Probe analysis method combined with near-field imaging system

Abstract

The invention discloses a probe analysis method combined with a near-field imaging system, belongs to the technical field of near-field imaging, and mainly solves the problem that an optical microscope cannot accurately judge the damage condition of the tip of a used metal probe. The method comprises the following steps: S110, observing the morphology of the tip of a probe under an optical microscope, and carrying out laser spot calibration on the tip of a new probe by using near-field imaging system software as a contrast reference; s120, classifying the used probes according to the tip morphology under an optical microscope; s130, analyzing the tips of the metal probes in each classification by using a near-field imaging system; and S140, judging the damage condition of the tip of the metal probe by combining the analysis results of the optical microscope and the near-field imaging system, and discussing the repair possibility. The method can effectively identify the damage condition of the tip of the metal probe, and has the characteristic of efficient and rapid operation process.

Description

Technical Field

[0001] The present invention belongs to the field of near-field imaging technology, and specifically relates to a probe analysis method combined with a near-field imaging system. The method can effectively improve the efficiency of judging the damage of the metal probe tip and become a new extension means of near-field imaging technology. Background Art

[0002] Metal probes, as core functional components in near-field imaging systems, transcend the diffraction limit of traditional optical microscopes through their unique physical properties and operating mechanisms, enabling super-resolution detection of optical responses in the terahertz region at the nanoscale. Their operating principle is based on the local field enhancement effect of a metalized tip (typically a gold- or platinum-plated atomic force microscope probe) under terahertz wave illumination. When a sharp tip (with a radius of curvature of approximately 20-50 nanometers) approaches the sample surface, the near-field interaction between the tip and the sample significantly enhances the local electromagnetic field, coupling localized optical information in the nanoscale region of the sample surface (such as surface plasmons, phonon polaritons, or carrier distributions) into the far-field scattered signal. To effectively extract the weak near-field signal and suppress background noise, the probe is typically mechanically vibrated at a high frequency (approximately tens to hundreds of kHz). The modulated signal of the scattered light is synchronously detected using a lock-in amplifier, thereby isolating specific harmonic components (such as doubled or tripled frequency signals) dominated by the near-field interaction between the tip and the sample. This modulation detection technique, combined with the topography feedback system of an atomic force microscope (AFM), enables near-field imaging systems to simultaneously capture nanoscale surface morphology and analyze localized terahertz optical properties (such as complex refractive index, conductivity, or polariton propagation) with spatial resolutions below 10 nanometers, far below the terahertz wavelength (300 GHz corresponds to approximately 1 mm). In applications, this technique provides a key tool for studying carrier dynamics in low-dimensional materials (such as graphene and transition metal sulfides), nanoscale optoelectronic responses in semiconductor heterojunctions, terahertz near-field manipulation of metamaterials and plasmonic structures, and terahertz fingerprint analysis of biomolecules and polymers. For example, probe-induced local field enhancement can be used to observe edge-state plasmon resonances at the boundaries of two-dimensional materials or directly image carrier diffusion behavior in pn junctions in semiconductor devices. Current technical challenges focus on improving the power stability of terahertz light sources, optimizing the field localization capability of probes to enhance signal strength, and developing multidimensional signal decoupling algorithms to distinguish the electric and magnetic components of electromagnetic responses. With advances in ultrafast laser technology and nanofabrication, near-field imaging systems are developing toward higher sensitivity and multimodal integration (such as time-resolved or cryogenic measurements), opening up new dimensions for nanophotonics and quantum materials research in the terahertz band. Therefore, effectively identifying damage to metal probe tips plays a crucial role in near-field imaging system imaging quality, signal enhancement, and laser calibration. Summary of the Invention

[0003] In response to the above technical problems, the present invention provides a probe analysis method combined with a near-field imaging system, which uses a new probe as a control, observes the probe tip morphology with an optical microscope, and performs laser calibration of the near-field imaging system to effectively identify the damage to the probe tip.

[0004] A probe analysis method combined with a near-field imaging system comprises the following steps:

[0005] S110, observe the probe tip morphology under an optical microscope and perform laser spot calibration on the new probe tip using the near-field imaging system software as a reference;

[0006] S120, classify the used probes according to the tip morphology under an optical microscope;

[0007] S130, analyzing each classification of metal probe tips using a near-field imaging system;

[0008] S140, combined with the analysis results of the optical microscope and near-field imaging system, the damage of the metal probe tip is judged and the repair possibility is discussed.

