An ambient temperature influence compensation device and method for near-field temperature measurement using a tuning fork FBG probe.

Abstract

This invention discloses a device and method for compensating for the influence of ambient temperature on near-field temperature measurement using a tuning fork FBG probe, belonging to the fields of fiber optic sensing, scanning probe microscopy, and micro / nano-scale temperature detection. The device includes a tuning fork FBG probe, a reference FBG, a tuning fork signal conditioning and acquisition module, a tuning fork frequency offset demodulation module, an FBG wavelength demodulation module, a frequency offset decoupling and Z-axis feedback control module, a Z-axis displacement driving module, and a Z-axis displacement execution module. The tuning fork FBG probe is used to acquire near-field temperature information of the sample, and the reference FBG is used to characterize the ambient temperature changes of the quartz tuning fork. This invention provides two compensation methods: real-time compensation during scanning and post-scanning compensation. Real-time compensation achieves Z-axis feedback control by separating the tuning fork temperature frequency offset; post-scanning compensation combines Z-axis height change and axial temperature distribution model to correct the temperature measurement results. This invention can reduce the influence of ambient temperature changes on near-field temperature measurement results and is suitable for chip local overheating analysis, thermal failure research of micro / nano devices, and near-field temperature detection in open environments.

Description

Technical Field

[0001] This invention belongs to the fields of fiber optic sensing, scanning probe microscopy, and micro / nano-scale temperature detection, specifically relating to a method and device for compensating for the influence of ambient temperature on near-field temperature measurement using a tuning fork FBG probe. Background Technology

[0002] Micro- and nano-sized devices within chips are prone to localized overheating during operation. This localized overheating can alter the device's operating state and potentially induce performance degradation or failure. Therefore, acquiring temperature information of micro- and nano-sized regions during device operation is crucial for analyzing localized heating and thermal failure issues. Far-field optical thermometry methods such as infrared, thermal reflection, and Raman spectroscopy can be used for temperature characterization, but their spatial resolution is limited by the optical diffraction limit. When the measured area is scaled down to the micro- and nano-scale, near-field thermometry methods based on scanning probe microscopy are more suitable for acquiring localized temperature information. Using a tuning fork fiber Bragg grating (FBG) probe, local information about the sample surface can be acquired under atomic force microscopy feedback. In this thermometry method, the quartz tuning fork acts as a mechanical feedback element, sensing the interaction between the probe tip and the sample and converting this interaction into a change in resonant frequency. The feedback system adjusts the relative position of the probe and the sample based on this frequency change to maintain a near-field distance. The FBG probe acts as a temperature sensor, characterizing the temperature information at the tip location through changes in the center wavelength. Thus, the quartz tuning fork is used to maintain the near-field measurement state, and the FBG probe is used to acquire near-field temperature information; together, they constitute the tuning fork FBG probe near-field thermometry method.

[0003] However, when performing near-field temperature measurement on the working device in an open environment, the sample's self-heating not only changes the sample surface temperature but also alters the ambient temperature of the quartz tuning fork through heat transfer. The resonant frequency of the quartz tuning fork drifts with changes in ambient temperature. Since the feedback system relies on the tuning fork frequency offset to maintain the near-field distance between the probe and the sample, the tuning fork temperature frequency offset caused by the ambient temperature, along with the tip-sample interaction frequency offset, enters the feedback loop, causing the feedback system to misjudge the relative position of the probe and the sample, and resulting in the Z-axis feedback position deviating from the set operating point. For near-field temperature measurement, there is usually an axially varying temperature distribution above the sample; changes in the probe position will cause the FBG probe to be at different axial temperature positions above the sample, thus causing deviations in the near-field temperature measurement results.

[0004] To address the temperature drift problem in scanning probe systems, existing technologies typically reduce the impact of ambient temperature by improving system thermal stability, such as using low thermal expansion structures, enclosed temperature-controlled environments, low-temperature high-vacuum conditions, or specially structured tuning forks. These methods can improve system stability to some extent, but often require additional structures, specific environmental conditions, or special processes to fabricate the tuning forks, making them difficult to directly apply to in-situ near-field temperature measurement of the working device in an open environment.

