Electrochemical etching processing method of palladium alloy needle tip and solution

Abstract

The invention provides an electrochemical etching processing method of a palladium alloy needle tip and a solution. The electrochemical etching processing method of the palladium alloy needle tip comprises the steps that a solution is prepared, the solution comprises phosphoric acid, a blocking agent, water, edible rock sugar syrup and ethylene glycol, the phosphoric acid, the blocking agent, the water, the edible rock sugar syrup and the ethylene glycol are proportioned according to the volume fraction of a: b: c: d: e, 0.1-1 g of a reducing agent is added into every 1000 ml of the solution, a belongs to (8 and 20), b belongs to (2 and 15), c belongs to (30 and 200), d belongs to (15 and 110), and e belongs to (0.5 and 3); switching on a direct-current power supply according to the set voltage upper limit and current upper limit until a preset power-on time is reached, the anode of the direct-current power supply is connected with the palladium alloy needle tip, and the cathode of the direct-current power supply is connected with the graphite cathode; and the palladium alloy needle tip is taken out, baked and cleaned, and the processed palladium alloy needle tip is obtained.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical machining, and in particular to an electrochemical etching method for palladium alloy tips and a solution for electrochemical etching. Background Art

[0002] With the rapid development of micro-nano technology, nano tips have been widely used in fields such as scanning tunneling microscopy, cell micro-operation, and micro-fabrication. Preparing high-quality nano tips has become one of the key technologies. Currently, the commonly used methods for preparing nano tips include lithography technology, electron beam induced deposition, laser pyrolysis, physical chemical vapor deposition, electrochemical etching, etc. Among them, the electrochemical etching method is widely adopted due to its advantages such as simple equipment, convenient operation, and low cost.

[0003] However, there are some deficiencies in the traditional electrochemical etching method for preparing nano tips. First, it is difficult to precisely control the morphology and size of the tips by the traditional electrochemical etching method, so it cannot meet the requirements of specific applications. Second, in the traditional electrochemical etching method, usually only a single tip can be prepared in one operation, and the production efficiency is low. Third, the surface of the tips prepared by the traditional electrochemical etching method is rough, which increases the surface friction of the needle and the contact resistance of the tip. In addition, improper treatment of the waste liquid generated during the electrochemical etching process will cause environmental pollution.

[0004] In order to overcome the above-mentioned defects existing in the prior art, there is an urgent need in the art for an electrochemical etching method for palladium alloy tips and a solution for electrochemical etching, which can prepare palladium alloy nano tips with a smooth surface, uniform size, and excellent morphology, and are easy to operate and low in cost. Summary of the Invention

[0005] The following presents a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to attempt to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0006] In order to overcome the above-mentioned defects existing in the prior art, the present invention provides an electrochemical etching method for palladium alloy tips and a solution for electrochemical etching, which can prepare palladium alloy nano tips with a smooth surface, uniform size, and excellent morphology, and are easy to operate and low in cost.

[0007] Specifically, the electrochemical etching method for the palladium alloy tip provided by the first aspect of the present invention includes the steps of: preparing a solution, the solution including phosphoric acid, a blocking agent, water, edible rock sugar syrup, and ethylene glycol, with the volume fraction ratio of phosphoric acid, the blocking agent, water, edible rock sugar syrup, and ethylene glycol being a:b:c:d:e, and adding 0.1 - 1 g of a reducing agent to every 1000 ml of the solution, where a ∈ (8, 20), b ∈ (2, 15), c ∈ (30, 200), d ∈ (15, 110), e ∈ (0.5, 3); connecting a DC power supply according to the set upper voltage limit and upper current limit until the preset power-on time is reached, where the anode of the DC power supply is connected to the palladium alloy tip, and the cathode of the DC power supply is connected to a graphite cathode; and taking out the palladium alloy tip and performing baking and cleaning to obtain the processed palladium alloy tip.

[0008] Preferably, in an embodiment of the present invention, the volume fraction of water is 3 - 5 times the volume fraction of phosphoric acid, the volume fraction of water is 7 - 10 times the volume fraction of the blocking agent, the volume fraction of water is 1.5 - 5 times the volume fraction of edible rock sugar syrup, and the volume fraction of water is 90 - 130 times the volume fraction of ethylene glycol.

[0009] Preferably, in an embodiment of the present invention, the palladium alloy tip is multiple palladium alloy tips, and the multiple palladium alloy tips are fixed by a ceramic plate.

[0010] Preferably, in an embodiment of the present invention, the ceramic plate clamps the multiple palladium alloy tips between an upper part and a lower part, and the upper part is provided with an opening.

[0011] Preferably, in an embodiment of the present invention, the palladium alloy tip further includes a pretreatment step: sequentially placing the palladium alloy tip in acetone, dilute sulfuric acid, and 75% alcohol for ultrasonic cleaning, and the cleaning time is 1 - 10 minutes.

[0012] Preferably, in an embodiment of the present invention, the step of connecting the DC power supply according to the set upper voltage limit and upper current limit includes: connecting the DC power supply using a constant current control method, and the current density is 0.5 - 20 A / cm 2 。

[0013] Preferably, in an embodiment of the present invention, the initial temperature of the solution is 18 - 28 °C and the initial temperature of the solution is higher than the initial temperature of the process environment.

