A hollow microneedle array chip and preparation method thereof

Abstract

The present invention provides a hollow microneedle array chip and a preparation method thereof, comprising: a substrate, the substrate comprising a front side and a back side relative to each other; a microneedle, the microneedle is located on the front side of the substrate, the microneedle comprises a needle tip, a needle hole and a needle surface, the needle surface is tilted to the substrate at a set angle; a groove, the groove is located at the periphery of the microneedle and half-wraps the microneedle; a flow guide groove, the flow guide groove is located on the back side of the substrate and is connected to the needle hole. The present invention can realize mass production of microneedles and solve the technical problem of difficulty in piercing the skin or reaching the depth of the skin by arranging grooves and flow guide grooves on the substrate and tilting the needle surface to the substrate at a set angle.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a hollow microneedle array chip and a preparation method thereof. Background Art

[0002] Hollow microneedle technology is a painless drug delivery technology with a certain internal space that can be used to fill effective drug dispersions or solutions. They have holes on the tip, and when inserted into the skin, the drug is directly deposited in the epidermis or upper dermis. Because of its fixed length, the injection depth is precise and injection pain is not caused.

[0003] At present, the main materials used to make hollow microneedles include metal, silicon, silicon dioxide, glass, nickel, titanium and biodegradable polymers. Metal microneedles are cheap and have high hardness, but it is difficult to reach a micron-level needle length, making it difficult to achieve painless injection. It is difficult to control the sharpness of the polymer microneedle tip, and the strength is poor. Under a certain pressure, plastic deformation will occur, making it difficult to pierce the skin. Some hollow needles made of silicon materials have insufficient hole diameters, insufficient needle heights, and poor needle height uniformity. In order to obtain reliable data, some modern blood analysis equipment requires at least 5ul to 50ul / hour of blood for analysis. In order to achieve sufficient flow, the needle hole diameter needs to be at least 10-100um.

[0004] Currently known methods for silicon-based microneedles mainly include laser drilling, which is difficult to mass-produce and has high requirements for the alignment of the laser and the silicon substrate, resulting in a low yield. Most other microneedles have disadvantages such as low needle tip sharpness, insufficient height, insufficient needle surface inclination, and poor needle tip uniformity, making it difficult to penetrate the skin or reach the intradermal depth. Summary of the invention

[0005] The purpose of the present invention is to provide a hollow microneedle array chip and a preparation method thereof, which can at least solve the technical problems that microneedles are difficult to mass produce and difficult to penetrate the skin or reach the depth within the skin.

[0006] In order to achieve the above object, the present invention provides a hollow microneedle array chip, comprising:

[0007] a substrate including opposite front and back surfaces;

[0008] A microneedle, wherein the microneedle is located on the front side of the substrate, the microneedle comprises a needle tip, a needle hole and a needle surface, and the needle surface is inclined to the substrate at a set angle;

[0009] A groove, wherein the groove is located at the periphery of the microneedle and half-wraps the microneedle;

[0010] A guide groove is located on the back side of the substrate and is connected to the pinhole.

[0011] Optionally, a microneedle array is formed by at least two microneedles, the microneedle array is a hollow microneedle array, and the microneedles are arranged on the substrate at a set interval.

[0012] Optionally, the distance between the needle tips of two adjacent microneedles is 600 um.

[0013] Optionally, the groove is in an inverted V shape.

[0014] Optionally, the groove has a depth of 30 to 80 um and a width of 50 to 100 um.

[0015] Optionally, the guide groove is circular or elliptical, and has a diameter of 100 um and a depth of 100-200 um.

[0016] Optionally, the diameter of the pinhole of the microneedle is 10-100 um, and the distance between the pinhole and the top of the needle tip is 40 um.

[0017] Optionally, the height of the microneedle is greater than 500 um, and the width is 200-420 um.