[0009] The present invention has the following beneficial effects:

[0010] The method can effectively identify the damage condition of the metal probe tip and has the characteristics of efficient and quick operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 The tip morphology of the new probe under an optical microscope and the laser calibration diagram in a near-field imaging system;

[0012] Figure 2 The following are the tip morphologies of different types of probes used under an optical microscope;

[0013] Figure 3 This is a laser calibration diagram of different types of probes used in the near-field imaging system. DETAILED DESCRIPTION

[0014] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0015] Example

[0016] This embodiment discloses a probe analysis method combined with a near-field imaging system, the steps of which are as follows:

[0017] Step S110, observe the probe tip morphology under an optical microscope and perform laser spot calibration on the new probe tip using the near-field imaging system software as a reference (see Figure 1 ).

[0018] Step S120: Classify the used probes according to their tip morphology under an optical microscope (see Figure 2 ), including the following 5 categories:

[0019] Category 1: The probe tip is completely twisted, tilted, disappeared, or turned black;

[0020] Category 2: The tip of the probe needle does not exist and the color of the needle tip has turned completely black;

[0021] Category 3: The tip of the probe needle exists and the color of the needle tip has mostly turned black;

[0022] Category 4: The tip of the probe needle is damaged and the color of the needle tip is partially blackened;

[0023] Category 5: The tip of the probe needle is present and the color of the needle tip is the same as that of a new probe, close to white.

[0024] Step S130, analyze each type of metal probe tip using a near-field imaging system (see Figure 3 ).

[0025] 1. Category 1: There is no laser signal at the probe laser receiving end;

[0026] 2. Category 2: There is no laser signal at the probe laser receiving end;

[0027] 3. Classification 3 The probe laser receiving end signal is divided into three types: the first type has no laser signal, the second type has a weak receiving signal but is not within the laser receiving range of the receiver, and the third type has a signal but is not within the laser receiving range of the receiver;

[0028] 4. Category 4: There is a signal at the laser receiving end, but it is not within the laser receiving range of the receiver;

[0029] 5. There is a signal at the receiving end of the laser in category 5, and the morphology is roughly the same as that of the new probe.

[0030] Step S140, combining the analysis results of the optical microscope and the near-field imaging system to determine the damage of the metal probe tip and discuss possible repairs, including:

[0031] Category 1 and 2 probes are completely damaged and cannot be repaired (the tip is dark black due to cantilever tilt and excessive tip bending);

[0032] Category 3 probes: The first type of probe is completely damaged; the second type of probe can be repaired and needs to be returned to the factory for adjustment of the cantilever and the curvature of the probe tip. After repair, the previously mentioned method can be used for testing and verification again; the third type of probe can adjust the receiving range of the laser (the vibration table shell needs to be opened, see Figure 3 If the probe tip is within the receiving range, it can be used. If it is not within the receiving range, it needs to be returned to the factory for repair.

[0033] Category 4 probes can adjust the laser's fixed receiving range (the vibration table housing needs to be opened, which is similar to the third operation step of Category 3). It can be seen that the receiver end of this type of probe can receive signals after adjustment.

[0034] The Class 5 probe is identical to the new probe in both morphology and laser adjustment.

[0035] In summary, the present invention provides a probe analysis method combined with a near-field imaging system, which mainly solves the problem that an optical microscope cannot accurately determine the damage condition of a used metal probe tip.

[0036] Step S110 is as follows: first, observe the probe tip morphology under an optical microscope and take multiple morphology images. Then, install the probe on the vibration stage, open the near-field imaging system software, turn on the laser, and coarsely adjust the external knob of the laser emission end on the vibration stage (see Figure 1 (Point at the arrow) so that the laser hits the needle tip, take a small piece of paper and place it on the receiving end, and fine-tune the laser transmitter knob again. When a red spot appears on the small piece of paper, adjust the external knob of the laser receiving end so that the scattered red laser is located in the middle of the receiver end as a reference.

[0037] Step S120 includes: taking a topographical image of each used metal probe with an optical microscope, and classifying the probes into five types according to their appearance;

[0038] Step 130 includes: Then, using a near-field imaging system to analyze the classified probes. The probes of Classification 1 cannot reflect the red laser due to the twisted, tilted, and missing needle tips. We cannot receive the laser signal at the receiving end (see Figure 3 Mark 1); Classification 2 probe is similar to Classification 1 probe, but the receiving end cannot receive the laser signal (see Figure 3 Mark 1); The first type of probe of classification 3 is the same as probes of types 1 and 2, and there is no signal at the receiving end (see Figure 3 The second receiving end has a weak red laser (see Figure 3 Mark 2), the third receiving end has a red laser, but is not within the range of the receiver (see Figure 3The third condition of the Classification 4 probe is the same as that of the Classification 3 probe. There is a signal at the receiving end, but the reflected red laser is out of the receiving range (see Figure 3 The Class 5 probe has a signal at the receiving end and is within the receiver range, which is the same as the new probe (see Figure 3 Mark 6);

