JP2013252580A - Method for manufacturing microneedle structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and easy method for manufacturing a microneedle structure having a high accuracy through-hole.SOLUTION: After a hollow through-hole 104 formed in a substrate 101 is plated to form a cylindrical metal structure 107, wax is supplied in such a manner that the wax gets into the through-hole of the metal structure 107, and the substrate 101 is attached to a dummy substrate 108. Next, after a tip of the metal structure 107 is ground off at an angle by machining from an opposite side of the dummy substrate, part of the substrate around the through-hole is dissolved and removed to form an array microneedle 111 having a high accuracy through-hole.

Description

  The present invention relates to a method for manufacturing a microneedle structure having a microneedle having an elongated through hole.

  In the medical field, a percutaneous absorption method is known as a method of infiltrating a drug from the skin and administering the drug into the body. This method applies a liquid or gel-like drug to the surface of a living body such as skin or mucous membrane, is non-invasive, and allows a drug to be easily administered without causing pain to the human body.

  However, the applied drug is easily removed by perspiration or external contact. In addition, if the administration period is long, problems such as skin disorders may occur in terms of safety. Furthermore, when the molecular weight of the target drug is large or when it is a water-soluble drug, it is hardly absorbed into the body even when applied to the surface of a living body, and it is difficult to administer these drugs transdermally.

  Therefore, in order to efficiently absorb these drugs into the body, a method of perforating the skin using a microneedle array having a large number of micron-order needles and administering the drug directly into the skin has attracted attention. According to this method, a drug can be easily administered subcutaneously without using a special device for medication (see, for example, Patent Document 1).

  The shape of the microneedle is required to have a sufficient fineness and a tip angle for piercing the skin, and a sufficient length for allowing the drug solution to penetrate subcutaneously. Therefore, the diameter of the needle is several microns to several hundred microns, and the length of the needle penetrates the stratum corneum, which is the outermost layer of the skin, and does not reach the nerve layer, specifically several tens of microns to several hundreds. It is considered desirable to be micron.

  In order to manufacture such a fine structure at a low cost and in large quantities, a transfer molding method represented by an injection molding method, an imprinting method, a casting method and the like is effective. However, in any method, in order to perform molding, a mold in which a desired shape is inverted is necessary, and an aspect ratio (height or depth ratio to the diameter of the structure) like a microneedle is required. However, in order to form a structure that requires a sharp tip, a very complicated manufacturing process is required.

  As a microneedle manufacturing method, for example, the tip of the needle can be sharpened by performing anisotropic wet etching using an etching rate difference for each crystal plane orientation of a single crystal material such as a silicon wafer. Proposed. However, the sharpening of the tip requires strict time control of anisotropic wet etching. Thus, advanced processing techniques are required for each process (see, for example, Patent Document 2).

  In addition, exposure is performed while moving the exposure mask, and the tip angle of the needle is controlled by changing the exposure amount (see, for example, Patent Document 3), or a combination of wet etching and chemical etching using a chemical solution ( For example, various methods such as Patent Document 4) have been proposed.

  Also, as a microneedle manufacturing method, isotropic etching is performed under a resist mask to form the tip of the microneedle, and then anisotropic etching is performed to form a microneedle patch having a microneedle of a desired height. Is disclosed (see, for example, Patent Document 5).

US Pat. No. 6,183,434 JP 2002-79499 A JP 2005-246595 A JP 2002-239014 A JP 2005-199392 A

  However, the manufacturing method described above involves the formation of a thermal oxide film, resist coating, mask pattern formation by photolithography, isotropic etching, anisotropic etching, removal of side-deposited layers, and gradient etching, and many complicated processes. This requires the problem of cost and time.

  Since the microneedles need to surely reach a living tissue such as the dermis, and particularly need to be formed uniformly with respect to the height, it is difficult to accurately form the microneedles by the above method.

