Preparation method of measurement probe based on Casimir effect and probe

Abstract

The present invention provides a preparation method and a probe for a measurement probe based on the Casimir effect. The method includes: depositing a first silicon nitride layer and a second silicon nitride layer on the upper and lower surfaces of a substrate respectively; etching the first silicon nitride layer with photoresist to form a first effective region on one side surface of the substrate; growing a covering layer on the substrate to cover the first effective region and the substrate; etching the second silicon nitride layer with photoresist to form a second effective region on the other side surface of the substrate; removing the substrate not covered by the second effective region with an alkaline solution; removing the covering layer with a buffered oxide etchant to obtain a probe cantilever beam; taking a microsphere dispersion and dropping it on a carrier, and drying to obtain microspheres adhered to the carrier; using a displacement platform to dip the tip of the probe cantilever beam into an ultraviolet glue; adhering the microspheres to the tip through the ultraviolet glue to form a microsphere tip; curing the ultraviolet glue by irradiating the microsphere tip with ultraviolet light to obtain a measurement probe including the microsphere tip.

Description

Technical Field

[0001] The present invention relates to the field of environmental catalysis, and particularly to a preparation method of a measurement probe based on the Casimir effect and the probe. Background Art

[0002] Currently, the Casimir theory prediction is proposed through calculations related to the vacuum zero-point energy, suggesting that there is an attractive force between adjacent plates in a vacuum. Later, based on the Casimir theory prediction, the dielectric function was introduced, revealing the important role of the dielectric function in the measurement of the Casimir effect. There is a certain connection between the Casimir effect as a microscopic picture of quantum fluctuations and the macroscopic force. Since this force effect is only on the order of piconewtons, it is relatively difficult to measure and achieve in parallel metal plates.

[0003] Until later, a force effect consistent with the modified Casimir effect was measured in the atomic force microscope using a sphere-plate experiment. After that, in order to completely eliminate the interference of other force effects such as electrostatic force and calibrate the Casimir force more accurately, new test platforms were explored and built based on the atomic force microscope. For example, a modulated AC voltage can be applied to the sphere, and a modulated AC voltage can be applied to the piezoelectric ceramic. By using the different response characteristics of different forces, the Casimir force, air resistance, and electrostatic force signals can be separated by a lock-in amplifier at different frequencies and phases. In this way, the electrostatic force is effectively excluded, and the variation of the Casimir force gradient with distance is obtained. The use of the atomic force microscope platform simultaneously solves the problems of accuracy, force range, and geometric structure during the measurement of the Casimir effect, and has thus been widely used ever since.

[0004] After that, the Casimir effect has also received further attention and has been measured under different materials and platforms. At the same time, due to its special properties, the Casimir effect has also found many applications. After making a relatively accurate calibration of the Casimir effect, scientific workers began to try to modulate the Casimir force and even further obtain the Casimir repulsive force. A series of experiments have shown that methods such as changing the geometric shape of the interacting objects, changing the dielectric function of the intermediate medium, and using some special materials (such as Weyl semimetals) can enhance or weaken the Casimir attraction or even obtain the Casimir repulsion, which also provides a wide application space for the Casimir effect. Currently, people can observe the Casimir effect in materials and media with different dielectric functions and under the action of external conditions such as magnetic fields, and strive to put the Casimir effect into practical applications. Summary of the Invention

[0005] Based on this, the present invention proposes a preparation method of a measurement probe based on the Casimir effect. Through the method provided by the present invention, cantilever beams can be batch-customized, and the bonding of the probe tip is efficient, precise, and controllable.

[0006] According to one aspect of the present invention, there is provided a method for preparing a measurement probe based on the Casimir effect, comprising:

[0007] Depositing a first silicon nitride layer and a second silicon nitride layer on the upper and lower surfaces of a substrate respectively;

[0008] Using photoresist as a mask to etch the first silicon nitride layer, and forming a first effective region on one side surface of the substrate;

[0009] Growing a covering layer on the substrate to cover the first effective region and the substrate;

[0010] Using photoresist as a mask to etch the second silicon nitride layer, and forming a second effective region on the other side surface of the substrate;

[0011] Using an alkaline solution to remove the substrate not covered by the second effective region;

[0012] Using a buffered oxide etchant to remove the covering layer to obtain a probe cantilever beam;

[0013] Taking a microsphere dispersion and dropping it on a carrier, and drying to obtain microspheres adhered to the carrier;

[0014] Using a displacement platform to dip the tip of the probe cantilever beam into ultraviolet glue;

[0015] Using the displacement platform to adhere the microspheres to the tip through the ultraviolet glue to form a microsphere tip;

[0016] Irradiating the microsphere tip with ultraviolet light to cure the ultraviolet glue, and obtaining the measurement probe including the microsphere tip.

