High-Q-value dynamic probe for measuring atomic force

Abstract

The invention discloses a high-Q-value dynamic probe for measuring atomic force. The high-Q-value dynamic probe comprises a probe seat, a base, a cantilever beam, a probe tip, a discrete piezoresistive unit, a connecting wire, a conductive fly wire and a conductive lining plate, the base and the conductive lining plate are respectively positioned at two ends of the needle seat; the cantilever beam is arranged on the base in a manner of extending outwards in a direction far away from the conductive lining plate; a hollow part is arranged on the cantilever beam; the tip is arranged at the top of the tail end of the cantilever beam; the discrete piezoresistive units are arranged on the root parts of the cantilever beams; the connecting wire is arranged on the base; the first end of the connecting wire is connected with the discrete piezoresistive unit, and the second end of the connecting wire is connected with the conductive lining plate. The high-Q-value dynamic probe for measuring the atomic force has the advantages that the yield of piezoresistive probes can be increased, the calorific value is reduced, the probes are convenient to replace, the measurement sensitivity is improved, and the like.

Description

Technical Field

[0001] The invention relates to an atomic force probe, in particular to a high Q value dynamic probe for measuring atomic force. Background Art

[0002] Atomic force microscope (AFM) is an important instrument for analyzing surface morphology and electromagnetic properties with atomic resolution. AFM probes are consumables of high-tech instruments because their application range is limited to atomic force microscopes. Atomic force probes have important application value and prospects in industrial production and basic scientific research, such as in-situ characterization of battery electrode materials, measurement and detection in integrated circuit and wafer manufacturing, surface physical analysis, material Young's modulus analysis, and nanoindentation mechanical measurement.

[0003] The atomic force probe is a miniature force sensor manufactured using semiconductor micro-nano processing technology. The tip of the atomic force probe is sharp and pointed, with a size of only about a few dozen atoms. The radius of curvature of the tip is about 20 nanometers, and the spatial resolution can reach 20 nanometers. There are two main types of atomic force probes: optical detection atomic force probes and self-sensing piezoresistive atomic force probes. The surface of the optical detection atomic probe is coated with a layer of metal reflective film to reflect the incident laser beam. The surface of the self-sensing piezoresistive atomic force probe does not have a metal reflective film, and the detection unit is a piezoresistor processed by semiconductor micro-nano processing technology. The atomic force probe is the most important consumable in atomic force measurement, with a large consumption and high price.

[0004] The quality of the atomic force probe directly determines the sensitivity of the atomic force measurement. When the atomic force probe approaches the surface of the sample, a weak attractive or repulsive force, that is, atomic force, will be generated between the atoms on the tip of the needle and the atoms on the surface of the sample. Slight changes in atomic force will cause the cantilever beam to deflect slightly. In the deflection and bending deformation of the atomic force probe using optical detection, in order to accurately measure this deflection and bending, a laser beam is usually used to illuminate the side of the cantilever beam coated with a reflective metal film and reflect the light onto a photodetector. As the cantilever beam deflects and bends, the reflected laser spot moves on the photodetector, causing the photodetector on one side to receive more light. This change is converted into an electrical signal that provides important information about the degree of bending of the probe perpendicular to the sample surface. This important information can provide researchers with details of mechanical measurements in the microscopic world.

[0005] In laser interferometry, in order to measure the tiny deflection and bending of the cantilever beam, a laser beam is used to irradiate vertically onto the side of the cantilever beam coated with a metal reflective film to form reflected light. The incident light and reflected light form interference fringes on the photodetector. As the cantilever beam deflects and bends, the intensity of the interference light changes. This changing optical signal is converted into an electrical signal, which provides important information about the degree of bending of the probe perpendicular to the sample surface. Similarly, this important information can provide researchers with mechanical measurement details of the microscopic world.