  As described above, in order to meet the structural requirements of microneedles that a conventional microneedle manufacturing method requires a sharp tip in addition to a high aspect ratio, it is generally used less frequently. In many cases, a special exposure apparatus that cannot be used, a high-precision machining technique, or a complicated manufacturing process is required, and there is a problem that a mask that has dropped off due to progress of etching contaminates the periphery.

  Further, depending on the purpose of use of the microneedle, there may be a case where a shape like an injection needle having a hole in the center is desirable instead of a simple protrusion shape. In order to obtain such a shape in a microneedle, it is difficult to simultaneously form a needle structure with a sharp tip and a tapered tip and a vertical and deep central hole. The method is common.

  This is because, in the manufacturing process, the needle structure portion may be etched halfway through the substrate, whereas the central hole portion needs to be etched through the entire substrate, and the depth required for each differs. . In the dry etching process, it is not easy to intentionally change the etching depth in the plane of the substrate. As a result, it becomes difficult to collectively manufacture the needle structure portion and the central hole portion by dry etching. It becomes necessary to perform etching twice.

  However, when lithography using a resist is performed for the purpose of forming a large number of microneedles at once, there is a problem that it is difficult to apply to a high aspect structure such as a microneedle. Furthermore, it is necessary to form the central hole with a precise alignment for all needle structures, and careful attention is required for their alignment.

  Also, even if the alignment can be performed accurately without error, if the central hole and the peripheral taper are both deep structures such as several hundred microns as in the microneedle structure, the central hole Alternatively, after either one of the peripheral tapered portions is formed, there is a problem that it is extremely difficult to uniformly apply a resist used for lithography for forming the other.

  On the other hand, a process of forming a central hole portion from the back surface and then forming a peripheral tapered portion from the front surface is also conceivable. According to this process, the problem that it is difficult to uniformly apply the resist is solved, but alignment from both the front and back sides is required. In general, in such a double-sided aligner, the alignment accuracy is lower than that of a single-sided aligner, and when the central hole opened from the back side is not etched vertically correctly, Even if the positioning is accurately performed, it is impossible to make a through hole in the center of the resulting microneedle structure.

  Even if all these problems can be avoided, it is still not easy to manufacture a microneedle having a through hole in the center.

  The reason for this is that the diameter of a general microneedle is at most about 100 to 200 microns at most. Therefore, when a through hole is provided in the center, the diameter of the microneedle is determined in consideration of space constraints and strength problems. Several microns to several tens of microns. It is not easy to process such a fine hole to penetrate through a length of about several hundred microns, which is a general height of a microneedle.

  As described above, in the conventional manufacturing method, as a first problem, it is necessary to accurately align the position of the through hole with the center of the microneedle. Have As a second problem, when the central through hole is removed by etching or machining, it is difficult to form a thin and long hole.

  The present invention has been made in view of the above circumstances, and provides a manufacturing method of a microneedle structure that can easily and easily manufacture a microneedle having a highly accurate elongated through hole. Objective.

  The present invention relates to a microneed structure that can easily and easily form a microneedle having an elongated through-hole by simply plating a hollow through-hole to form a microneedle. The manufacturing method is characterized.

  That is, the method for manufacturing a microneedle structure according to the present invention includes a first step of forming a through hole in a substrate, a second step of applying metal plating to at least an inner wall of the through hole, and applying the metal plating. A third step of scraping off the tip of the through hole to form a needle tip; and a fourth step of dissolving and removing the substrate portion around the through hole to form a needle tip shaped microneedle. Configured.

  According to the present invention, there is provided a method for manufacturing a microneedle structure that can easily form a microneedle having an elongated through-hole easily and easily because deterioration in accuracy due to an alignment error is prevented because alignment is not required. be able to.

