JP2009190213A - Manufacturing method of needle-shaped body - Google Patents

Abstract

An object of the present invention is to provide a method for producing a needle-like body suitable for producing a needle-like body having a uniform shape.
A method for manufacturing a needle-shaped body according to the present invention is characterized in that a columnar body array is formed on a substrate, and isotropic dry etching treatment is performed on the columnar body array. According to the configuration of the present invention, by using isotropic dry etching, the etching rate changes stepwise from the upper part of the columnar body to the root part. It can be processed into a tapered shape that gradually increases in thickness over the part.
[Selection] Figure 1

Description

  The present invention relates to a method for producing a fine needle-like body.

  The percutaneous absorption method, which is a method of infiltrating a drug from the skin and administering the drug into the body, is used as a method that can be easily administered without causing pain to the human body. There are drugs that are difficult to administer by transdermal absorption. As a method for efficiently absorbing these drugs into the body, a method of perforating the skin using a fine needle of the order of μm and directly administering the drug into the skin has attracted attention. According to this method, it is possible to easily administer a drug subcutaneously without using a special medication device (see Patent Document 1).

  It is desirable that the fine needle-shaped body used in this case has a sufficient fineness and tip angle for piercing the skin and a sufficient length for allowing the drug solution to penetrate subcutaneously. The diameter of the body is several μm to several hundred μm, and the length of the acicular body is a length that penetrates the stratum corneum, which is the outermost layer of the skin, and does not reach the nerve layer, specifically several tens μm to several hundred μm It is said that it is desirable to have a degree.

  More specifically, it is required to penetrate the stratum corneum that is the outermost skin layer. The thickness of the stratum corneum varies slightly depending on the part of the human body, but is about 20 μm on average. In addition, an epidermis having a thickness of about 200 μm to 350 μm exists under the stratum corneum, and further, a dermis layer in which capillaries are stretched exists under the epidermis. For this reason, in order to penetrate the stratum corneum and allow the chemical solution to penetrate, a needle of at least 20 μm or more is required. Further, when producing a needle-like body for the purpose of blood collection, a needle-like body having a height of at least 350 μm or more is required due to the above-described skin structure.

  Further, the material constituting the needle-like body is desirably a material that does not adversely affect the human body even if the damaged needle-like body remains in the body. For example, biocompatible materials such as medical silicone resins, maltose, and dextran are promising (see Patent Document 2).

  In order to produce such a fine structure at a low cost and in large quantities, a transfer molding method represented by an injection molding method, an imprint method, a casting method, or the like is effective, but molding is performed in any method. In order to achieve this, it is necessary to have a prototype in which the desired shape is inverted, the aspect ratio (height or depth ratio to the width of the structure) is high like a needle, and the tip must be sharpened. In order to form the structure, the manufacturing process becomes very complicated.

For example, as a method for forming a fine structure as described above, a method for manufacturing a needle-like body using lithography and etching has been proposed (see Patent Document 3).
US Pat. No. 6,183,434 Japanese Patent Laid-Open No. 2005-21677 JP 2006-341089 A

  However, it is difficult to produce a uniform needle array by controlling the angle finely in the prior art. Alternatively, a complicated procedure is required for producing the needle-like body as described above.

  Then, this invention is made | formed in order to solve the above-mentioned problem, and it aims at providing the manufacturing method of a needlelike body suitable for manufacturing a needlelike body with a uniform shape.

  The present invention according to claim 1 includes a step of forming a columnar body array on a substrate and a step of performing an isotropic dry etching process on the columnar body array. Is the method.

  The present invention described in claim 2 is the method of manufacturing the needle-shaped body according to claim 1, wherein the columnar body array is gradually increased in thickness from the center of the substrate toward the end of the substrate. A method for manufacturing a needle-like body, which is a columnar body array.

  The present invention described in claim 3 is the method for manufacturing the needle-shaped body according to any one of claims 1 and 2, wherein the step of manufacturing the columnar body array includes manufacturing the columnar body array using grinding. It is a manufacturing process of the needle-like body characterized by being the process to carry out.

  The present invention described in claim 4 is a method for manufacturing the needle-shaped body according to any one of claims 1 to 3, further comprising a step of performing transfer processing molding using the manufactured needle-shaped body as an original plate, This is a method for manufacturing a needle-like body.

