A local temperature quantitative characterization system and method based on thermal probe

Abstract

The present invention provides a local temperature quantitative characterization system based on a thermal probe, including a thermal probe module for sensing the local temperature, a three-dimensional differential motion module for controlling the contact state between the thermal probe tip and the sample to be tested in a segmented manner, a position feedback module for monitoring and feeding back the contact degree between the tip and the sample to be tested, a control module for controlling all modules, and a digital processing module for collecting, processing and synchronizing the local temperature signal obtained by the thermal probe; the thermal probe module is controlled by the control module to obtain the local temperature, and then the thermal probe signal under different contact states between the probe and the sample is obtained by the three-dimensional differential motion module, and the signal collected by the position feedback module and the thermal probe signal under different contact states are transmitted to the digital processing module for collection, processing and synchronization, so as to realize quantitative temperature measurement of the local temperature. Based on the thermal probe and three-dimensional differential scanning, the present invention can realize rapid and quantitative measurement of nanoscale local temperature in an atmospheric environment.

Description

Technical Field

[0001] The present invention relates to the technical field of scanning probe microscope systems and control methods, and in particular to a local temperature quantitative characterization system and method based on a thermal probe. Background Art

[0002] With the increasing development of science and technology such as nanomaterials and integrated circuits, heat transport mechanisms and thermal failure analysis at the nanoscale have gradually become important scientific and technological issues in the research of new materials and devices. Among them, achieving high spatial resolution and high sensitivity local temperature characterization at the nanoscale for nanomaterials and devices is the core and key to the above scientific and technological issues.

[0003] Scanning probe microscopes can achieve local measurements of a variety of physical quantities and are important equipment and means for high spatial resolution characterization at the nanoscale. In particular, combining a thermal probe with a local temperature sensing unit with a scanning probe microscope can achieve quantitative temperature measurement with a spatial resolution of less than 10 nm under ultra-high vacuum conditions (ACS Nano 16, 939-950 (2022)). However, affected by gas convection and the thermal contact resistance between the tip and the sample, although a temperature contrast distribution with a spatial resolution of 50 nm can be obtained, traditional systems based on thermal probes and scanning probe microscopes cannot achieve quantitative measurement of local temperature under atmospheric conditions, and many nanomaterials and nanodevices work under atmospheric conditions. Therefore, systems and methods based on thermal probes that can achieve quantitative measurement of local temperature under atmospheric conditions are of great demand and significance. At present, the industry has developed several new quantitative temperature measurement methods under atmospheric conditions, such as the secondary scanning method that uses a thermal probe to measure the two-dimensional temperature distribution in the contact mode and the needle lifting mode (ACS Nano 5, 8700 (2011)), and the zeroing method that changes the temperature of the thermal probe to offset the temperature difference between the "full" contact state and the "just" contact state (Rev. Sci. Instrum. 85, 114901 (2014)). However, the interval between the two scans of the secondary scanning method is too long, and the thermal drift of the system and the contact thermal resistance between the needle tip and the sample will affect the measurement accuracy; although the zeroing method can quantitatively measure the temperature, each measurement point needs to scan and relax the needle tip temperature, resulting in a long measurement time.

[0004] In summary, it is of great significance to achieve quantitative measurement of local temperature under atmospheric conditions. At present, there is still an urgent need for characterization systems and methods based on thermal probes that can quickly and accurately measure temperature. Summary of the invention

[0005] In view of the above-mentioned technical problem that the systems and methods in the prior art cannot achieve fast and accurate temperature measurement, a system and method for quantitative characterization of local temperature based on a thermal probe is provided, which controls the contact state between the thermal probe and the sample to be measured by segmented continuous modulation of the longitudinal (z-axis) translation stage, and then uses a three-dimensional differential scanning method to eliminate the influence of thermal drift in the secondary scanning method, so that the quantitative temperature measurement is more accurate; and the quantitative measurement is made faster by identifying the characteristic area of ​​the sample to be measured and calibrating the sample-needle tip contact proportional factor of a few characteristic points by using a zeroing method.