It is sectional drawing shown in order to demonstrate the manufacturing method of the microneedle structure which concerns on one embodiment of this invention. It is the structure explanatory drawing shown in order to demonstrate the shape example of the front-end | tip part and through-hole of the microneedle shown in FIG. It is sectional drawing shown in order to demonstrate the manufacturing method of the microneedle structure which concerns on other embodiment of this invention.

  Hereinafter, a method for manufacturing a microneedle structure according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a method for manufacturing a microneedle structure according to an embodiment of the present invention. In a substrate 101, a microneedle called a hollow microneedle is formed in a first step as will be described later. A plurality of vertical through-holes 104, for example, are provided corresponding to (see FIGS. 1A and 1B). This through-hole 104 is not a through-hole itself at the center of the microneedle, but serves as a mold for molding the outer shape of the microneedle. For this reason, the opening width of the through hole 104 is approximately several hundred microns, and it is not necessary to open an extremely narrow hole. For this reason, the process of providing the through-hole 104 which will be described in detail later is not so difficult.

  The material of the substrate 101 may be any material that can be processed by wet etching, plasma etching, blasting, or the like. A typical example is silicon, but a metal material such as aluminum or stainless steel, or a synthetic resin such as polycarbonate, polystyrene, or acrylic resin may be used as long as the processing of this embodiment is possible.

  As a method of providing the through-hole 104, various removable processing methods such as various types of machining, laser processing, reactive ion etching, and focused ion beam processing can be used. Further, if there is no problem in the subsequent process, a technique such as punching, die cutting, imprinting or the like may be used. Here, it is important to form a single through hole 104 or a plurality of through holes 104 having a desired opening diameter and depth in the substrate 101 to be used, and the forming method is not limited.

  In forming the through hole 104, it is most desirable from the viewpoint of efficiency to penetrate from the front surface to the back surface of the substrate 101 in one process, but the process is not necessarily limited to such a process. For example, by using a substrate 101 having a thickness of 1.2 mm and forming a hole from the surface to a depth of 1 mm, the substrate 101 is polished and thinned by 0.2 mm or more from the back surface, and a hole is also opened from the back surface. The through hole 104 may be formed.

  The shape of the through-hole 104 is typically the circular shape shown in FIG. 2A, but the elliptical shape or polygonal shape shown in FIG. 2B, for example, the quadrilateral shape shown in FIG. The triangular shape shown in 2 (d) is possible. However, in the case of a polygon having vertices, it is desirable to have a shape with R at the vertex. This is because, in addition to the fact that it is practically impossible to drill a hole with an extremely small R at the apex, defects are likely to occur even in the plating process described later. For this reason, the shape of the through hole 104 is preferably a circle or an ellipse.

  Here, when providing the through-hole 104 by reactive ion etching, first, the etching mask layer 102 having the hole pattern 103 corresponding to the shape and width of each microneedle is formed on the substrate 101 (see FIG. 1a). ). As an etching mask, a resist may be used, a hard mask having an opening pattern in a metal film may be used, or direct etching is formed on the substrate 101 by CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition). A metal film, an organic metal film, a silicon oxide film, or a silicon nitride film may be used. If the substrate 101 is silicon, a silicon oxide film formed by thermal oxidation may be used.

  When manufacturing a microneed structure in which a plurality of microneedles are formed in an array, the pattern layout of the etching mask to be formed can be appropriately designed, and any number of microneedles can be formed side by side at any interval. Is possible.

  The through hole 104 is formed by etching the substrate exposed from the hole pattern 103 of the etching mask layer 102 by reactive ion etching. Thereafter, the etching mask layer 102 is removed to obtain the substrate 101 in which the through holes 104 shown in FIG. 1b are formed.

  Next, the process proceeds to the second step (surface plating step), and the surface of the substrate 101 including the inner wall of the through hole 104 is subjected to metal plating to form the metal layer 105 as shown in FIG. By this second step, a cylindrical metal structure 107, which becomes the basic structure of the subsequent microneedle, is formed.

). Note that pores 106 are simultaneously formed inside the cylindrical metal structure 107.