[0014] Preferably, in an embodiment of the present invention, the humidity of the process environment is 50% - 70%.

[0015] Preferably, in an embodiment of the present invention, the baking temperature is 40 - 70 °C, and the baking time is 40 - 80 min.

[0016] Preferably, in an embodiment of the present invention, the tip length of the processed palladium alloy tip is 100 - 800 μm, and the tip width is 2 - 30 μm.

[0017] In addition, according to the solution for electrochemical etching processing provided by the second aspect of the present invention, the solution is composed of phosphoric acid, a blocker, water, edible rock sugar syrup, and ethylene glycol according to the volume fraction ratio of a:b:c:d:e, and 0.1 - 1 g of a reducing agent is added to every 1000 ml of the solution, where a ∈ (8, 20), b ∈ (2, 15), c ∈ (30, 200), d ∈ (15, 110), and e ∈ (0.5, 3).

[0018] Preferably, in an embodiment of the present invention, the volume fraction of water is 3 - 5 times that of phosphoric acid, the volume fraction of water is 7 - 10 times that of the blocker, the volume fraction of water is 1.5 - 5 times that of edible rock sugar syrup, and the volume fraction of water is 90 - 130 times that of ethylene glycol. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] After reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings, the above features and advantages of the present invention can be better understood. In the drawings, the components are not necessarily drawn to scale, and components with similar relevant characteristics or features may have the same or similar reference numerals.

[0020] Figure 1 Shows a flowchart of a method for electrochemical etching processing of a palladium alloy tip according to some embodiments of the present invention;

[0021] Figure 2 Shows a schematic diagram of a ceramic plate according to some embodiments of the present invention;

[0022] Figure 3 Shows an effect diagram of a needle row after etching processing according to some embodiments of the present invention;

[0023] Figure 4 Shows a schematic diagram of the effect of a processed palladium alloy tip according to some embodiments of the present invention;

[0024] Figure 5 Shows a schematic diagram of the effect of each palladium alloy tip in a processed palladium alloy tip array according to Embodiment 1 of the present invention;

[0025] Figure 6 Shows a schematic diagram of the effect of each palladium alloy tip in a processed palladium alloy tip array according to Embodiment 2 of the present invention;

[0026] Figure 7Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Embodiment 3 of the present invention;

[0027] Figure 8 Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Embodiment 4 of the present invention;

[0028] Figure 9 Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Embodiment 5 of the present invention;

[0029] Figure 10 Shows the schematic diagram of the effect of the processed palladium alloy tip provided by Comparative Example 1 of the present invention;

[0030] Figure 11 Shows the schematic diagram of the effect of the processed palladium alloy tip provided by Comparative Example 2 of the present invention;

[0031] Figure 12 Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Comparative Example 3 of the present invention;

[0032] Figure 13 Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Comparative Example 4 of the present invention;

[0033] Figure 14 Shows the schematic diagram of the effects of each palladium alloy tip in the processed palladium alloy tip array provided by Comparative Example 4 of the present invention; and

[0034] Figure 15 Shows the schematic diagram of the effect of the processed palladium alloy tip provided by Comparative Example 5 of the present invention.

[0035] Reference numerals:

[0036] 210: Upper part;

[0037] 211: Opening;

[0038] 220: Lower part;

[0039] 230: Needle row;

[0040] 1310, 1320: Positions; and

[0041] S110~S130: Steps. Detailed embodiments

[0042] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the aspects described below in conjunction with the accompanying drawings and specific embodiments are merely exemplary and should not be construed as imposing any limitations on the protection scope of the present invention.

[0043] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] In addition, the "upper", "lower", "left", "right", "top", "bottom", "horizontal", and "vertical" used in the following description should be understood as the orientations shown in this paragraph and the relevant drawings. This relative term is only for convenience of description and does not represent that the device described needs to be manufactured or operated in a specific orientation, so it should not be construed as a limitation to the present invention.

[0045] It can be understood that although terms such as "first", "second", and "third" can be used herein to describe various components, regions, layers, and / or parts, these components, regions, layers, and / or parts should not be limited by these terms, and these terms are only used to distinguish different components, regions, layers, and / or parts. Therefore, the first component, region, layer, and / or part discussed below can be referred to as the second component, region, layer, and / or part without departing from some embodiments of the present invention.

[0046] As described above, there are some deficiencies in the traditional electrochemical etching method when preparing nano-tips. First, it is difficult to precisely control the morphology and size of the tips by the traditional electrochemical etching method, so it cannot meet the requirements of specific applications. Second, in the traditional electrochemical etching method, usually only a single tip can be prepared in one operation, and the production efficiency is low. Third, the surface of the tips prepared by the traditional electrochemical etching method is rough, which increases the surface friction of the needle and the contact resistance of the tip. In addition, improper treatment of the waste liquid generated during the electrochemical etching process will cause environmental pollution.

[0047] In order to overcome the above-mentioned defects existing in the prior art, there is an urgent need in the art for an electrochemical etching processing method for palladium alloy tips and a solution for electrochemical etching processing, which can prepare palladium alloy nano-tips with a smooth surface, uniform size, and excellent morphology, and are easy to operate and low in cost.

