc.). The energized shielding shell can be powered by the first AC power supply or the second AC power supply, or by other external power supplies. The multi-point grounding technology is to set multiple grounding points on the energized shielding shell, and connect these grounding points together through low-impedance conductors (such as copper tape, metal braided mesh, etc.) to form a grounding plane. For example, 16 grounding points are evenly distributed in the cylindrical cavity of the probe, and these grounding points are connected with copper tape to ensure that the grounding impedance is as low as possible. Multiple filtering circuits are set between the multiple grounding points and the energized shielding shell. The filter circuit uses a high-frequency through-hole capacitor and inductor. An inductor with an inductance value of several microhenries to several tens of microhenries is connected in series to the power line, and then a through-hole capacitor with a capacity of several hundred picofarads to several thousand picofarads is connected in parallel.

[0065] In the embodiment of the present invention, the first controller and the second controller are switch circuits.

[0066] The display and input-output unit is used to set measurement parameters and display measurement results.

[0067] The main control unit receives the measurement parameters set by the display and input-output unit, controls the on-off of the circuits in the first probe and the second probe through the first controller and the second controller, measures the square resistance values ​​of the first film layer and the second film layer in turn, and calculates the square resistance values ​​of the first film layer and the second film layer according to the measurement results of the first probe and the second probe.

[0068] Under the control of the main control unit, the first controller controls the on-off connection between the first AC power supply and the first excitation circuit, the on-off connection between the first shielding circuit and the first excitation circuit, and the on-off connection between the first shielding circuit and the first auxiliary circuit. The first AC power supply is connected to the first excitation circuit, and the first shielding circuit is connected to the first auxiliary circuit, so that the first excitation circuit is in a working state, and the first auxiliary circuit and the first shielding circuit form a loop, thereby shielding the influence of the first auxiliary circuit on the first excitation circuit, which is equivalent to shutting down the first auxiliary circuit. The first AC power supply is disconnected from the first excitation circuit, and the first shielding circuit is connected to the first excitation circuit, so that the first auxiliary circuit is in a working state, and the first excitation circuit and the first shielding circuit form a loop, thereby shielding the influence of the first excitation circuit on the first auxiliary circuit, which is equivalent to shutting down the first excitation circuit.

[0069] Under the control of the main control unit, the second controller controls the on-off connection between the second AC power supply and the second excitation circuit, the on-off connection between the second shielding circuit and the second excitation circuit, and the on-off connection between the second shielding circuit and the second auxiliary circuit. When the second AC power supply is connected to the second excitation circuit and the second shielding circuit is connected to the second auxiliary circuit, the second excitation circuit can be put into operation and the second auxiliary circuit can be turned off. When the second AC power supply is disconnected from the second excitation circuit and the second shielding circuit is connected to the second excitation circuit, the second auxiliary circuit can be put into operation and the second excitation circuit can be turned off.

[0070] In an embodiment of the present invention, the non-contact dual-probe square resistance measuring device further comprises a transmission and support device, and the transmission and support device moves the sample to a detection range of the non-contact dual-probe square resistance measuring device.

[0071] like Figure 7 As shown, an embodiment of the present invention further provides a non-contact dual-probe square resistance measurement method, which is applied to the non-contact dual-probe square resistance measurement device as described above, and the method comprises the following steps:

[0072] Step S1, adjusting the oscillation frequency of the excitation circuit and the height of the probe so that the penetration depth of the probe covers a portion of the substrate and does not penetrate into the film layer opposite to the sample.