  This technique is very similar to a technique called through-hole plating used in the manufacture of printed circuit boards and the like. In the case of performing such plating, generally, a thin metal layer is first formed by electroless plating, and then, the thin metal layer is used as a conductive layer and an electric current is applied to perform electrolytic plating. This is not suitable as a method for forming a uniform conductive film inside a deep hole, but by physical deposition such as sputtering or vapor deposition, while in electroless plating, a uniform film is formed on the inside of the hole. This is because a film can be expected. However, if a conductive layer can be formed inside the hole by a technique such as sputtering or vapor deposition, these techniques may be used, and the method for forming the conductive layer is not limited.

  For example, if the substrate 101 itself is conductive and a current for performing electroplating can be passed through the substrate 101, the above-described thin metal layer 105 does not need to be formed. Therefore, in the description of the present invention, the step of forming the thin metal layer 105 serving as the conductive layer and the subsequent electrolytic plating are combined and referred to as a surface plating step.

  The metal used in general through-hole plating is often copper or an alloy thereof, but copper or an alloy thereof may be used as a material for the surface plating process. On the other hand, examples of other materials include nickel and its alloys. Nickel and its alloys are often used for plating of fine molds and have higher mechanical strength than copper. Therefore, it is considered that nickel is preferable as a material for the microneedle. The material is not particularly limited.

  In this surface plating step (second step), plating is performed so that the inside of the through hole 104 is not completely filled, but the pore 106 is left in the center. This is because the pores 106 become the through-holes 104 in the microneedle that is finally formed, and since it does not function as a microneedle when it is completely filled, special care is required.

  In this step, it should be noted that the width of the through hole 104 is narrower than that in the case of general through hole plating. The external width of the microneedle is considered to be slightly narrower than the size of the hole used in general through-hole plating. For this reason, if the plating is performed at a high speed, there is a possibility that all the through holes 104 are filled. In order to prevent such a situation from occurring, it is necessary to strictly control the plating conditions and the like.

  As described above, the cylindrical metal structure 107 which is the basis of the needle structure in the microneedle is formed by the surface plating process (second process). Since the positions of the pores 106 are arranged almost at the center of the cylindrical metal structure 107 even if they are not aligned, the problem of positional misalignment between them does not basically occur.

  Further, it is clear that the pore diameter of the pore 106 formed by this process is smaller than the original pore diameter of the through hole 104. On the other hand, since the height of the pore 106 is substantially the same as the height of the through-hole 104, the aspect ratio determined by (height / hole diameter) of the pore 106 is larger than that of the through-hole 104. As described above, it is not easy to form pores having a large aspect ratio by removal processing such as dry etching or machining. For this reason, for example, assuming that the aspect ratio of pores that can be formed by dry etching is 10 and forming a microneedle having a height of 1 mm, if the through-hole 104 is formed by the removal process as described above, The pore size can only be reduced to a minimum of 100 microns.

  On the other hand, according to the manufacturing method of the present invention, considering the case of forming a microneedle having a height of 1 mm, the hole diameter of the through hole 104 can be reduced to 100 microns. If the through-hole 104 is subjected to surface plating with a thickness of 30 microns, for example, the diameter of the pore 106 is 40 microns, and a pore with an aspect ratio of 25 can be formed. Thus, according to the manufacturing method of the present invention, it is possible to form microneedles having through holes having an aspect ratio that cannot be achieved by the conventional method.

With the above steps, the basic portion of the microneedle structure has been formed, so that the processing for subsequently forming the needle tip portion is performed. As this processing step (third step), machining such as cutting and grinding is suitable, but the processing method itself is not limited as long as processing of a desired shape is possible. Here, as an example, the case of grinding using a dicing saw will be described. First, the back surface of the substrate 101 is covered with wax 109 and simultaneously fixed to the dummy substrate 108 (see FIG. 1D). At this time, the type and amount of the wax 109, the pasting temperature, and the like are adjusted so that the wax 109 is also filled with the pores 106. This serves to prevent the cylindrical metal structure 107 from being plastically deformed and blocking the pores 106 during the next grinding process. If there is no possibility that such a problem will occur during this process, this adjustment may be omitted.