[0048] The following will be combined with Figure 1The electrochemical etching method of a palladium alloy tip provided by some embodiments of the present invention is described in detail.

[0049] In some embodiments, preparation work can be carried out first to implement the electrochemical etching method of the palladium alloy tip. The preparation work can include the pretreatment of the palladium alloy tip and the preparation of the ceramic plate.

[0050] Specifically, the pretreatment of the palladium alloy tip can first place the palladium alloy tip in acetone, dilute sulfuric acid, and 75% alcohol in sequence for ultrasonic cleaning, and the cleaning time is 1 - 10 minutes. Then, the cleaned palladium alloy probe is put into alcohol for sealed storage.

[0051] In addition, before implementing the electrochemical etching process, a ceramic plate with a specific shape for placing and fixing at least one palladium alloy tip can be prepared through processes such as cutting. The material of the ceramic plate can be Si3N4 (silicon nitride), and the shape of the ceramic plate can be determined by the model and quantity of the probe.

[0052] Then, as Figure 1 shown, perform step S110: Prepare a solution. The solution includes phosphoric acid, a blocking agent, water, edible rock sugar syrup, and ethylene glycol. Phosphoric acid, the blocking agent, water, edible rock sugar syrup, and ethylene glycol are proportioned according to the volume fractions of a:b:c:d:e, and 0.1 - 1 g of a reducing agent is added to every 1000 ml of the solution, where a ∈ (8, 20), b ∈ (2, 15), c ∈ (30, 200), d ∈ (15, 110), and e ∈ (0.5, 3).

[0053] Preferably, the volume fraction of water is 3 - 5 times that of phosphoric acid, the volume fraction of water is 7 - 10 times that of the blocking agent, the volume fraction of water is 1.5 - 5 times that of edible rock sugar syrup, and the volume fraction of water is 90 - 130 times that of ethylene glycol. Since the solution will evaporate during the tip etching process, when the proportion of water is larger, the instability caused by the increase in solute concentration due to solution evaporation can be reduced. For example, the volume fraction of water can be more than 2 times that of edible rock sugar syrup, which can give full play to the role of edible rock sugar syrup while avoiding the solution from being viscous due to too little water, reducing the diffusion rate of the solute, and affecting the heat dissipation of the solution.

[0054] After adding the reducing agent according to the above solution components and solution ratio, stir evenly to obtain the prepared solution. The prepared solution can achieve precise control of the tip morphology and size through the optimized solution components and solution ratio.

[0055] Here, the blocking agent can include polyethylene glycol, and the reducing agent can include ascorbic acid or glutathione.

[0056] Phosphoric acid in the solution composition is a polybasic medium-strength acid, which can generate a viscous film layer on the surface of the workpiece and in the anodic region. Compared with strong acids, it can effectively reduce the substances entering the solution during the etching process and reduce the impact on the density and viscosity of the solution. Moreover, the viscous film layer can reduce the current density of the anode to control the morphology of the tip, improve the roughness and flatness of the metal surface, and effectively enhance the effect of electrochemical polishing.

[0057] The blocking agent added to the solution composition can generate an adsorption film in the anodic region, thereby causing anodic passivation. The passivation film formed by this adsorption film is thick at the surface depressions and thin at the surface protrusions, thereby achieving the control of the tip morphology and simultaneously significantly improving the surface roughness of the tip.

[0058] In addition, edible rock sugar syrup also has the function of a blocking agent and can improve the tip morphology during tip etching. Moreover, edible rock sugar syrup can also increase the solution density. During the electrochemical etching process, hydrogen gas is generated at the cathode, and a force that pushes the solution away will be formed around the hydrogen gas generated at the cathode. When the solution density is low, the solution cannot fully contact the surface of the workpiece, affecting the polishing efficiency and quality. Therefore, by adding edible rock sugar syrup, the solution density can be increased, enabling the solution to better contact the surface of the workpiece and improving the polishing efficiency and etching quality. However, adding too much edible rock sugar syrup may affect the fluidity of the solution. Therefore, in practical applications, the specific proportion of edible rock sugar syrup can be determined based on the solution temperature and the volume fraction ratio of each solution component provided.

[0059] In addition, the blocking agent and edible rock sugar syrup in the solution can act synergistically to control the morphology of palladium alloy nanoneedles.

[0060] During the electrochemical etching process, the water in the solution will evaporate. Ethylene glycol added to the solution composition can be used to lock water and slow down the evaporation of water. At the same time, ethylene glycol can also lower the freezing point of the solution to prevent the prepared solution from freezing at a lower ambient temperature.

[0061] The reducing agent added to the solution composition can significantly increase the reaction rate of the electrochemical etching process and reduce energy consumption, contributing to more accurate analysis and more reliable control. Moreover, the reducing agent can also affect the electrode potential, thereby affecting the equilibrium state and thermodynamic properties of the electrochemical reaction.

[0062] Thus, under the composition and ratio of the solution provided by the present invention, the components in the solution cooperate and act with each other. Combined with the electrochemical etching processing method of the palladium alloy tip provided by the present invention, palladium alloy nanoneedles with a smooth surface, uniform size, and excellent morphology can be prepared.