[0006] In the actual process of using an atom probe to measure atomic force, the atomic force probe of the optical detection method requires an external laser as a light source and an optical path system. Lasers with stable laser output are expensive and will significantly increase the cost of using the probe. When the laser is irradiated to the back of the optical detection probe, the laser will more or less irradiate the sample, increasing the experimental variables. For light-sensitive materials such as photoresist, the light will also cause the material to be denatured and destroy the sample. The optical path system is composed of many optical components, which makes the optical path system have the disadvantages of large overall volume, loose structure and poor rigidity. Atomic force measurement is easily affected by external environmental vibration and is not compatible with narrow sample cavities, especially mechanical measurements in extreme physical environments such as extremely low temperatures and strong magnetic fields. The optical path system must also have good temperature stability. Temperature changes will cause the optical components to move relative to each other due to thermal expansion and contraction, destroying the debugged optical path. This requires that when doing temperature changes, the experimenter needs to recalibrate the optical path after the temperature change is completed. The result is that extra time and energy are consumed and the experimental efficiency is reduced. Especially for situations where rotation measurements need to be performed under strong magnetic field conditions, the experimental device is required to rotate in a small magnetic field space. However, the optical system is difficult to insert into such a test environment. The optical system cannot be flexibly rotated therein.

[0007] The self-sensing piezoresistive probe does not require an external light source and a complex optical path system, and there is no light interference during imaging. It has a compact structure and small size, and can rotate flexibly in a narrow sample cavity. Therefore, the atomic force probe with optical detection is not compatible with the measurement of rotational force under a strong magnetic field, and the piezoresistive probe provides an ideal solution. Therefore, due to the advantages of small size, easy integration and no optical interference, the piezoresistive probe has become more and more popular as a force sensor.

[0008] The quality factor (Q-factor, Q value) of the cantilever in an atomic force microscope characterizes the response of the cantilever. The cantilever usually has a higher Q value. A higher Q value can make the probe more sensitive to the sample during imaging, thereby improving the imaging resolution. Piezoresistive probes have problems such as low yield, low mechanical quality factor Q value, low force measurement sensitivity, large thermal noise, low signal-to-noise ratio, and severe heat generation at extremely low temperatures.

[0009] The piezoresistance on the piezoresistive probe is made by ion implantation process, and there is a certain yield rate. When the yield rate is low, it will directly lead to the defective rate of wafer manufacturing, significantly increasing the production and use cost of the probe. Impurity ions are injected into the silicon substrate with a certain incident energy and incident angle to form a doped region with a certain depth and doping concentration. Therefore, the incident energy, incident angle, doping concentration and depth need to be precisely controlled. The doped area is then annealed to activate the impurities and eliminate the lattice defects generated during ion implantation. The annealing time and temperature must also be precisely controlled. After annealing, piezoresistance will be formed in the doped area. The yield problem is an important issue that needs to be solved in the process of promoting the large-scale application of piezoresistive probes.

[0010] The mechanical quality factor Q value of the piezoresistive probe is about 100 under room temperature atmospheric conditions and about 800 under room temperature vacuum conditions. The Q value is too low; the force measurement sensitivity of the piezoresistive probe is proportional to the Q value of the probe. A too low Q value will reduce the force measurement sensitivity of the piezoresistive probe. When the piezoresistive probe is working, the piezoresistance will generate Joule heat, which will directly radiate onto the sample and heat the sample. The heating effect of the piezoresistive probe is particularly obvious in mechanical measurements in extremely low temperature environments, and may even destroy the low temperature conditions. Increasing the resistance value of a single piezoresistor can reduce the heat generation power of the piezoresistor, but increasing the resistance value of a single piezoresistor will significantly increase the electrical noise of the piezoresistor, greatly reducing the signal-to-noise ratio of the piezoresistive resistance value signal change and reducing the sensitivity of force measurement.

[0011] As a consumable, the probe needs to be replaced after a period of use. When changing the needle, the experimenter needs to change the needle manually. Because the probe base is very small, the probe needs to be gently picked up with the tip of tweezers when changing the probe. At this time, it is easy for the probe to slip or collapse, causing the fragile cantilever beam to break due to impact. Even if experienced experimenters operate carefully, mistakes will still occur, resulting in a large amount of probe waste.

