A thickness measurement system, method, electronic device, and storage medium

Abstract

This invention discloses a thickness measurement system, method, electronic device, and storage medium. The system includes an eddy current sensor, a driving circuit, a sampling feedback circuit, and a control unit. The eddy current sensor includes a first tap and multiple second taps. The driving circuit receives externally input control commands and generates an oscillating current based on the control commands. The driving circuit is connected to the eddy current sensor, which generates an alternating magnetic field based on the oscillating current. The alternating magnetic field senses the sample under test and generates a feedback value. The sampling feedback circuit acquires the feedback value from the eddy current sensor and inputs it to the control unit. The control unit controls the switching of the eddy current sensor's range based on changes in the feedback value. This invention, by setting multiple second taps in the eddy current sensor, enables the matching of the resonant frequency and parallel capacitance with optimal linearity and resolution for samples of different thicknesses, achieving impedance matching and frequency selection over a wide thickness range in hardware.

Description

Technical Field

[0001] This invention relates to the field of integrated circuit manufacturing technology, and more specifically to a thickness measurement system, device, electronic device, and storage medium. Background Technology

[0002] With the development of integrated circuit manufacturing technology, various processes have gradually strengthened the technical means of real-time feedback control of wafer surface morphology in order to improve overall process capability and product yield. The measurement of metal films on the surface of integrated circuit wafers is usually achieved by contact probe resistance measurement devices or non-contact eddy current sensors, while the eddy current sensor modules integrated into the process equipment are usually non-contact.

[0003] Generally, probe resistance measurement of metal film thickness involves measuring the sheet resistance of the metal film using a probe to calculate its thickness. This method is widely used in offline metal film measurement during semiconductor manufacturing due to its simplicity, reliability, high efficiency, and broad applicability. However, because this measurement method is contact-based, it can affect the wafer surface morphology and roughness, and introduce wafer contamination risks, making it unsuitable for the online measurement requirements of process equipment. Furthermore, the probe contact area limits the measurement range of the metal film at the wafer edge, creating measurement blind spots and preventing the acquisition of complete measurement data.

[0004] Eddy current measurement of metal film thickness typically involves applying an alternating voltage of a certain frequency to a sensor coil. This causes the LC circuit at the sensor end to oscillate, generating an alternating magnetic field. This alternating magnetic field creates an eddy current effect on the surface of the metal film being measured, forming a magnetic field opposite to that of the sensor coil. This alters the apparent impedance of the sensor coil, and by correlating the metal film thickness with relevant electrical parameters, the metal film thickness can be measured. This measurement method has advantages such as being non-contact, having a wide bandwidth, and high environmental tolerance, and is widely used in online measurement modules of process equipment. However, current mainstream eddy current online film thickness measurement systems still suffer from problems such as complex demodulation circuits with low stability, low linearity and resolution consistency across different thicknesses, and unreliable test results due to complex calibration processes. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of unreliable test results for samples of different thicknesses in the prior art, thereby providing a thickness measurement system, device, electronic device and storage medium.

[0006] According to a first aspect, the present invention discloses a thickness measurement system, comprising: an eddy current sensor, a driving circuit, a sampling feedback circuit, and a control unit. The eddy current sensor includes a first tap and multiple second taps, each second tap corresponding to a setting. The input terminal of the driving circuit receives an externally input control command and generates an oscillating current according to the control command. The output terminal of the driving circuit is connected to the eddy current sensor. The eddy current sensor generates an alternating magnetic field according to the oscillating current and senses the sample to be measured according to the alternating magnetic field to generate a feedback value. The sampling feedback circuit acquires the feedback value of the eddy current sensor and inputs the feedback value to the control unit. The control unit controls the switching of the setting of the eddy current sensor according to the change of the feedback value.