The method for manufacturing a needle-shaped body of the present invention is characterized in that a columnar body array is formed on a substrate, and isotropic dry etching treatment is performed on the columnar body array.
According to the configuration of the present invention, by using isotropic dry etching, the etching rate changes stepwise from the upper part of the columnar body to the root part. It can be processed into a tapered shape that gradually increases in thickness over the part.
Therefore, it is possible to provide a method for manufacturing a needle-shaped body suitable for manufacturing a needle-shaped body having a uniform shape.

  Hereinafter, the manufacturing method of the acicular body of the present invention will be specifically described with reference to FIG.

<Step of Forming Columnar Array on Substrate (FIGS. 1A to 1B)>
First, the columnar bodies 11 are formed in an array on the substrate 10.

  The columnar body may be formed using a known processing technique. For example, a method in which columnar bodies having the same structure can be collectively formed in an array, such as machining, etching, and lithography is preferable.

  As an example of the columnar array, FIG. 3 shows a top view of the columnar array. 3A is a quadrangle, FIG. 3B is a circle, and FIG. 3C is a triangle. The shape of the top view of the columnar array is a matter of design, and various shapes that can be inferred may be formed.

  Moreover, it is preferable that the process of producing a columnar body array is a process of producing a columnar body array using grinding. The grinding process is suitable for processing into a linear shape, and the columnar array can be processed and formed for each column.

  Moreover, it is preferable that the process of producing a columnar body array is a process of producing a columnar body array using lithography processing. By using lithography processing, a mask formed by patterning a resist is formed into various shapes, whereby a columnar array having various top view shapes can be formed.

Further, the columnar body array is preferably a columnar body array whose thickness gradually increases from the center of the substrate toward the end of the substrate (see, for example, FIG. 3D).
In the isotropic dry etching process to be described later, the taper angle of the needle-like body is determined in a self-aligned manner according to the width of the columnar body, so the thickness gradually increases from the substrate center to the substrate edge. By using the columnar body array, it is possible to form a needle-like body having an aspect ratio that increases stepwise from the substrate end to the center of the substrate.
In general, the smaller the aspect ratio, the higher the mechanical strength of the needle-shaped body. Further, when a needle-like body is punctured into a stretchable object, the outer peripheral portion of the array region is easily damaged because it receives stress from outside the puncture direction due to the elasticity of the object. For this reason, a needle-shaped body whose aspect ratio gradually increases from the substrate end to the center of the substrate has a high mechanical strength at the substrate end, and is particularly suitable for use in puncturing a stretchable object. I can do it.

<Process for Forming Needle-Shaped Body by Applying Isotropic Dry Etching to Columnar Body (FIGS. 1 (c) to (d))>
Next, the columnar body 11 is subjected to isotropic dry etching. The gas used for isotropic dry etching may be appropriately selected according to the material selected for the substrate. For example, a gas species such as SF ₆ or XeF ₂ may be used as the etching gas.

  When an isotropic dry etching process is performed on a columnar array, the area of the etched portion for the etchant is microscopically different between the top and bottom of the columnar body, and a part of the etchant is etched at the top of the columnar body. In order to spend the reaction, the etching rate is different from the upper part to the lower part of the columnar body, and a forward tapered shape is formed from the upper part to the lower part as the etching progresses. Since the forward tapered shape is inclined as the etching progresses, the taper angle of the needle-like body 12 is determined in a self-aligning manner by defining the initial columnar width.

  Further, since the taper angle of the needle-like body depends on the etching processing conditions (processing time, etching gas type, etc.), the shape of the needle-like body can be controlled by selecting the etching processing conditions.

  Moreover, it is preferable that the manufacturing method of the acicular body of this invention further performs the process of performing transfer processing shaping | molding by using the manufactured acicular body as an original plate. By producing a replica plate with high mechanical strength that is integrally molded, a large amount of needle-like bodies can be manufactured with the same replica plate, which makes it possible to reduce production costs and increase productivity. . Moreover, since a filling material can be selected widely, it is particularly suitable for the production of a needle-shaped body made of a biocompatible material.

  Hereinafter, transfer processing and molding will be specifically described with reference to FIG. 2 as an example.

<The process of producing a replica from a needle-like body (FIGS. 2A to 2B)>
First, using the acicular body formed by the above-mentioned method as an original plate, the filling layer 13 is formed on the original plate, and the concave duplication plate 14 is formed by peeling the filling layer 13 from the acicular body original plate.

  The material of the filling layer is not particularly limited, and a material that takes into account the shape following ability to function as a duplicate plate, transfer production in transfer processing molding described later, durability, and releasability may be selected. For example, nickel, a thermosetting silicone resin, or the like may be used as the filling layer. When nickel is selected, examples of the method for forming the filling layer include plating, PVD, and CVD.