[0006] The technical means adopted by the present invention are as follows:

[0007] A local temperature quantitative characterization system based on a thermal probe comprises: a thermal probe module for sensing local temperature, a three-dimensional differential motion module for controlling the contact state between the thermal probe tip and a sample to be measured in a segmented manner, a position feedback module for monitoring and feeding back the contact degree between the tip and the sample to be measured, a control module for controlling all the above modules, and a digital processing module for collecting, processing and synchronizing the local temperature signal obtained by the thermal probe; the thermal probe module is controlled by the control module to obtain the local temperature, and then the thermal probe signal under different contact states between the probe and the sample is obtained by the three-dimensional differential motion module, and the signal collected by the position feedback module is transmitted together with the thermal probe signal under different contact states to the digital processing module for collection, processing and synchronization, so as to finally realize the quantitative temperature measurement of the local temperature.

[0008] Furthermore, the present invention also includes a quantitative temperature measurement method of a local temperature quantitative characterization system based on a thermal probe, comprising the following steps:

[0009] Step 1: Use a standard sample with known temperature to calculate the temperature-voltage conversion coefficient S of the thermal probe. p and background temperature T 0 Carry out calibration;

[0010] Step 2: by changing the temperature of the thermal probe, the contact ratio factor between the thermal probe and the sample to be tested in the characteristic area of ​​the sample to be tested is increased. Carry out calibration;

[0011] Step 3: obtain the thermal probe signals at different positions and under different contact conditions by three-dimensional differential scanning, and calibrate the parameters S p , T 0 and Get the two-dimensional distribution of local temperature T s (x,y);

[0012]

[0013] Where, Vc represents the temperature difference electromotive force signal output by the thermal probe when the thermal probe is in full contact with the sample; V nc It indicates the temperature difference electromotive force signal output by the thermal probe when the thermal probe just contacts the sample.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The present invention controls the contact state between the thermal probe and the sample to be measured by segmented continuous modulation of the longitudinal (z-axis) translation stage, thereby realizing a three-dimensional differential scanning mode. The three-dimensional differential scanning mode is the same as the secondary scanning method, and can also suppress the interference of atmospheric convection on the quantitative measurement of local temperature. In addition, the "segmented" control in the three-dimensional scanning differential method can make the thermal signal collected by the thermal probe fully relaxed and stable, and can eliminate the influence of thermal drift caused by two separate measurements in the secondary scanning method, thereby making the quantitative measurement of local temperature more accurate.

[0016] Moreover, the present invention can significantly reduce the number of contact proportional factors that need to be calibrated in traditional zeroing methods by identifying and dividing the characteristic areas of the sample to be tested according to its material composition, and calibrating the sample-needle tip contact proportional factors at a few characteristic points in each characteristic area, thereby making the quantitative measurement of local temperature faster. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 It is a system block diagram of the local temperature quantitative characterization system based on the thermal probe of the present invention;

[0019] Figure 2 The flowchart of the method for quantitatively characterizing local temperature based on a thermal probe of the present invention;

[0020] Figure 3 This is a control data diagram of an asymmetric three-dimensional differential scanning mode in an embodiment of the present invention;

[0021] Figure 4 This is a control data diagram of the symmetrical three-dimensional differential scanning mode in an embodiment of the present invention.

[0022] Figure 5 2 is a two-dimensional distribution diagram of local temperature obtained in an embodiment of the present invention.

[0023] In the figure: 10 is a local temperature quantitative characterization system based on a thermal probe; 100 is a thermal probe module; 110 is a cantilever beam probe; 120 is a thermal sensing unit; 130 is a probe control unit; 140 is a pre-processing unit; 200 is a three-dimensional differential motion module; 210 is a longitudinal (z-axis) displacement stage; 220 is a lateral (x, y-axis) displacement stage; 230 is a sample to be tested; 300 is a position feedback module; 400 is a control module; 500 is a digital processing module. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 only 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 should fall within the scope of protection of the present invention.