  Next, in accordance with the position of the pore 106, grinding is performed using a dicing saw or the like as shown in FIG. At this time, the tip 110 of the dicing blade to be used is different from a normal one, and it is desirable to use a V-shaped or slanted edge shape. This is to form a sharp needle tip by scraping off the cylindrical metal structure 107 obliquely. In the case of using a V-type dicing blade, it is only necessary to align and process the cylindrical metal structure 107 on one side of the blade edge.

  When the cylindrical metal structure 107 is very thin, as shown in FIG. 1 (e), there is a possibility that a puncture property can be obtained even if it is ground substantially horizontally without being obliquely ground. In such a case, it is not always necessary to grind diagonally, but it is generally desirable to grind obliquely in order to further improve the puncture performance.

  As an example of the shape of the microneedle processed obliquely by this process, for example, as shown in FIGS. 2A to 2D, it is formed in a circular shape, an elliptical shape, a quadrilateral shape, a triangular shape, etc. It is formed in a tip shape that is cut obliquely. Thereby, the same high puncture property as a general injection needle is obtained.

  In a general injection needle, the angle of the cut surface is set to 20 ° or less, and the puncture property is enhanced by making it sharp. Even with a microneedle, although it is not impossible to mold with an equivalent cut surface, there may be problems in practical use. This is because, as is apparent from FIG. 2 (a), when the needle tip is cut obliquely, the opening height of the hollow hole is lowered with respect to the most distal end portion of the needle. This means that the length of the substantial needle is shortened in consideration of the intended use of the microneedle, in which the chemical solution is injected from the hollow hole. The decrease in the opening position of the hollow hole becomes more remarkable as the angle of the cut surface is reduced.

  One of the purposes of the microneedle is to reduce pain when the skin is punctured by making the needle small, that is, making the height low and making it thin. For this reason, the needle height is not so high, and is generally about several hundred microns. With such a needle, if the angle of the cut surface is made very small, the decrease in the opening height of the hollow hole cannot be ignored, so the situation where the angle of the cut surface has to be increased to some extent is fully conceivable. is there.

  In the first place, since the outer shape of the microneedle is thinner than that of a normal injection needle, there is a high possibility that sufficient puncture properties can be obtained without reducing the angle of the cut surface. For this reason, the angle of the cut surface may be determined according to the purpose of use in consideration of the opening position of the hollow hole and the puncture property. Of course, the angle of the cut surface may be reduced in the case of a purpose of use and shape in which a decrease in the opening height of the hollow hole due to such an oblique cut does not become a problem.

  In addition, when sufficient puncture property is not obtained only by oblique cutting, it is also conceivable that the horizontal cross section 212 of the microneedle 202 is made into a hollow ellipse as shown in FIG. By cutting the longitudinal direction of the ellipse obliquely, the cut surface becomes an elongated oval shape compared to the horizontal cross section 211 of FIG. 2A, so that a sharper needle tip is formed and the puncture property is improved. Be expected.

  If there is an advantage in design, manufacture, or use, as shown in FIGS. 2C and 2D, the horizontal cross sections 213 and 214 of the microneedles 203 and 204 are formed into quadrilaterals and triangles. You can make it. In the present invention, the horizontal cross-sectional shape of the microneedle is not limited.

  In this way, after the processing of the needle tip shape is completed, the wax 109 is removed and peeled off from the dummy substrate 108. Then, the process proceeds to a removal step (fourth step), and the substrate 101 is dissolved and removed. By removing unnecessary portions of the metal layer 105, a structure in which a plurality of hollow microneedles 111 are arranged in an array is obtained (see FIG. 1 (f)).