[0063] Such as Figure 1As shown, perform step S120: Connect the DC power supply according to the set upper voltage limit and upper current limit until the preset power-on time is reached. Here, the anode of the DC power supply is connected to the palladium alloy tip, and the cathode of the DC power supply is connected to the graphite cathode.

[0064] The anode of the DC power supply is connected to the palladium alloy tip, and the cathode of the DC power supply is connected to the graphite cathode. The graphite cathode can be located in the solution. The palladium alloy tip can be directly immersed in the solution or can be fixed by a ceramic plate and then immersed in the solution. The palladium alloy tip can be multiple palladium alloy tips.

[0065] One operation of the traditional electrochemical etching method can usually only prepare a single tip, with low production efficiency and difficulty in realizing batch preparation.

[0066] In some embodiments, multiple palladium alloy tips can be fixed by the prepared ceramic plate. The ceramic plate is an insulator and does not react with the solution.

[0067] Due to the tolerance in the size of each probe, the ceramic plate can be divided into upper and lower parts to adapt to the shape of the probe and facilitate the removal of the probe.

[0068] Please refer to Figure 2 , Figure 2 which shows a schematic diagram of the ceramic plate provided according to some embodiments of the present invention.

[0069] As Figure 2 shown, the prepared ceramic plate can include an upper part 210 and a lower part 220. The needle row 230 composed of multiple palladium alloy tips can be clamped between the upper part 210 and the lower part 220.

[0070] The upper part 210 can be provided with an opening 211, and during the electrochemical etching process, the opening 211 is completely immersed in the prepared solution.

[0071] Place the needle row 230 according to the shape of the ceramic plate and the determined distance of the tip penetrating into the solution. Specifically, place the needle row 230 on the lower part 220 of the ceramic plate. The distance of the tip of the needle row 230 that extends beyond the opening 211 and is exposed outside the ceramic plate through the opening 211 is the determined distance of the tip penetrating into the solution.

[0072] The distance of the tip penetrating into the solution is the longitudinal length of the needle body in contact with the solution. Different penetration distances result in different surface areas of the probe being energized. The penetration distance can be determined according to the actual situation. In some embodiments, the penetration distance can be 100 μm or 400 μm.

[0073] The prepared ceramic plate can be used to assist multi-tip etching. The ceramic plate can control the contact area of each tip with the solution, thereby adjusting the current distribution. By combining the prepared solution environment that can improve the stability of the tip etching process and controlling the contact area of each tip with the solution through the auxiliary ceramic plate, it is possible to prepare multiple tips with high morphological consistency in one operation. The effect diagram of the needle row 230 after etching is as shown in Figure 3 shown, and the morphology of each tip of the needle row 230 is highly consistent.

[0074] In this way, by fixing multiple palladium alloy tips on the ceramic plate to achieve electrochemical etching processing, batch preparation of nano-tips can be realized, greatly improving production efficiency, with simple operation and low cost.

[0075] More preferably, in some embodiments, a high-precision needle planting arm can also be used to control the immersion of the ceramic plate and the needle row fixed in the ceramic plate into the solution, thereby further improving the processing accuracy and ensuring the tip quality.

[0076] After connecting the anode and cathode of the DC power supply to the palladium alloy tip and the graphite cathode respectively, the upper voltage limit, upper current limit can be adjusted, and the energization time can be determined.

[0077] By controlling the upper voltage limit and upper current limit, the current density in the solution can be controlled. In some embodiments, a constant current control method is used in the electrochemical etching process.

[0078] When different currents are applied, the morphologies of the etched tips are different, and those skilled in the art can adjust the current intensity according to the required morphology of the tips. Under the constant current control method, the actual current is constant. In this way, the actual current, that is, the upper current limit, is consistent with the set energization current.

[0079] Correspondingly, the actual voltage fluctuates. Setting the upper voltage limit can prevent the tip from fusing. Here, the upper voltage limit can be determined by the total resistance of the loop and the set energization current, and it is necessary to ensure that the current value is stable at the maximum value.

[0080] More preferably, in some embodiments, the current density is 0.5 - 20 A / cm 2 .

[0081] The energization time can be determined according to factors such as the upper current limit, the model of the palladium alloy tip, and the intrusion distance. The longer the energization time, the greater the proportion of metal dissolved into the solution.

[0082] During the electrochemical etching process, in addition to controlling the current density, parameters such as solution temperature, environmental humidity, and environmental temperature can also be controlled to avoid large fluctuations in tip quality, thereby making the finished product process more stable.

[0083] The ambient temperature is generally constant. During the electrochemical etching process, the optimal current parameters and solute ratios corresponding to different ambient temperatures are different. Once the ambient temperature changes, the corresponding optimal current parameters and solute ratios will also change accordingly.

[0084] The temperature of the solution affects the diffusion rate of solute ions and the viscosity of the solution. During the electrochemical etching process, the tip acts as an electrode to participate in the reaction and generate heat. Therefore, the solution temperature is in a dynamic change of rising while dissipating heat. Under different ambient temperatures and the same other parameters, the etched tip effects are different. So when setting experimental parameters (such as power supply parameters), the ambient temperature must be noted, and the experimental parameters should be set based on the noted ambient temperature.