[0012] Therefore, it is urgent to design a high-Q piezoresistive probe to solve the problems of low yield rate, low mechanical quality factor Q value, low force measurement sensitivity, high heat generation and high needle replacement error rate of existing piezoresistive probes. At the same time, it is expected that the probe is suitable for rotational force measurement in extreme physical environments such as ultra-low temperature, ultra-high vacuum and strong magnetic field. Summary of the invention

[0013] The present invention is to avoid the deficiencies in the above-mentioned prior art and provide a high-Q value dynamic probe for measuring atomic force, so as to improve the yield of the piezoresistive probe, reduce heat generation, facilitate needle replacement and improve measurement sensitivity.

[0014] The present invention adopts the following technical solutions to solve the technical problems.

[0015] A high-Q dynamic probe for measuring atomic force of the present invention comprises a needle seat 1, a base 2, a cantilever beam 3, a needle tip 4, a discrete piezoresistive unit 5, a connecting wire 6, a conductive flying wire 7 and a conductive lining plate 8; The base 2 and the conductive liner 8 are respectively located at two ends of the needle seat 1; the cantilever beam 3 is arranged on the base 2 to extend outward in a direction away from the conductive liner 8; The cantilever beam 3 is provided with a hollow portion 31; the end of the cantilever beam 3 away from the needle seat 1 is the cantilever beam end, and the top of the cantilever beam end is provided with the needle tip 4; One end of the cantilever beam 3 close to the needle seat 1 is the root of the cantilever beam; the discrete piezoresistive unit 5 is arranged on the root of the cantilever beam; the discrete piezoresistive unit 5 includes a first discrete piezoresistive unit 5a and a second discrete piezoresistive unit 5b; The base 2 is provided with the connecting wire 6 ; a first end of the connecting wire 6 is connected to the discrete piezoresistive unit 5 , and a second end of the connecting wire 6 is connected to the conductive backing plate 8 .

[0016] The structural features of a high Q value dynamic probe for measuring atomic force of the present invention are also as follows: Furthermore, the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are arranged on the same cantilever beam 3 .

[0017] Furthermore, the hollow portion 31 extends from the end of the cantilever beam to the root of the cantilever beam; the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are respectively located on both sides of the hollow portion 31 .

[0018] Furthermore, the hollow portion 31 extends from the end of the cantilever beam to the discrete piezoresistive unit 5 ; the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are located on a side of the hollow portion 31 away from the end of the cantilever beam.

[0019] Furthermore, the second end of the connecting wire 6 is connected to the conductive lining plate 8 via a conductive flying wire 7 .

[0020] Furthermore, the conductive lining 8 includes a first conductive lining 8a, a second conductive lining 8b, a third conductive lining 8c and a fourth conductive lining 8d.

[0021] Further, the connecting wire 6 includes a first connecting wire 6a, a second connecting wire 6b, a third connecting wire 6c and a fourth connecting wire 6d; The first discrete piezoresistive unit 5a is connected to the first conductive backing plate 8a via a first connecting wire 6a; The first discrete piezoresistive unit 5a is connected to the second conductive backing plate 8b via a second connecting wire 6b; The second discrete piezoresistive unit 5b is connected to the third conductive backing plate 8c via a third connecting wire 6c; The second discrete piezoresistive unit 5b is connected to the fourth conductive substrate 8d via a fourth connecting wire 6d.

[0022] Further, the conductive flying wire 7 includes a first conductive flying wire 7a, a second conductive flying wire 7b, a third conductive flying wire 7c and a fourth conductive flying wire 7d; The first connecting wire 6a is connected to the first conductive lining plate 8a through the first conductive flying wire 7a; The second connecting wire 6b is connected to the second conductive lining plate 8b via a second conductive flying wire 7b; The third connecting wire 6c is connected to the third conductive lining plate 8c via a third conductive flying wire 7c; The fourth connecting wire 6d is connected to the fourth conductive lining plate 8d via a fourth conductive flying wire 7d.

