Microsphere driving method, mask preparation method, and micro-needle array preparation method

Abstract

The present disclosure provides a microsphere driving method, a mask preparation method and a microneedle array preparation method, comprising: dispersing microspheres in a first liquid, wherein the first liquid is contained in a cavity; and injecting a second liquid towards a local area of the cavity, wherein the surface energy of the second liquid is lower than that of the first liquid; as the second liquid diffuses from the local area to other areas of the cavity, the concentration of the second liquid in the cavity is distributed in a gradient, and under the driving of the surface energy difference generated by the concentration difference of the second liquid, the microspheres move towards the direction where the concentration of the second liquid decreases. The present disclosure realizes the driving of the microsphere movement in a concentration gradient induced manner, so that a large area of microsphere etching mask and microneedle array can be quickly prepared, the preparation efficiency is high, and the preparation cost is low.

Description

Technical Field

[0001] This invention relates to the technical field of micro / nano structure fabrication, and in particular to a microsphere driving method, a mask fabrication method, and a microneedle array fabrication method. Background Technology

[0002] Microneedle arrays are functional substrates with micro / nano structures widely applicable in fields such as biomedicine, energy devices, and hydrophilic / hydrophobic surfaces. With the development of related applications, the demand for microneedle arrays and the technical requirements for them are increasing. Taking hydrophilic / hydrophobic surfaces as an example, traditional methods only require fabricating microneedle arrays with the same morphology on the substrate to change the overall hydrophilic or hydrophobic properties of the substrate. To better control droplet movement and more accurately separate various liquids, microneedle arrays need to be fabricated at specific locations on the substrate. To meet the needs of practical applications, rapid patterned microneedle array fabrication technology, especially technology suitable for large-area microneedle fabrication, is crucial.

[0003] Currently, the main difficulty in fabricating microneedle arrays lies in the fabrication of the etching mask. Traditional microneedle array fabrication methods are based on a photolithography-etching process. Fabricating patterned microneedle arrays using this process path suffers from long fabrication cycles, expensive equipment, and high production costs. If large-area microneedle arrays are fabricated using traditional methods, the photolithography process has a particularly significant impact on the fabrication. To ensure the uniformity of the structure of a large-area (4-inch) microneedle array, specialized high-precision exposure machines are often required. These machines cost several million RMB and require skilled operators, undoubtedly further increasing production costs and technical difficulty.

[0004] To address the problems arising from etching template preparation in the fabrication of microneedle arrays, the use of microspheres as etching masks has gained increasing attention. The mainstream method for fabricating microsphere etching masks is based on the Langmuir-Blodgett method. However, this technique is time-consuming; preparing a 4-inch sample typically takes several hours. Furthermore, this method demands highly sophisticated equipment and experienced personnel. Therefore, it is unsuitable for large-scale production and fabrication of microneedle arrays. Besides the Langmuir-Blodgett technique, spin coating has also been used to fabricate microsphere etching masks. During spin coating, the microspheres are subjected to centripetal forces due to rotation, and these forces are highly dependent on the microsphere's position. Therefore, this method is difficult to apply to the fabrication of etching masks for large-area microneedle arrays.

[0005] It should be noted that the above description of the background technology is only for the purpose of providing a clear and complete explanation of the technical solutions of this disclosure and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this disclosure. Summary of the Invention

[0006] The purpose of this disclosure is to provide a microsphere driving method, a mask preparation method, and a microneedle array preparation method to solve at least some of the problems pointed out in the background art or other similar problems.

[0007] According to a first aspect of the present disclosure, a microsphere driving method is provided, comprising: dispersing microspheres in a first liquid, wherein the first liquid is contained in a cavity; and injecting a second liquid toward a local region of the cavity, wherein the surface energy of the second liquid is lower than that of the first liquid; as the second liquid diffuses from the local region toward other regions of the cavity, the concentration of the second liquid in the cavity is gradient-distributed, and driven by the surface energy difference generated by the concentration difference of the second liquid, the microspheres move toward the direction where the concentration of the second liquid decreases.

[0008] In some embodiments, the cavity is defined by a container, the local region is a region of the cavity near one sidewall of the container, and the movement direction of the microsphere includes at least a direction from one sidewall of the container toward the other sidewall of the container.