[0025] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0026] like Figure 1 As shown, the system 10 of the present invention includes: a thermal probe module 100, a three-dimensional differential motion module 200, a position feedback module 300, a control module 400 and a digital processing module 500. The thermal probe module 100 is used to sense the local temperature, the three-dimensional differential motion module 200 is used to control the contact state between the thermal probe tip and the sample to be tested in a segmented manner, the position feedback module 300 is used to monitor and feedback the contact degree between the tip and the sample to be tested, the control module 400 is used to control the thermal probe module 100, the three-dimensional differential motion module 200 and the position feedback module 300, and the digital processing module 500 is used to collect, process and synchronize the local temperature signal obtained by the thermal probe.

[0027] The thermal probe module 100 includes a cantilever probe 110, a thermal sensing unit 120, a probe control unit 130 and a pre-processing unit 140. The cantilever probe 110 is mechanically connected to the probe control unit 130, the thermal sensing unit 120 is integrated in the needle tip of the cantilever probe 110, the pre-processing unit 140 is electrically connected to the thermal sensing unit 120, and the probe control unit 130 is electrically connected to the control module 400. As a preferred embodiment, in the present application, the thermal sensing unit 120 can be a micro-nano thermocouple composed of a bimetallic coating, or a micro-nano thermal resistor composed of a doped semi-monomer material. The bimetallic film material can be Au, Cr, Pt, Cr, Pt, W, NiSi, NiCrSi, Cu, CuNi, etc.; the doped semiconductor material can be Si, Ge, SiGe, etc.

[0028] Furthermore, the pre-processing unit 140 can pre-amplify the DC sensing signal of the thermal sensing unit 120 and heat the thermal sensing unit 120 using high-frequency AC or modulated optical signals to change the needle tip temperature. The frequency of the high-frequency AC or modulated optical signals must be greater than 10 kHz.

[0029] In addition, the three-dimensional differential motion module 200 includes a longitudinal (z-axis) displacement stage 210, a transverse (x, y-axis) displacement stage 220, and a sample to be tested 230. The sample to be tested 230 is placed above the longitudinal (z-axis) displacement stage 210 and is mechanically connected to the longitudinal (z-axis) displacement stage 210; the longitudinal (z-axis) displacement stage 210 is placed on the transverse (x, y-axis) displacement stage 220, and the sample to be tested is mechanically connected to the transverse (x, y-axis) displacement stage 220; the longitudinal (z-axis) displacement stage 210 and the transverse (x, y-axis) displacement stage 220 are both electrically connected to the control module 400.

[0030] Furthermore, the longitudinal (z-axis) displacement stage 210 needs to realize segmented continuous modulation of the contact state or spacing between the thermal sensing unit 120 and the sample to be tested 230. In each modulation cycle, the contact state or spacing is divided into three stages in sequence: the first stage is the disengagement stage, in which the longitudinal (z-axis) displacement stage 210 quickly moves away from the thermal sensing unit 120, and the displacement of the longitudinal (z-axis) displacement stage 210 is a fixed displacement; the second stage is the half-needle insertion stage, in which the longitudinal (z-axis) displacement stage 210 quickly moves toward the thermal sensing unit 120, and the displacement of the longitudinal (z-axis) displacement stage 210 is one-half of the fixed displacement; the third stage is the variable contact stage, in which the longitudinal (z-axis) displacement stage 210 slowly moves toward the thermal sensing unit 120 until it reaches the stop standard of the position feedback module 300, and this stage will go through the "just" contact state and finally reach the "full" contact state. The "just" contact state refers to the state when the force between the sample 230 to be tested and the thermal sensing unit 120 is close to zero, and the "full" contact state refers to the state when the repulsive force between the sample 230 to be tested and the thermal sensing unit 120 is not less than 100nN. The modulation frequency of the longitudinal (z-axis) translation stage movement is between 0.1Hz and 100Hz; in each modulation cycle, there is a waiting time between the three stages for relaxing the local temperature signal and stabilizing it; the waiting time is not less than 5ms. Preferably, in the present application, the fast speed range is 10 to 100um / s; the slow speed range is 1 to 10um / s.