[0023] Furthermore, the needle seat 1 is provided with a groove, and the conductive liner 8 is located in the groove.

[0024] Furthermore, a magnetic wrapping layer is provided on the needle tip 4 at the end of the cantilever beam.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention discloses a high-Q dynamic probe for measuring atomic force, comprising a needle seat, a base, a cantilever beam, a needle tip, a discrete piezoresistive unit, a connecting wire, a conductive flying lead and a conductive lining plate; the base and the conductive lining plate are respectively located at two ends of the needle seat; the cantilever beam is arranged on the base to extend outward in a direction away from the conductive lining plate; a hollow portion is arranged on the cantilever beam; the needle tip is arranged on the top of the end of the cantilever beam; the discrete piezoresistive unit is arranged on the root of the cantilever beam; the connecting wire is arranged on the base; the first end of the connecting wire is connected to the discrete piezoresistive unit, and the second end of the connecting wire is connected to the conductive lining plate.

[0026] The high-Q value dynamic probe for measuring atomic force of the present invention has the advantages of being able to improve the yield rate of the piezoresistive probe, reduce heat generation, facilitate needle replacement, and improve measurement sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a front view (first hollowing method) of a high-Q value dynamic probe for measuring atomic force according to the present invention.

[0028] Figure 2 This is a left view of a high-Q value dynamic probe for measuring atomic force according to the present invention.

[0029] Figure 3 It is a schematic diagram of a second hollowing method of a high-Q value dynamic probe for measuring atomic force of the present invention.

[0030] The present invention will be further described below through specific implementation modes in conjunction with the accompanying drawings. DETAILED DESCRIPTION

[0031] See also Figure 1 to Figure 3 A high-Q dynamic probe for measuring atomic force of the present invention comprises a needle seat 1, a base 2, a cantilever beam 3, a needle tip 4, a discrete piezoresistive unit 5, a connecting wire 6, a conductive flying wire 7 and a conductive lining plate 8; The base 2 and the conductive liner 8 are respectively located at two ends of the needle seat 1; the cantilever beam 3 is arranged on the base 2 to extend outward in a direction away from the conductive liner 8; The cantilever beam 3 is provided with a hollow portion 31; the end of the cantilever beam 3 away from the needle seat 1 is the cantilever beam end, and the top of the cantilever beam end is provided with the needle tip 4; One end of the cantilever beam 3 close to the needle seat 1 is the root of the cantilever beam; the discrete piezoresistive unit 5 is arranged on the root of the cantilever beam; the discrete piezoresistive unit 5 includes a first discrete piezoresistive unit 5a and a second discrete piezoresistive unit 5b; The base 2 is provided with the connecting wire 6 ; a first end of the connecting wire 6 is connected to the discrete piezoresistive unit 5 , and a second end of the connecting wire 6 is connected to the conductive backing plate 8 .

[0032] like Figures 1 to 3 As shown, a high-Q dynamic probe for measuring atomic force of the present invention has a cantilever beam 3 extending outward from a base 2, and the cantilever beam 3 is an integral structure with the base 2. A hollow portion is provided on the cantilever beam. A discrete piezoresistive unit is provided at the root of the cantilever beam. A needle tip is provided at the end of the cantilever beam. A connecting wire connected to the discrete piezoresistive unit is provided on the base. The base is provided on a needle seat, and a conductive lining plate is provided on the needle seat, and the connecting wire and the conductive lining plate are connected by a conductive flying wire. The high-Q dynamic probe for measuring atomic force of the present invention can improve the yield of the probe, improve the mechanical quality factor Q value, reduce thermal noise, improve the signal-to-noise ratio, improve the force measurement sensitivity, and reduce heat generation. At the same time, it also has the characteristics of easy needle replacement, expanded application fields, and is particularly suitable for rotational force measurement in extreme physical environments such as extremely low temperature, ultra-high vacuum and strong magnetic field.