[0009] In some embodiments, the first liquid is a non-volatile solvent and the second liquid is a volatile solvent.

[0010] In some embodiments, the first liquid is water, and / or the second liquid is ethanol.

[0011] In some embodiments, dispersing the microspheres in a first liquid includes: placing the microspheres in a dispersion; subjecting the dispersion containing the microspheres to ultrasonic treatment to uniformly disperse the microspheres within the dispersion; injecting the ultrasonically treated dispersion into the first liquid within the cavity; and allowing the cavity to stand still so that the microspheres remain stationary in the first liquid.

[0012] In some embodiments, the dispersion is prepared by a first liquid and a second liquid in a preset volume ratio.

[0013] In some embodiments, injecting the second liquid into a local area of ​​the cavity includes injecting the second liquid at an injection rate of 15 μl / min to 25 μl / min.

[0014] According to a second aspect of the present disclosure, a mask preparation method is provided, comprising: pretreating a substrate; driving microspheres to move using the microsphere driving method of the first aspect embodiment until the microspheres are closely arranged on the liquid surface in a cavity to form a monolayer microsphere array; and transferring the microsphere array onto the pretreated substrate to obtain a microsphere mask layer.

[0015] In some embodiments, the mask preparation method further includes: placing the pretreated substrate at the bottom of the cavity. The transfer of the microsphere array onto the pretreated substrate includes: draining the liquid from the cavity to lower the liquid level until the monolayer microsphere array bonds to the substrate; or, lifting the substrate at the bottom of the cavity upwards until the substrate bonds to the monolayer microsphere array.

[0016] In some embodiments, the pretreatment includes at least one of ultrasonic treatment, baking treatment, and cleaning treatment.

[0017] According to a third aspect of the present disclosure, a method for fabricating a microneedle array is provided, comprising: pretreating a substrate; forming a patterned photoresist layer on the pretreated substrate; driving microspheres to move using the microsphere driving method of the first aspect embodiment until the microspheres are closely arranged on the liquid surface of a cavity to form a monolayer microsphere array; transferring the microsphere array to a substrate on which the photoresist layer has been formed to obtain a microsphere mask layer covering the photoresist layer; and performing ion etching on the substrate, wherein the surface of the substrate not covered by the photoresist layer but covered by the microsphere mask layer is etched to form microneedles, and the surface of the substrate covered by both the photoresist layer and the microsphere mask layer does not form microneedles, so as to obtain a patterned microneedle array.

[0018] In some embodiments, the method for fabricating a microneedle array further includes cleaning the etched substrate to remove microsphere residues and photoresist layers from the surface of the substrate.

[0019] The beneficial effects of the embodiments disclosed herein include:

[0020] This disclosure generates a surface energy difference by establishing a liquid concentration gradient. The force field generated by this surface energy difference can drive microspheres to move in the direction of decreasing concentration. Compared with the prior art, the microsphere driving method of this disclosure is very simple and convenient to operate, requires very little equipment and operator experience, has a fast preparation speed, short preparation time, and low cost. It is particularly suitable for driving the movement of microspheres over a large area, thereby rapidly forming a large-area monolayer microsphere array with close packing. This monolayer microsphere array can be used to form a large-area microsphere mask. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0022] Figure 1 This is a flowchart of a microsphere driving method according to an embodiment of the present disclosure;

[0023] Figure 2 It refers to the concentration distribution of the second liquid within the cavity at the first moment;

[0024] Figure 3 It refers to the concentration distribution of the second liquid within the cavity at the second moment;

[0025] Figure 4 This is a flowchart of step S100 in a microsphere driving method according to an embodiment of the present disclosure;

[0026] Figure 5 This is a flowchart of a mask preparation method according to an embodiment of the present disclosure;

[0027] Figure 6 This is a flowchart of a method for preparing a microneedle array according to an embodiment of the present disclosure;

[0028] Figure 7 This is a scanning electron microscope image of a monolayer microsphere array prepared according to an embodiment of this disclosure;

[0029] Figure 8 This is a scanning electron microscope image of a microsphere mask layer prepared according to an embodiment of this disclosure;

[0030] Figure 9 This is a scanning electron microscope image of a patterned microneedle array prepared according to an embodiment of this disclosure; and

[0031] Figure 10 yes Figure 9 The image shows a magnified view of a microneedle array. Detailed Implementation

[0032] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this specification.