[0018] Optionally, the inclination angle between the needle surface and the substrate is 54.74°

[0019] Optionally, the substrate is in the shape of a cuboid, and the length of the substrate is 2300 um, the width is 900 um, and the height is 300 um.

[0020] The present invention also provides a method for preparing a hollow microneedle array chip, comprising:

[0021] providing a substrate, the substrate comprising opposite front and back surfaces;

[0022] forming a microneedle on the substrate, wherein the microneedle comprises a needle tip, a needle hole and a needle surface, and the needle surface is inclined to the substrate at a set angle;

[0023] A groove is formed on the front side of the substrate, wherein the groove is formed on the periphery of the microneedle and half includes the microneedle;

[0024] A guide groove is formed on the back side of the substrate and is communicated with the pinhole.

[0025] Optionally, after forming the substrate, the method further comprises:

[0026] The guide groove is formed on the back side of the substrate by photolithography and etching processes.

[0027] Optionally, after forming the guide groove, the method for forming the microneedle includes:

[0028] Forming a mask layer on the back side of the substrate by a deposition process, and etching a portion of the mask layer to form a first groove;

[0029] Forming a second groove and a trench on the front side of the substrate by photolithography and etching processes, wherein the second groove and the first groove are arranged correspondingly up and down;

[0030] Etching the back side of the substrate by deep reactive ion etching process so that the first groove and the second groove are connected to form a pinhole;

[0031] After forming the pinhole, forming a protective layer, the protective layer being formed on the front and back surfaces of the substrate and the inner wall of the pinhole;

[0032] The needle tip and the needle surface are formed by silicon anisotropic wet etching, and the needle surface is inclined to the substrate at a set angle;

[0033] The needle tip, needle surface and needle hole constitute the microneedle;

[0034] The microneedles are diced into microneedle arrays through a dicing process.

[0035] Optionally, it is characterized in that the material of the mask layer is SiO2, and the material of the protection layer is Si3N4.

[0036] Optionally, after forming the first groove and before forming the second groove and the trench, the method further includes:

[0037] Forming a photoresist on the front side of the substrate, and forming a second reserved groove and a reserved trench on the photoresist by a photolithography process;

[0038] After forming the second recess and the trench, the photoresist is removed.

[0039] Optionally, after forming the protective layer and before forming the needle tip and the needle surface, the method further comprises:

[0040] Removing the protective layer on the front side of the substrate, and retaining the protective layer on the back side of the substrate and the inner wall of the pinhole;

[0041] After the needle tip and needle surface are formed, the protective layer is removed.

[0042] Optionally, after removing the protective layer, the method further includes depositing a protective film on the front and back sides of the substrate and the inner walls of the pinholes by a high temperature process.

[0043] Optionally, the material of the protective film is SiO2.

[0044] Optionally, the inclination angle between the needle surface and the substrate is 54.74°.

[0045] Optionally, the guide groove is circular or elliptical in shape.

[0046] The beneficial effects of the structure of the present invention are:

[0047] The present invention can realize mass production of microneedles, achieve good needle tip sharpness, and solve the technical problem of difficulty in piercing the skin or reaching the depth within the skin by arranging grooves and guide grooves on the substrate and tilting the needle surface to a set angle toward the substrate.

[0048] Furthermore, the height of the microneedle is set to be greater than 500um, the uniformity of the pinhole diameter and the needle tip height is less than 2%, and the inclination angle between the needle surface and the substrate is 54.74°, so that the needle tip can completely penetrate the skin or reach the intradermal depth.

[0049] Furthermore, the guide groove designed on the back side of the substrate of the present invention improves the fixation and sealing between the fluid tube and the hollow microneedle array chip, and the design of the guide groove improves the fluid flow rate.

[0050] Furthermore, the structure of the present invention has small size, high precision, simple process, low cost and is easy to mass produce.