[0007] Optionally, the driving circuit includes: a clock circuit, a waveform generator, a power amplifier, an amplitude stabilization circuit, and a reference voltage circuit; the clock circuit inputs a clock signal to the waveform generator according to the control command of the control unit; the waveform generator generates a sinusoidal AC waveform according to the clock signal; the reference voltage circuit is connected to the amplitude stabilization circuit and inputs a reference voltage signal to the amplitude stabilization circuit; the power amplifier receives the sinusoidal AC waveform, amplifies it, and inputs it to the amplitude stabilization circuit; the amplitude stabilization circuit stabilizes the amplified sinusoidal AC waveform according to the reference voltage signal and outputs an oscillating current.

[0008] Optionally, the sampling feedback circuit includes: a small signal acquisition circuit, a small signal amplification circuit, an AC / DC conversion circuit, and an analog-to-digital conversion circuit connected in sequence.

[0009] Optionally, the thickness measurement system further includes a data processing unit; the data processing unit is connected to the control unit and is used to convert the feedback value into the thickness of the sample to be measured.

[0010] According to a second aspect, the present invention also discloses a thickness measurement method, applied to a thickness measurement system as described in the first aspect and any optional embodiment of the first aspect, the thickness measurement method comprising: acquiring a feedback value of a sample to be measured sensed by an eddy current sensor; determining whether to switch the current setting of the eddy current sensor based on the feedback value and the change of the feedback value at adjacent time intervals; and sensing the thickness of the sample to be measured at the next time interval based on the switched setting.

[0011] Optionally, obtaining the feedback value of the sample under test sensed by the eddy current sensor includes: obtaining the theoretical feedback value-thickness curve for each setting and the available thickness range corresponding to each setting; selecting the corresponding initial setting based on the initial thickness of the sample under test and the available thickness range; and sensing the feedback value of the sample under test based on the initial setting.

[0012] Optionally, determining whether to switch the current gear of the eddy current sensor based on the feedback value and the change of the feedback value at adjacent times includes: determining the actual slope between two adjacent feedback values ​​based on the feedback value; calculating the theoretical slope in the corresponding interval of the next gear based on the theoretical feedback value-thickness curve of the next gear based on the currently selected gear; and adjusting the eddy current sensor to the next gear when the difference between the actual slope and the theoretical slope is less than a preset slope difference threshold.

[0013] Optionally, obtaining the theoretical feedback value-thickness curve and the usable thickness range for each gear level includes: testing the theoretical feedback value of a standard sample at different gear levels of the eddy current sensor; fitting and generating the theoretical feedback value-thickness curve for each gear level based on the thickness of the standard sample and the theoretical feedback value; calculating the theoretical interval slope of the theoretical feedback value-thickness curve for each gear level in different intervals; and when the theoretical interval slope is greater than a preset usable slope threshold, using the corresponding interval as the usable thickness range for that gear level.

[0014] According to a third aspect, the present invention also discloses an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor to perform the steps of the thickness measurement method as described in the second aspect and any alternative embodiment of the second aspect.

[0015] According to a fourth aspect, the present invention also discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the thickness measurement method as described in the second aspect and any optional embodiment of the second aspect.

[0016] The technical solution of this invention has the following advantages:

[0017] 1. The thickness measurement system disclosed in this invention, by incorporating multiple second taps in the eddy current sensor, enables a single coil to provide multiple settings. This allows for real-time switching of the eddy current sensor settings based on the sample thickness, thereby achieving optimal linearity and resolution between the resonant frequency and parallel capacitance. This hardware-based implementation of impedance matching and frequency selection over a wide thickness range is achieved. A driving circuit provides alternating current to the eddy current sensor, enabling it to generate an alternating magnetic field. A sampling feedback circuit acquires minute changes occurring within the eddy current sensor and provides feedback via electrical signals.

[0018] 2. The thickness measurement system disclosed in this invention, by respectively setting up a clock circuit, a waveform generator, a power amplifier, an amplitude stabilization circuit, and a reference voltage circuit, can provide an alternating current of suitable amplitude to the eddy current sensor, enabling it to generate the required alternating magnetic field. By separately setting up a micro-signal acquisition circuit, a micro-signal amplification circuit, an AC / DC conversion circuit, and an analog-to-digital conversion circuit, it can acquire minute changes in the eddy current sensor and ultimately convert them into digital signals, achieving precise visualization of the measurement. By setting up a data processing unit, it can convert the electrical signal into the thickness of the sample to be measured and display it to the user, realizing human-computer interaction in the thickness measurement system.