[0033] In a specific implementation, the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are arranged on the same cantilever beam 3 .

[0034] In specific implementation, two or more cantilever beams may be provided. The arrangement of the hollowed-out portion of the cantilever beam and the discrete piezoresistive unit is similar to the structure of one cantilever beam of the present invention.

[0035] In a specific implementation, the hollow portion 31 extends from the end of the cantilever beam to the root of the cantilever beam; the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are respectively located on both sides of the hollow portion 31 .

[0036] In a specific implementation, the hollow portion 31 extends from the end of the cantilever beam to the discrete piezoresistive unit 5 ; the first discrete piezoresistive unit 5 a and the second discrete piezoresistive unit 5 b are located on a side of the hollow portion 31 away from the end of the cantilever beam.

[0037] In a high-Q dynamic probe for measuring atomic force of the present invention, the shape of the hollow portion of the cantilever beam 3 is consistent with the shape of the cantilever beam 3, and the spatial position of the hollow portion includes but is not limited to the following two hollowing methods.

[0038] The first hollowing method is Figure 1 As shown, the hollow part of the cantilever beam 3 extends from the end of the cantilever beam 3 to the root of the cantilever beam 3, and the lower end line of the hollow part is in a straight line with the lower end line of the cantilever beam 3. The lower end line of the cantilever beam 3 is the boundary line between the cantilever beam 3 and the base 2. Figure 1 In the embodiment, the lower end line of the cantilever beam 3 extends into the base 2, and the lower end line position of the cantilever beam 3 is lower than the upper end surface of the base 2. At this time, the first discrete piezoresistive unit 5a and the second discrete piezoresistive unit 5b are respectively located on the left and right sides of the lower end of the hollow portion.

[0039] The second hollowing method is Figure 3 The hollow portion of the cantilever beam 3 extends from the end of the cantilever beam 3 to the top of the discrete piezoresistive unit 5, but does not reach the bottom line of the cantilever beam 3. At this time, the first discrete piezoresistive unit 5a and the second discrete piezoresistive unit 5b are respectively located below the hollow portion.

[0040] During specific implementation, the second end of the connecting wire 6 is connected to the conductive lining plate 8 via a conductive flying wire 7 .

[0041] In a specific implementation, the conductive lining 8 includes a first conductive lining 8a, a second conductive lining 8b, a third conductive lining 8c and a fourth conductive lining 8d.

[0042] like Figure 1 and Figure 2 The conductive lining 8 is divided into four parts: a first conductive lining 8a, a second conductive lining 8b, a third conductive lining 8c and a fourth conductive lining 8d.

[0043] In a specific implementation, the connecting wire 6 includes a first connecting wire 6a, a second connecting wire 6b, a third connecting wire 6c and a fourth connecting wire 6d; The first discrete piezoresistive unit 5a is connected to the first conductive backing plate 8a via a first connecting wire 6a; The first discrete piezoresistive unit 5a is connected to the second conductive backing plate 8b via a second connecting wire 6b; The second discrete piezoresistive unit 5b is connected to the third conductive backing plate 8c via a third connecting wire 6c; The second discrete piezoresistive unit 5b is connected to the fourth conductive substrate 8d via a fourth connecting wire 6d.

[0044] In a specific implementation, the conductive flying wire 7 includes a first conductive flying wire 7a, a second conductive flying wire 7b, a third conductive flying wire 7c and a fourth conductive flying wire 7d; The first connecting wire 6a is connected to the first conductive lining plate 8a through the first conductive flying wire 7a; The second connecting wire 6b is connected to the second conductive lining plate 8b via a second conductive flying wire 7b; The third connecting wire 6c is connected to the third conductive lining plate 8c via a third conductive flying wire 7c; The fourth connecting wire 6d is connected to the fourth conductive lining plate 8d via a fourth conductive flying wire 7d.