[0085] Different initial solution temperatures and initial ambient temperatures will affect the heat dissipation rate of the solution during etching, and thus affect the dynamic change of the solution temperature. In some embodiments, the initial temperature of the solution can be set to 18 - 28 °C, the initial temperature of the environment can be set to 10 - 25 °C, and it is ensured that the initial temperature of the solution is higher than the initial temperature of the environment to ensure higher efficiency at the beginning of etching, reduce the starting voltage, and facilitate solute diffusion, thereby increasing the influence on the diffusion rate of solute ions and reducing the solution viscosity to achieve an ideal etching effect.

[0086] In some embodiments, the humidity of the process environment for electrochemical etching can be 50% - 70%. By increasing the humidity of the process environment, the evaporation of water in the solution can be reduced.

[0087] In addition, by controlling parameters such as the solution temperature and the humidity of the process environment, a large amount of waste liquid can also be avoided during the electrochemical etching process, which has good environmental protection.

[0088] After determining various parameters such as the upper voltage limit, upper current limit, power-on time, initial temperature of the solution, and humidity of the process environment, the DC power supply is turned on. Until the preset power-on time is reached, the palladium alloy tip is taken out of the solution. The taken-out palladium alloy tip can be first sealed and stored in alcohol.

[0089] By precisely controlling key parameters such as the solution ratio, current density, initial temperature of the solution, and environmental humidity, palladium alloy nanometer tips with smooth surfaces, uniform sizes, and excellent morphologies can be prepared, and the service performance of the palladium alloy tips can be improved to meet the requirements of specific applications.

[0090] Such as Figure 1As shown, perform step S130: Take out the palladium alloy tip and bake and clean it to obtain the processed palladium alloy tip. Specifically, the taken-out palladium alloy tip can be first placed in an oven for baking at a temperature of 40-70°C for 40-80 minutes. Then, the palladium alloy tip can be cleaned to obtain a palladium alloy nano-tip with a smooth surface and excellent morphology.

[0091] In some embodiments, the palladium alloy tip can include multiple palladium alloy tips clamped in a ceramic plate. Thus, after baking and cleaning, a palladium alloy nano-tip array with a smooth surface, uniform size, and excellent morphology can be obtained, as Figure 3 shown.

[0092] In some embodiments, the tip length of the processed palladium alloy tip can be 100-800 μm, and the tip width can be 2-30 μm.

[0093] Please refer to Figure 4 , Figure 4 which shows a schematic diagram of the effect of the processed palladium alloy tip provided in some embodiments of the present invention.

[0094] Figure 4 (a) and (b) show two different tip morphologies. Under different solute ratios, power supply parameters, and initial temperatures of the solution, the tip morphologies of the processed palladium alloy tips are different, but the processed palladium alloy tips all have a smooth surface and excellent morphology. Figure 4 (c) is an optical microscope photograph of the tip morphology. Through Figure 4 (c), it can be observed that the tip position shows specular reflection, which means the tip surface is very smooth. Similarly, Figure 4 (d) is an SEM photograph of the tip morphology, and it can be observed that the surface of the tip is very smooth and the roughness is very low.

[0095] The following are five specific embodiments to illustrate the processing effect of the electrochemical etching processing method of the palladium alloy tip proposed by the present invention.

[0096] In the first embodiment, the palladium alloy tip array can be fixed in a ceramic plate, and the leakage distance of the tip at the opening is 600 μm, that is, the intrusion distance is 600 μm.

[0097] In the first embodiment, the solution can be prepared with phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, and ethylene glycol in a volume fraction ratio of 10:5:40:20:3, and 0.2 g of ascorbic acid is added to every 1000 ml of the solution.

[0098] The initial temperature of the environment can be 20 °C, the initial temperature of the solution can be 23 °C, and the upper limit of the current is set to 0.1237 A, the upper limit of the voltage is set to 10 V, and the current density is 1.258 A / cm 2 . After that, the DC power supply is turned on, and baking and cleaning are carried out after 25 minutes of power-on, and a palladium alloy tip with a tip width of about 10 μm is obtained.

[0099] Please refer to Figure 5 , Figure 5 which shows a schematic diagram of the effects of the palladium alloy tips in the processed palladium alloy tip array provided in Embodiment 1 of the present invention.

[0100] As Figure 5 shown, the scale (length unit) is 6 μm. In Embodiment 1, the roughness of the palladium alloy tips in the processed palladium alloy tip array is very low, the surface of the most tip part of each palladium alloy tip is very smooth, and the morphology of each palladium alloy tip has high consistency and excellent morphology.

[0101] In Embodiment 2, the palladium alloy tip array can be fixed in a ceramic plate, and the intrusion distance of the tip is 500 μm.

[0102] In Embodiment 2, the solution can be prepared by mixing phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, and ethylene glycol according to a volume fraction ratio of 11:6:40:18:1, and 0.1 g of ascorbic acid is added to every 1000 ml of the solution.

[0103] The initial temperature of the environment can be 20 °C, the initial temperature of the solution can be 25 °C, and the upper limit of the current is set to 0.0975 A, the upper limit of the voltage is set to 10 V, and the current density is 1.211 A / cm 2 . After that, the DC power supply is turned on, and baking and cleaning are carried out after 27 minutes of power-on, and a palladium alloy tip with a tip width of about 4 μm is obtained.