[0005] Therefore, it is necessary to propose a method and device for compensating for the influence of ambient temperature on near-field temperature measurement of tuning fork FBG probes. Without changing its basic near-field temperature measurement method, the method can characterize the changes in ambient temperature of the quartz tuning fork, separate the frequency deviation of tuning fork temperature caused by ambient temperature, and compensate for the near-field temperature measurement deviation caused by changes in feedback position. Summary of the Invention

[0006] The purpose of this invention is to address the problem that ambient temperature changes cause frequency deviations in the temperature of the quartz tuning fork during near-field temperature measurement using a tuning fork FBG probe in an open environment, further affecting the Z-axis feedback position and near-field temperature measurement results. This invention provides a method and apparatus for compensating for the influence of ambient temperature during near-field temperature measurement using a tuning fork FBG probe. Without altering the basic near-field temperature measurement method of the tuning fork FBG probe, this method and apparatus utilize a reference FBG to characterize the ambient temperature changes of the quartz tuning fork, and combines temperature calibration relationships, frequency deviation separation, and position compensation to correct for the influence of ambient temperature.

[0007] The technical solution of this invention: An environmental temperature influence compensation device for near-field temperature measurement of a tuning fork FBG probe includes a quartz tuning fork 10, on which an FBG probe 9 and a reference FBG 8 are mounted. Both the FBG probe 9 and the reference FBG 8 are connected to an FBG wavelength demodulation module 7. The FBG wavelength demodulation module 7 obtains the center wavelengths of the FBG probe 9 and the reference FBG 8 and sends them to a control module 3. The quartz tuning fork 10 is connected to a tuning fork signal conditioning and acquisition module 1. The tuning fork signal conditioning and acquisition module 1 sends the response signal of the quartz tuning fork to a tuning fork frequency offset demodulation module 2. The tuning fork frequency offset demodulation module 2 obtains the total frequency offset of the quartz tuning fork 10 and sends it to the control module 3. The control module 3 receives the total frequency offset of the quartz tuning fork and the center wavelength information of the reference FBG 8, obtains the environmental temperature change of the quartz tuning fork 10 based on the change in the center wavelength of the reference FBG 8, and calculates the tuning fork temperature frequency offset in conjunction with the quartz tuning fork temperature calibration relationship, separating the tip-sample interaction frequency offset from the total frequency offset.

[0008] The control module 3 generates a Z-axis feedback control quantity based on the difference between the sample's applied frequency deviation and the set frequency deviation working point, and sends it to the Z-axis displacement drive module 4. The Z-axis displacement drive module 4 controls the displacement execution module 5 to adjust the relative position between the FBG probe 9 and the sample 6 to be tested.

[0009] A method for compensating for the influence of ambient temperature on near-field temperature measurement using a tuning fork FBG probe includes: S101 Installs an FBG probe and a reference FBG on the quartz tuning fork; S102 Place the quartz tuning fork in a uniform temperature field and establish the calibration relationship between the center wavelength of the FBG probe and temperature, the center wavelength of the reference FBG and temperature, and the frequency deviation of the quartz tuning fork and temperature. S103 sets the driving parameters and parasitic capacitance compensation parameters of the quartz tuning fork to stabilize the oscillation, and sets the tuning fork frequency deviation operating point for near-field feedback. S104 brings the FBG probe closer to the sample surface and performs Z-axis feedback based on the tip-sample interaction frequency deviation, thus entering the near-field temperature measurement state. S105 uses real-time compensation during scanning or post-scanning processing compensation to compensate for near-field temperature measurement deviations caused by ambient temperature. S106 outputs the compensated near-field temperature measurement results.