[0045] In one embodiment, the discrete piezoresistive unit 5 includes two: a first discrete piezoresistive unit 5a and a second discrete piezoresistive unit 5b; the connecting wire 6 includes four: a first connecting wire 6a, a second connecting wire 6b, a third connecting wire 6c and a fourth connecting wire 6d; the conductive flying wire 7 includes four: a first conductive flying wire 7a, a second conductive flying wire 7b, a third conductive flying wire 7c and a fourth conductive flying wire 7d; the conductive lining 8 includes four: a first conductive lining 8a, a second conductive lining 8b, a third conductive lining 8c and a fourth conductive lining 8d.

[0046] When specifically connected, the first connecting wire 6a and the second connecting wire 6b are connected to the first discrete piezoresistive unit 5a, and the third connecting wire 6c and the fourth connecting wire 6d are connected to the second discrete piezoresistive unit 5b. The first conductive flying lead 7a, the second conductive flying lead 7b, the third conductive flying lead 7c and the fourth conductive flying lead 7d are respectively connected to the first connecting wire 6a, the second connecting wire 6b, the third connecting wire 6c and the fourth connecting wire 6d; the first conductive lining 8a, the second conductive lining 8b, the third conductive lining 8c and the fourth conductive lining 8d are respectively connected to the first conductive flying lead 7a, the second conductive flying lead 7b, the third conductive flying lead 7c and the fourth conductive flying lead 7d. The first conductive lining 8a and the second conductive lining 8b are electrically connected to the first discrete piezoresistive unit 5a, and the third conductive lining 8c and the fourth conductive lining 8d are connected to the second discrete piezoresistive unit 5b.

[0047] For the case of more than two discrete piezoresistive units, the same logic can be applied to the arrangement of connecting wires, conductive flying leads, conductive lining plates and other components.

[0048] In a specific implementation, a groove is provided on the needle seat 1, and the conductive liner 8 is located in the groove.

[0049] In specific implementation, the second conductive liner 8 can be attached to the surface of the needle seat 1, or one or more shallow grooves can be set in the lower half of the needle seat 1, and the conductive liner 8 can be set in one groove as a whole, or the four parts can be set in four grooves respectively.

[0050] In a specific implementation, a magnetic wrapping layer is provided on the needle tip 4 at the end of the cantilever beam.

[0051] In a specific implementation, the magnetic coating layer can be set to be a metal or alloy containing iron, cobalt, nickel, gadolinium, etc.

[0052] The high Q value dynamic probe for measuring atomic force of the present invention dynamically vibrates at its first order natural frequency f0 or second order natural frequency f1, or close to its natural frequency, above the sample surface. When the probe tip 4 approaches the sample surface, the atomic force between the atoms of the tip 4 and the atoms on the sample surface will cause the vibration frequency of the probe cantilever beam to change, resulting in a frequency shift d f The attractive force between the atoms at the probe tip and the atoms on the sample surface causes a negative frequency shift, while the repulsive force between the atoms at the probe tip and the atoms on the sample surface causes a positive frequency shift. The periodic vibration of the probe cantilever generates an electrical signal of the periodic change in the resistance of the piezoresistive unit, △R. The electrical signal of the periodic change in the resistance of the piezoresistive unit, △R, can provide the vibration frequency shift d generated by the probe cantilever after being acted upon by the atomic force. f Signal. The frequency deviation of the change d f The signal provides real-time information on the atomic forces generated between the probe tip and the sample.

[0053] A high Q value dynamic probe for measuring atomic force of the present invention has the following technical features.

[0054] 1. The yield rate of the probe can be improved. The design of the discrete piezoresistive unit of the present invention can significantly improve the yield rate of the piezoresistive probe and significantly reduce the production cost and use cost of the piezoresistive probe.

[0055] 2. The mechanical quality factor Q value of the probe can be improved. In the present invention, a hollow portion is provided on the cantilever beam, which can reduce the energy dissipation inside the probe, thereby improving the mechanical quality factor Q of the cantilever beam. Experiments have shown that the mechanical quality factor Q value of the probe of the present invention can reach more than 10,000 under room temperature vacuum, and can reach more than 20,000 under low temperature vacuum, and the Q value is significantly improved.