[0104] Please refer to Figure 6 , Figure 6 which shows a schematic diagram of the effects of the palladium alloy tips in the processed palladium alloy tip array provided in Embodiment 2 of the present invention.

[0105] As Figure 6 shown, the scale (length unit) is 10 μm. In Embodiment 2, the palladium alloy tips in the processed palladium alloy tip array present as smooth tips, with a very smooth surface, excellent morphology, and consistent size.

[0106] In Embodiment 3, the palladium alloy tip array can be fixed in a ceramic plate, and the intrusion distance of the tip is 300 μm.

[0107] In Example 3, the solution can be prepared by mixing phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, and ethylene glycol in a volume fraction ratio of 9:7:40:22:1, and 0.1 g of glutathione is added to every 1000 ml of the solution.

[0108] The initial temperature of the environment can be 25 °C, the initial temperature of the solution can be 28 °C, the upper limit of the current is set to 0.1800 A, the upper limit of the voltage is set to 10 V, and the current density is 1.992 A / cm 2 . After that, the DC power supply is turned on, and baking and cleaning are carried out after 27 minutes of power-on to obtain a palladium alloy tip with a tip width of about 3 μm.

[0109] Please refer to Figure 7 , Figure 7 which shows the effect schematic diagram of each palladium alloy tip in the processed palladium alloy tip array provided in Example 3 of the present invention.

[0110] As Figure 7 shown in the optical microscope photograph of the tip morphology, in Example 3, the tip position of each palladium alloy tip in the processed palladium alloy tip array is specular reflection, the tip surface is very smooth, and the morphology consistency of the shown tips is high.

[0111] In Example 4, the palladium alloy tip array can be fixed in a ceramic plate, and the intrusion distance of the tip is 300 μm.

[0112] In Example 4, the solution can be prepared by mixing phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, and ethylene glycol in a volume fraction ratio of 20:15:100:15:2, and 1 g of glutathione is added to every 1000 ml of the solution.

[0113] The initial temperature of the environment can be 18 °C, the initial temperature of the solution can be 21 °C, the upper limit of the current is set to 0.1500 A, the upper limit of the voltage is set to 20 V, and the current density is 1.859 A / cm 2 . After that, the DC power supply is turned on, and baking and cleaning are carried out after 20 minutes of power-on to obtain a palladium alloy tip with a tip width of about 6 μm.

[0114] Please refer to Figure 8 , Figure 8 which shows the effect schematic diagram of each palladium alloy tip in the processed palladium alloy tip array provided in Example 4 of the present invention.

[0115] As Figure 8 shown, the scale (length unit) is 6 μm. In Example 4, the roughness of each palladium alloy tip in the processed palladium alloy tip array is very low, the surface of the most tip part of each palladium alloy tip is very smooth, the morphology consistency of each palladium alloy tip is high and the morphology is excellent.

[0116] In Example 5, the palladium alloy tip array can be fixed within a ceramic plate, and the penetration distance of the tips is 600 μm.

[0117] In Example 5, the solution can be prepared with phosphoric acid, polyethylene glycol, water, edible rock sugar syrup, and ethylene glycol in a volume fraction ratio of 10:5:40:20:1, and 0.1 g of glutathione is added to every 1000 ml of the solution.

[0118] The initial temperature of the environment can be 20 °C, the initial temperature of the solution can be 21 °C, the upper limit of the current is set to 0.3 A, the upper limit of the voltage is set to 20 V, and the current density is 18 A / cm 2 . Then, a DC power supply is turned on, and baking and cleaning are performed after 8 minutes of power-on to obtain palladium alloy tips with a tip width of approximately 2 μm.

[0119] Please refer to Figure 9 , Figure 9 , which shows a schematic diagram of the effects of the respective palladium alloy tips in the processed palladium alloy tip array provided in Example 5 of the present invention.

[0120] As Figure 9 shown, the scale (length unit) is 6 μm. In Example 5, the surfaces of the respective palladium alloy tips in the processed palladium alloy tip array are very smooth, with excellent morphology and consistent dimensions.

[0121] It can be seen that the electrochemical etching process for palladium alloy tips provided by the present invention can precisely control the solution composition and solution ratio, and precisely control the current density in combination with the upper limit of the voltage and the upper limit of the current. By combining key parameters such as temperature and humidity, palladium alloy nano-tips with smooth surfaces and excellent morphology can be prepared, meeting the requirements of specific applications and improving the performance of the tips; with the assistance of a ceramic plate, a palladium alloy tip array with uniform dimensions and high morphological consistency can be batch-produced, with simple operation, low cost, and improved production efficiency.

[0122] Next, the processing effects of the electrochemical etching process for palladium alloy tips proposed by the present invention will be further elaborated with reference to the following five comparative examples.

[0123] Please refer to Figure 10 , Figure 10 , which shows a schematic diagram of the effects of the processed palladium alloy tips provided in Comparative Example 1 of the present invention.

[0124] In Comparative Example 1, the components of the solution used for etching are nitric acid, sulfuric acid, hydrochloric acid, and water, and nitric acid, sulfuric acid, hydrochloric acid, and water are prepared in a volume fraction ratio of 4:2:2:40.