  The substrate 101 is preferably removed by wet treatment. For example, when the substrate 101 is silicon and the metal layer 105 is nickel, only silicon is selected using a strong alkaline aqueous solution such as a potassium hydroxide aqueous solution. Can be dissolved. As long as the substrate 101 can be selectively dissolved and removed with respect to the metal layer 105, another means may be used, or a thermal spraying method in which the substrate 101 is peeled mechanically may be used, and the means is not limited. .

  In the above embodiment, the side wall of the through-hole 104 has been described as being vertical. However, the present invention is not limited to this, and the side wall of the through-hole 104 can be inclined as shown in FIG. The effect of is described.

  That is, in this embodiment, instead of the vertical through-hole 104, the through-hole 304 is formed in the substrate 301 in a forward tapered shape (a shape with a narrow tip and a wide base) that is narrowed and inclined upward. It is comprised so that it may do. In this case as well, the method of forming the through hole 304 is not limited, and the through hole 304 may be formed in a reverse taper shape that is inclined so as to be wide above the shape, or may be configured to be inclined in a curved shape. Expected to be effective.

  In the case of this embodiment, first, through holes 304 are formed as shown in FIG. 3A by the same process, and microneedles 311 and pores 306 are formed as shown in FIG. It is formed.

  An advantage of this embodiment is that the injection resistance when the chemical solution is allowed to flow inside the pores 306 can be reduced. In the microneedles 111 on the vertical side wall shown in FIG. 1, when the chemical solution is injected through the pores 106, the inner diameter of the pores 106 is very narrow. Therefore, depending on the nature of the chemical solution, the injection resistance may be very high. It is done. In contrast, in the microneedle 311 having the forward tapered side wall shown in FIG. 3, the injection path becomes narrower in stages, so that the injection resistance can be lowered if the inner diameter of the narrowest part is the same as that of the vertical side wall. I can do it.

  For this reason, the microneedle 311 shown in FIG. 3 is particularly desirable when the injection resistance needs to be lowered, such as when using a highly viscous chemical solution. On the other hand, it is clear that the forward-tapered microneedle 311 is inferior in terms of puncture when the tip is made the same thickness as the microneedle 111 on the vertical side wall. In particular, as the structure of the needle array, when the pitch of each needle is narrowed, the influence of this puncture reduction becomes significant, which is further disadvantageous. For this reason, it is considered that the microneedles 111 on the vertical side wall shown in FIG.

  In the embodiment of FIG. 3A, the side wall shape of the through-hole 304 is reverse tapered. However, when the through-hole 304 is formed by etching or the like, it is not necessarily reverse-tapered but has a forward tapered shape. It doesn't matter. This is because, when the through hole 304 is formed in a forward tapered side wall shape, the direction of the substrate 301 is changed so that the upper and lower sides of the substrate 301 are changed, and then the subsequent process is performed to obtain the shape of the microneedle to be manufactured. This is because the same forward tapered shape as 311 is obtained.

  In each of the above embodiments, the microneedle structure in which a plurality of microneedles 111 and 311 are arranged in an array has been described. However, the present invention is not limited to this. For example, the microneedles in which the microneedles 111 and 311 are independently arranged. The present invention can be applied to the structure and the same effect is expected.

  Hereinafter, specific examples based on the embodiment of the present invention will be described. In addition, this invention is not limited to this Example.

  In this embodiment, a manufacturing example of a microneedle having a shape in which a cylindrical tip is scraped off at an angle of 45 ° will be described in accordance with the procedure shown in FIG.