[0031] In addition, the position feedback module 300 uses an optical lever to monitor the deflection degree of the cantilever beam probe 110, and the output deflection signal is used to feedback and control the contact state between the thermal sensing unit 120 and the sample to be tested 230. The position of the "just" contact state can be determined using the zero point of the second-order difference of the deflection signal. The position feedback module 300 is electrically connected to the control module 400. The digital processing module 500 is electrically connected to the control module 400 and the pre-processing unit 140, and collects longitudinal (z-axis) displacement signals, deflection signals, and local temperature signals, respectively, and performs digital filtering and time synchronization processing on the above signals, and then outputs the two-dimensional distribution of the morphology and local temperature.

[0032] like Figure 2 As shown, the present invention specifically comprises the following steps:

[0033] Step 1: Use a standard sample of known temperature to convert the temperature-voltage coefficient S of the thermal probe. p and background temperature T 0 Carry out calibration;

[0034] Step 2: Calibrate the contact proportional factor φ between the thermal probe and the sample to be tested in the characteristic area of ​​the sample to be tested by changing the temperature of the thermal probe;

[0035] Step 3: Obtain the thermal probe signals at different positions and under different contact conditions by three-dimensional differential scanning, and calibrate the parameters S p , T 0 and φ to obtain the two-dimensional distribution of local temperature T s (x,y),

[0036] Where Vc represents the temperature difference electromotive force signal output by the thermal probe when the thermal probe is in full contact with the sample; V nc It indicates the temperature difference electromotive force signal output by the thermal probe when the thermal probe just contacts the sample.

[0037] In step 1, firstly, the standard sample and the thermal sensing unit are subjected to longitudinal segmented continuous modulation in the contact mode; secondly, the temperature of the standard sample is maintained at T s , the temperature of the thermal sensing unit is changed by the pre-processing module to obtain the temperature sensing signal and the z-axis displacement signal sequence {V 1 , z 1} m , the temperature sensing signal and z-axis displacement signal sequence after the half-needle insertion stage {V 2 , z 2} m , the temperature sensing signal and z-axis displacement signal sequence {V 3 , z 3} m And the z-axis displacement signal sequence {z 4} m (the subscript m corresponds to different temperatures of the thermal sensing unit), and then the independent variable {V nc -V c} m and dependent variable {V c} m Perform linear regression to obtain the intercept μ c . Where V c =V 3 、V nc =(V 2 -V 1 )×z 4 / (z 2 -z 1 )+(z 2 ×V 1 -z 1 ×V 2 ) / (z2 -z 1 ); Again, change the standard sample temperature T s , obtain different temperature series {T s} n The intercept sequence {μ c} n (subscript n corresponds to different standard sample temperatures), and then the independent variable {T s} n and the dependent variable {μ c} n Perform linear regression to obtain the slope S p With intercept-S p ×T 0 .

[0038] In addition, in step 2, firstly, the sample to be tested and the thermal sensing unit are subjected to longitudinal segmented continuous modulation in the contact mode; secondly, in the normal working state, the temperature of the thermal sensing unit is changed by the pre-processing module to obtain the temperature sensing signal and the z-axis displacement signal sequence {V 1 , z 1} m , the temperature sensing signal and z-axis displacement signal sequence after the half-needle insertion stage {V 2 , z 2} m , the temperature sensing signal and z-axis displacement signal sequence {V 3 , z 3} m And the z-axis displacement signal sequence {z 4} m (the subscript m corresponds to different temperatures of the thermal sensing unit), and then the independent variable {V nc -V c} m and dependent variable {V c} m Linear regression is performed to obtain the slope φ, where V c =V 3 、V nc =(V 2 -V 1 )×z 4 / (z 2 -z 1 )+(z 2 ×V 1 -z 1 ×V 2 ) / (z 2 -z 1); again, according to the material composition of the sample, the sample is divided into different characteristic regions, and the same material is located in the same characteristic region; repeating step 23, the slope of the above characteristic region Take measurements.