[0010] The real-time compensation during scanning in step S105 includes: acquiring the total frequency deviation of the quartz tuning fork and the center wavelength of the reference FBG; obtaining the ambient temperature change of the quartz tuning fork from the change in the center wavelength of the reference FBG; calculating the tuning fork temperature frequency deviation based on the tuning fork temperature calibration relationship; and separating the tip-sample interaction frequency deviation from the total frequency deviation of the quartz tuning fork for Z-axis feedback control. The specific real-time compensation steps during scanning include: S301 brings the FBG probe close to the surface of the sample to be tested and enters the near-field temperature measurement state at the set frequency offset operating point. S302A collects the total frequency deviation of a quartz tuning fork. ; S302B acquires the reference FBG center wavelength and the FBG probe center wavelength; S303 obtains the ambient temperature change of the quartz tuning fork from the change of the center wavelength of the reference FBG based on the temperature calibration relationship of the reference FBG. S304 Calculates the temperature frequency deviation of the tuning fork caused by changes in ambient temperature based on the temperature calibration relationship of the quartz tuning fork. ; S305 separates the tip-sample interaction frequency from the total frequency deviation of a quartz tuning fork. ; S306 will The Z-axis feedback control value is generated based on the comparison result and compared with the set frequency offset operating point to adjust the relative position between the FBG probe and the sample. The S307 acquires the center wavelength of the FBG probe and outputs the near-field temperature measurement results.

[0011] The post-scanning compensation in step S105 includes: establishing an axial temperature distribution model above the sample, acquiring Z-axis height data under reference and working conditions, calculating the Z-axis height change at the same scanning position, and correcting the FBG probe center wavelength result or near-field temperature measurement result based on the Z-axis height change and the axial temperature distribution model. Specific post-scanning compensation steps include: S201 Establish an axial temperature distribution model above the sample to be tested; The S202A performs a reference state scan on the area to be measured to obtain the Z-axis height data under the reference state. ; The S202B performs a working state scan on the same area to obtain the Z-axis height data under working conditions. and FBG probe center wavelength data ; S203 performs position registration on the reference state scan data and the working state scan data, and calculates the Z-axis height change at the same scan position. ; S204 will Substitute the axial temperature distribution model above the sample into the model to calculate the local temperature difference caused by the position change of the FBG probe. S205 Based on the temperature calibration relationship of the FBG probe, the local temperature difference is converted into a temperature compensation amount or a center wavelength compensation amount. The center wavelength of the FBG probe was corrected, and the result was adjusted: the compensated center wavelength of the FBG probe. ; S206 outputs the compensated near-field temperature measurement results.

[0012] The beneficial effects of this invention are: (1) The present invention uses a reference FBG to characterize the temperature change of the environment where the quartz tuning fork is located. The FBG probe and the reference FBG can be demodulated by the same FBG wavelength demodulation module, and two center wavelength information can be obtained simultaneously by wavelength division multiplexing. There is no need to set up an independent temperature demodulation module. The structure is compact and easy to integrate with the tuning fork FBG probe.

[0013] (2) The present invention introduces the change in ambient temperature of the quartz tuning fork into the feedback compensation process, which can reduce the interference of the tuning fork temperature frequency deviation caused by ambient temperature on the tip-sample interaction frequency deviation, and make the frequency deviation based on the Z-axis feedback control closer to the tip-sample interaction itself, thereby reducing the impact of feedback position offset on near-field temperature measurement results.

[0014] (3) The present invention provides two methods: real-time compensation during scanning and post-scanning compensation. Real-time compensation during scanning can separate the frequency deviation of the tuning fork temperature during the measurement process, making the Z-axis feedback control closer to the set working state; post-scanning compensation can correct the acquired near-field temperature measurement results without changing the original scanning control link, and is suitable for different measurement systems and data processing needs.