[0073] The probe of the embodiment of the present invention is a non-contact probe, which uses the eddy current method to measure the square resistance. The depth of the eddy current method detection, that is, the penetration depth, is limited by physical properties. The penetration depth determines how deep below the surface of the material the eddy current method can detect. The embodiment of the present invention needs to measure the square resistance of the first film layer and the second film layer separately to determine the thickness uniformity of the first film layer and the second film layer. Therefore, it is necessary to control the penetration depth so that the penetration depth covers part of the substrate and does not penetrate the film layer opposite to the sample. Specifically, according to the thickness values ​​of the substrate, the first film layer and the second film layer in the sample, the penetration depth is adjusted by adjusting the oscillation frequency of the excitation circuit and the height of the probe. When the square resistance of the first film layer and the second film layer measured by the measuring device are both within the floating range allowed by the nominal value, and the results are stable, it means that the adjustment is in place. For the convenience of measurement, the oscillation frequency of the first excitation circuit is usually the same as the oscillation frequency of the second excitation circuit, and the vertical distance of the first probe from the sample is the same as the vertical distance of the second probe from the sample. The oscillation frequency of the first excitation circuit and the second excitation circuit is 1-100 MHz. In practical applications, the oscillation frequency is usually set to about 10 MHz.

[0074] Step S2, setting a switching frequency for measuring the square resistance values ​​of the first film layer and the second film layer and a detection frequency of the probe.

[0075] In actual applications, the user sets the switching frequency and the detection frequency through the display and input-output unit. In an embodiment of the present invention, in step S2, the detection frequency of the first probe is the same as the detection frequency of the second probe, and the detection frequency is an integer multiple of the switching frequency. In actual applications, the switching frequency is usually set to 10Hz-50Hz, and the single-sided detection frequency is usually 1000Hz, that is, detection is performed once every 1 millisecond (ms), and the average value is usually taken after 10 or more detections. The above detection frequency and switching frequency can fully meet the production line rhythm.

[0076] Step S3, controlling the on and off of the circuits in the first probe and the second probe according to the switching frequency, and measuring the square resistance of the first film layer and the second film layer in turn.

[0077] In the embodiment of the present invention, the specific method of step S3 is:

[0078] When measuring the square resistance of the first film layer, the first controller is controlled to connect the first excitation circuit to the first AC power supply and the first shielding circuit to the first auxiliary circuit, and the second controller is controlled to disconnect the second excitation circuit from the second AC power supply and connect the second shielding circuit to the second excitation circuit. The above circuit connection method allows the first excitation circuit and the second auxiliary circuit to work at the same time, the first auxiliary circuit and the second excitation circuit are turned off, and the square resistance of the first film layer is measured.

[0079] When measuring the square resistance of the second film layer, the first controller is controlled to disconnect the first excitation circuit from the first AC power supply and connect the first shielding circuit to the first excitation circuit, and the second controller is controlled to connect the second excitation circuit to the second AC power supply and connect the second shielding circuit to the second auxiliary circuit. The above circuit connection method allows the second excitation circuit and the first auxiliary circuit to work at the same time, the first excitation circuit and the second auxiliary circuit are turned off, and the square resistance of the second film layer is measured.

[0080] When measuring the square resistance values ​​of the first film layer and the second film layer, the measuring device obtains the measurement result according to the set detection frequency.

[0081] Step S4 , calculating the square resistance of the first film layer and the square resistance of the second film layer according to the square resistances measured by the first probe and the second probe and the square resistance of the substrate.

[0082] In the embodiment of the present invention, the specific method of step S4 is:

[0083] Assuming that the square resistance of the substrate is R0, when measuring the square resistance of the first film layer, the square resistance measured by the first probe is R1. If R0>R1, the square resistance of the first film layer RA=R1*R0 / (R0-R1); if R0<=R1, the square resistance of the first film layer RA=R1; when measuring the square resistance of the second film layer, the square resistance measured by the second probe is R2. If R0>R2, the square resistance of the second film layer RB=R2*R0 / (R0-R2); if R0<=R2, the square resistance of the second film layer RB=R2.

[0084] When measuring the first film layer, because the substrate is usually an insulator or a material with high resistivity, R0 is usually much larger than R1. If R0>R1, the reading of the first probe is equivalent to the parallel value of the square resistance of the first film layer and the substrate. Therefore, the square resistance value of the first film layer is RA=R1*R0 / (R0-R1). If R0<=R1, it means that the reading of the first probe is little affected by the substrate, and the value of R1 can be directly used as the square resistance value of the first film layer. The calculation principle of the square resistance value of the second film layer is the same as that of the first film layer.