[0033] In the embodiments of this disclosure, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the terms listed in association and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0034] In the embodiments of this disclosure, the singular forms "a," "the," etc., may include the plural forms and should be broadly understood as "a kind" or "a class" rather than limited to the meaning of "one." Furthermore, the term "the" should be understood to include both the singular and plural forms unless the context explicitly indicates otherwise. Furthermore, the term "according to" should be understood as "at least partially based on..." and the term "based on" should be understood as "at least partially based on..." unless the context explicitly indicates otherwise. Furthermore, the term "a plurality" means two or more, unless otherwise stated.

[0035] It should be understood that the order of the steps shown in the figures is merely illustrative and should not be construed as limiting. For example, some steps may occur in a different order, and / or may occur simultaneously with other steps besides those shown herein. Furthermore, not all steps may be necessary when implementing one or more embodiments of this disclosure; or one or more steps shown may be replaced by other steps, or other steps may be included.

[0036] First aspect of the embodiments

[0037] An embodiment of the first aspect of this disclosure provides a microsphere driving method, which can be used for microsphere self-assembly, for example, to form a closely packed monolayer microsphere array, and can also be applied to other application scenarios that require driving microsphere movement.

[0038] like Figure 1 As shown, the microsphere driving method of this disclosure includes the following steps:

[0039] S100: Disperse microspheres in a first liquid, wherein the first liquid is contained in a cavity, and the microspheres are dispersed and float on the surface of the first liquid.

[0040] S200: A second liquid is injected toward a local area of ​​the cavity, wherein the surface energy of the second liquid is lower than that of the first liquid; as the second liquid diffuses from the local area to other areas of the cavity, the concentration of the second liquid in the cavity is distributed in a gradient. Driven by the (induced) surface energy difference generated by the concentration difference of the second liquid, the microspheres move toward the direction in which the concentration of the second liquid decreases (i.e., the direction in which the surface energy increases).

[0041] This disclosure establishes a surface energy difference through a liquid concentration gradient. The force field generated by this surface energy difference can drive microspheres to move in the direction of decreasing concentration. Compared with the prior art, the microsphere driving method of this disclosure is very simple and convenient to operate, requires very little equipment and operator experience, has a fast preparation speed, short preparation time, and low cost. It is particularly suitable for driving the movement of microspheres over a large area, thereby rapidly forming a large-area monolayer microsphere array with close packing. This monolayer microsphere array can be used to form a large-area microsphere mask.

[0042] The term "local region" as used in this disclosure can be understood as a portion of the entire cavity in a planar direction (e.g., the entire liquid surface of the first liquid in the cavity). This disclosure does not limit the area of ​​this local region, nor does it limit the proportion of this local region to the entire cavity. The local region defined in this disclosure is not a region with a clearly defined boundary, but rather refers to a portion of the cavity.

[0043] For example, when a syringe pump is used to inject a second liquid into the cavity through an injection tube, the local area can be the area corresponding to the outlet of the injection tube or it can also include the adjacent area around the corresponding area. The area of ​​the local area is approximately equal to the area of ​​the outlet of the injection tube.

[0044] The above examples illustrate the injection method and local area of ​​the second liquid, but this disclosure is not limited thereto. In actual operation, the operator can determine the injection method, location and size of the local area of ​​the second liquid according to actual needs, as long as the required concentration gradient distribution of the second liquid can be formed.

[0045] It is understood that, since the second liquid is only directly injected into a local area of ​​the cavity, rather than into the entire cavity, the concentration of the second liquid is highest in that local area within the planar range of the entire cavity immediately after injection or for a period of time thereafter. As the second liquid gradually diffuses from that local area to other areas, at least during the diffusion period, the concentration of the second liquid at different locations within the entire cavity exhibits a gradient distribution along the planar direction. It should be noted that, unless otherwise stated, the "concentration of the second liquid" mentioned in this disclosure refers to the concentration of the second liquid in the solution of different areas along the planar direction within the cavity; it can be understood as a regional concentration, not the total concentration of all the second liquid contained in the solution of the entire cavity.