[0015] (4) This invention does not require a closed temperature control cavity, a low temperature and high vacuum environment, a low thermal expansion main structure or a special process tuning fork as necessary conditions. It can be implemented in a tuning fork FBG probe near-field temperature measurement system in an open environment. It is suitable for local overheating analysis, thermal failure research and near-field temperature detection of self-heating samples of micro and nano devices in chips. Attached Figure Description

[0016] Figure 1 A schematic diagram of an environmental temperature influence compensation device used for near-field temperature measurement of tuning fork FBG probes. In the attached diagram: 1- Tuning fork signal conditioning and acquisition module, 2- Tuning fork frequency offset demodulation module, 3- Control module (frequency offset decoupling and Z-axis feedback control module), 4- Z-axis displacement drive module, 5- Z-axis displacement execution module, 6- Sample under test, 7- FBG wavelength demodulation module, 8- Reference FBG, 9- FBG probe, 10- Quartz tuning fork.

[0017] Figure 2 This is a flowchart of the environmental temperature influence compensation method for near-field temperature measurement using a tuning fork FBG probe. Figure 3 Flowchart for post-scan processing compensation for the influence of ambient temperature; Figure 4 Flowchart for real-time compensation during scanning for the effects of ambient temperature; Figure 5 The image shows the calibration results of the tuning fork FBG probe, reference FBG, and quartz tuning fork under a uniform temperature field. Figure 5 (a) shows the calibration results between the center wavelength of the FBG probe and temperature. Figure 5 (b) For reference, the calibration results between the center wavelength of the FBG and temperature. Figure 5 (c) shows the calibration results between the frequency deviation of the quartz tuning fork and temperature; Figure 6 This is a comparison chart of near-field temperature measurement results before and after post-scanning processing compensation. Detailed Implementation

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments. The following examples are used to illustrate the technical solutions of the present invention. Equivalent substitutions or modifications made by those skilled in the art to the device module form, signal demodulation method, calibration method and compensation algorithm without departing from the essence of the present invention should all fall within the protection scope of the present invention.

[0019] Example 1: Device Structure and Basic Working Process like Figure 1 As shown, this embodiment provides an environmental temperature influence compensation device for near-field temperature measurement using a tuning fork FBG probe. The device includes a tuning fork signal conditioning and acquisition module 1, a tuning fork frequency offset demodulation module 2, a control module 3, a Z-axis displacement drive module 4, a Z-axis displacement execution module 5, a sample to be tested 6, an FBG wavelength demodulation module 7, a reference FBG 8, an FBG probe 9, and a quartz tuning fork 10.

[0020] Both the FBG probe 9 and the reference FBG 8 are mounted on the quartz tuning fork 10. The FBG probe 9 is used to acquire near-field temperature information of the sample, while the reference FBG 8 is used to characterize the temperature changes of the environment in which the quartz tuning fork 10 is located. The FBG probe 9 can be set on one side or the top of the vibrating arm of the quartz tuning fork, while the reference FBG 8 can be set on the crossbeam of the quartz tuning fork or at other positions on the quartz tuning fork.

[0021] Both FBG probe 9 and reference FBG 8 are connected to FBG wavelength demodulation module 7. FBG wavelength demodulation module 7 obtains the center wavelengths of FBG probe 9 and reference FBG 8 and sends them to control module 3. FBG probe 9 and reference FBG 8 can use different center wavelengths and be connected to the same FBG wavelength demodulation module 7 through wavelength division multiplexing, or they can be achieved through other optical demodulation methods that can obtain changes in the center wavelength of the FBG.

[0022] The quartz tuning fork 10 is connected to the tuning fork signal conditioning and acquisition module 1. The tuning fork signal conditioning and acquisition module 1 is used for driving the quartz tuning fork, compensating for parasitic capacitance, acquiring the response signal, and amplifying the signal. It also sends the response signal of the quartz tuning fork to the tuning fork frequency offset demodulation module 2. The tuning fork frequency offset demodulation module 2 acquires the total frequency offset of the quartz tuning fork 10 and sends it to the control module 3. It can use a phase-locked loop, a phase-locked amplifier, an analog demodulation circuit, a digital demodulation circuit, or other equivalent frequency offset demodulation methods.