[0056] 3. Reduce thermal noise. In the present invention, a hollow portion is provided on the cantilever beam, which can reduce the energy dissipation inside the probe, thereby improving the mechanical quality factor Q of the cantilever beam, and further reducing the thermal noise n. The calculation formula of the thermal noise n is shown in the following formula (1).

[0057] (1) In formula (1), K B is the Boltzmann constant, △f represents the cantilever beam at the resonant frequency f R The deflection of the cantilever beam during vibration, thermal represents thermal energy, T represents the temperature of the cantilever beam when the cantilever beam produces a deflection △f (in K, Kelvin), f0 is the first-order natural frequency of the cantilever beam, k is the stiffness coefficient of the cantilever beam, Q is the mechanical quality factor of the cantilever beam, and A is the mechanical quality factor of the cantilever beam at the resonant frequency f R The amplitude of vibration, π is the circumference of a circle. From formula (1), we can see that the thermal noise n (white noise) is inversely proportional to the mechanical quality factor Q of the cantilever beam. Therefore, increasing the Q value of the cantilever beam can reduce the thermal noise (white noise) of the probe and improve the signal-to-noise ratio.

[0058] 4. Improve the atomic force measurement sensitivity of the probe. In the present invention, a hollow portion is provided on the cantilever beam, which can reduce the energy dissipation inside the probe, thereby improving the mechanical quality factor Q of the cantilever beam, and further improving the atomic force measurement sensitivity of the probe; according to the following formula (2): In formula 2, D f It is the minimum measurable force value of the probe, which is used to measure the atomic force measurement sensitivity of the probe. f The smaller the value, the higher the sensitivity. f Larger values ​​indicate lower sensitivity.

[0059] (2) In formula (2), K B is the Boltzmann constant, △f represents the cantilever beam at the resonant frequency f R The deflection of the cantilever beam during vibration, thermal represents thermal energy, T represents the temperature of the cantilever beam when the cantilever beam produces a deflection of △f (in K, Kelvin), k is the stiffness coefficient of the cantilever beam, B is the measurement bandwidth of the probe, f R is the resonant frequency of the cantilever beam, Q is the mechanical quality factor of the cantilever beam, and A is the mechanical strength of the cantilever beam at the resonant frequency f R The amplitude of vibration, π is the ratio of the circumference of a circle. The minimum measurable force D f It is inversely proportional to the Q value of the cantilever's mechanical quality factor. The larger the Q value, the smaller the minimum measurable force. The smaller the minimum measurable force, the smaller the measurement value that the probe can achieve, that is, the more sensitive the probe's measurement is. Therefore, increasing the Q value of the cantilever can improve the cantilever's force measurement sensitivity.

[0060] 5. It can reduce the heat generated by the probe during measurement. The probe of the present invention can connect the discrete piezoresistive units end to end through a conductive lining to increase the overall piezoresistive resistance. Since the power supply of the discrete piezoresistive units in the present invention is a constant voltage power supply, according to the resistance heat W=U 2 t / R, when the voltage is constant, the larger the resistance R, the smaller the heat generated per unit time, thereby reducing the piezoresistive heat generation, which is particularly suitable for mechanical measurements in extreme physical environments such as ultra-low temperature, ultra-high vacuum and strong magnetic field.

[0061] 6. Easy needle replacement. The probe of the present invention adopts an integrated design of the base and the needle holder. The base 2 is fixedly arranged on the needle holder 1. When in use, the experimenter only needs to clamp the needle holder 1 with the tip of the tweezers. Since the size of the needle holder 1 is relatively large, it is not easy to slip or fall off when clamped by the tweezers. The operation is convenient and quick, and at the same time, it can also avoid the waste of probe resources.