[0019] 3. The thickness measurement method disclosed in this invention switches the range of the eddy current sensor according to the changes in the feedback value and the feedback value at adjacent time moments. It can utilize the optimal matching relationship between frequency and film thickness to complete a large range of metal film thickness changes and realize high linearity and high resolution real-time thickness monitoring throughout the frequency conversion process.

[0020] 4. The thickness measurement method disclosed in this invention correlates the feedback data with the segmented thickness of the metal film through a theoretical feedback value-thickness curve, achieving high linearity and high resolution real-time thickness monitoring over a large range. It exhibits high repeatability and consistency, and is simpler and more reliable than complex circuitry for frequency conversion. By using slope tracking comparison logic, frequency switching is achieved at appropriate times, completing a frequency conversion algorithm that reasonably balances linearity and resolution over a large range. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram illustrating a specific example of the thickness measurement system in an embodiment of the present invention.

[0023] Figure 2 This is a schematic diagram of another specific example of the thickness measurement system in this invention.

[0024] Figure 3 This is a schematic diagram of another specific example of the thickness measurement system in this invention.

[0025] Figure 4 This is a schematic diagram of another specific example of the thickness measurement system in this invention.

[0026] Figure 5This is a flowchart illustrating a specific example of the thickness measurement method in an embodiment of the present invention;

[0027] Figure 6 This is a flowchart illustrating another specific example of the thickness measurement method in this invention.

[0028] Figure 7 This is a flowchart illustrating another specific example of the thickness measurement method in this invention.

[0029] Figure 8 This is a specific example diagram of an electronic device in an embodiment of the present invention. Detailed Implementation

[0030] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0032] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can also refer to the internal connection of two components; and they can refer to a wireless connection or a wired connection. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0033] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0034] This invention discloses a thickness measurement system, such as... Figure 1As shown, the system includes: an eddy current sensor 1, a drive circuit 2, a sampling feedback circuit 3, and a control unit 4. The eddy current sensor 1 includes a first tap 11 and multiple second taps 12, each second tap 12 corresponding to a gear position. The input terminal of the drive circuit 2 receives externally input control commands and generates an oscillating current according to the control commands. The output terminal of the drive circuit 2 is connected to the eddy current sensor 1. The eddy current sensor 1 generates an alternating magnetic field according to the oscillating current and senses the sample under test according to the alternating magnetic field to generate a feedback value. The sampling feedback circuit 3 collects the feedback value of the eddy current sensor 1 and inputs the feedback value to the control unit 4. The control unit 4 controls the switching of the gear positions of the eddy current sensor 1 according to the changes in the feedback value.

[0035] Specifically, the control unit 4 controls the drive circuit 2 to generate a sinusoidal AC waveform and output it to both ends of the eddy current sensor 1. The eddy current sensor 1 generates an alternating magnetic field based on the sinusoidal AC waveform. This magnetic field interacts with the sample under test, causing a change in the apparent impedance of the coil in the eddy current sensor 1. The change in the apparent impedance of the coil in the eddy current sensor 1 is measured by the sampling feedback circuit 3. The change in the feedback value reflects the change in the thickness of the wafer metal film of the sample under test. When the wafer metal film interacts with the eddy current sensor 1 during the thinning process, the number of coil turns is switched by adjusting the position corresponding to the second tap 12 in the eddy current sensor 1, thereby adjusting the inductance. This achieves the optimal resonant frequency and parallel capacitance for linearity and resolution within different thickness ranges, realizing impedance matching and frequency selection over a wide thickness range from a hardware perspective.

[0036] The thickness measurement system disclosed in this invention, by incorporating multiple second taps in the eddy current sensor, enables a single coil to provide multiple settings. This allows for real-time switching of the eddy current sensor settings based on sample thickness, thereby achieving optimal linearity and resolution with the resonant frequency and parallel capacitance. This hardware-based implementation of impedance matching and frequency selection over a wide thickness range is achieved. A driving circuit provides alternating current to the eddy current sensor, enabling it to generate an alternating magnetic field. A sampling feedback circuit acquires minute changes occurring within the eddy current sensor and provides feedback via electrical signals.