  As the substrate 101, a single-side polished silicon wafer having a diameter of 200 mm was prepared. The thickness of this silicon wafer is 725 microns. On the surface of the silicon substrate 101, a resist film 102 having a thickness of 50 microns was applied by spin coating. The resist used is a negative photoresist PMER-N CA3000 manufactured by Tokyo Ohka Co., Ltd. Further, a large number of hole patterns 103 having a diameter of 100 microns were formed using a photomask and a contact aligner. The arrangement of the hole pattern 103 was regularly arranged in the substrate 101 at intervals of 20 mm with a 500 micron pitch square array and a total of 100 holes arranged in 10 rows × 10 columns.

  Next, the hole pattern 103 is masked by the etching mask layer 102, and the back surface of the substrate is formed by ICP-RIE (Inductively Coupled Plasma-Reactive Ion Etching) using a fluorine-based gas. The reaching through hole 104 was formed. Further, the remaining resist and reaction residues were removed using an organic solvent, an acid solution, an alkali solution, etc., and the silicon substrate 101 was washed.

  Subsequently, after the electroless plating of nickel is performed on the silicon substrate 101 in which the through-holes 104 are formed, the electroplating is performed in an aqueous solution mainly composed of nickel sulfate, and the surface of the silicon substrate 101 and A nickel metal layer 105 having a thickness of 30 microns was obtained on the inner surface of the through hole 104. By this step, a cylindrical nickel metal structure 107 was formed inside the through hole 104. At this time, the diameter of the pore 106 is 40 microns.

  Next, another silicon dummy substrate 108 was heated on a hot plate to melt the temporarily fixed solid wax 109 on the surface, and then the silicon substrate 101 was attached. At this time, it was visually confirmed that the melted wax 109 filled the pores 106.

  The tip of the cylindrical nickel metal structure 107 was subjected to oblique grinding using a diamond blade whose blade edge was cut at an angle of 45 °.

  In this grinding process, wax 109 was melted on a hot plate, the silicon substrate 101 was peeled off from the silicon dummy substrate 108, and then washed with an organic solvent. Further, by immersing the silicon substrate 101 in a 40 wt% potassium hydroxide aqueous solution heated to 90 ° C. and dissolving the silicon portion, a plurality of nickel microneedles 111 finally arranged in an array are obtained. It was.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention at the stage of implementation. Furthermore, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, the problems described in the column of problems to be solved by the invention can be solved, and the effects described in the effects of the invention can be obtained. In some cases, a configuration from which this configuration requirement is deleted can be extracted as an invention.

  According to the present invention, since alignment is not necessary, deterioration of accuracy due to alignment error is prevented, and manufacturing of a microneedle structure that can easily and easily form a microneedle having a highly accurate elongated through-hole is easy. A method can be provided.

DESCRIPTION OF SYMBOLS 101,301 ... Board | substrate 102 ... Etching mask layer 103 ... Hole pattern 104 ... Through-hole 105 ... Metal layer 106 ... Pore 107 ... Cylindrical metal structure 108 ... Dummy board 109 ... Wax 110 ... Dicing blade tip 111 ... Microneedle 201, 202, 203, 204 ... Microneedle 211, 212, 213, 214 ... Horizontal section 304 ... Through-hole 306 ... Pore 311 ... Microneedle

Claims (5)

A first step of forming a through hole in the substrate;
A second step of applying metal plating to at least the inner wall of the through hole;
A third step of scraping off the tip of the through hole subjected to metal plating to form a needle tip;
A fourth step of dissolving and removing the substrate portion around the through hole to form a needle-shaped microneedle;
A method for producing a microneedle structure, comprising:   2. The method of manufacturing a microneedle structure according to claim 1, wherein the tip end portion of the through hole is formed by shaving off obliquely.   The method of manufacturing a microneedle structure according to claim 1 or 2, wherein the through hole has an inner wall formed vertically.   3. The method of manufacturing a microneedle structure according to claim 2, wherein the through-hole has an inner wall formed in a forward taper shape or a reverse taper shape.   The method of manufacturing a microneedle structure according to any one of claims 1 to 4, wherein the microneedles are formed by arranging the plurality of microneedles in an array.

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