[0046] When injecting the second liquid, in order to avoid turbulence or impact on the first liquid and microspheres, the second liquid should be injected at a low injection rate. Optionally, the injection rate of the second liquid is 15 μl / min to 25 μl / min, for example, the injection rate of the second liquid is 20 μl / min.

[0047] In this embodiment of the disclosure, the particle size of the microspheres can be 100 nm to 100 μm, and the material of the microspheres can be selected from one or more of polystyrene, silicon dioxide, and polytetrafluoroethylene (PTFE). For example, the diameter of the microspheres is 1 μm.

[0048] In this embodiment of the disclosure, the cavity is defined by a container, for example, the container is square, circular, or other shapes, and correspondingly, the cavity is square, circular, or other shapes. Optionally, the container is made of transparent glass to facilitate the operator's observation of the movement of the microspheres inside the container.

[0049] In one embodiment, in step S200, the local region is the area of ​​the cavity near the side wall of the container (referred to as the first side), and the movement direction of the microsphere includes at least a direction from one side wall of the container toward the other side wall of the container (referred to as the second side). The first side wall and the second side wall are the two side walls of the container that are furthest apart.

[0050] For the sake of brevity, Figure 2 and Figure 3 The cavity is only schematically divided into two regions to schematically show the concentration difference of the second liquid in different regions, without showing each small region with different second liquid concentrations in detail.

[0051] Figure 2 The concentration distribution of the second liquid Q2 within the cavity is shown at the first time t1. Figure 2 As shown, a second liquid Q2 is injected into a local area within the cavity of container 1 from the first sidewall 12. In the first region A, which is close to the injection position of the second liquid Q2, the concentration of the second liquid Q2 is relatively high and the surface energy of the liquid is relatively low. In the second region B, which is far from the injection position of the second liquid Q2, the concentration of the second liquid Q2 is relatively low and the surface energy of the liquid is relatively high. Therefore, there is a concentration difference between the first region A and the second region B. This concentration difference generates a surface energy difference, and the force field generated by the surface energy difference drives the microspheres in the first region A to move towards the second region B. Figure 2 and Figure 3 The middle arrow F represents the direction of the force field.

[0052] As the second liquid Q2 is continuously injected, the second liquid Q2 continuously diffuses toward the second region B. The range of the first region A, which has a higher concentration of the second liquid, gradually expands, while the range of the second region B, which has a lower concentration of the second liquid, gradually decreases. In other words, the first region A expands toward the second region B, and correspondingly, the microspheres in the first region A also move toward the second region B.

[0053] Figure 3 The concentration distribution of the second liquid Q2 within the cavity is shown at a second time t2, following the first time t1. Figure 3 As shown, with Figure 2 compared to, Figure 3 The area of ​​the second region B decreases, while the area of ​​the first region A expands. Taking the boundary line L between the first region A and the second region B as an example, and... Figure 2 compared to, Figure 3 The boundary line L has shifted to the left, and the microsphere M2 has also shifted to the left to be closely aligned with the microsphere M1.

[0054] By continuously injecting a second liquid at the same location, the distribution of the concentration gradient (i.e., the direction of the concentration gradient) can be kept constant, thus keeping the direction of movement of the microspheres constant. Of course, by changing the injection location of the second liquid, the distribution of the concentration gradient (i.e., the direction of the concentration gradient) can also be changed, thus changing the direction of movement of the microspheres.

[0055] In one embodiment, the first liquid is a non-volatile solvent, and the second liquid is a volatile solvent. For example, the first liquid is water, and the second liquid is ethanol.

[0056] By using a volatile solvent as the second liquid, the concentration gradient of the second liquid can be maintained for a longer period of time. Specifically, during the continuous injection of the second liquid, although the second liquid will diffuse from a local area to other areas, it is difficult for the second liquid to accumulate in other areas and reach a large concentration due to continuous evaporation. Therefore, even if the injection concentration of the second liquid is not changed, the concentration gradient will always exist.