[0037] As an optional embodiment of the present invention, such as Figure 2As shown, the driving circuit 2 includes: a clock circuit 21, a waveform generator 22, a power amplifier 23, an amplitude stabilization circuit 24, and a reference voltage circuit 25. The clock circuit 21 inputs a clock signal to the waveform generator 22 according to the control command of the control unit 4. The waveform generator 22 generates a sinusoidal AC waveform according to the clock signal. The reference voltage circuit 25 is connected to the amplitude stabilization circuit 24 and inputs a reference voltage signal to the amplitude stabilization circuit 24. The power amplifier 23 receives the sinusoidal AC waveform, amplifies it, and then inputs it to the amplitude stabilization circuit 24. The amplitude stabilization circuit 24 stabilizes the amplified sinusoidal AC waveform according to the reference voltage signal and outputs an oscillating current.

[0038] The clock circuit 21 is capable of generating an oscillating circuit that moves as accurately as a clock, producing pulse current at a standard frequency. The clock circuit typically consists of a crystal oscillator, a crystal control chip, and a capacitor. Specifically, the clock circuit can be implemented using a crystal oscillator containing a quartz crystal, or other clock circuit structures from the prior art can be selected; this invention does not limit the choice of these structures.

[0039] The waveform generator 22 generates a sinusoidal waveform signal with a periodic time function according to the pulse current frequency of the clock circuit, providing alternating current for the eddy current sensor 1. Specifically, the waveform generator 22 can first connect a hysteresis comparator and an integral comparator end to end to form a positive feedback closed-loop system, and then convert the triangular wave into a sine wave through low-pass filtering. Other waveform generator structures in the prior art can also be used, and the present invention does not limit them.

[0040] The power amplifier 23 is capable of generating maximum power output to drive the eddy current sensor 1 under a given distortion rate. It amplifies the alternating current generated by the waveform generator 22 to achieve the required current amplitude to drive the eddy current sensor 1. Specifically, the power amplifier 23 can utilize the current control of a transistor or the voltage control of a field-effect transistor to convert power, or it can use other power amplifier structures in the prior art; this invention does not limit its application to these methods.

[0041] The amplitude stabilization circuit 24 uses the reference voltage provided by the reference circuit 25 as a threshold to stabilize the amplitude of the alternating current signal amplified by the power amplifier, preventing distortion during amplification. Specifically, the amplitude stabilization circuit 24 can employ a thermistor or other limiting circuits; this invention does not limit its application to these methods.

[0042] The reference circuit 25 provides a stable reference voltage to the amplitude stabilization circuit 24 after being connected to the circuit, so that the amplitude stabilization circuit can use this reference voltage as a reference voltage for amplitude stabilization. In particular, the reference circuit 25 can be selected from existing voltage reference chips or other reference circuits, and the present invention does not limit this.

[0043] As an optional embodiment of the present invention, such as Figure 3 As shown, the sampling feedback circuit 3 includes: a small signal acquisition circuit 31, a small signal amplification circuit 32, an AC / DC conversion circuit 33, and an analog-to-digital conversion circuit 34 connected in sequence.

[0044] The micro-signal acquisition circuit 31 is capable of acquiring minute voltage and current changes. Because the apparent impedance of the coil in the eddy current sensor 1 changes due to variations in the thickness of the wafer's metal film, and this change in apparent impedance can be reflected by minute voltage and current changes, the micro-signal acquisition circuit 31 can acquire these minute voltage and current changes to obtain the change in the apparent impedance of the coil in the eddy current sensor 1. Specifically, the micro-signal acquisition circuit 31 can be composed of a minute current signal acquisition circuit and a minute voltage signal acquisition circuit, or it can employ other signal acquisition circuits from the prior art; this invention does not limit its application to these methods.