[0017] According to an embodiment of the present invention, wherein the covering layer is formed by alternately growing at least two layers of silicon oxide and at least two layers of silicon nitride, and the thicknesses of the silicon oxide and the silicon nitride are both 200 - 800 nm.

[0018] According to an embodiment of the present invention, wherein the buffered oxide etchant comprises a 49% by mass HF aqueous solution and a 40% by mass NH4F aqueous solution with a volume ratio of 1:7.

[0019] According to an embodiment of the present invention, wherein the probe cantilever beam is 200 - 300 μm long, 20 - 40 μm wide, 200 - 800 nm thick, and the elastic coefficient is between 0.02 N / m and 0.06 N / m.

[0020] According to an embodiment of the present invention, it further comprises in-situ evaporation coating of a metal film to completely cover the surface of the measurement probe including the microsphere tip.

[0021] According to an embodiment of the present invention, wherein the metal film is a gold film or an aluminum film, and the thickness of the metal film is 50 - 300 nm.

[0022] According to an embodiment of the present invention, wherein the microsphere dispersion liquid is an absolute ethanol dispersion liquid including polystyrene microspheres, and the diameter of the polystyrene microspheres is 20 - 150 μm.

[0023] According to an embodiment of the present invention, wherein etching the first silicon nitride layer using a photoresist as a mask to form a first effective region on one side surface of the substrate includes:

[0024] Spin - coat the photoresist on the first silicon nitride layer at a position covering the first effective region, and bake and cure it.

[0025] Expose and develop the photoresist.

[0026] After fixing the photoresist with ultrapure water, heat it on a hot plate to harden the film.

[0027] Use ion etching to remove the silicon nitride on the first silicon nitride layer that is not covered by the photoresist.

[0028] Use an NMP solution to heat in a water bath to remove the photoresist, and form the first effective region of the first silicon nitride layer on one side surface of the substrate.

[0029] According to an embodiment of the present invention, wherein etching the second silicon nitride layer using a photoresist as a mask to form a second effective region on the other side surface of the substrate includes:

[0030] Use reactive ion etching to remove the silicon nitride on the second silicon nitride layer except for the position of the second effective region.

[0031] Use a KOH solution to heat and soak to remove the substrate and the photoresist covered by the second effective region.

[0032] According to one aspect of the present invention, there is provided a measurement probe prepared by using the above - mentioned method.

[0033] It can be seen from the above technical solutions that the preparation method and the probe of the measurement probe based on the Casimir effect provided by the present invention have the following beneficial effects:

[0034] Through micro - nano processing methods, batch preparation of a cantilever beam without a tip can be realized, and the size, thickness, and pattern of the cantilever beam can be customized.

[0035] During the process of etching the back silicon substrate, a deposition masking film is used as a protective layer on the front side, replacing the black wax protection method used in conventional probe preparation. This masking film has good stress balance and will not bring additional stress to the silicon nitride cantilever beam, thus avoiding the problem of beam fracture.

[0036] The displacement platform is used for the needle sticking operation, which can precisely control the amount of glue picked up and the precise alignment of the tip of the cantilever beam and the position of the polystyrene microsphere, ensuring that the tip of the microsphere does not deviate from the center position of the tip of the cantilever beam, with a high success rate.

[0037] For the bonding of the microspheres, ultraviolet glue is used instead of the silver glue or epoxy resin AB glue used in conventional colloidal probe preparation. The AB glue has a high viscosity and requires a certain time for curing, while the viscosity of the ultraviolet glue is appropriate, and in-situ rapid curing can be achieved by irradiating with a portable ultraviolet light pen. Brief Description of the Drawings

[0038] Figure 1 It is a flowchart for the preparation of the probe cantilever beam of the measurement probe in the embodiment of the present invention.