[0051] The beneficial effects of the method of the present invention are:

[0052] The present invention simplifies the process of making hollow microneedles by forming a guide groove on the back side of the substrate and forming grooves and microneedles on the front side of the substrate, thereby realizing mass production and reducing production costs. The preparation method of the present invention can manufacture a needle tip with a bevel at a certain angle, achieve good needle tip sharpness and uniformity of the needle hole, and enable the needle tip to completely penetrate the skin or reach the intradermal depth.

[0053] Furthermore, the present invention adopts MEMS process technology, manufactures guide grooves, trenches and pinholes through photolithography and etching processes, and then uses wet etching to produce a microneedle with a height of >500um, and an inclination angle of 54.74° between the needle surface and the substrate, so that the needle tip can completely penetrate the skin or reach the intradermal depth. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0055] Figure 1 A schematic diagram of the three-dimensional structure of the hollow microneedle array chip provided in Example 1 of the present invention;

[0056] Figure 2 A schematic diagram of the three-dimensional structure of the hollow microneedle array chip provided in Example 1 of the present invention;

[0057] Figures 3 to 12 This is a schematic structural diagram corresponding to different steps in the method for making a hollow microneedle array chip provided in Example 2 of the present invention.

[0058] Figure numerals: 10, substrate; 11, first photoresist; 12, mask layer; 13, second photoresist; 14, first groove; 15, third photoresist; 16, second groove; 16a, second reserved groove; 17a, reserved groove; 17, groove; 18, pinhole; 19, protective layer; 20, needle tip; 21, needle surface; 31, protective film; 30, guide groove. DETAILED DESCRIPTION

[0059] The following is a further detailed description of a hollow microneedle array chip and a preparation method thereof of the present invention in conjunction with the accompanying drawings and specific embodiments. According to the following description and drawings, the advantages and features of the present invention will become clearer. However, it should be noted that the concept of the technical solution of the present invention can be implemented in a variety of different forms and is not limited to the specific embodiments described herein. The accompanying drawings are all in a very simplified form and are not in precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.

[0060] The terms "first", "second", etc. in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe a specific order or time sequence. It is to be understood that, where appropriate, these terms used in this way are interchangeable, for example, so that the embodiments of the invention described herein can be operated in an order other than that described or shown herein. Similarly, if the method described herein includes a series of steps, the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some of the steps described may be omitted and / or some other steps not described herein may be added to the method. If the components in a certain figure are the same as the components in other figures, although these components can be easily identified in all figures, in order to make the description of the figures clearer, this specification will not mark all the same component numbers in each figure.

[0061] Example 1

[0062] refer to Figure 1 and Figure 2 This embodiment provides a hollow microneedle array chip. Figure 1 and Figure 2 A schematic diagram of the structure of a hollow microneedle array chip in Example 1 is shown. Figure 1 and Figure 2 , the hollow microneedle array chip comprises:

[0063] A substrate 10, wherein the substrate 10 includes a front side and a back side opposite to each other;

[0064] A microneedle, the microneedle is located on the front side of the substrate 10, the microneedle comprises a needle tip 20, a needle hole 18 and a needle surface 21, and the needle surface 21 is inclined at a set angle toward the substrate 10;

[0065] A groove 17, wherein the groove 17 is located at the periphery of the microneedle and half-wraps the microneedle;

[0066] The guide groove 30 is located on the back side of the substrate 10 and is connected to the pinhole 18 .

[0067] The substrate 10 can be any suitable substrate material known to those skilled in the art, such as semiconductor substrate materials such as silicon, germanium, silicon germanium, gallium arsenide, indium phosphide, etc. <100> of single crystal silicon wafers.

[0068] The chip comprises four parts, a microneedle array consisting of at least two microneedles, a substrate 10, a groove 17 and a guide groove 30. The microneedles are arranged on the substrate 10 at a set interval. In this embodiment, the interval between the needle tips 20 of two adjacent microneedles is 600um.