[0045] The micro-signal amplification circuit 32 amplifies the micro-signal acquired by the micro-signal acquisition circuit 31 for subsequent signal processing steps. Specifically, the micro-signal amplification circuit 32 can be implemented using existing operational amplifiers or integrated amplifiers, and this invention does not limit its implementation to these components.

[0046] The AC / DC conversion circuit 33 can accurately convert the effective value of the amplified AC signal into a DC signal output for analog-to-digital conversion. Specifically, the AC / DC conversion circuit 33 can be implemented using a rectifier circuit composed of multiple rectifier diodes, or it can be implemented using other components such as existing AC / DC converters; this invention does not limit its implementation in this regard.

[0047] The analog-to-digital converter circuit 34 samples the DC signal converted by the AC-DC converter circuit 33 and then quantizes and encodes it into a binary digital signal for processing by the control unit. Specifically, the analog-to-digital converter circuit 34 can be implemented using an existing analog-to-digital converter (ADC), or other analog-to-digital conversion components; this invention does not limit its implementation in this regard.

[0048] As an optional embodiment of the present invention, such as Figure 4As shown, the thickness measurement system further includes a data processing unit 5; the data processing unit 5 is connected to the control unit 4 and is used to convert the feedback value into the thickness of the sample to be measured.

[0049] Specifically, the data processing unit 5 can be a computer or microcontroller capable of directly sending operation commands, and can provide a user interface to display feedback data to the user. Through a host computer algorithm, the feedback value can be converted into the thickness of the sample to be measured.

[0050] The thickness measurement system disclosed in this invention, by separately incorporating a clock circuit, waveform generator, power amplifier, amplitude stabilization circuit, and reference voltage circuit, can provide an alternating current of suitable amplitude to the eddy current sensor, enabling it to generate the required alternating magnetic field. By separately incorporating a micro-signal acquisition circuit, a micro-signal amplification circuit, an AC / DC conversion circuit, and an analog-to-digital conversion circuit, it can acquire minute changes in the eddy current sensor and ultimately convert them into digital signals, achieving precise visualization of the measurement. By including a data processing unit, it can convert the electrical signal into the thickness of the sample to be measured and display it to the user, realizing human-computer interaction in the thickness measurement system.

[0051] This invention also discloses a thickness measurement method, applied to a thickness measurement system as described in the system embodiments of this invention and any optional implementation thereof, such as... Figure 5 As shown, the thickness measurement method includes the following steps:

[0052] Step S1: Obtain the feedback value of the sample under test sensed by the eddy current sensor.

[0053] Specifically, the eddy current sensor in the thickness measurement system generates an alternating magnetic field based on the sinusoidal AC waveform generated by the drive circuit 2. This magnetic field interacts with the sample under test, causing a change in the apparent impedance of the coil in the eddy current sensor 1. The feedback value is obtained by measuring the change in the apparent impedance of the coil in the eddy current sensor 1 through the sampling feedback circuit 3.

[0054] Step S2: Based on the feedback value and the changes in the feedback value at adjacent time points, determine whether to switch the current gear of the eddy current sensor.

[0055] Specifically, the sample thickness at the current moment can be determined based on the feedback value, and the resolution of the current setting can be determined based on the changes in the feedback value at adjacent moments. By selecting and switching to the appropriate setting based on the thickness and resolution, it is possible to achieve a suitable resonant frequency and impedance matching at the current thickness value, thereby ensuring linearity and resolution during the measurement process.

[0056] Step S3: Sensing the thickness of the sample to be measured at the next moment based on the switched gear.

[0057] Further, repeat steps S1-S3 until the preset final thickness is reached, thus completing the thickness measurement process.

[0058] The thickness measurement method disclosed in this invention switches the range of the eddy current sensor according to the changes in the feedback value and the feedback value at adjacent time moments. It can complete a large range of metal film thickness changes by utilizing the optimal matching relationship between frequency and film thickness, and realize high linearity and high resolution real-time thickness monitoring throughout the frequency conversion process.

[0059] As an optional embodiment of the present invention, such as Figure 6 As shown, obtaining the feedback value of the sample under test sensed by the eddy current sensor includes the following steps:

[0060] Step S11: Obtain the theoretical feedback value-thickness curve for each gear level and the available thickness range for each gear level.