[0039] Figure 2 In the embodiment of the present invention Figure 1 Top view of (d).

[0040] Figure 3 It is a flowchart for the preparation of the microsphere tip of the measurement probe in the embodiment of the present invention.

[0041] Figure 4 It is an electron microscope image of the probe cantilever beam of the measurement probe in the embodiment of the present invention.

[0042] Figure 5 It is an electron microscope image of the microsphere tip of the measurement probe in the embodiment of the present invention.

[0043] Figure 6 It is an electron microscope image of the measurement probe in the embodiment of the present invention.

[0044] In the figure, substrate - 1;

[0045] First silicon nitride layer - 2;

[0046] Second silicon nitride layer - 3;

[0047] First effective region - 4;

[0048] Second effective region - 5;

[0049] Silicon nitride layer one - 6;

[0050] Silicon oxide layer two - 7;

[0051] Silicon nitride layer two - 8;

[0052] Probe cantilever beam - 9;

[0053] Microsphere - 10;

[0054] Carrier - 11;

[0055] Silica layer one - 12. Detailed implementation manners

[0056] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further elaborates on the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0057] Currently, the research on the Casimir force mainly focuses on how to accurately measure and modulate the Casimir force. Since the Casimir force is a long - range force that is greatly affected by the material's dielectric function, by reducing the area of the probe and initiating scanning, the Casimir force can also be used to implement a scanning Casimir microscope. This microscope has the following advantages:

[0058] 1. The Casimir force has a relatively long range and can scan the surface topography at a distance from the sample surface (tens to hundreds of nanometers), thus minimizing the damage to the sample surface as much as possible;

[0059] 2. The Casimir force contains relatively rich information, including surface topography, the dielectric function of materials, plasmon dispersion relations, etc. Some physical properties that are inconvenient to detect by conventional means can be obtained through Casimir scanning.

[0060] In the related art, in order to detect the Casimir force, a triangular - shaped stable cantilever beam is required, and then a PS sphere needs to be adhered as the tip. Currently, the common method is to purchase commercially available cantilevers with fixed sizes and specifications and use silver glue to manually adhere the spheres. This method cannot meet the requirements for different sizes of the cantilever beam and the cleanliness of the tip surface. In addition, due to problems such as the shape of the Casimir sphere and its own electrostatic adsorption, it becomes particularly difficult to fabricate the tip for a scanning Casimir microscope and a high - precision Casimir measurement device. Therefore, based on the above research background, the present invention has invented a new preparation method for a scanning probe based on the measurement of the Casimir effect.

[0061] According to one general inventive concept of the present invention, there is provided a preparation method for a measurement probe based on the Casimir effect, including:

[0062] Step one: Deposit a first silicon nitride layer 2 and a second silicon nitride layer 3 on the upper and lower surfaces of the substrate 1 respectively.

[0063] Step two: Use photoresist as a mask to etch the first silicon nitride layer 2, and form a first effective region 4 on one side surface of the substrate 1.

[0064] Step 3: Grow a covering layer on the substrate 1 to cover the first effective region 4 and the substrate 1.

[0065] Step 4: Use photoresist as a mask to etch the second silicon nitride layer 3, and form a second effective region 5 on the other surface of the substrate 1.

[0066] Step 5: Use an alkaline solution to remove the substrate 1 not covered by the second effective region 5.

[0067] Step 6: Use a buffered oxide etchant to remove the covering layer to obtain the probe cantilever 9.

[0068] Step 7: Take the microsphere dispersion liquid and drop it on the carrier 11, and dry it to obtain the microspheres 10 adhered to the carrier 11.

[0069] Step 8: Use a displacement platform to dip the tip of the probe cantilever 9 into the ultraviolet glue.

[0070] Step 9: Use the displacement platform to adhere the microspheres 10 to the tip through the ultraviolet glue to form a microsphere tip.

[0071] Step 10: Cure the ultraviolet glue by irradiating the microsphere tip with ultraviolet light to obtain a measurement probe including the microsphere tip.