[0039] Finally, in step 3, first, the three-dimensional differential scanning control is implemented on the sample to be tested and the thermal sensing unit in the contact mode; secondly, the second-order differential information of the deflection signal and the z-axis displacement signal is synchronously obtained. c (x,y) and V nc The two-dimensional distribution of (x, y), at each (x, y) position V c =V 3 、V nc =(V 2 -V 1 )×z 4 / (z 2 -z 1 )+(z 2 ×V 1 -z 1 ×V 2 ) / (z 2 -z 1 ), where V 1 and z 1 is the temperature sensing signal and z-axis displacement signal after the disengagement stage, V 2 and z 2 is the temperature sensing signal and z-axis displacement signal after the half-needle insertion stage, V 3 and z 3 is the temperature sensing signal and z-axis displacement signal in the "sufficient" contact state, and z 4 is the z-axis displacement signal in the “just” contact state; again, based on the calibration parameter S p , T 0 and φ, and obtain the local temperature distribution T of the sample to be tested s (x,y)=(1-φ) / S p ×V c (x,y)+1 / S p ×V nc (x,y)+T 0 .

[0040] In order to facilitate understanding of the present invention, the following optional embodiments are provided.

[0041] like Figure 3As shown, the first embodiment adopts an asymmetric three-dimensional differential scanning control mode to perform local temperature measurement, and the thermal probe is a thermocouple probe composed of Cr and Au coatings. In each longitudinal (z-axis) modulation cycle of this control mode, the needle is quickly withdrawn in the disengagement stage, which is different from the control of the half-needle insertion stage and the variable contact stage (presenting an asymmetric control), and the lateral (x, y axis) displacement stage moves laterally after the variable contact stage. The fixed displacement of this control mode is 200nm, the modulation cycle is about 10Hz, the waiting time between the three stages is not less than 10ms, and the force between the thermal sensing unit and the sample to be measured in the "sufficient" contact state is about 200nN. The zero point of the second-order difference of the optical feedback information in the position feedback module can be used to determine the synchronous position of the "just" contact state.

[0042] like Figure 4 As shown, Example 2 adopts a symmetrical three-dimensional differential scanning control mode to perform local temperature measurement, and the thermal probe is a thermocouple probe composed of NiSi and NiCrSi coatings. In each longitudinal (z-axis) modulation cycle of this control mode, the disengagement stage is divided into two stages of needle withdrawal, which is the same as the half-needle insertion stage and the variable contact stage (presenting symmetrical control), and the lateral (x, y-axis) displacement stage moves laterally during the stabilization time between the disengagement stage and the half-needle insertion stage. The fixed displacement of this control mode is 200nm, the modulation cycle is about 1.5Hz, the waiting time between the three stages is fixed at 60ms, and the force between the thermal sensing unit and the sample to be measured in the "full" contact state is about 500nN. The zero point of the second-order difference of the optical feedback information in the position feedback module can be used to determine the synchronous position of the "just" contact state (i.e., z 4 The corresponding time and displacement). The waiting time after the disengagement stage and the inflection point position of the half-insertion stage can be used to determine the thermal probe temperature difference electromotive force V 1 and displacement z 1 The thermoelectric potential V of the thermal probe can be determined by using the waiting time after the half-insertion stage and the inflection point position of the variable contact stage. 2 and displacement z 2 The position of the thermal probe after the waiting time after the variable contact stage can be used to determine the thermal probe temperature difference electromotive force V 3 and displacement z 3 , and then according to V c =V 3 、V nc =(V 2 -V 1 )×z 4 / (z 2 -z 1 )+(z 2 ×V 1 -z 1 ×V 2 ) / (z2 -z 1 ) Determine the temperature difference electromotive force signal when "full" contact and "just" contact. Using the Ni wire structure of the four-probe architecture as the temperature standard, calibrate the temperature voltage conversion coefficient S of the thermal probe in this embodiment p About 35μV / K and the system background temperature T during measurement 0 The temperature of the Ni wire is about 24℃. A 2μm wide Ni wire structure on a quartz substrate is used as the sample to be tested. The working condition is that 3mA DC is applied to the Ni wire under atmospheric conditions to heat it. A 100kHz AC is applied to the thermal sensing unit by the pre-processing unit to change the needle tip temperature. The contact scale factors of the Ni area and the quartz substrate area are calibrated to be about 40K / K and 50K / K respectively. Then, the V c (x,y) and V nc (x,y) distribution signal and calibration to S p , T 0 and φ parameters, according to T s (x,y)=(1-φ) / S p ×V c (x,y)+1 / S p ×V nc (x,y)+T 0 The quantitative distribution of local temperature is obtained. The quantitative distribution result of temperature in this embodiment is as follows: Figure 5 shown.