[0125] Sulfuric acid and hydrochloric acid are strong oxidants that can improve the conductivity of the solution during the electrochemical reaction, thereby improving production efficiency. However, too high a solution conductivity is not conducive to controlling the needle tip morphology, because too high a solution conductivity will reduce the accuracy of controlling the power supply parameters (voltage / current).

[0126] Given that the area of ​​the needle tip is very small, compared to other electrochemical etching situations, the total current required by the needle tip is smaller while ensuring the same current per unit area. Therefore, in order to achieve the desired effect, more precise control of parameters such as current is required.

[0127] Therefore, adding oxidizing acids such as sulfuric acid and hydrochloric acid to the solution is not conducive to controlling the needle tip morphology.

[0128] like Figure 10 As shown, the scale (unit of length) is 6 μm. In comparative example 1, when the solution components are oxidizing acid and water, the surface quality of the etched needle tip is very poor. The etching is uneven, resulting in an uneven surface of the needle.

[0129] Please refer to Figure 11 , Figure 11 A schematic diagram showing the effect of the processed palladium alloy needle tip provided in Comparative Example 2 of the present invention is shown.

[0130] In Comparative Example 2, the components of the etching solution are nitric acid, sulfuric acid, hydrochloric acid, water, polyethylene glycol and ethylene glycol, and the nitric acid, sulfuric acid, hydrochloric acid, water, polyethylene glycol and ethylene glycol are prepared according to a volume fraction ratio of 4:2:2:40:5:2.

[0131] Due to the addition of oxidizing acid in the solution, the conductivity of the etching solution is too high, and the blocking agent polyethylene glycol cannot play an effective role. Figure 11 As shown, the scale (unit of length) is 20 μm. The surface of the palladium alloy needle tip obtained in Comparative Example 2 is uneven. In addition, Comparative Example 2 uses an oxidizing acid as an etching solution. Figure 6 By comparing the palladium alloy needle tip obtained in Example 2 shown, it can be seen that the tip part of the palladium alloy needle tip obtained in Comparative Example 2 is still a square needle. Compared with before etching, its size is only proportionally reduced, and it does not present the smooth tip of Example 2.

[0132] Please refer to Figure 12 , Figure 12 A schematic diagram showing the effect of each palladium alloy needle tip in the processed palladium alloy needle tip array provided in Comparative Example 3 of the present invention is shown.

[0133] In comparative example 3, the components of the solution used for etching are phosphoric acid and water, and the phosphoric acid and water are prepared according to a volume fraction ratio of 1:1. Figure 12As shown, the scale (length unit) is 10 μm. Compared with the above five embodiments, in Comparative Example 3, only phosphoric acid was added for etching. After the etching process, the tip of the palladium alloy tip obtained is sharp, but the surface quality is relatively rough. Moreover, the consistency of the tip morphology of each palladium alloy tip in the palladium alloy tip array obtained after the etching process is not good. Some tips are sharp, while some tips are rounder.

[0134] Please refer to Figure 13 and Figure 14 , Figure 13 and Figure 14 which show the effect diagrams of each palladium alloy tip in the processed palladium alloy tip array provided by Comparative Example 4 of the present invention.

[0135] In Comparative Example 4, the composition of the solution for etching is phosphoric acid, polyethylene glycol, and water, and phosphoric acid, polyethylene glycol, and water are formulated according to a volume fraction ratio of 1:1:4.

[0136] As Figure 13 shown, adding polyethylene glycol to the solution in Comparative Example 4 can make the surface of the tip smooth and without burrs. However, the corrosion effect of the needle is too large, resulting in inconsistent tip morphology after etching.

[0137] Compared with Figure 3 the needle row after etching in Figure 3 as shown, the edge of the tip is overly smooth and there are no mutation points. However, in Figure 13 as shown at positions 1310 and 1320, obvious smoothness mutation points can be observed on the etched tips provided by Comparative Example 4. In the case where there are mutation points at the tip edge, the morphology consistency of the etched tips will be very poor. It can be seen that the tip edge etched based on the solution provided by the present invention is smooth and without mutation points, so the morphology consistency of the etched needle row is very high.

[0138] The experimental results of multiple etched tips provided by Comparative Example 4 are as Figure 14 shown, and the morphology of each probe can be observed with the naked eye to be very different. This shows that under the same experimental parameters, the probe widths of the probes provided by Comparative Example 4 are inconsistent and asymmetric.

[0139] In addition, adding blocking agents such as polyethylene glycol to the solution can make the tip maintain a flat head shape after etching. As can be seen from Figure 14 , most of the metal of the tip has become cations and dissolved in the solution, but the tip part of the tip can still maintain a flat head, instead of showing the round head tip shape of the tip etched with the solution of only phosphoric acid as in Figure 12 shown in Comparative Example 3.

[0140] Please refer to Figure 15 , Figure 15The figure shows a schematic diagram of the effect of the processed palladium alloy tip provided by Comparative Example 5 according to the present invention.

[0141] In Comparative Example 5, the components of the solution for etching are phosphoric acid, edible rock sugar syrup, and water, and phosphoric acid, edible rock sugar syrup, and water are formulated according to a volume fraction ratio of 1:1:4.