[0072] The batch preparation of the needleless cantilever can be realized by micro-nano processing methods, and the size, thickness, and pattern of the cantilever can be customized;

[0073] During the process of etching the back silicon substrate 1, a deposited covering film is used as a protective layer on the front, replacing the black wax protection method used in the preparation of conventional probes. This covering film has good stress balance and will not bring additional stress to the silicon nitride cantilever, resulting in beam fracture problems;

[0074] The bonding of the microspheres 10 uses ultraviolet glue instead of the epoxy resin AB glue used in the preparation of conventional colloidal probes. The AB glue has a high viscosity and requires a certain time to cure, while the viscosity of the ultraviolet glue is appropriate, and in-situ rapid curing can be achieved by irradiating with a portable ultraviolet light pen.

[0075] Among them, the displacement platform can be an AFM test system.

[0076] Figure 1 It is a flowchart for the preparation of the probe cantilever 9 of the measurement probe according to the embodiment of the present invention.

[0077] (a) is a structural diagram of the substrate 1 of the measurement probe according to the embodiment of the present invention;

[0078] (b) is a structural diagram of Step 1 according to the embodiment of the present invention;

[0079] (c) is the structure of Step 2 according to the embodiment of the present invention Figure I ;

[0080] (d) is the structure of Step 2 of the embodiment of the present invention Figure II ;

[0081] (e) is the structural diagram of Step 3 of the embodiment of the present invention;

[0082] (f) is the structure of Step 4 of the embodiment of the present invention Figure I ;

[0083] (g) is the structure of Step 4 of the embodiment of the present invention Figure II ;

[0084] (h) is the structural diagram of Step 5 of the embodiment of the present invention;

[0085] (i) is the structural diagram of Step 6 of the embodiment of the present invention.

[0086] Figure 2 is in the embodiment of the present invention Figure 1 (d)'s top view.

[0087] As Figure 1 (a) shows that according to the embodiment of the present invention, in Step 1, the substrate 1 can be a 4-inch double-sided polished silicon wafer with a crystal orientation of (100) and a thickness of 300 - 500 μm, for example, it can be a silicon wafer with a thickness of 300 μm, 350 μm, 400 μm, 450 μm, or 500 μm.

[0088] As Figure 1 (b) shows that according to the embodiment of the present invention, in Step 1, the first silicon nitride layer 2 and the second silicon nitride layer 3 can be deposited on both sides of the substrate 1 by low-pressure chemical vapor deposition (LPCVD) with a thickness of 200 - 800 nm and a stress value of 300 MPa of silicon nitride.

[0089] According to the embodiment of the present invention, in Step 2, a photoresist is used as a mask to etch the first silicon nitride layer 2, and a first effective region 4 is formed on one side surface of the substrate 1, including:

[0090] Spin-coat the photoresist on the first silicon nitride layer 2 at the position covering the first effective region 4, and bake and cure it;

[0091] Expose and develop the photoresist;

[0092] After fixing the photoresist with ultrapure water, heat it on a hot plate to harden the film;

[0093] Use ion etching to remove the silicon nitride on the first silicon nitride layer 2 that is not covered by the photoresist;

[0094] Use an NMP solution to heat in a water bath to remove the photoresist, and form the first effective region 4 of the first silicon nitride layer 2 on one side surface of the substrate 1.

[0095] As Figure 1 (c) shows that, according to an embodiment of the present invention, step two specifically includes spin-coating S1813 photoresist with a thickness of 1.2 um on the first silicon nitride layer 2, and baking it on a hot plate at 115 °C for 90 s; exposing it using a SUSS MA6 ultraviolet lithography machine with an exposure dose of 146 mJ / cm2, then developing it with a developer AZ MIF300 for 40 s, fixing it with ultrapure water for 60 s, and finally baking the sample on a hot plate at 115 °C for 2 minutes to harden the film.

[0096] As Figure 1 (d) and Figure 2 show that, according to an embodiment of the present invention, step two further includes using an Oxford NGP80 reactive ion etching machine to remove the silicon nitride film on 2 that is not covered by the photoresist, and removing the photoresist with a buffered oxide etchant in an 80 °C water bath for 10 minutes.

[0097] According to an embodiment of the present invention, in step two, the buffered oxide etchant includes an aqueous solution of HF with a mass fraction of 49% and an aqueous solution of NH4F with a mass fraction of 40% in a volume ratio of 1:7.

[0098] According to an embodiment of the present invention, in step two, the etching time is 15 - 30 minutes.