[0085] After the main control unit collects the measurement data of the first probe and the second probe, it calculates the square resistance values ​​of the first film layer and the second film layer according to the above method, and sends the data to the display and input-output unit for output display, or for subsequent processing, including but not limited to detecting whether there are defects, drawing output images, and sending signals to the PLC (Programmable Logic Controller) to achieve automated control of the production process, such as automatically cutting defective areas, or reprocessing, etc.

[0086] The non-contact dual-probe square resistance measuring device provided in the embodiment of the present invention has a square resistance detection range of 10 mΩ / □ to 1000 Ω / □.

[0087] The present invention has the following beneficial effects: In this solution, a controller, an excitation circuit, an auxiliary circuit, a shielding circuit, and an AC power supply are arranged in the upper and lower probes, and the controller is used to control the on and off of the excitation circuit and the AC power supply, the on and off of the auxiliary circuit and the shielding circuit, and the on and off of the excitation circuit and the shielding circuit. When the shielding circuit and the auxiliary circuit are connected, only the excitation circuit works, and when the shielding circuit and the excitation circuit are connected, only the auxiliary circuit works. When detecting the square resistance value of the film layer on the upper surface of the sample, the excitation circuit of the upper probe and the auxiliary circuit of the lower probe work simultaneously, and when detecting the square resistance value of the film layer on the lower surface of the sample, the auxiliary circuit of the upper probe and the excitation circuit of the lower probe work simultaneously. The on and off of the internal circuits of the upper and lower probes are controlled according to the set switching frequency, and the square resistance values ​​of the film layers on the upper and lower surfaces of the sample are measured in turn. By adopting the solution of the present invention, the square resistance of the same position on the upper and lower surfaces of the sample can be measured simultaneously without additionally moving or flipping the sample and the probe, and there is no need to re-purchase a set of square resistance meter, and no additional installation space or rotation and translation mechanism is required, which not only saves costs, but also ensures detection accuracy and improves detection efficiency.

[0088] The above are only specific implementations of the present invention, which cannot be used to limit the scope of the present invention. Equivalent changes made by ordinary technicians in this technical field based on this creation, as well as changes known to technicians in this field, should still fall within the scope of the present invention.

Claims

1. A non-contact dual-probe square resistance measuring device, used to simultaneously measure the square resistance of the same position on the upper and lower surfaces of a moving sample on a production line, wherein the sample comprises a first film layer, a substrate, and a second film layer, wherein the first film layer and the second film layer are respectively located on the upper and lower surfaces of the substrate, characterized in that: The non-contact dual-probe square resistance measuring device comprises: A first probe, a second probe, a main control unit, a display and an input-output unit; The first probe, the second probe, and the display and input-output unit are respectively connected to the main control unit; The first probe is vertically arranged above the sample, and the second probe is vertically arranged below the sample, the centers of the first probe and the second probe are in a straight line, and neither the first probe nor the second probe is in contact with the sample; The first probe is provided with a first controller, a first excitation circuit, a first auxiliary circuit, a first shielding circuit, and a first AC power supply; the second probe is provided with a second controller, a second excitation circuit, a second auxiliary circuit, a second shielding circuit, and a second AC power supply; The first auxiliary circuit and the second auxiliary circuit are both mutual inductance circuits; The first shielding circuit and the second shielding circuit are used for electromagnetic field isolation; The display and input-output unit is used to set measurement parameters and display measurement results; The main control unit receives the measurement parameters set by the display and input-output unit, controls the on-off of the circuits in the first probe and the second probe through the first controller and the second controller, measures the square resistance values ​​of the first film layer and the second film layer in turn, and calculates the square resistance values ​​of the first film layer and the second film layer according to the measurement results of the first probe and the second probe.