[0023] The control module 3 receives the total frequency deviation of the quartz tuning fork and the center wavelength information of the reference FBG 8. Based on the change in the center wavelength of the reference FBG 8, it obtains the ambient temperature change of the quartz tuning fork 10 and calculates the tuning fork temperature frequency deviation using the quartz tuning fork temperature calibration relationship. The tip-sample interaction frequency deviation is then separated from the total frequency deviation. Further, the control module 3 generates a Z-axis feedback control quantity based on the difference between the tip-sample interaction frequency deviation and the set frequency deviation operating point and sends it to the Z-axis displacement drive module 4. The Z-axis displacement drive module 4 converts the feedback control quantity into a drive signal, controlling the Z-axis displacement execution module 5 to adjust the relative position between the FBG probe 9 and the sample 6 under test. The drive signal can be a piezoelectric ceramic drive voltage, a displacement stage control signal, a power amplification signal, or other equivalent signals capable of driving the displacement actuator. The Z-axis displacement execution module 5 can drive the sample 6 under test or the tuning fork FBG probe.

[0024] like Figure 2 As shown, the basic workflow of this invention includes: S101, configuring the tuning fork FBG probe and reference FBG; S102, establishing the temperature calibration relationship between the FBG probe, reference FBG, and quartz tuning fork; S103, setting the quartz tuning fork driving parameters and parasitic capacitance compensation parameters, and setting the tuning fork frequency offset operating point; S104, bringing the FBG probe close to the sample surface, and performing Z-axis feedback based on the tip-sample interaction frequency offset, entering the near-field temperature measurement state; S105A, performing post-scan processing compensation, or S105B, performing real-time compensation during scanning; S106, outputting the compensated near-field temperature measurement result. Real-time compensation during scanning and post-scan processing compensation are two independent compensation methods, both based on the temperature calibration relationship.

[0025] Example 2: Establishment of Temperature Calibration Relationship Based on Example 1, this example is used to illustrate... Figure 2 The temperature calibration relationship established as described in section S102. This calibration relationship serves as the common basis for real-time compensation during scanning and post-scanning processing compensation.

[0026] The configured tuning fork FBG probe and reference FBG are placed in a uniform temperature field, ensuring that the FBG probe, reference FBG, and quartz tuning fork are under the same or approximately the same ambient temperature conditions. The temperature of the uniform temperature field is changed, and after each temperature point stabilizes, the center wavelength of the FBG probe, the center wavelength of the reference FBG, the frequency deviation of the quartz tuning fork, and the thermocouple temperature are recorded simultaneously.

[0027] Based on the above data, the relationships between the center wavelength of the FBG probe and the temperature reference value, the relationship between the center wavelength of the reference FBG and the temperature reference value, and the relationship between the frequency deviation of the quartz tuning fork and the temperature reference value are established. These calibration relationships can be established using linear fitting, polynomial fitting, table lookup interpolation, or other methods that can express the corresponding relationships.

[0028] In one specific embodiment, the tuning fork FBG probe and the reference FBG are calibrated by three temperature increases and decreases within the range of 32°C to 45°C. Figure 5 The calibration results under a uniform temperature field are given, where Figure 5 (a) shows the calibration results between the center wavelength of the FBG probe and the temperature reference value. Figure 5 (b) The calibration results are based on the reference FBG center wavelength and the temperature reference value. Figure 5 (c) shows the calibration results between the frequency deviation of the quartz tuning fork and the temperature reference value. When using linear fitting, the temperature response between the FBG probe center wavelength and the temperature reference value is 13.6 pm / ℃, with a coefficient of determination R0. 2 The coefficient of determination is 0.996; the temperature response between the reference FBG center wavelength and the temperature reference value is 11.7 pm / ℃, and the coefficient of determination R0 is 0.996. 2 The coefficient of determination is 0.997; the temperature response of the quartz tuning fork frequency deviation to the temperature reference value is -1.49 Hz / ℃, and the coefficient of determination R0 is 0.997. 2 It is 0.992.