[0039] Step S140 includes: combining the optical microscope and the near-field imaging system to discuss the possibility of probe repair. The category 1 and 2 probes cannot be repaired because the needle tip is damaged or the degree of bending is too large. The first category 3 probe cannot be repaired, and the second category probe can be repaired. It needs to be sent back to the manufacturer to use precision tools to adjust the cantilever and the curvature of the probe tip. After repair, it can be tested and verified again using the previously mentioned method. The third category requires opening the vibration table housing and re-adjusting the receiving range of the receiving laser. If it is within the receiver range, the probe tip can be used. If it is not within the receiving range, it needs to be returned to the factory for repair. Category 4 probes can adjust the receiving range of the laser that has been fixed (the vibration table housing needs to be opened and the screws that fix the telescopic laser receiver are adjusted. See Figure 3 As can be seen at 5, the receiver end of this type of probe can still receive signals after adjustment and does not need to be returned to the factory for processing. The Class 5 probe is consistent with the new probe in both morphology and laser adjustment and can be used normally.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A probe analysis method combined with a near-field imaging system, characterized in that: The following steps are involved: S110, observe the probe tip morphology under an optical microscope and perform laser spot calibration on the new probe tip using the near-field imaging system software as a reference; S120, classify the used probes according to the tip morphology under an optical microscope; S130, analyzing each classification of metal probe tips using a near-field imaging system; S140, combining the analysis results of the optical microscope and the near-field imaging system to determine the damage condition of the metal probe tip.

2. The probe analysis method combined with a near-field imaging system according to claim 1, characterized in that: In step S120 , the used metal probe tips are observed under an optical microscope, and the probes are classified according to the appearance of the tips.

3. The probe analysis method combined with a near-field imaging system according to claim 2, characterized in that: In step S130 , a near-field imaging system is used to further analyze the probe type observed under the microscope.

4. The probe analysis method combined with a near-field imaging system according to claim 3, characterized in that: In step S140, the damage of the metal probe tip is determined by combining the analysis results of the optical microscope and the near-field imaging system, and the possibility of repair is discussed.

5. The probe analysis method combined with a near-field imaging system according to claim 4, characterized in that: Step S110 is specifically as follows: first observe the morphology of the probe tip under an optical microscope, take multiple morphology images, then install the probe on the vibration table, open the near-field imaging system software, turn on the laser, coarsely adjust the external knob of the laser transmitting end on the vibration table so that the laser hits the tip of the needle, take a small piece of paper and place it on the receiving end, and fine-tune the knob of the laser transmitting end again. When red spots appear on the small piece of paper, adjust the external knob of the laser receiving end so that the scattered red laser is located in the middle position of the receiver receiving end as a reference.

6. The probe analysis method combined with a near-field imaging system according to claim 5, characterized in that: Probes include the following 5 categories: Category 1: The probe tip is completely twisted, tilted, disappeared, or turned black; Category 2: The tip of the probe needle does not exist and the color of the needle tip has turned completely black; Category 3: The tip of the probe needle exists and the color of the needle tip has mostly turned black; Category 4: The tip of the probe needle is damaged and the color of the needle tip is partially blackened; Category 5: The tip of the probe needle is present and the color of the needle tip is the same as that of a new probe, close to white.

7. The probe analysis method combined with a near-field imaging system according to claim 6, characterized in that: In step 130, when the probe is classified as 1, there is no laser signal at the laser receiving end; when the probe is classified as 2, there is no laser signal at the laser receiving end; when the probe is classified as 3, the signal at the laser receiving end is divided into 3 types: the first type has no laser signal, the second type has a weak receiving signal but is not within the laser receiving range of the receiver, and the third type has a signal but is not within the laser receiving range of the receiver; when the probe is classified as 4, there is a signal at the laser receiving end but is not within the laser receiving range of the receiver; when the probe is classified as 5, there is a signal at the laser receiving end, and the morphology is the same as that of the new probe.

8. The probe analysis method combined with a near-field imaging system according to claim 7, characterized in that: Category 1 and 2 probes are completely damaged and cannot be repaired.

9. The probe analysis method combined with a near-field imaging system according to claim 7, characterized in that: Category 3 probes: The first type of probe is completely damaged; the second type of probe can be repaired and needs to be returned to the factory for adjustment of the cantilever and the curvature of the probe tip; the third type of probe can adjust the fixed receiving range of the laser. If it is within the receiving range, the probe tip can be used. If it is not within the receiving range, it needs to be returned to the factory for repair.

10. The probe analysis method combined with a near-field imaging system according to claim 7, characterized in that: Category 4 probes can adjust the laser's fixed receiving range. The receiver end of this type of probe can still receive signals after adjustment. Category 5 probes are consistent with new probes in terms of morphology and laser adjustment.

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