[0099] According to an embodiment of the present invention, in step three, the cover layer is formed by alternating growth of at least two layers of silicon oxide and at least two layers of silicon nitride, and the thicknesses of both the silicon oxide and the silicon nitride are 200 - 800 nm.

[0100] As Figure 1 (e) shows that, according to an embodiment of the present invention, step three specifically includes using an Oxford PECVD plasma-enhanced chemical vapor deposition to alternately grow a 200 nm silicon oxide layer 12 and a 200 nm silicon nitride layer 6 on the first silicon nitride layer 2 first, and then alternately grow a 500 nm silicon oxide layer 7 and a 500 nm silicon nitride layer 8.

[0101] During the wet etching of the backside silicon, a SiO2 / SiN x alternating film grown by low-pressure chemical vapor deposition PECVD on the front side is used as a protective layer, replacing the black wax protection method used in conventional probe preparation, and avoiding the problems of demolding and removal during the use of black wax.

[0102] The alternately grown SiO2 / SiN x film can well balance the stress and will not bring additional stress to the silicon nitride cantilever beam, resulting in beam fracture problems.

[0103] The main body for preparing the needleless cantilever beam is a silicon wafer with a thickness of 300 - 500 μm. Silicon nitride layers with a thickness of 200 - 800 nm are grown on both sides by LPCVD. First, the cantilever beam pattern is obtained on the front side through dry etching, and then the cantilever beam in the effective area is released and suspended by wet etching from the back side. To prevent the corrosion of the front-side structure during the long-time back-side wet etching process, a new front-side protection method is proposed here, which is to alternately grow 200 nm SiO2 / 200 nm SiN on the surface of the already etched cantilever beam by PECVD x / 500 nm SiO2 / 500 nm SiN x .

[0104] According to an embodiment of the present invention, in step four, using a photoresist as a mask to etch the second silicon nitride layer 3, forming a second effective area 5 on the other surface of the substrate 1 includes:

[0105] Spin-coating the photoresist on the second silicon nitride layer 3 to cover the position of the second effective area 5, and baking and curing;

[0106] Performing exposure and development on the photoresist;

[0107] Using ion etching to remove the silicon nitride on the second silicon nitride layer 3 that is not covered by the photoresist;

[0108] Using a KOH solution for heating and soaking to remove the substrate 1 and the photoresist covered by the second effective area 5.

[0109] As Figure 1 (f) shows, according to an embodiment of the present invention, step four specifically is: Spin-coating a 1.2 μm thick S1813 photoresist on the second silicon nitride layer 3, and baking on a hot plate at 115 °C for 90 s; Using a SUSS MA6 ultraviolet lithography machine for overlay exposure, with an exposure dose of 146 mJ / cm2, then developing with a developer AZ MIF300 for 40 s, and finally placing the sample on a 115 °C hot plate for hard baking for 2 minutes.

[0110] As Figure 1 (g) shows, according to an embodiment of the present invention, step four further includes using an Oxford NGP80 reactive ion etching machine to remove the silicon nitride film on the second silicon nitride layer 3 that is not covered by the photoresist.

[0111] As Figure 1 (h) shows, according to an embodiment of the present invention, step five specifically is to soak the sample in an 80 °C KOH solution to completely remove the substrate 1 that is not covered by the photoresist and the second silicon nitride layer 3, and the etching time is 10 hours.

[0112] As Figure 1(i) As shown, according to an embodiment of the present invention, step six specifically involves using a buffered oxide etchant with a volume ratio of 49% HF aqueous solution: 40% NH4F aqueous solution = 1:7 to remove the alternately grown silicon oxide layer 12, silicon nitride layer 6, silicon oxide layer 7, and silicon nitride layer 8. The etching time is 25 minutes, and finally a silicon nitride cantilever beam without a tip is obtained.

[0113] Figure 4 This is an electron micrograph of the probe cantilever 9 of the measurement probe in the embodiment of the present invention.

[0114] As Figure 4 shown, according to an embodiment of the present invention, in step six, the probe cantilever 9 has a length of 200 - 300 μm, a width of 20 - 40 μm, a thickness of 200 - 800 nm, and an elastic coefficient between 0.02 N / m and 0.06 N / m.

[0115] Figure 3 This is a flowchart for preparing the microsphere tip of the measurement probe in the embodiment of the present invention.