[0061] Specifically, the process of obtaining the theoretical feedback value-thickness curve for each setting and the corresponding usable thickness range for each setting can be achieved by first testing the theoretical feedback value of a standard sample at different settings of the eddy current sensor; then, based on the thickness of the standard sample and the theoretical feedback value, a theoretical feedback value-thickness curve for each setting is fitted and generated; next, the theoretical interval slope of the theoretical feedback value-thickness curve for each setting is calculated in different intervals; finally, when the theoretical interval slope is greater than a preset usable slope threshold, the corresponding interval is taken as the usable thickness range for that setting. In particular, the standard sample refers to a sample with a known and uniform thickness.

[0062] The process of obtaining the theoretical feedback value-thickness curve for each gear can be achieved by first selecting a corresponding number of standard samples based on the required thickness range for measurement; then using the standard samples, the theoretical feedback values ​​are tested at different eddy current sensor gears; finally, the theoretical feedback value-thickness curve for each gear is generated by fitting the thickness of the standard samples and the corresponding theoretical feedback values.

[0063] For example, taking a measurement range of 0-10000 nm as an example, standard samples with thicknesses of 2000 nm, 4000 nm, 6000 nm, 8000 nm, and 10000 nm are selected at 2000 nm intervals. The eddy current sensor is set to the first setting, and the above five samples are measured sequentially to obtain the corresponding five theoretical feedback values ​​sensed by the eddy current sensor. These five theoretical feedback values ​​are then fitted to generate the feedback value-thickness curve for the first setting. Similarly, by setting the eddy current sensor to each setting and repeating the above process, the feedback value-thickness curve for each setting can be generated. Specifically, the higher the required accuracy for thickness measurement, the smaller the thickness interval of the standard samples, and the more standard samples need to be selected; conversely, the lower the required accuracy for thickness measurement, the larger the thickness interval of the standard samples, and the fewer standard samples need to be selected. The selection interval and number of standard samples can be selected according to the actual required accuracy, and this invention does not limit this.

[0064] The process of obtaining the thickness available range corresponding to each gear level can be as follows: First, calculate the theoretical interval slope between any two points based on the feedback value-thickness curve for each gear level. Then, when the theoretical interval slope is greater than a preset available slope threshold, the corresponding interval is taken as the thickness available range for that gear level. Alternatively, based on the preset available slope threshold, traverse the line connecting any two points in the feedback value-thickness curve to find the interval corresponding to the theoretical interval slope being greater than the preset available slope threshold, and take the corresponding interval as the thickness available range for that gear level.

[0065] Step S12: Select the corresponding initial setting based on the initial thickness of the sample to be tested and the available thickness range.

[0066] Specifically, based on the initial thickness of the sample to be tested, the available thickness range of each setting is traversed, and the setting with the highest frequency that includes the initial thickness within the available thickness range is selected as the initial setting. In particular, the initial thickness of the sample to be tested can be coarsely measured by selecting the setting with the highest frequency of the eddy current sensor, or it can be obtained by other detection methods; this invention does not limit this.

[0067] Step S13: Obtain the feedback value of the sample to be tested based on the initial gear position sensor.

[0068] As an optional embodiment of the present invention, such as Figure 7 As shown, determining whether to switch the current setting of the eddy current sensor based on the feedback value and the changes in the feedback value at adjacent time points includes the following steps:

[0069] Step S21: Determine the actual slope between two adjacent feedback values ​​based on the feedback value.

[0070] Specifically, the actual slope of the current measurement curve is calculated based on the current feedback value and the feedback value at the previous moment.

[0071] Step S22: Based on the currently selected gear, calculate the theoretical slope within the corresponding interval of the next gear according to the theoretical feedback value-thickness curve of the next gear.

[0072] Specifically, the current thickness value and the previous thickness value are obtained based on the current feedback value and the previous feedback value. Then, based on the theoretical feedback value-thickness curve of the next gear, the theoretical slope within the interval between the current thickness value and the previous thickness value is calculated.