[0069] In this embodiment, the groove 17 is in an inverted V shape. The groove 17 is located at the periphery of the microneedle and half-wraps the microneedle. The depth of the groove 17 is 30 to 80 um and the width is 50 to 100 um. By setting the groove 17 on the front side of the substrate 10, it can help the needle tip 20 to penetrate completely.

[0070] In this embodiment, the guide groove 30 is circular or elliptical, the diameter of the guide groove 30 is 100um, and the depth is 100-200um; the guide groove 30 is located on the back side of the substrate 10, and the guide groove 30 is connected to the pinhole 18 of the microneedle. The present invention improves the fixity and sealing between the fluid tube and the hollow microneedle array chip by designing the guide groove 30 on the back side of the substrate 10, and the design of the guide groove 30 improves the fluid flow rate.

[0071] The microneedle includes a needle tip 20 , a needle hole 18 , and a needle surface 21 , and the needle surface 21 is inclined toward the substrate 10 at a set angle.

[0072] Specifically, the diameter of the needle hole 18 of the microneedle is 10 to 100 um, and the distance between the needle hole 18 and the top of the needle tip 20 is 40 um; the height of the microneedle is greater than 500 um, and the width is 200 to 420 um; the inclination angle between the needle surface 21 and the substrate 10 is 54.74°; the height of the microneedle is set to be greater than 500 um, so that the uniformity of the diameter of the needle hole 18, the height of the needle tip 20 and the width of the microneedle are all less than 2% and the inclination angle between the needle surface 21 and the substrate 10 is 54.74°, so that the needle tip 20 can completely penetrate the skin or reach the intradermal depth.

[0073] In this embodiment, the substrate 10 is in the shape of a cuboid, and the length of the substrate 10 is 2300 um, the width is 900 um, and the height is 300 um.

[0074] The present invention can realize mass production of microneedles, achieve good needle tip 20 sharpness, and solve the technical problem of difficulty in piercing the skin or reaching the intradermal depth by arranging grooves 17 and guide grooves 30 on the substrate 10 and tilting the needle surface 21 to the substrate 10 at a set angle; in addition, the present invention has a small structure size, high precision, simple process, low cost, and is easy to mass produce.

[0075] Example 2

[0076] This embodiment 2 provides a method for preparing a hollow microneedle array chip, comprising the following steps:

[0077] S01: providing a substrate 10, wherein the substrate 10 includes a front side and a back side opposite to each other;

[0078] S02: forming a microneedle on the substrate 10, wherein the microneedle comprises a needle tip 20, a needle hole 18 and a needle surface 21, and the needle surface 21 is inclined to the substrate 10 at a set angle;

[0079] S03: A groove 17 is formed on the front surface of the substrate 10, and the groove 17 is formed on the periphery of the microneedle and half includes the microneedle;

[0080] S04: A guide groove 30 is formed on the back side of the substrate 10 and is connected to the pinhole 18.

[0081] It should be noted that steps S0N do not represent a sequential order.

[0082] Figures 3 to 12 This is a schematic diagram of the structure corresponding to each step of this embodiment 2. Figures 3 to 12 The preparation method of hollow microneedle array chip is described.

[0083] refer to Figure 3 , a substrate 10 is provided, wherein the substrate 10 includes a front side and a back side opposite to each other.

[0084] The substrate 10 can be any suitable substrate material known to those skilled in the art, such as semiconductor substrate materials such as silicon, germanium, silicon germanium, gallium arsenide, indium phosphide, etc. <100> The thickness of the silicon wafer is selected according to the height of the microneedle to be prepared, and the silicon wafer is cleaned with chemicals.

[0085] refer to Figure 4 A guide groove 30 is formed on the back side of the substrate 10 .

[0086] The method for forming the guide groove 30 includes:

[0087] A first photoresist 11 is coated on the back of the substrate 10, and the photoresist is selectively exposed and developed using a pattern transfer technique in a conventional microelectronics process, so that a photoresist pattern is formed on the back of the substrate 10. Figure 4 The substrate 10 is etched with the photoresist as a masking film, so that the guide groove 30 is formed on the back of the substrate 10. It should be noted that the photolithography and etching processes are well known to those skilled in the art and will not be described in detail here.