[0057] However, this disclosure is not limited to this; the second liquid may also be a non-volatile solvent. In this case, the injection concentration of the second liquid needs to be gradually increased to maintain the concentration gradient over a longer period of time. For example, a second liquid with a concentration of C1 may be injected into a local area of ​​the cavity during the first period, a second liquid with a concentration of C2 may be injected during the second period, and a second liquid with a concentration of C3 may be injected during the third period, where C1 < C2 < C3.

[0058] In some embodiments, such as Figure 4 As shown, step S100 includes:

[0059] Step S110: Place the microspheres into the dispersion;

[0060] Step S120: The dispersion containing microspheres is subjected to ultrasonic treatment to make the microspheres uniformly dispersed in the dispersion.

[0061] Step S130: Inject the ultrasonically treated dispersion into the first liquid in the cavity;

[0062] Step S140: Allow the cavity to stand still, so that the microspheres remain stationary in the first liquid.

[0063] In step S110, the dispersion can be a solution prepared by a first liquid and a second liquid in a preset volume ratio. For example, the dispersion can be a solution prepared by ethanol and water in a volume ratio of 9:1. Compared with the volume of the first liquid in the cavity in step S130, the volume of the dispersion is smaller. The dispersion is only used to pre-disperse the microspheres, facilitating more uniform dispersion of the microspheres in the first liquid in the cavity. The mass percentage of microspheres in the dispersion can be, for example, 1% wt.

[0064] In step S120, the dispersion containing microspheres can be subjected to ultrasonic vibration in ice water to make the microspheres disperse more uniformly.

[0065] In step S130, the ultrasonically treated dispersion can be injected into the first liquid in the cavity at a low injection rate of 100 μl / min. The low injection rate can keep the microspheres in a dispersed state and avoid the microspheres from stacking or aggregating.

[0066] In step S130, the cavity can be left to stand for about 10 minutes to allow the injected microspheres to stop moving and remain stationary, making it easier to drive the microspheres in the future.

[0067] Second aspect of the embodiments

[0068] An embodiment of the second aspect of this disclosure provides a mask preparation method for preparing a microsphere mask layer.

[0069] like Figure 5 As shown, the mask preparation method of this disclosure includes the following steps:

[0070] Step S10: Pre-treat the substrate;

[0071] Step S30: Drive the microspheres to move using the microsphere driving method of the first aspect embodiment until the microspheres are closely arranged on the liquid surface in the cavity to form a monolayer microsphere array;

[0072] Step S40: Transfer the microsphere array onto the pretreated substrate to obtain a microsphere mask layer.

[0073] For example, the substrate may include a substrate, which may be a semiconductor substrate such as a silicon substrate, a dielectric substrate such as a glass substrate, a circuit board such as a printed circuit board, or any other type of substrate. This disclosure does not limit the type of substrate.

[0074] For example, the substrate may also include one or more film layers formed on the substrate, which may be selected from one or more of dielectric layers, semiconductor layers, metal layers, and other types of material layers.

[0075] In step S10, the pretreatment of the substrate may include at least one of ultrasonic treatment, baking treatment, and cleaning treatment.

[0076] For example, in step S10, the pretreatment of the substrate includes ultrasonic treatment, baking treatment, and cleaning treatment. For instance, ultrasonic treatment involves placing the substrate in an acetone solution and ultrasonically treating the substrate for 3 minutes; baking treatment involves placing the substrate on a hot plate at a temperature of 200°C and heating the substrate for 5 minutes; and cleaning treatment may involve placing the substrate in a plasma cleaner and cleaning the substrate for 120 seconds with a power of 100W, a steady-state pressure of 10mTorr, and oxygen as the process gas.

[0077] In step S30, the microsphere driving method used is the microsphere driving method of the first aspect embodiment. Since the steps and beneficial effects of the microsphere driving method have been described in detail in the first aspect embodiment, their content is incorporated herein and will not be repeated. Using the microsphere driving method of the first aspect embodiment, the movement of microspheres can be driven quickly over a large area, thereby rapidly forming a large-area single-layer microsphere array, which is simple and convenient to operate.