[0062] 7. Expand the application field of the probe. The probe tip of the present invention is provided with a magnetic coating layer. The magnetic coating layer can be provided with a metal or alloy containing iron, cobalt, nickel, gadolinium, etc., so that the probe can measure not only atomic force but also magnetic force, thus expanding the types of force to be measured.

[0063] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0064] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high Q value dynamic probe for measuring atomic forces, characterized in that: It comprises a needle seat (1), a base (2), a cantilever beam (3), a needle tip (4), a discrete piezoresistive unit (5), a connecting wire (6), a conductive flying wire (7) and a conductive lining plate (8); The base (2) and the conductive lining (8) are respectively located at two ends of the needle seat (1); the cantilever beam (3) is arranged on the base (2) to extend outwardly in a direction away from the conductive lining (8); The cantilever beam (3) is provided with a hollow portion (31); the end of the cantilever beam (3) away from the needle seat (1) is the cantilever beam end, and the top of the cantilever beam end is provided with the needle tip (4); The end of the cantilever beam (3) close to the needle seat (1) is the root of the cantilever beam; the discrete piezoresistive unit (5) is arranged on the root of the cantilever beam; the discrete piezoresistive unit (5) comprises a first discrete piezoresistive unit (5a) and a second discrete piezoresistive unit (5b); The base (2) is provided with the connecting wire (6); a first end of the connecting wire (6) is connected to the discrete piezoresistive unit (5), and a second end of the connecting wire (6) is connected to the conductive lining (8).

2. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The first discrete piezoresistive unit (5a) and the second discrete piezoresistive unit (5b) are arranged on the same cantilever beam (3).

3. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The hollow portion (31) extends from the end of the cantilever beam to the root of the cantilever beam; the first discrete piezoresistive unit (5a) and the second discrete piezoresistive unit (5b) are respectively located on both sides of the hollow portion (31).

4. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The hollow portion (31) extends from the end of the cantilever beam to the discrete piezoresistive unit (5); the first discrete piezoresistive unit (5a) and the second discrete piezoresistive unit (5b) are located on a side of the hollow portion (31) away from the end of the cantilever beam.

5. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The second end of the connecting wire (6) is connected to the conductive lining plate (8) via a conductive flying wire (7).

6. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The conductive lining (8) comprises a first conductive lining (8a), a second conductive lining (8b), a third conductive lining (8c) and a fourth conductive lining (8d).

7. A high Q value dynamic probe for measuring atomic force according to claim 6, characterized in that: The connecting wire (6) comprises a first connecting wire (6a), a second connecting wire (6b), a third connecting wire (6c) and a fourth connecting wire (6d); The first discrete piezoresistive unit (5a) is connected to the first conductive liner (8a) via a first connecting wire (6a); The first discrete piezoresistive unit (5a) is connected to the second conductive liner (8b) via a second connecting wire (6b); The second discrete piezoresistive unit (5b) is connected to the third conductive liner (8c) via a third connecting wire (6c); The second discrete piezoresistive unit (5b) is connected to the fourth conductive liner (8d) via a fourth connecting wire (6d).

8. A high Q value dynamic probe for measuring atomic force according to claim 7, characterized in that: The conductive flying lead (7) comprises a first conductive flying lead (7a), a second conductive flying lead (7b), a third conductive flying lead (7c) and a fourth conductive flying lead (7d); The first connecting wire (6a) is connected to the first conductive lining plate (8a) via a first conductive flying wire (7a); The second connecting wire (6b) is connected to the second conductive lining plate (8b) via a second conductive flying wire (7b); The third connecting wire (6c) is connected to the third conductive lining plate (8c) via a third conductive flying wire (7c); The fourth connecting wire (6d) is connected to the fourth conductive lining plate (8d) via a fourth conductive flying wire (7d).

9. A high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: The needle seat (1) is provided with a groove, and the conductive lining (8) is located in the groove.

10. The high Q value dynamic probe for measuring atomic force according to claim 1, characterized in that: A magnetic wrapping layer is provided on the needle tip (4) at the end of the cantilever beam.

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