[0088] In this embodiment, the guide groove 30 is circular or elliptical, the diameter of the guide groove 30 is 100um, and the depth is 100-200um; the guide groove 30 is located on the back side of the substrate 10, and the guide groove 30 is connected to the pinholes of the microneedles formed subsequently. The present invention improves the fixation and sealing between the fluid tube and the hollow microneedle array chip by designing the guide groove 30 on the back side of the substrate 10, and the design of the guide groove 30 improves the fluid flow rate.

[0089] After the guide groove 30 is formed, the first photoresist 11 is removed.

[0090] The first photoresist 11 may be removed by a plasma process, or may be removed by a wet process, which is not limited here.

[0091] refer to Figures 5 to 12 After removing the first photoresist, a microneedle is formed on the substrate 10, wherein the microneedle includes a needle tip 20, a pinhole 18 and a needle surface 21, and the needle surface 21 is inclined to the substrate 10 at a set angle; a groove 17 is formed on the front side of the substrate 10, and the groove 17 is formed on the periphery of the microneedle and half includes the microneedle.

[0092] The method for forming the microneedle comprises:

[0093] refer to Figure 5 A mask layer 12 is formed on the back side of the substrate 10 by a deposition process, and a portion of the mask layer 12 is etched to form a first groove 14 .

[0094] The material SiO2 of the mask layer 12 is mainly used for etching the pinhole 18 of the microneedle later. The deposition thickness of SiO2 is determined according to the etching depth of the pinhole 18 of the microneedle.

[0095] The method for forming the first groove 14 includes:

[0096] refer to Figure 6 After forming the mask layer 12, a second photoresist 13 is coated on the mask layer 12, and a first groove 14 is formed through photolithography and etching processes.

[0097] In this embodiment, the first groove 14 penetrates the mask layer 12 .

[0098] The first groove 14 is used for subsequently forming the needle hole of the microneedle.

[0099] The etching process may be dry etching or wet etching, and this embodiment adopts the dry etching process.

[0100] After the first groove 14 is formed, the second photoresist 13 is removed. The method of removing the second photoresist 13 is as described above and will not be described again here.

[0101] refer to Figure 7 and Figure 8 A second groove 16 and a groove 17 are formed on the front surface of the substrate 10 by photolithography and etching processes, and the second groove 16 and the first groove 14 are arranged correspondingly in the upper and lower parts.

[0102] After forming the first groove 14 and before forming the second groove 16 and the trench 17, the method further includes:

[0103] A third photoresist 15 is formed on the front surface of the substrate 10, and a second reserved groove 16a and a reserved groove 17a are formed on the photoresist by a photolithography process;

[0104] The second recess 16 and the trench 17 are formed by an etching process, and then the third photoresist 15 is removed.

[0105] The groove 17 is in an inverted V shape. The groove 17 is located at the periphery of the subsequently formed microneedle and half-wraps the subsequently formed microneedle. The depth of the groove 17 is 30 to 80 um and the width is 50 to 100 um. By setting the groove 17 on the front side of the substrate 10, it can help the needle tip 20 to penetrate completely.

[0106] The photolithography process and the etching process are common knowledge to those skilled in the art and will not be described in detail here. The method for removing the third photoresist 15 is described above.

[0107] refer to Fig. 9The back side of the substrate 10 is etched by deep reactive ion etching process, so that the first groove 14 and the second groove 16 are connected to form a pinhole 18.

[0108] The pinhole 18 is in communication with the guide groove 30;

[0109] refer to Fig.10 After the pinhole 18 is formed, a protective layer 19 is formed. The protective layer 19 is formed on the front and back sides of the substrate 10 and the inner wall of the pinhole 18 .