2. The non-contact dual-probe square resistance measuring device according to claim 1, characterized in that: The first controller, under the control of the main control unit, controls the on-off connection between the first AC power supply and the first excitation circuit, the on-off connection between the first shielding circuit and the first excitation circuit, and the on-off connection between the first shielding circuit and the first auxiliary circuit; Under the control of the main control unit, the second controller controls the on-off connection between the second AC power supply and the second excitation circuit, the on-off connection between the second shielding circuit and the second excitation circuit, and the on-off connection between the second shielding circuit and the second auxiliary circuit.

3. The non-contact dual-probe square resistance measurement device according to claim 1, characterized in that: The first shielding circuit and the second shielding circuit both include a powered shielding shell, a multi-point grounding circuit and a filtering circuit.

4. The non-contact dual-probe square resistance measurement device according to claim 1, characterized in that: The non-contact dual-probe square resistance measuring device further comprises a transmission and support device, and the transmission and support device moves the sample to a detection range of the non-contact dual-probe square resistance measuring device.

5. A non-contact dual-probe square resistance measurement method, characterized in that: Applied to the non-contact dual-probe square resistance measurement device according to any one of claims 1 to 4, the method comprises the following steps: Step S1, adjusting the oscillation frequency of the excitation circuit and the height of the probe so that the penetration depth of the probe covers part of the substrate and does not penetrate into the film layer opposite to the sample; Step S2, setting a switching frequency for measuring the square resistance values ​​of the first film layer and the second film layer and a detection frequency of the probe; Step S3, controlling the on and off of the circuits in the first probe and the second probe according to the switching frequency, and measuring the square resistance values ​​of the first film layer and the second film layer in sequence; Step S4 , calculating the square resistance of the first film layer and the square resistance of the second film layer according to the square resistances measured by the first probe and the second probe and the square resistance of the substrate.

6. The non-contact dual-probe square resistance measurement method according to claim 5, characterized in that: In the step S1 , the oscillation frequency of the first excitation circuit is the same as the oscillation frequency of the second excitation circuit, and the vertical distance between the first probe and the sample is the same as the vertical distance between the second probe and the sample.

7. The non-contact dual-probe square resistance measuring device according to claim 6, characterized in that: The oscillation frequency of the first excitation circuit and the second excitation circuit is 1-100 MHz.

8. The non-contact dual-probe square resistance measurement method according to claim 5, characterized in that: In the step S2, the detection frequency of the first probe is the same as the detection frequency of the second probe, and the detection frequency is an integer multiple of the switching frequency.

9. The non-contact dual-probe square resistance measurement method according to claim 5, characterized in that: The specific method of step S3 is: When measuring the square resistance of the first film layer, controlling the first controller to connect the first excitation circuit to the first AC power supply and the first shielding circuit to the first auxiliary circuit, and controlling the second controller to disconnect the second excitation circuit from the second AC power supply and connect the second shielding circuit to the second excitation circuit; When measuring the square resistance value of the second film layer, the first controller is controlled to disconnect the first excitation circuit from the first AC power supply and connect the first shielding circuit to the first excitation circuit, and at the same time, the second controller is controlled to connect the second excitation circuit to the second AC power supply and connect the second shielding circuit to the second auxiliary circuit.

10. The non-contact dual-probe square resistance measurement method according to claim 5, characterized in that: The specific method of step S4 is: Assuming that the square resistance of the substrate is R0, when measuring the square resistance of the first film layer, the square resistance measured by the first probe is R1. If R0>R1, the square resistance of the first film layer RA=R1*R0 / (R0-R1); if R0<=R1, the square resistance of the first film layer RA=R1; when measuring the square resistance of the second film layer, the square resistance measured by the second probe is R2. If R0>R2, the square resistance of the second film layer RB=R2*R0 / (R0-R2); if R0<=R2, the square resistance of the second film layer RB=R2.

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