[0116] (a) shows the structure of step seven in the embodiment of the present invention Figure I ;

[0117] (b) shows the structure of step seven in the embodiment of the present invention Figure II ;

[0118] (c) shows the structure of step eight in the embodiment of the present invention Figure I ;

[0119] (d) shows the structure of step eight in the embodiment of the present invention Figure II ;

[0120] (e) shows the structure diagram of step nine in the embodiment of the present invention;

[0121] (f) shows the structure diagram of step ten in the embodiment of the present invention.

[0122] Figure 5 This is an electron micrograph of the microsphere tip of the measurement probe in the embodiment of the present invention.

[0123] As Figure 3 (a) and Figure 3 (b) shown, according to an embodiment of the present invention, step seven specifically involves taking an appropriate amount of a polystyrene microsphere 10 solution with a diameter of 50 μm and dropping it into a beaker containing absolute ethanol for ultrasonic dispersion. Then, 200 μl of the solution is measured with a pipette and dropped onto a clean coverslip, and then dried and left to cool to room temperature.

[0124] According to an embodiment of the present invention, in step seven, the microsphere dispersion is an absolute ethanol dispersion including polystyrene microspheres 10, and the diameter of the polystyrene microspheres 10 is 20 - 150 μm.

[0125] As Figure 3 (c) and Figure 3 (d) show, according to an embodiment of the present invention, step eight specifically is to pick up a tip-sized amount of ultraviolet glue onto a coverslip, place this coverslip on the experimental table, use a displacement platform to bring the needleless cantilever beam close to the surface of the ultraviolet glue, pick up a small amount of ultraviolet glue and then move the needleless cantilever beam upward, and adjust the XY horizontal direction by moving left and right to make the sample stage find a suitable polystyrene microsphere 10.

[0126] As Figure 3 (e) show, according to an embodiment of the present invention, step nine specifically is to slowly control the needleless cantilever beam to descend, and at the same time move left and right to make the microsphere 10 directly below the cantilever beam. The cantilever beam descends until it touches the microsphere 10, and wait for a few seconds and then move the cantilever beam upward.

[0127] As Figure 3 (f) and Figure 5 show, according to an embodiment of the present invention, step ten specifically is to simultaneously use a portable ultraviolet light pen to irradiate the tip position to quickly cure the ultraviolet glue, and finally obtain a probe with a polystyrene microsphere 10 adhered thereto.

[0128] According to an embodiment of the present invention, it further includes performing a full-coverage in-situ evaporation coating of a metal film on the surface of the measurement probe including the microsphere tip.

[0129] According to an embodiment of the present invention, the metal film is a gold film or an aluminum film, and the thickness of the metal film is 50 - 300 nm.

[0130] The bonding of the polystyrene microsphere 10 uses ultraviolet glue instead of the epoxy resin AB glue used in the preparation of conventional colloidal probes. The AB glue has a high viscosity and requires a certain time to cure, while the viscosity of the ultraviolet glue is appropriate, and in-situ rapid curing can be achieved by irradiating with a portable ultraviolet light pen.

[0131] The highly efficient, precise and controllable integrated needle-bonding technology is to use a displacement platform to bond a polystyrene microsphere 10 with a diameter of 20 - 150 μm to the top of the prepared cantilever beam through ultraviolet glue. Due to the precise control of AFM operation, the efficiency and accuracy of the bonding technology can be guaranteed, and at the same time, the surface of the microsphere 10 and the beam are smooth and clean. Except for the bonding part, there is no excess glue, and the ultraviolet glue can be directly cured in-situ by ultraviolet lamp irradiation without long-term baking.

[0132] Using a displacement platform for needle-bonding operation can precisely control the amount of glue picked up, as well as the precise alignment of the tip of the cantilever beam and the position of the polystyrene microsphere 10, ensuring that the microsphere tip does not deviate from the center position of the tip of the cantilever beam, with a high success rate;

[0133] Using a self-made Bluetooth-controlled rotating sample stage, a 5nm Cr / 50nm Au full-coverage in-situ evaporation was achieved on the surface of the cantilever beam and the microsphere 10 through two rotations of the sample rod in a thermal evaporation device, without the need to open the chamber and manually change the probe evaporation direction.