[0078] In some embodiments, such as Figure 5 As shown, the mask preparation method also includes:

[0079] Step S20: Place the pretreated substrate at the bottom of the cavity to facilitate the subsequent transfer of the monolayer microsphere array onto the substrate.

[0080] In this embodiment, step S40 includes:

[0081] The liquid inside the cavity is drained out, causing the liquid level in the cavity to drop until the monolayer microsphere array bonds with the substrate; this is the liquid drainage method used to transfer the monolayer microsphere array onto the substrate. Alternatively,

[0082] The substrate located at the bottom of the cavity is pulled upwards until it combines with the monolayer microsphere array, that is, the monolayer microsphere array is transferred to the substrate by the pulling method.

[0083] Third aspect of the embodiments

[0084] An embodiment of the third aspect of this disclosure provides a method for preparing a microneedle array, used to prepare a patterned microneedle array.

[0085] like Figure 6 As shown, the method for fabricating a microneedle array according to an embodiment of this disclosure includes the following steps:

[0086] Step S1: Pre-treat the substrate;

[0087] Step S2: Form a patterned photoresist layer on the pretreated substrate;

[0088] Step S3: Drive the microspheres using the microsphere driving method of the first aspect embodiment until the microspheres are closely arranged on the liquid surface of the cavity to form a monolayer microsphere array (e.g., Figure 7 (as shown);

[0089] Step S4: Transfer the microsphere array onto a substrate with a photoresist layer to obtain a microsphere mask layer covering the photoresist layer (e.g., ...). Figure 8 (as shown);

[0090] Step S5: Ion etching is performed on the substrate, wherein the surface of the substrate not covered by the photoresist layer but covered by the microsphere mask layer is etched to form microneedles, and the surface of the substrate covered by both the photoresist layer and the microsphere mask layer does not form microneedles, to obtain a patterned microneedle array (e.g. Figure 9 and Figure 10 (As shown).

[0091] In this embodiment, the substrate can be a silicon substrate, so the microneedles formed in step S5 are silicon microneedles.

[0092] As described in the second aspect embodiment, the pretreatment of the substrate in step S1 may include at least one of ultrasonic treatment, baking treatment, and cleaning treatment. Preferably, the pretreatment of the substrate includes ultrasonic treatment, baking treatment, and cleaning treatment.

[0093] In step S2, a patterned photoresist layer can be formed on the substrate using existing photoresist patterning methods. For example, step S2 may include a spin coating step, an exposure step, and a development step. Taking positive photoresist S1813 as an example, in the spin coating step, the spin coating speed can be 3000 rpm / s, and the pre-baking time can be 60s; in the exposure step, the exposure metering can be 180 mJ / cm². 2 During the development step, a transition metal dichalcogenide (TMD) developer can be used to dissolve the substance for 25 seconds.

[0094] In step S3, the microsphere driving method used is the microsphere driving method of the first aspect embodiment. Since the steps and beneficial effects of the microsphere driving method have been described in detail in the first aspect embodiment, the content is incorporated herein and will not be described again.

[0095] Step S3 of this embodiment employs the microsphere driving method of the first aspect embodiment, which can drive the movement of microspheres quickly over a large area, thereby rapidly forming a large-area monolayer microsphere array, and further enabling the preparation of a large-area microneedle array. Compared with the prior art, this disclosure effectively improves the preparation speed and efficiency of large-area microneedle arrays, shortens the preparation time, eliminates the need for high-precision equipment, and uses very simple equipment (such as injection pumps and containers), significantly reducing preparation costs and requiring less experience from operators.

[0096] As described in the second aspect embodiment, in step S4, the monolayer microsphere array can be transferred to the substrate with the photoresist layer by either the draining method or the lifting method. In actual operation, the substrate with the photoresist layer can be placed at the bottom of the cavity after step S2 and before step S3, so that the monolayer microsphere array can be transferred to the substrate in step S3.

[0097] In step S5, the substrate can be ion-etched using existing ion etching methods, such as plasma etching. The etching process parameters can be determined according to actual needs. For example, the ICP power can be 200W, the RF power can be 50W, the SF6 flow rate can be 30sccm, the temperature can be 5℃, the pressure can be 10mTorr, and the time can be 200s.