[0043] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages and disadvantages of the embodiments. In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A local temperature quantitative characterization system based on a thermal probe, characterized in that: include: A thermal probe module for sensing local temperature, a three-dimensional differential motion module for segmented control of the contact state between the thermal probe tip and the sample to be tested, a position feedback module for monitoring and feeding back the contact degree between the tip and the sample to be tested, a control module for controlling all the above modules, and a digital processing module for collecting, processing and synchronizing the local temperature signal obtained by the thermal probe; The control module controls the thermal probe module to acquire the local temperature, and then the three-dimensional differential motion module is used to obtain the thermal probe signal under different contact states between the probe and the sample. The signal collected by the position feedback module is transmitted together with the thermal probe signal under different contact states to the digital processing module for collection, processing and synchronization, thereby finally realizing quantitative measurement of the local temperature.

2. A local temperature quantitative characterization system based on a thermal probe according to claim 1, characterized in that: The thermal probe module includes: a cantilever probe, a thermal sensing unit, a probe control unit and a pre-processing unit; the cantilever probe is mechanically connected to the probe control unit, the thermal sensing unit is integrated on the needle tip of the cantilever probe, the pre-processing unit is electrically connected to the thermal sensing unit, and the probe control unit is electrically connected to the control module.

3. A local temperature quantitative characterization system based on a thermal probe according to claim 1, characterized in that: The three-dimensional differential motion module includes: a longitudinal displacement stage and a transverse displacement stage; the sample to be tested is placed on the longitudinal displacement stage, and the sample to be tested is mechanically connected to the longitudinal displacement stage; the longitudinal displacement stage is placed above the transverse displacement stage and is mechanically connected to the transverse displacement stage; the longitudinal displacement stage and the transverse displacement stage are both electrically connected to the control module.

4. A local temperature quantitative characterization system based on a thermal probe according to claim 3, characterized in that: The longitudinal translation stage performs segmented continuous modulation on the contact state or the distance between the thermal sensing unit and the sample to be tested.

5. A local temperature quantitative characterization system based on a thermal probe according to claim 4, characterized in that: In each modulation cycle, the contact state or spacing is divided into three stages in sequence: the first stage is a disengagement stage, in which the longitudinal displacement stage quickly moves away from the thermal sensing unit, and the displacement of the longitudinal displacement stage is a fixed displacement; the fixed displacement is between 50nm and 500nm; The second stage is the half-needle insertion stage, in which the longitudinal displacement stage quickly moves toward the thermal sensing unit, and the displacement of the longitudinal displacement stage is half of the fixed displacement amount; The third stage is the variable contact stage, in which the longitudinal displacement stage moves slowly toward the thermal sensing unit until it reaches the stop standard of the position feedback module, and the moving speed of the longitudinal displacement stage in the third stage does not exceed 10 μm / s; the third stage finally reaches the full contact state from the just-contact state; wherein, the just-contact state is defined as a state when the force between the sample to be tested and the thermal sensing unit is close to zero; the full contact state is a state when the repulsive force between the sample to be tested and the thermal sensing unit is not less than 100 nN; the fast speed range is 10 to 100 um / s; the slow speed range is 1 to 10 um / s.

6. A local temperature quantitative characterization system based on a thermal probe according to claim 2, characterized in that: The position feedback module monitors the deflection degree of the cantilever beam probe by means of an optical lever, and outputs a deflection signal for feedback and control of the contact state between the thermal sensing unit and the sample to be tested; the zero point of the second-order difference of the deflection signal is the position of the just-contact state.