[0134] Figure 6 This is the electron microscope image of the measurement probe in the embodiment of the present invention.

[0135] According to the general inventive concept of one aspect of the present invention, a measurement probe prepared by a utilization method is provided.

[0136] Through micro-nano processing, batch preparation of cantilever beams without tips can be achieved, and the size, thickness, and pattern of the cantilever beams can be customized;

[0137] During the etching of the back silicon substrate 1, a deposition masking film is used as a protective layer on the front, replacing the black wax protection method used in the preparation of conventional probes. This masking film has good stress balance and will not bring additional stress to the silicon nitride cantilever beam, resulting in beam fracture problems;

[0138] The bonding of the microsphere 10 uses ultraviolet glue instead of the silver glue or epoxy resin AB glue used in the preparation of conventional colloidal probes. The AB glue has a high viscosity and requires a certain time to cure, while the viscosity of the ultraviolet glue is appropriate, and in-situ rapid curing can be achieved by irradiating with a portable ultraviolet light pen.

[0139] The specific embodiments described above further elaborate on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only for the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a measurement probe based on the Casimir effect, comprising: Depositing a first silicon nitride layer and a second silicon nitride layer on the upper and lower surfaces of a substrate respectively; Using photoresist as a mask to etch the first silicon nitride layer, and forming a first effective region on one side surface of the substrate; Growing a covering layer on the substrate to cover the first effective region and the substrate; Using photoresist as a mask to etch the second silicon nitride layer, and forming a second effective region on the other side surface of the substrate; Removing the substrate not covered by the second effective region by using an alkaline solution; Removing the covering layer by using a buffered oxide etchant to obtain a probe cantilever beam; Taking a microsphere dispersion liquid and dropping it on a carrier, and drying to obtain microspheres adhered to the carrier; Using a displacement platform to dip the tip of the probe cantilever beam into ultraviolet glue; Using the displacement platform to adhere the microspheres to the tip through the ultraviolet glue to form a microsphere tip; Irradiating the microsphere tip with ultraviolet light to cure the ultraviolet glue, and obtaining the measurement probe including the microsphere tip.

2. The method according to claim 1, wherein, The covering layer is formed by alternately growing at least two layers of silicon oxide and at least two layers of silicon nitride, and the thicknesses of both the silicon oxide and the silicon nitride are 200 - 800 nm.

3. The method according to claim 1, wherein, The buffered oxide etchant includes an HF aqueous solution with a mass fraction of 49% and an NH4F aqueous solution with a mass fraction of 40% in a volume ratio of 1:

7.

4. The method according to claim 1, wherein, The probe cantilever beam has a length of 200 - 300 μm, a width of 20 - 40 μm, a thickness of 200 - 800 nm, and an elastic coefficient between 0.02 N / m and 0.06 N / m.

5. The method according to claim 1, wherein It further includes in-situ evaporation coating of a metal film over the entire surface of the measurement probe including the microsphere tip.

6. The method according to claim 5, wherein The metal film is a gold film or an aluminum film, and the thickness of the metal film is 50 - 300 nm.

7. The method according to claim 1, wherein The microsphere dispersion liquid is an anhydrous ethanol dispersion liquid including polystyrene microspheres, and the diameter of the polystyrene microspheres is 20 - 150 μm.

8. The method according to claim 1, wherein The step of using photoresist as a mask to etch the first silicon nitride layer and forming a first effective region on one side surface of the substrate includes: Spinning the photoresist on the first silicon nitride layer at the position covering the first effective region, and baking and curing; Exposing and developing the photoresist; After fixing the photoresist with ultrapure water, heating on a hot plate for hardening the film; Using reactive ion etching to remove the silicon nitride on the first silicon nitride layer not covered by the photoresist; Removing the photoresist by heating the NMP solution in a water bath, and forming the first effective region of the first silicon nitride layer on one side surface of the substrate.

9. The method according to claim 1, wherein The step of using photoresist as a mask to etch the second silicon nitride layer and forming a second effective region on the other side surface of the substrate includes: Using reactive ion etching to remove the silicon nitride on the second silicon nitride layer except for the position of the second effective region; Removing the substrate covered by the second effective region by heating and soaking in a KOH solution.

10. A measurement probe prepared by using the method according to any one of claims 1 - 9.

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