[0073] Step S23: When the difference between the actual slope and the theoretical slope is less than a preset slope difference threshold, the eddy current sensor is adjusted to the next level.

[0074] Specifically, when the difference between the actual slope and the theoretical slope is less than a preset slope difference threshold, it can be considered that the current actual slope matches the theoretical slope of the next gear. At this time, switching can minimize the impact of gear switching.

[0075] The thickness measurement method disclosed in this invention correlates feedback data with the metal film thickness in segments through a theoretical feedback value-thickness curve, achieving high linearity and high resolution real-time thickness monitoring over a large range. It exhibits high repeatability and consistency, and is simpler and more reliable than frequency conversion achieved through complex circuit changes. By using slope tracking comparison logic, frequency switching is achieved at appropriate times, completing a frequency conversion algorithm that reasonably balances linearity and resolution over a large range.

[0076] This invention also provides an electronic device, such as... Figure 8 As shown, the electronic device may include a processor 101 and a memory 102, wherein the processor 101 and the memory 102 may be connected via a bus or other means. Figure 8 Taking the example of a connection between China and Israel via a bus.

[0077] Processor 101 may be a central processing unit (CPU). Processor 101 may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof.

[0078] The memory 102, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the thickness measurement system in the embodiments of the present invention. The processor 101 executes various functional applications and data processing of the processor by running the non-transitory software programs, instructions, and modules stored in the memory 102, thereby realizing the thickness measurement system in the above method embodiments.

[0079] The memory 102 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created by the processor 101, etc. Furthermore, the memory 102 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 102 may optionally include memory remotely located relative to the processor 101, and these remote memories may be connected to the processor 101 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0080] One or more modules are stored in memory 102, and when executed by processor 101, they perform actions such as... Figure 5 The thickness measurement system in the illustrated embodiment.

[0081] While exemplary embodiments and their advantages have been described in detail, those skilled in the art can make various changes, substitutions, and modifications to these embodiments without departing from the spirit of the invention and the scope of protection defined by the appended claims. Such modifications and variations all fall within the scope defined by the appended claims. For other examples, those skilled in the art should readily understand that the order of process steps can be changed while remaining within the scope of the invention.

[0082] Furthermore, the scope of this invention is not limited to the processes, mechanisms, manufacturing methods, material compositions, means, methods, and steps of the specific embodiments described in the specification. From the disclosure of this invention, those skilled in the art will readily understand that any existing or future processes, mechanisms, manufacturing methods, material compositions, means, methods, or steps that perform substantially the same function or obtain substantially the same results as the corresponding embodiments described in this invention can be applied according to this invention. Therefore, the appended claims are intended to include these processes, mechanisms, manufacturing methods, material compositions, means, methods, or steps within their scope of protection.

Claims

1. A thickness measurement system, characterized in that, include: The system includes an eddy current sensor, a drive circuit, a sampling feedback circuit, and a control unit. The eddy current sensor includes a first tap and multiple second taps, with each second tap corresponding to a gear position. The input terminal of the driving circuit receives external control commands and generates an oscillating current according to the control commands. The output terminal of the driving circuit is connected to the eddy current sensor. The eddy current sensor generates an alternating magnetic field according to the oscillating current and generates a feedback value based on the sample to be tested according to the alternating magnetic field. The sampling feedback circuit collects the feedback value of the eddy current sensor and inputs the feedback value to the control unit. The control unit controls the switching of the eddy current sensor's range according to the change of the feedback value. The sampling feedback circuit specifically acquires the feedback value of the eddy current sensor, including: Obtain the theoretical feedback value for each gear level – the thickness curve and the available thickness range for each gear level; Select the corresponding initial setting based on the initial thickness of the sample to be tested and the available thickness range; The feedback value of the sample to be tested is obtained based on the initial gear position sensor. The process of obtaining the theoretical feedback value-thickness curve for each gear level and the usable thickness range for each gear level includes: The theoretical feedback values ​​of the standard sample were measured at different settings of the eddy current sensor. Based on the thickness of the standard sample and the theoretical feedback value, a theoretical feedback value-thickness curve is generated for each grade. Calculate the theoretical feedback value for each gear level and the theoretical slope of the thickness curve in different intervals. When the slope of the theoretical interval is greater than the preset available slope threshold, the corresponding interval will be used as the available thickness interval for that grade. Specifically, the control unit determines whether to switch the current setting of the eddy current sensor based on the feedback value and the changes in the feedback value at adjacent time moments; and senses the thickness of the sample to be measured at the next time moment based on the switched setting. Based on the feedback value and the changes in feedback values ​​at adjacent time points, determine whether to switch the current setting of the eddy current sensor, including: The actual slope between two adjacent feedback values ​​is determined based on the feedback value; Based on the currently selected gear, calculate the theoretical slope within the corresponding interval of the next gear according to the theoretical feedback value-thickness curve of the next gear; When the difference between the actual slope and the theoretical slope is less than a preset slope difference threshold, the eddy current sensor is adjusted to the next level.