[0110] The material of the protection layer 19 is Si3N4, which serves as the protection layer 19 for the needle tip 20 of the microneedle to be subsequently etched.

[0111] refer to Fig.11 and Fig.12 The needle tip 20 and the needle surface 21 are formed by silicon anisotropic wet etching, and the needle surface 21 is inclined to the substrate 10 at a set angle; the needle tip 20, the needle surface 21 and the pinhole 18 constitute the microneedle; and the microneedle is diced into a microneedle array by a dicing process.

[0112] Specifically, the diameter of the needle hole 18 of the microneedle is 10 to 100 um, and the distance between the needle hole 18 and the top of the needle tip 20 is 40 um; the height of the microneedle is greater than 500 um, and the width is 200 to 420 um; the inclination angle between the needle surface 21 and the substrate 10 is 54.74°; the height of the microneedle is set to be greater than 500 um, so that the uniformity of the diameter of the needle hole 18, the height of the needle tip 20 and the width of the microneedle are all less than 2% and the inclination angle between the needle surface 21 and the substrate 10 is 54.74°, so that the needle tip 20 can completely penetrate the skin or reach the intradermal depth.

[0113] It should be noted that after forming the protective layer 19 and before forming the needle tip 20 and the needle surface 21, the following steps are also included:

[0114] The protective layer 19 on the front side of the substrate 10 is removed, and the protective layer 19 on the back side of the substrate 10 and the inner wall of the pinhole 18 is retained;

[0115] After the needle tip 20 and the needle surface 21 are formed, the protective layer 19 is removed.

[0116] Specifically, the different etching rates of KOH on each crystal plane of silicon are used to etch out a needle surface with an inclination of 54.74°, and the height of the microneedle is determined by the KOH etching time; the corrosiveness of HF on the Si3N4 protective layer 19 is used to etch out the needle tip 20, and the remaining Si3N4 protective layer 19 on the inner wall of the pinhole 18 of the microneedle and in the groove 17 is removed.

[0117] Continue to refer Fig.12After removing the protective layer 19 , the method further includes depositing a protective film 31 on the front and back sides of the substrate 10 and the inner wall of the pinhole 18 through a high temperature process.

[0118] Specifically, the material of the protective film 31 is SiO2; the method of depositing SiO2 is low pressure chemical vapor deposition (LPCVD) or high temperature furnace tube thermal oxidation SiO2; in addition, the sharpness of the needle tip 20 can be increased by high temperature, and the hardness of the needle tip 20 can be increased by sputtering metal on the surface.

[0119] It should be noted that the present invention completes the entire preparation process by adopting MEMS process technology.

[0120] The present invention simplifies the process flow of making hollow microneedles by forming a guide groove 30 on the back side of the substrate 10 and forming a groove 17 and a microneedle on the front side of the substrate 10, thereby realizing mass production and reducing production costs. The preparation method of the present invention can manufacture a needle tip 20 with a bevel at a certain angle, achieve good needle tip 20 sharpness and uniformity of the needle hole 18, and enable the needle tip 20 to completely penetrate the skin or reach the intradermal depth.

[0121] Furthermore, the present invention adopts MEMS process technology, and manufactures the guide groove 30, the groove 17 and the pinhole 18 through photolithography and etching processes, and then uses wet etching to produce a microneedle with a height of >500um, and the inclination angle between the needle surface 21 and the substrate 10 is 54.74°, so that the needle tip 20 can completely penetrate the skin or reach the intradermal depth.

[0122] It should be noted that the various embodiments in this specification are described in a related manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0123] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall within the scope of protection of the claims.