  As a method for peeling the filling layer and the needle-like body, a suitable method may be used as appropriate according to the selected material. For example, peeling by a physical peeling force, a selective etching method, or the like may be used.

<Transfer processing molding using duplicate plates (FIGS. 2 (c) to (d))>
Next, the replica plate 14 is filled with the needle-shaped body material 15.
The needle-shaped body material is not particularly limited, and may be appropriately selected depending on the application. Moreover, although there is no restriction | limiting about the filling method of needle-shaped body material, from a viewpoint of productivity, the imprint method, the hot embossing method, the injection molding method, the extrusion molding method, and the casting method can be used suitably.

Next, the needle-shaped body material is released from the duplicate plate to obtain a transfer-molded needle-shaped body.
At this time, in order to improve the peelability of the duplicate plate, a release layer for increasing the mold release effect may be formed on the surface of the duplicate plate before filling with the needle-shaped material (not shown). . As the release layer, for example, a well-known fluorine-based resin can be used. Moreover, as a formation method of a mold release layer, thin film formation methods, such as PVD method, CVD method, a spin coat method, a dip coat method, can be used suitably.

As mentioned above, the manufacturing method of the acicular body of this invention can be implemented.
In addition, the manufacturing method of the acicular body of this invention is not limited to the said embodiment, The other well-known method which can be estimated in each process shall also be included.

<Example 1>
First, a silicon substrate having a thickness of 525 μm was prepared as a substrate.

  Next, the silicon substrate was ground into a grid pattern using a dicing blade. At this time, the upper plane of the columnar body formed by processing was formed into a square shape with a side length of 100 μm. The processing depth was 250 μm.

Next, the formed columnar body was dry-etched. SF ₆ gas was used as a reactive gas species, and etching was performed until one side of the tip plane became 3 μm. The etching time was 40 minutes, and in this example, a needle-like array with a columnar body angle of 7 degrees on one side and a tip angle of 14 degrees could be produced with this etching time.

  From the above, a needle-like body having a root diameter of 60 μm and a height of 250 μm and a tip angle of 14 degrees could be formed.

<Example 2>
The needle-shaped body produced in Example 1 was used as a plate, and transfer processing was performed.
First, nickel was formed on the acicular body as a filling layer by electroforming. A nickel sulfamate solution was used for the plating bath. A 60% sulfamic acid solution was used, the bath temperature was 45 ° C., and a filling layer was formed by plating for 5 hours.
Next, the silicon needle-like body, which is a plate mold, was subjected to a dissolution treatment at 80 ° C. for 4 hours using a 25% KOH solution to produce a duplicate plate.

Next, a needle-shaped body was produced on the duplicated plate using an imprint method.
A polycarbonate resin was used as the needle-shaped body material to be filled.

  From the above, a needle-like body made of polycarbonate resin could be produced.

  The manufacturing method of the needlelike object of the present invention is applicable not only to medical treatment but also to various fields that require a fine needlelike object. For example, semiconductor devices, optical elements, wiring circuits, recording devices (such as hard disks and DVDs), medical testing chips (such as DNA analysis applications), display panels, microchannels, microreactors, MEMS devices, probe tips of test equipment, It can be expected to be suitably used in the manufacturing process of field emission devices, drug discovery, cosmetics and the like.

It is a schematic sectional process drawing of the manufacturing method of the acicular body of the present invention. It is a schematic sectional process drawing of the manufacturing method of the acicular body of the present invention. It is a top view which shows an example of the columnar body array shape of the manufacturing method of the acicular body of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Board | substrate 11 ... Columnar body 12 ... Needle-like body 13 ... Packing layer 14 ... Duplicating plate 15 ... Needle-like body filling material

Claims (4)

Forming a columnar array on the substrate;
Performing an isotropic dry etching process on the columnar array;
A method for producing a needle-like body comprising: It is a manufacturing method of the acicular body according to claim 1,
The columnar body array is a columnar body array whose thickness gradually increases from the center of the substrate toward the end of the substrate. It is a manufacturing method of the acicular body according to any one of claims 1 and 2,
The method of manufacturing a columnar body array is a step of manufacturing a columnar body array using a grinding process. It is a manufacturing method of the needlelike object according to any one of claims 1 to 3,
Furthermore,
A process of performing transfer processing molding using the produced needle-shaped body as an original plate,
A method for producing a needle-like body comprising: