A method for preparing a micro-pore array by a pulse laser electroforming hybrid processing technology

Abstract

The application provides a method for preparing a micro-hole array by a pulse laser electroforming hybrid processing technology, and comprises the following steps: pretreating a glass substrate; conducting a conductive treatment on the surface of the glass substrate to attach a conductive layer to the surface of the glass substrate, thereby forming a conductive glass; setting an insulation array pattern according to the position and size of a micro-hole array unit of a micro-hole array surface sheet to be prepared; removing the conductive layer of the conductive glass in regions corresponding to the insulation array pattern by pulse laser ablation, and retaining conductive regions opposite to the insulation array pattern; taking the conductive glass as a cathode to perform electroforming processing, so that an electroforming layer is formed on the surface of the conductive regions of the conductive glass, and the electroforming layer forms a horn-shaped micro-hole at a position opposite to the insulation array pattern; and performing demolding by decomposing the conductive layer to separate the electroforming layer from the glass substrate. The method is simple to operate, simple in process, low in processing cost, easy to demold, can avoid product damage during demolding, and can realize mass production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro-pore structure manufacturing process, more particularly to a method for preparing micro-pore array by using a mixed process of pulse laser and electroforming. BACKGROUND

[0002] The micro-pore array has been applied to parts such as inkjet printer nozzles, fine screens, microscope grids, and mesh atomizing sheets. For example, the mesh atomizing sheet with a certain structure of fine pores can greatly improve the atomization efficiency of medical drugs, and atomize the medical drugs into fine droplets to promote the absorption of the medical drugs by patients, thereby improving the medical effect.

[0003] However, the preparation of high-quality micro-pore array is a great challenge. For traditional processing technologies such as mechanical processing, electro-spark processing, laser etching processing, and electrochemical forming processing, it is difficult to prepare micro-pore array with high precision. The most commonly used LIAG technology and quasi-LIGA technology use photolithography technology to prepare a mask, and then use electroforming to prepare the micro-pore array. The photoresist and photolithography equipment used to prepare the mask are expensive, and the process is complex, so this method is not suitable for mass production.

[0004] In addition, demolding is one of the important processes of electroforming, which is the process of separating the substrate from the electroformed product. The difficulty of demolding will affect the surface and micro-pore quality of the product, and further affect the performance of the product. SUMMARY

[0005] To overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a method for preparing micro-pore array by using a mixed process of pulse laser and electroforming. The method is simple to operate, simple in process, low in processing cost, easy to demold, can avoid product damage during demolding, and can realize mass production.

[0006] To achieve the above purpose, the present application realizes the technical scheme as follows: a method for preparing micro-pore array by using a mixed process of pulse laser and electroforming, comprising the following steps:

[0007] S1, pretreating a glass substrate to obtain a clean and dry glass substrate;

[0008] S2, conducting a surface conductive treatment on the glass substrate to attach a conductive layer to the surface of the glass substrate, thereby forming a conductive glass;

[0009] S3, setting an insulating array pattern according to the micro-pore array unit position and size of the micro-pore array surface sheet to be prepared, and using pulse laser ablation to remove the area corresponding to the insulating array pattern from the conductive layer of the conductive glass, and to retain the conductive area opposite to the insulating array pattern;

[0010] S4, using the conductive glass as a cathode to perform electroforming processing, so that the conductive area surface of the conductive glass forms an electroforming layer, and the electroforming layer forms a horn-shaped micropore at a position opposite to the insulating array pattern, to obtain an electroforming layer with a micropore array;

[0011] S5, demolding: since the conductive layer is very thin, the electroforming layer can be easily separated from the glass substrate after electroforming processing; the electroforming layer after demolding is a prepared micropore array.

[0012] Preferably, in step S1, the pretreatment refers to ultrasonic cleaning of the glass substrate, followed by constant temperature drying.

[0013] Preferably, in step S3, the pulse laser ablation refers to ablation by using a high-speed low-frequency pulse laser scanning mode; the high-speed low-frequency refers to a scanning speed v>500mm / s and a repetition frequency f<40kHz; the diameter of the laser ablation is changed by adjusting the laser power, so as to adjust the diameter of each unit of the insulating array; the spacing between the units of the insulating array is adjusted by adjusting the laser parameters.

[0014] Preferably, in step S4, a pulse, a reciprocating movement of the cathode, a cycle liquid spraying, and a gas blowing are used together to ensure the uniformity of the electroforming of the micropore array.

[0015] Preferably, an electroforming device is used for electroforming processing; the electroforming device includes a single pulse power supply, an electroforming tank, an anode, a cathode mounting clamp, and a cathode moving conductive rod.

[0016] The electroforming tank is used for injecting an electroforming liquid; the anode is immersed in the electroforming liquid and connected to the positive pole of the single pulse power supply; the conductive glass is mounted below the cathode mounting clamp and immersed in the electroforming liquid; the conductive glass is parallel to the anode; the conductive glass is connected to the negative pole of the single pulse power supply through the cathode mounting clamp and the cathode moving conductive rod, so as to realize pulse electroforming.

[0017] The cathode mounting clamp is connected to the cathode moving conductive rod; the cathode moving conductive rod is provided through a horizontal moving mechanism, so as to realize the reciprocating movement process of the cathode.

[0018] Preferably, in step S5, a repeated heating and cooling method is used for demolding; or a chemical reaction dissolution method is used for demolding according to the material of the conductive layer.

[0019] In one scheme, the conductive layer formed in step S2 includes In2O3 and SnO2; the composition of the electroforming liquid used in step S4 is: 500g / L nickel sulfamate, 10g / L nickel chloride, 30g / L boric acid, and 0.3g / L wetting agent; and a physical method is used for demolding in step S5.

[0020] Alternatively, the conductive layer formed in the step S2 is an indium tin oxide film; and the electroforming solution used in the step S4 comprises: 180 g / L copper sulfate pentahydrate, 60 g / L sulfuric acid (98 wt%), 40 g / L boric acid, 0.2 g / L sodium chloride, 0.6 g / L sodium polydithiobispropyl sulfonate, and 0.3 g / L polyethylene glycol-600.

[0021] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0022] 1. In the present application, glass is used as the base material, and a conductive layer is attached to the glass substrate. The electroformed layer with a micropore array is formed through electroforming in the conductive area of the conductive layer, and then the conductive layer is removed by decomposition. This method is simple to operate and simple in process, only requires commonly used electroforming devices, laser processing equipment, and has low processing cost, and can realize mass production.

[0023] 2. In the present application, the insulating array pattern is removed by pulse laser, and the size and spacing of the micropore array structure can be accurately controlled. In particular, the micrometer-scale conductive layer material can be removed by single pulse, so that an ultra-fine array through-hole sheet can be realized.

[0024] 3. The electroformed layer prepared by the method of the present application has a slightly higher surface than the surface of the glass substrate, and the micropores will undergo a shrinkage process under the action of the electric field in the electroforming process. Therefore, the micropores with a certain slope can be realized, especially the preparation of horn-shaped array through-hole sheets. The electroforming process using the synergistic effect of electric pulse, cathode reciprocating movement, circulating liquid spraying, air inflation, and heating at constant temperature solves the problems of incomplete micropore growth caused by poor flowability of the electroforming solution in the blind hole of the high aspect ratio micropit array structure and insufficient ion exchange in the electroforming solution in the electroforming process. At the same time, the problem of coarse grain and poor density of the electroformed layer is also solved, so that the electroformed surface is smoother and more uniform.

[0025] 4. In the present application, the electroformed layer with a micropore array can be easily separated from the glass substrate after electroforming, avoiding product damage during demolding, and obtaining a high-quality micropore array surface sheet. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a flow chart of the method for preparing a micropore array by the pulse laser electroforming hybrid processing technology of the present application;

[0027] Figure 2 is a structural schematic diagram of an electroforming device in the method for preparing a micropore array by the pulse laser electroforming hybrid processing technology of the present application;

[0028] Fig. 3(a) and Fig. 3(b) are structural schematic diagrams of the micropore array surface sheet obtained by the method for preparing a micropore array by the pulse laser electroforming hybrid processing technology of the present application, respectively;

[0029] Figures 4(a) to 4(d)are metallographic microscope graphs of micro-hole array surface sheets obtained by the micro-hole array method of Example One;

[0030] Figures 5(a) to 5(f) are metallographic microscope graphs of conductive glass patterns obtained by the micro-hole array method of Example Two by laser etching;

[0031] Figures 6(a) to 6(c) are metallographic microscope graphs of micro-hole arrays obtained by the micro-hole array method of Example Two. DETAILED DESCRIPTION

[0032] The application will be further described in detail below in combination with the accompanying drawings and specific embodiments.

[0033] Example One

[0034] The micro-hole array method of the embodiment of the application is shown in the following steps: Figure 1

[0035] S1, pretreat the glass substrate to obtain a clean and dry glass substrate. Using glass as the substrate can reduce the difficulty of demolding after electroforming.

[0036] The pretreatment refers to ultrasonic cleaning of the glass substrate, followed by constant temperature drying.

[0037] S2, conductive treatment of the glass substrate surface to attach a conductive layer to the glass substrate surface to form conductive glass. The specific method includes electrochemical diffusion, high-temperature spraying, plasma spraying, vapor deposition, magnetron sputtering, laser-induced plasma-assisted ablation, etc. In the embodiment, magnetron sputtering and laser-induced plasma-assisted ablation will be used to prepare the conductive glass.

[0038] S3, set the insulating array pattern according to the micro-hole array unit position and size of the micro-hole array surface sheet to be prepared. The micro-hole array unit refers to each micro-hole in the micro-hole array. The conductive layer of the conductive glass is removed in the area corresponding to the insulating array pattern by pulse laser ablation, and the conductive area opposite to the insulating array pattern is retained. Pulse laser ablation is used to remove part of the conductive layer. Since the laser can penetrate the glass, it will not ablate the surface of the glass, but only remove the conductive layer above the glass, thereby forming the insulating array pattern.

[0039] ​The present invention utilizes high-speed, low-frequency pulsed laser scanning for ablation. High speed and low frequency refers to a scanning speed v > 500 mm / s and a repetition rate f < 40 kHz. Optionally, the diameter of the laser ablation can be varied by adjusting the laser power, thereby adjusting the diameter of each cell in the insulating array. The spacing between cells in the insulating array can also be adjusted by adjusting laser parameters. For example, the diameter of each cell in the microwell array is only equal to the laser spot radius, which is 30 microns. Furthermore, a shape-filling array method can be used to create a full array of patterns of varying shapes and sizes.

[0040] S4. Conductive glass is used as the cathode for electroforming, and an electroforming process is adopted that combines pulses, reciprocating cathode movement, cyclic liquid spraying, and air pumping to form an electroforming layer on the surface of the conductive area of ​​the conductive glass, and the electroforming layer forms trumpet-shaped micropores at positions opposite to the insulating array pattern.

[0041] Electroforming processing is performed using an electroforming device; Figure 2 As shown, the electroforming apparatus includes a single-pulse power supply 6, an electroforming tank 1, an anode 2, a cathode mounting fixture 3, and a cathode movable conductive rod 5. The electroforming tank 1 is used to inject the electroforming liquid. The anode 2 is immersed in the electroforming liquid and connected to the positive electrode of the single-pulse power supply 6. A conductive glass 4 serves as the cathode, mounted below the cathode mounting fixture 3 and immersed in the electroforming liquid. The conductive glass 4 is parallel to the anode 2 and opposite to it. The conductive glass 4 is connected to the negative electrode of the single-pulse power supply 6 via the cathode mounting fixture 3 and the cathode movable conductive rod 5 to achieve pulse electroforming. The cathode mounting fixture 6 is connected to the cathode movable conductive rod 5. The cathode movable conductive rod 5 is arranged via a horizontal movement mechanism to achieve a reciprocating cathode movement process. Electroforming processes such as cyclic liquid spraying and air pumping can be implemented using the existing modules of the electroforming apparatus.

[0042] Because the surface of the conductive layer in the electroforming template prepared by the present invention is slightly higher than that of the glass substrate, the micropores shrink under the action of the electric field during the electroforming process. This allows for the production of holes with a certain slope, particularly trumpet-shaped arrays of through-hole sheets, and very thin thicknesses. The electroforming process, which utilizes the synergistic effects of electric pulses, reciprocating cathode movement, cyclic liquid spraying, air pumping, and constant temperature heating, solves the problem of incomplete micropore growth caused by poor fluidity of the electroforming liquid and insufficient ion exchange in the blind holes of the high-aspect-ratio micro-pit array structure during the electroforming process. It also solves the problem of coarse grains and poor density in the metal layer, resulting in a smoother and flatter electroforming surface.

[0043] S5. Demolding: The conductive layer is very thin, and it is easy to separate the electroformed layer from the glass substrate after electroforming. The electroformed layer after demolding is the completed micropore array.

[0044] The electroforming layer prepared by the method can be easily separated from the glass surface. Alternatively, repeated heating and cooling can be used for demolding to ensure that the surface of the micro-pore array sheet prepared after demolding is smooth. According to the material of the conductive layer, chemical reaction dissolution can also be used for demolding, and it is necessary to note that the chemical reaction does not occur with the electroforming layer.

[0045] The method for preparing a micro-pore array by a pulse laser electroforming hybrid processing technology adopts glass as a substrate material and performs conductive treatment on the surface of the glass. The size and spacing of the micro-pore array structure of the conductive layer material can be accurately controlled by using a pulse laser. In particular, a single pulse can be used to remove the micron-level conductive layer material, so that an ultra-fine micro-array through-hole sheet can be realized. The electroforming layer prepared by the method has a slightly higher surface than the glass substrate surface, and the micro-pores will undergo a shrinkage process under the action of an electric field during the electroforming process, so that a pore with a certain slope can be realized, especially a horn-shaped array through-hole sheet. In addition, the electroforming process using the synergistic effect of electric pulses, cathode reciprocating movement, cyclic liquid spraying, air inflation, and heating at a constant temperature solves the problems of incomplete micro-pore growth caused by poor flowability of the electroforming liquid in the blind hole of the high-aspect-ratio micro-pit array structure and insufficient ion exchange in the electroforming liquid during the electroforming process. At the same time, the problems of coarse grains and poor density of the electroformed layer are also solved, so that the electroformed surface is smoother and more uniform. After the electroforming is completed, the array micro-pore sheet can be easily separated from the glass substrate.

[0046] The method will be further described in detail below.

[0047] The method for preparing a micro-pore array by a pulse laser electroforming hybrid processing technology comprises the following steps:

[0048] S1, pre-treating the glass substrate: ultrasonic cleaning the glass substrate with acetone, anhydrous ethanol, and deionized water for 15 minutes, respectively, and then baking the glass substrate in an oven at a constant temperature of 100 DEG C or above for 1 hour or above, taking out the glass substrate after drying, and naturally cooling the glass substrate for standby;

[0049] S2, conductive treatment on the surface of the glass substrate: using a laser-induced plasma-assisted ablation method, taking an indium-tin alloy as a sacrificial target material, covering the glass substrate on the top of the target material, adjusting the focal length of a laser to the upper surface of the indium-tin alloy target material, and performing laser ablation scanning to obtain a metallized glass. The main components of the conductive layer are In2O3 and SnO2.

[0050] S3, removing part of the conductive layer by pulse laser ablation: removing part of the conductive layer by using a pulse laser ablation high-speed low-frequency scanning method to form an insulating array pattern.

[0051] S4, electroforming: using phosphor copper anode plate as anode, conductive glass after step S3 as cathode, electroforming liquid composition: 180 g / L copper sulfate pentahydrate, 60 g / L sulfuric acid (98 wt%), 40 g / L boric acid, 0.2 g / L sodium chloride, 0.6 g / L polydithiopropanesulfonic acid sodium, 0.3 g / L polyethylene glycol-600. Using heating to keep the electroforming liquid constant temperature at 45℃, PH value at 4, anode current density is 1A / dm 2 , and adopting pulse, cathode reciprocating movement, circulating liquid spray, and air blowing, the electroforming process is carried out.

[0052] S5, demolding: after a period of electroforming, the conductive layer is decomposed due to chemical reaction in the electroforming liquid, and is easy to separate from the glass substrate surface, and then the electroforming layer is easy to demold.

[0053] With the increase of electroforming time, the diameter of the micropore array unit gradually decreases, and the structure diagram and sectional view of the micropore array surface sheet obtained by theoretical electroforming are shown in FIG. 3(a) and FIG. 3(b).

[0054] In this embodiment, the laser parameters used in the step S3 of removing part of the conductive layer by pulse laser ablation are 10000 mm / s, repetition frequency 20 kHz, power 20 W, and scanning times 1 time, and the removed material diameter is one spot diameter size; the electroforming time in step S4 is 20 minutes. The metallographic microscope diagram of the micropore array surface sheet obtained after demolding is shown in FIG. 2(a) and FIG. 2(b); FIG. 4(a) and FIG. 4(b) are front metallographic microscope diagrams, and FIG. 4(c) and FIG. 4(d) are back metallographic microscope diagrams. Figures 4(a) to 4(d)

[0055] Example Two

[0056] The method for preparing micropore array by pulse laser electroforming mixed processing technology in this embodiment comprises the following steps:

[0057] S1, same as step S1 in the embodiment;

[0058] S2, conductive treatment of glass substrate surface: using the method of magnetron sputtering to plate a layer of indium tin oxide (ITO) film on the surface of the glass substrate, so that the surface has conductivity, and form conductive glass;

[0059] S3, using pulse array method, different diameter sizes of insulating array pattern units can be obtained by adjusting laser power and repetition frequency, and the distance between the conductive layer insulating array pattern units can be adjusted by adjusting the array spacing parameters, as shown in FIG. 3(a) and FIG. 3(b), which are metallographic microscope diagrams of conductive layer insulating array pattern units with different diameters and spacings; Figures 5(a) to 5(f)

[0060] ​​S4, electroforming: using a nickel anode plate as an anode and the conductive glass after step S3 as a cathode, and an electroforming solution with a composition of 500 g / L nickel sulfamate, 10 g / L nickel chloride, 30 g / L boric acid, and 0.3 g / L wetting agent. The electroforming solution is kept at a constant temperature of 45°C by heating, and the anode current density is 1 A / dm 2 , and the electroforming process is carried out for 15 min by using pulse, reciprocating movement of the cathode, circulating liquid spraying, and air blowing.