Claims

1. A hollow microneedle array chip, characterized in that: include: a substrate including opposite front and back surfaces; A microneedle, wherein the microneedle is located on the front side of the substrate, the microneedle comprises a needle tip, a needle hole and a needle surface, and the needle surface is inclined at a set angle to the substrate; the height of the microneedle is greater than 500um, and the width is 200 to 420um; A groove, wherein the groove is located at the periphery of the microneedle and half-wraps the microneedle; A guide groove, the guide groove is located on the back side of the substrate and is connected to the pinhole; The inclination angle between the needle surface and the substrate is 54.74°.

2. The hollow microneedle array chip according to claim 1, characterized in that: The microneedle array is composed of at least two microneedles, and the microneedles are arranged on the substrate at a set interval.

3. The hollow microneedle array chip according to claim 1, characterized in that: The distance between the needle tips of two adjacent microneedles is 600 um.

4. The hollow microneedle array chip according to claim 1, characterized in that: The groove is in an inverted V shape.

5. The hollow microneedle array chip according to claim 1, characterized in that: The groove has a depth of 30 to 80 um and a width of 50 to 100 um.

6. The hollow microneedle array chip according to claim 1, characterized in that: The guide groove is circular or elliptical, has a diameter of 100 um, and a depth of 100-200 um.

7. The hollow microneedle array chip according to claim 1, characterized in that: The diameter of the pinhole of the microneedle is 10-100 um, and the distance between the pinhole and the top of the needle tip is 40 um.

8. The hollow microneedle array chip according to claim 1, characterized in that: The substrate is in the shape of a cuboid, with a length of 2300um, a width of 900um, and a height of 300um.

9. A method for preparing the hollow microneedle array chip according to any one of claims 1 to 8, characterized in that: include: providing a substrate, the substrate comprising opposite front and back surfaces; forming a microneedle on the substrate, wherein the microneedle comprises a needle tip, a needle hole and a needle surface, and the needle surface is inclined to the substrate at a set angle; The needle tip and the needle surface are formed by anisotropic silicon wet etching; A groove is formed on the front side of the substrate, wherein the groove is formed on the periphery of the microneedle and half includes the microneedle; A guide groove is formed on the back side of the substrate and is communicated with the pinhole.

10. The preparation method according to claim 9, characterized in that: After forming the substrate, the method comprises: The guide groove is formed on the back side of the substrate by photolithography and etching processes.

11. The preparation method according to claim 10, characterized in that: After the guide groove is formed, the method for forming the microneedle includes: Forming a mask layer on the back side of the substrate by a deposition process, and etching a portion of the mask layer to form a first groove; Forming a second groove and a trench on the front side of the substrate by photolithography and etching processes, wherein the second groove and the first groove are arranged correspondingly up and down; Etching the back side of the substrate by deep reactive ion etching process so that the first groove and the second groove are connected to form a pinhole; After forming the pinhole, forming a protective layer, the protective layer being formed on the front and back surfaces of the substrate and the inner wall of the pinhole; The needle surface is inclined at a set angle to the substrate; The needle tip, needle surface and needle hole constitute the microneedle; The microneedles are diced into microneedle arrays through a dicing process.

12. The preparation method according to claim 11, characterized in that: The material of the mask layer is SiO2, and the material of the protection layer is Si3N4.

13. The preparation method according to claim 12, characterized in that: After forming the first groove and before forming the second groove and the trench, the method further includes: Forming a photoresist on the front side of the substrate, and forming a second reserved groove and a reserved trench on the photoresist by a photolithography process; After forming the second recess and the trench, the photoresist is removed.

14. The preparation method according to claim 11, characterized in that: After forming the protective layer and before forming the needle tip and the needle surface, the method further includes: Removing the protective layer on the front side of the substrate, and retaining the protective layer on the back side of the substrate and the inner wall of the pinhole; After the needle tip and needle surface are formed, the protective layer is removed.

15. The preparation method according to claim 11, characterized in that: After removing the protective layer, the method further includes depositing a protective film on the front and back sides of the substrate and the inner walls of the pinholes through a high temperature process.

16. The preparation method according to claim 15, characterized in that: The material of the protective film is SiO2.

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