[0142] Figure 15 The scale (length unit) is 10 μm. As Figure 15 shown, adding edible rock sugar syrup to the solution can significantly change the surface morphology of the tip part of the tip, making the surface very smooth and it is difficult to observe surface defects. The roughness of the needle body part at the upper end of the tip is below 0.1 μm, and the roughness is very low. It can be seen from Figure 15 that the tip part of the tip is obviously smoother than the position of the needle body, which indicates that the tip part of the tip is very smooth. Adding edible rock sugar syrup to the solution helps to improve the surface finish of the tip. A smooth tip can reduce the friction between the tip and the wafer when contacting the wafer and increase the service life of the tip.

[0143] Correspondingly, in the components of the solution for electrochemical etching provided by the present invention, it includes phosphoric acid, a blocking agent, and edible rock sugar syrup. Those skilled in the art can control the morphology of the tip to be "square" or "conical" or between the two by adjusting the relative proportions of the blocking agent polyethylene glycol and edible rock sugar syrup, as Figure 8 the processed tip provided in Example 4, Figure 9 the processed tip provided in Example 5 in Figure 5 and the processed tip provided in Example 1 in

[0144] shown. On this basis, by adjusting the upper limit of the current and the energization time, the electrochemical etching processing method of the palladium alloy tip provided by the present invention can further adjust the width of the tip to control the tip to become round or square.

[0145] In summary, based on the above embodiments and comparative examples, it can be seen that the palladium alloy nano-tips prepared by the electrochemical etching processing method of the palladium alloy tip provided by the present invention have a smooth surface, uniform size, excellent morphology, and the electrochemical etching processing method of the palladium alloy tip is easy to operate and has a low cost.

[0146] The previous description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples and designs described herein, but should be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An electrochemical etching method for a palladium alloy tip, characterized in that, Including the steps: Prepare a solution, the solution includes phosphoric acid, a blocking agent, water, edible rock sugar syrup and ethylene glycol, and the phosphoric acid, the blocking agent, water, edible rock sugar syrup and ethylene glycol are proportioned according to the volume fractions of a:b:c:d:e. 0.1 - 1 g of a reducing agent is added to every 1000 ml of the solution, where a ∈ (8, 20), b ∈ (2, 15), c ∈ (30, 200), d ∈ (15, 110), e ∈ (0.5, 3); Connect a DC power supply according to the set upper limit of voltage and upper limit of current until a preset energization time is reached. Among them, the anode of the DC power supply is connected to the palladium alloy tip, and the cathode of the DC power supply is connected to the graphite cathode; and Take out the palladium alloy tip and perform baking and cleaning to obtain the processed palladium alloy tip.

2. The electrochemical etching method according to claim 1, wherein The volume fraction of water is 3 - 5 times the volume fraction of phosphoric acid, the volume fraction of water is 7 - 10 times the volume fraction of the blocking agent, the volume fraction of water is 1.5 - 5 times the volume fraction of edible rock sugar syrup, and the volume fraction of water is 90 - 130 times the volume fraction of ethylene glycol.

3. The electrochemical etching method according to claim 1, characterized in that, The palladium alloy tip is multiple palladium alloy tips, and the multiple palladium alloy tips are fixed by a ceramic plate.

4. The electrochemical etching method according to claim 3, wherein, The ceramic plate clamps the multiple palladium alloy tips between the upper part and the lower part, and the upper part is provided with an opening.

5. The electrochemical etching method according to claim 1, characterized in that, The palladium alloy tip further includes a pretreatment step: Place the palladium alloy tip in acetone, dilute sulfuric acid and 75% alcohol in sequence for ultrasonic cleaning, and the cleaning time is 1 - 10 minutes.

6. The electrochemical etching method according to claim 1, characterized in that, The step of connecting the DC power supply according to the set upper limit of voltage and upper limit of current includes: The DC power supply is turned on by using a constant current control method, and the current density is 0.5 - 20 A / cm 2 .

7. The electrochemical etching method according to claim 1, characterized in that, The initial temperature of the solution is 18 - 28 °C, the initial temperature of the environment is 10 - 25 °C, and the initial temperature of the solution is higher than the initial temperature of the environment.

8. The electrochemical etching method according to claim 1, characterized in that, The humidity of the environment is 50% - 70%.

9. The electrochemical etching method according to claim 1, characterized in that, The baking temperature is 40 - 70 °C, and the baking time is 40 - 80 min.

10. The electrochemical etching method according to claim 1, characterized in that The tip length of the processed palladium alloy tip is 100 - 800 μm, and the tip width is 2 - 30 μm.

11. A solution for electrochemical etching processing, characterized in that, The solution is composed of phosphoric acid, a blocking agent, water, edible rock sugar syrup and ethylene glycol proportioned according to the volume fractions of a:b:c:d:e. 0.1 - 1 g of a reducing agent is added to every 1000 ml of the solution, where a ∈ (8, 20), b ∈ (2, 15), c ∈ (30, 200), d ∈ (15, 110), e ∈ (0.5, 3).

12. The solution according to claim 11, wherein, The volume fraction of water is 3 - 5 times the volume fraction of phosphoric acid, the volume fraction of water is 7 - 10 times the volume fraction of the blocking agent, the volume fraction of water is 1.5 - 5 times the volume fraction of edible rock sugar syrup, and the volume fraction of water is 90 - 130 times the volume fraction of ethylene glycol.

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