7. A quantitative temperature measurement method based on a local temperature quantitative characterization system of a thermal probe, using the system described in any one of claims 1 to 6, characterized in that: The steps include: Step 1: Use a standard sample with known temperature to calculate the temperature-voltage conversion coefficient S of the thermal probe. p And the background temperature T0 is calibrated; Step 2, calibrating the contact proportional factor φ between the thermal probe and the sample to be tested in the characteristic area of ​​the sample to be tested by changing the temperature of the thermal probe; Step 3: obtain the thermal probe signals at different positions and under different contact conditions by three-dimensional differential scanning, and calibrate the parameters S p , T0 and φ to obtain the two-dimensional distribution of local temperature T s (x,y); T s (x,y)=(1-φ) / S p ×V c (x,y)+1 / S p ×V nc (x,y)+T0; Among them, V c It indicates the temperature difference electromotive force signal output by the thermal probe when the thermal probe is in full contact with the sample; V nc It indicates the temperature difference electromotive force signal output by the thermal probe when the thermal probe just contacts the sample.

8. The quantitative temperature measurement method of the local temperature quantitative characterization system based on a thermal probe according to claim 7, characterized in that: The step 1 also includes the following steps: Step 11: Implementing longitudinal segmented continuous modulation on the sample to be tested and the thermal sensing unit in a contact mode; Step 12: Maintain the temperature of the sample to be tested at T s , the temperature of the thermal sensing unit is changed by the pre-processing module, and the temperature sensing signal and the z-axis displacement signal sequence {V1, z1} after the disengagement stage are obtained respectively. m , temperature sensing signal and z-axis displacement signal sequence {V2, z2} after the half-needle insertion stage m , temperature sensing signal and z-axis displacement signal sequence {V3, z3} in full contact state m And the z-axis displacement signal sequence {z4} when just in contact m ; Wherein, m represents the temperature of different thermal sensing units; Step 13: For the independent variable {V nc -V c } m and dependent variable {V c } m Perform linear regression and get the intercept μ c ; Among them, V c =V3,V nc =(V2-V1)×z4 / (z2-z1)+(z2×V1-z1×V2) / (z2-z1); Step 14: Change the temperature T of the sample to be tested s , obtain different temperature series {T s } n The intercept sequence {μ c } n , and then the independent variable {T s } n and the dependent variable {μ c } n Perform linear regression to obtain the slope S p With intercept-S p ×T0; where n represents different standard sample temperatures; S p It represents the temperature-voltage conversion coefficient of the thermal probe, which is the Seebeck coefficient for the thermocouple probe; T0 represents the background temperature of the system environment.

9. The quantitative temperature measurement method of the local temperature quantitative characterization system based on a thermal probe according to claim 7, characterized in that: The step 2 further comprises the following steps: Step 21: Implementing longitudinal segmented continuous modulation on the sample to be tested and the thermal sensing unit in a contact mode; Step 22: Under normal working conditions, the temperature of the thermal sensing unit is changed by the pre-processing module to obtain the temperature sensing signal and the z-axis displacement signal sequence {V1, z1} after the disengagement stage. m , temperature sensing signal and z-axis displacement signal sequence {V2, z2} after the half-needle insertion stage m , temperature sensing signal and z-axis displacement signal sequence {V3, z3} in full contact state m And the z-axis displacement signal sequence {z4} when just in contact m ; Wherein, m represents the temperature of the corresponding thermal sensing unit; Step 23: For the independent variable {V nc -V c } m and dependent variable {V c } m Linear regression is performed to obtain the slope φ, where V c =V3,V nc =(V2-V1)×z4 / (z2-z1)+(z2×V1-z1×V2) / (z2-z1); Step 24: Divide the sample into different characteristic areas according to the material composition of the sample, and the same material is located in the same characteristic area; repeat step 23 to measure the slope φ of the above characteristic area.

10. The quantitative temperature measurement method of the local temperature quantitative characterization system based on a thermal probe according to claim 7, characterized in that: The step 3 also includes the following steps: Step 31: Implementing three-dimensional differential scanning control on the sample to be tested and the thermal sensing unit in a contact mode; Step 32: Synchronize the second-order differential information of the deflection signal and the z-axis displacement signal to obtain V c (x,y) and V nc (x, y) two-dimensional distribution; at each (x, y) position, V c =V3, V nc =(V2-V1)×z4 / (z2-z1)+(z2×V1-z1×V2) / (z2-z1); Step 33: Based on the calibration parameter S p , T0 and φ, to obtain the local temperature distribution T of the sample to be tested s (x,y).

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