2. The thickness measurement system according to claim 1, characterized in that, The driving circuit includes: a clock circuit, a waveform generator, a power amplifier, an amplitude stabilization circuit, and a reference voltage circuit; The clock circuit inputs a clock signal to the waveform generator according to the control command of the control unit; the waveform generator generates a sinusoidal AC waveform according to the clock signal; The reference voltage circuit is connected to the amplitude stabilization circuit and inputs a reference voltage signal to the amplitude stabilization circuit; the power amplifier receives the sinusoidal AC waveform, amplifies it, and then inputs it to the amplitude stabilization circuit; the amplitude stabilization circuit stabilizes the amplified sinusoidal AC waveform according to the reference voltage signal and outputs an oscillating current.

3. The thickness measurement system according to claim 1, characterized in that, The sampling feedback circuit includes: a small signal acquisition circuit, a small signal amplification circuit, an AC / DC conversion circuit, and an analog-to-digital conversion circuit connected in sequence.

4. The thickness measurement system according to claim 1, characterized in that, Also includes: Data processing unit; The data processing unit is connected to the control unit and is used to convert the feedback value into the thickness of the sample to be measured.

5. A thickness measurement method, characterized in that, The thickness measurement method, applied to the thickness measurement system as described in any one of claims 1-4, comprises: Obtain the feedback value of the sample under test sensed by the eddy current sensor; Obtain the feedback value of the sample under test sensed by the eddy current sensor, including: Obtain the theoretical feedback value for each gear level – the thickness curve and the available thickness range for each gear level; Select the corresponding initial setting based on the initial thickness of the sample to be tested and the available thickness range; The feedback value of the sample to be tested is obtained based on the initial gear position sensor. The process of obtaining the theoretical feedback value-thickness curve for each gear level and the usable thickness range for each gear level includes: The theoretical feedback values ​​of the standard sample were measured at different settings of the eddy current sensor. Based on the thickness of the standard sample and the theoretical feedback value, a theoretical feedback value-thickness curve is generated for each grade. Calculate the theoretical feedback value for each gear level and the theoretical slope of the thickness curve in different intervals. When the slope of the theoretical interval is greater than the preset available slope threshold, the corresponding interval will be used as the available thickness interval for that grade. Based on the feedback value and the changes in the feedback value at adjacent time points, determine whether to switch the current setting of the eddy current sensor; The thickness of the sample to be measured is sensed at the next moment based on the switched gear. Based on the feedback value and the changes in feedback values ​​at adjacent time points, determine whether to switch the current setting of the eddy current sensor, including: The actual slope between two adjacent feedback values ​​is determined based on the feedback value; Based on the currently selected gear, calculate the theoretical slope within the corresponding interval of the next gear according to the theoretical feedback value-thickness curve of the next gear; When the difference between the actual slope and the theoretical slope is less than a preset slope difference threshold, the eddy current sensor is adjusted to the next level.

6. An electronic device, characterized in that, include: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to cause the at least one processor to perform the steps of the thickness measurement method as described in claim 5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the thickness measurement method as described in claim 5.

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