[0061] S5, demolding: the conductive layer is very thin, and separation of the electroformed layer from the glass substrate is easily achieved after electroforming processing; the electroformed layer after demolding is a prepared micropore array, and Fig. 3 shows three kinds of micropore arrays with different hole spacings. Figures 6(a) to 6(c)

[0062] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above examples, and any changes, modifications, substitutions, combinations, simplifications, etc. made without departing from the spirit and principles of the present application are equivalent replacement modes and are included in the protection scope of the present application.​

Claims

1. A method for preparing a microwell array by a pulsed laser electroforming hybrid process, characterized in that: The following steps are involved: S1. Pre-treating the glass substrate to obtain a clean and dry glass substrate; S2. Conductively treating the surface of the glass substrate so that a conductive layer is attached to the surface of the glass substrate to form conductive glass; S3. Setting an insulating array pattern according to the position and size of the microporous array unit of the microporous array sheet to be prepared; Using pulsed laser ablation, the conductive glass conductive layer is removed from the area corresponding to the insulating array pattern to form an insulating array, while retaining the conductive area that is opposite to the insulating array pattern; S4. Using the conductive glass as a cathode, electroforming is performed to form an electroformed layer on the surface of the conductive region of the conductive glass, wherein the electroformed layer forms trumpet-shaped micropores at positions opposite to the insulating array pattern, thereby obtaining an electroformed layer with a micropore array. S5. Demolding: The conductive layer is decomposed to separate the electroformed layer from the glass substrate; the electroformed layer after demolding is the completed microporous array sheet; In step S4, an electroforming process is adopted that combines pulses, cathode reciprocating movement, circulating liquid spraying, and air pumping; The electroforming process is performed using an electroforming device; the electroforming device includes a single pulse power supply, an electroforming tank, an anode, a cathode mounting fixture, and a cathode moving conductive rod; The electroforming tank is used to inject electroforming liquid; the anode is immersed in the electroforming liquid and connected to the positive electrode of a single-pulse power supply; the conductive glass is installed below the cathode mounting fixture and immersed in the electroforming liquid; the conductive glass is parallel to the anode and opposite to it; the conductive glass is connected to the negative electrode of the single-pulse power supply through the cathode mounting fixture and the cathode movable conductive rod to achieve pulse electroforming; The cathode mounting fixture is connected to the cathode movable conductive rod; the cathode movable conductive rod is arranged through a horizontal moving mechanism to realize the reciprocating movement of the cathode.

2. The method for preparing a microhole array by a pulsed laser electroforming hybrid process according to claim 1, characterized in that: In the step S1, the pretreatment refers to: ultrasonically cleaning the glass substrate and then drying it at a constant temperature.

3. The method for preparing a microhole array by a pulsed laser electroforming hybrid process according to claim 1, characterized in that: In step S3, pulse laser ablation refers to: ablation is performed using a high-speed, low-frequency pulse laser scanning method; the high speed and low frequency refers to: a scanning speed v>500mm / s, a repetition frequency f<40kHz; the diameter of the laser ablation is changed by adjusting the laser power, thereby adjusting the diameter of each unit of the insulating array; and the unit spacing of the insulating array is adjusted by adjusting the laser parameters.

4. The method for preparing a microhole array by a pulsed laser electroforming hybrid process according to claim 1, characterized in that: In step S5, demoulding is performed by repeatedly heating and cooling; or, depending on the material of the conductive layer, by chemical reaction dissolution.

5. The method for preparing a microhole array by a pulsed laser electroforming hybrid process according to claim 1, characterized in that: The conductive layer formed in step S2 is an indium tin oxide film; the electroforming liquid used in step S4 comprises the following components: 500 g / L nickel sulfamate, 10 g / L nickel chloride, 30 g / L boric acid, and 0.3 g / L wetting agent.

6. The method for preparing a microhole array by pulse laser electroforming hybrid processing according to claim 1, characterized in that: The conductive layer formed in step S2 includes In2O3 and SnO2; the electroforming liquid used in step S4 includes: 180g / L copper sulfate pentahydrate, 60g / L sulfuric acid, 40g / L boric acid, 0.2g / L sodium chloride, 0.6g / L sodium polydisulfide dipropane sulfonate, and 0.3g / L polyethylene glycol-600; the sulfuric acid refers to sulfuric acid with a mass percentage of 98wt%.

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