[0098] In step S5, during ion etching of the substrate, the photoresist blocks ions, so the substrate surface covered by the photoresist layer will not be etched, thus preventing the formation of microneedles. However, the substrate surface not covered by the photoresist layer will be ion-etched into microneedles, resulting in a patterned microneedle array.

[0099] In some embodiments, the method for preparing the microneedle array further includes:

[0100] Step S6: Clean the etched substrate to remove microsphere residues and photoresist layer from the substrate surface to obtain the finished microneedle array structure.

[0101] In step S6, for example, the substrate that has undergone ion etching can be placed in acetone, ethanol and deionized water in sequence for ultrasonic cleaning, and then air-dried to obtain the final product.

[0102] The microneedle array fabrication method of this disclosure is applicable to the fabrication of patterned microneedle arrays required for biomedical devices, energy devices, and hydrophilic / hydrophobic surface modification.

[0103] The microneedle array structure obtained by the microneedle array preparation method of this disclosure can be used in fields such as biomedicine, photovoltaic devices, energy devices, flexible electronic devices, and hydrophilic and hydrophobic surface preparation, and has a wide range of application scenarios and considerable application value.

[0104] The above description is merely an embodiment of this specification and is not intended to limit this specification. Various modifications and variations can be made to this specification by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this specification should be included within the scope of the claims of this specification.

Claims

1. A method for preparing a microneedle array, characterized in that, include: Pretreatment of the substrate; A patterned photoresist layer is formed on the pretreated substrate; A microsphere-driven method is used to drive the movement of microspheres until the microspheres are closely arranged on the liquid surface of the cavity to form a monolayer microsphere array; wherein, the microsphere-driven method includes: The microspheres are dispersed in a first liquid, wherein the first liquid is contained within the cavity; and A second liquid is injected into a local area of ​​the cavity, wherein the surface energy of the second liquid is lower than that of the first liquid; as the second liquid diffuses from the local area to other areas of the cavity, the concentration of the second liquid in the cavity is distributed in a gradient, and driven by the surface energy difference generated by the concentration difference of the second liquid, the microspheres move in the direction where the concentration of the second liquid decreases; The microsphere array is transferred onto a substrate having a photoresist layer, resulting in a microsphere mask layer covering the photoresist layer; and The substrate is subjected to ion etching, wherein the surface of the substrate not covered by the photoresist layer but covered by the microsphere mask layer is etched to form microneedles, and the surface of the substrate covered by both the photoresist layer and the microsphere mask layer does not form microneedles, so as to obtain a patterned microneedle array.

2. The method for preparing the microneedle array according to claim 1, characterized in that, Also includes: The etched substrate is cleaned to remove microsphere residues and photoresist layers from the substrate surface.

3. The method for preparing the microneedle array according to claim 1, characterized in that, The cavity is defined by a container, the local area is the region of the cavity near one sidewall of the container, and the movement direction of the microsphere includes at least a direction from one sidewall of the container toward the other sidewall of the container.

4. The method for preparing the microneedle array according to claim 1, characterized in that, The first liquid is a non-volatile solvent, and the second liquid is a volatile solvent.

5. The method for preparing the microneedle array according to claim 4, characterized in that, The first liquid is water, and / or the second liquid is ethanol.

6. The method for preparing a microneedle array according to any one of claims 1 to 5, characterized in that, The process of dispersing microspheres in a first liquid includes: Place the microspheres into the dispersion; The dispersion containing microspheres is subjected to ultrasonic treatment to ensure that the microspheres are uniformly dispersed in the dispersion. The ultrasonically treated dispersion is injected into the first liquid within the cavity; and The cavity is left to stand, allowing the microspheres to remain stationary in the first liquid.

7. The method for preparing a microneedle array according to claim 6, characterized in that, The dispersion is prepared by mixing a first liquid and a second liquid in a preset volume ratio.

8. The method for preparing a microneedle array according to any one of claims 1 to 5, characterized in that, The injection of the second liquid into a localized area of ​​the cavity includes: With 15 μl / min ~25 μl The second liquid is injected at an injection rate of / min.

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