[0029] Example 3: Real-time compensation method during scanning This embodiment provides a real-time compensation method during scanning, which is based on Embodiments 1 and 2, and the specific process is as follows. Figure 4 This method separates the frequency deviation of the tuning fork temperature caused by the ambient temperature in real time during near-field temperature measurement, enabling Z-axis feedback control to be based on the frequency deviation of the needle tip-sample interaction.

[0030] In step S301, the FBG probe is brought close to the surface of the sample to be tested and enters the near-field temperature measurement state at the set frequency offset operating point. The set frequency offset operating point refers to the target frequency offset value used by the quartz tuning fork to maintain the tip-sample distance during the near-field feedback process.

[0031] In S302A and S302B, the tuning fork frequency offset demodulation module acquires the total frequency offset of the quartz tuning fork. The FBG wavelength demodulation module acquires the center wavelength of the reference FBG and the center wavelength of the FBG probe. The total frequency deviation includes both the frequency deviation caused by the tip-sample interaction and the tuning fork temperature frequency deviation caused by changes in ambient temperature.

[0032] In S303 and S304, the ambient temperature change of the quartz tuning fork is obtained from the change of the center wavelength of the reference FBG according to the temperature calibration relationship of the reference FBG; then, the temperature frequency deviation of the tuning fork caused by the change of ambient temperature is calculated according to the temperature calibration relationship of the quartz tuning fork.

[0033] The total frequency deviation of a quartz tuning fork can be expressed as: in, The frequency shift is caused by the interaction between the needle tip and the sample. This is the frequency deviation due to the temperature of the tuning fork. Therefore, in S305, we obtain: In S306, the frequency offset decoupling and Z-axis feedback control module will... The input is compared with the set frequency offset operating point, and a Z-axis feedback control value is generated based on the comparison result. This control value is input to the Z-axis displacement execution module via the Z-axis displacement drive module to adjust the relative position between the FBG probe and the sample. In S307, the center wavelength of the FBG probe is acquired and the near-field temperature measurement result is output.

[0034] In this embodiment, the compensation process directly applies to the Z-axis feedback link. Since the frequency deviation of the tuning fork caused by ambient temperature is separated before feedback control, the signal upon which the Z-axis feedback control is based is closer to the tip-sample interaction itself, which can reduce the feedback position shift caused by changes in ambient temperature.

[0035] Example 4: Post-scanning compensation method and result verification This embodiment provides a post-scanning compensation method, which is based on Embodiments 1 and 2, and the specific process is as follows. Figure 3 and Figure 6 This method does not alter the Z-axis feedback control link during the scanning process; instead, it corrects the obtained near-field temperature measurement results after the scan is completed. This method is independent of the real-time compensation method during scanning described in Example 3.

[0036] In S201, an axial temperature distribution model is established above the sample to be tested. This axial temperature distribution model describes the temperature decay relationship along the axial direction of the FBG probe when the sample is under heating conditions. This model can be obtained through finite element simulation, analytical calculation, experimental calibration, or table lookup. For the same heating state, the local temperature at different locations corresponds to different relative distances between the FBG probe and the sample surface.

[0037] In S202A, a reference state scan is performed on the area to be tested to obtain Z-axis height data under the reference state. This height data is used to characterize the reference height under conditions where temperature influence is minimal. In S202B, an operating state scan is performed on the same area to obtain Z-axis height data and FBG probe center wavelength data under the operating state.

[0038] In S203, the reference state scan data and the working state scan data are registered, and the Z-axis height change at the same scan position is calculated: in, The Z-axis height is in the reference state. This refers to the Z-axis height during operation. This represents the relative Z-axis height change under the two conditions. This is under the condition that the sample's thermal expansion or morphological changes are negligible, or have been corrected for independently. It can be used to characterize the relative position change caused by the influence of ambient temperature on the feedback of a tuning fork.

[0039] In S204 and S205, Substituting the axial temperature distribution model above the sample, the local temperature difference caused by the positional change of the FBG probe is calculated. Then, according to the FBG probe temperature calibration relationship, the local temperature difference is converted into a temperature compensation amount or a center wavelength compensation amount, and the FBG probe center wavelength result is corrected. When using center wavelength correction, it can be expressed as: in, The center wavelength of the FBG probe before compensation. This is the center wavelength compensation amount corresponding to the position change. This is the compensated center wavelength of the FBG probe. In S206, the compensated near-field temperature measurement results are output.

[0040] In one specific implementation, the post-scanning compensation method was validated using a heated sample. The test included two sets of near-field temperature measurement data. The first set was closed-loop continuous measurement data, where the sample was continuously heated after the quartz tuning fork established a near-field feedback operating point at the initial temperature. The system maintained Z-axis closed-loop control throughout the heating process, but did not re-establish the tuning fork operating point at each temperature point. The second set was point-by-point reconstruction operating point measurement data, where after each sample temperature point stabilized, the quartz tuning fork was restarted and brought closer to the sample surface, and measurements were taken at the same set frequency offset operating point. This set of data was used to provide a near-field temperature measurement reference under relatively stable spacing conditions.

[0041] Based on the Z-axis position change during the closed-loop continuous measurement process, and combined with the axial temperature distribution model above the sample, the center wavelength of the FBG probe obtained from the closed-loop continuous measurement is compensated. The results before and after compensation are as follows: Figure 6 As shown. In this specific embodiment, the response of the FBG probe center wavelength to the sample temperature change during closed-loop continuous measurement is 6.50 pm / ℃, and during point-by-point reconstruction of the working point measurement it is 8.54 pm / ℃, and after scanning post-processing compensation it is 8.50 pm / ℃.

[0042] It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and should not be construed as limiting the scope of protection of the present invention. Any equivalent changes made to the reference FBG arrangement, FBG wavelength demodulation method, tuning fork frequency offset demodulation method, Z-axis execution method, calibration relationship expression method, and compensation algorithm form based on the technical concept of the present invention should fall within the scope of protection of the present invention.

Claims

1. An environmental temperature influence compensation device for near-field temperature measurement of a tuning fork FBG probe, comprising a quartz tuning fork (10), characterized in that: An FBG probe (9) and a reference FBG (8) are installed on the quartz tuning fork (10). Both the FBG probe (9) and the reference FBG (8) are connected to the FBG wavelength demodulation module (7). The FBG wavelength demodulation module (7) obtains the center wavelength of the FBG probe 9 and the reference FBG 8 and sends it to the control module (3). The quartz tuning fork (10) is connected to the tuning fork signal conditioning and acquisition module (1). The tuning fork signal conditioning and acquisition module (1) sends the response signal of the quartz tuning fork to the tuning fork frequency offset demodulation module (2). The tuning fork frequency offset demodulation module (2) obtains the total frequency offset of the quartz tuning fork (10) and sends it to the control module (3). The control module (3) receives the total frequency offset of the quartz tuning fork and the center wavelength information of the reference FBG (8). Based on the change in the center wavelength of the reference FBG (8), it obtains the change in the ambient temperature of the quartz tuning fork (10) and calculates the tuning fork temperature frequency offset in combination with the quartz tuning fork temperature calibration relationship. The tip-sample interaction frequency offset is separated from the total frequency offset.

2. The ambient temperature influence compensation device for near-field temperature measurement of tuning fork FBG probe according to claim 1, characterized in that: The control module (3) generates a Z-axis feedback control quantity based on the difference between the sample action frequency deviation and the set frequency deviation working point and sends it to the Z-axis displacement drive module (4). The Z-axis displacement drive module (4) controls the displacement execution module (5) to adjust the relative position between the FBG probe (9) and the sample to be tested (6).

3. A method for compensating for the influence of ambient temperature on near-field temperature measurement using a tuning fork FBG probe, characterized in that... include: S101 Installs an FBG probe and a reference FBG on the quartz tuning fork; S102 Place the quartz tuning fork in a uniform temperature field and establish the calibration relationship between the center wavelength of the FBG probe and temperature, the center wavelength of the reference FBG and temperature, and the frequency deviation of the quartz tuning fork and temperature. S103 sets the driving parameters and parasitic capacitance compensation parameters of the quartz tuning fork to stabilize the oscillation, and sets the tuning fork frequency deviation operating point for near-field feedback. S104 brings the FBG probe closer to the sample surface and performs Z-axis feedback based on the tip-sample interaction frequency deviation, thus entering the near-field temperature measurement state. S105 uses real-time compensation during scanning or post-scanning processing compensation to compensate for near-field temperature measurement deviations caused by ambient temperature. S106 outputs the compensated near-field temperature measurement results.

4. The method for compensating for the influence of ambient temperature on near-field temperature measurement of a tuning fork FBG probe according to claim 3, characterized in that... The real-time compensation during scanning in step S105 includes: acquiring the total frequency deviation of the quartz tuning fork and the center wavelength of the reference FBG; obtaining the ambient temperature change of the quartz tuning fork from the change in the center wavelength of the reference FBG; calculating the tuning fork temperature frequency deviation in combination with the tuning fork temperature calibration relationship; and separating the tip-sample interaction frequency deviation from the total frequency deviation of the quartz tuning fork for Z-axis feedback control.

5. The method for compensating for the influence of ambient temperature on near-field temperature measurement of a tuning fork FBG probe according to claim 4, characterized in that... The specific real-time compensation steps during scanning include: S301 brings the FBG probe close to the surface of the sample to be tested and enters the near-field temperature measurement state at the set frequency offset operating point. S302A collects the total frequency deviation of a quartz tuning fork. ; S302B acquires the reference FBG center wavelength and the FBG probe center wavelength; S303 obtains the ambient temperature change of the quartz tuning fork from the change of the center wavelength of the reference FBG based on the temperature calibration relationship of the reference FBG. S304 calculates the temperature frequency deviation of the tuning fork caused by changes in ambient temperature based on the temperature calibration relationship of the quartz tuning fork. ; S305 separates the tip-sample interaction frequency from the total frequency deviation of a quartz tuning fork. ; S306 will The Z-axis feedback control value is generated based on the comparison result and compared with the set frequency offset operating point to adjust the relative position between the FBG probe and the sample. The S307 acquires the center wavelength of the FBG probe and outputs the near-field temperature measurement results.

6. The method for compensating for the influence of ambient temperature on near-field temperature measurement of a tuning fork FBG probe according to claim 3, characterized in that... The post-scanning compensation in step S105 includes: establishing an axial temperature distribution model above the sample, obtaining Z-axis height data in the reference state and the working state, calculating the Z-axis height change at the same scanning position, and correcting the FBG probe center wavelength result or near-field temperature measurement result based on the Z-axis height change and the axial temperature distribution model.

7. The method for compensating for the influence of ambient temperature on near-field temperature measurement of a tuning fork FBG probe according to claim 6, characterized in that... The specific post-scanning compensation steps include: S201 Establish an axial temperature distribution model above the sample to be tested; The S202A performs a reference state scan on the area to be measured to obtain the Z-axis height data under the reference state. ; The S202B performs a working state scan on the same area to obtain the Z-axis height data under working conditions. and FBG probe center wavelength data ; S203 performs position registration on the reference state scan data and the working state scan data, and calculates the Z-axis height change at the same scan position. ; S204 will Substitute the axial temperature distribution model above the sample into the model to calculate the local temperature difference caused by the position change of the FBG probe. S205 Based on the temperature calibration relationship of the FBG probe, the local temperature difference is converted into a temperature compensation amount or a center wavelength compensation amount. The center wavelength of the FBG probe was corrected, and the result was adjusted: the compensated center wavelength of the FBG probe. ; S206 outputs the compensated near-field temperature measurement results.

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