JP3696513B2 - Manufacturing method of needle-shaped body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is, for example, percutaneously the silicon needle body is used like when injected into the body of the drug, to a method of forming steel Ri by the etching of the silicon wafer.
[0002]
[Prior art]
Attempts have been made to use silicon needles (microneedles) that do not cause pain to the subject as a device for transdermally injecting a drug into the subject's body. This needle-like body has a desired taper angle and has a sharp tip, and the needle-like body in which the tip is immersed in a chemical solution or coated with a drug is inserted into the skin of the subject from the tip. To inject those drugs into the body. If the tip to which the drug is attached penetrates the epidermis of the skin and reaches the dermis where the capillaries and nerve endings exist, drug injection is effective. Therefore, if the needle has a length of about 150 μm good.
[0003]
A semiconductor integrated circuit manufacturing technique can be applied to the manufacture of such silicon needles. Conventionally, a large number of needle-like bodies 51 as shown in the perspective view of FIG. 9 are manufactured by etching a silicon wafer with plasma generated by introducing SF ₆ / O ₂ gas as a reaction gas using a plasma processing apparatus. are doing. This conventional needle-like body 51 is formed in a tapered shape as a whole from its proximal end portion to its distal end portion.
[0004]
[Problems to be solved by the invention]
With the conventional manufacturing method, it is difficult to control the process for obtaining a desired taper shape, particularly the introduction ratio of SF ₆ gas and O ₂ gas. In addition, it is difficult to manufacture a mask for obtaining a desired tapered shape. Due to such a problem, there is a problem that a needle-like body having a predetermined taper shape cannot be manufactured with a high yield. In addition, in order to improve the production efficiency, it is desired to increase the density of needles.
[0005]
The present invention has been made in view of such circumstances, and by combining isotropic etching and anisotropic etching, a needle-shaped body that can easily produce a needle-shaped body having a predetermined tapered shape with a high yield is obtained. an object of the present invention is to provide a manufacturing how.
[0006]
Another object of the present invention is to provide a method for manufacturing a needle-shaped body that can increase the density and increase the manufacturing efficiency.
[0007]
[Means for Solving the Problems]
The method for manufacturing a needle-shaped body according to claim 1 is a method for manufacturing a silicon needle-shaped body having a predetermined taper shape by etching a silicon wafer, wherein a mask is provided at a portion where the needle-shaped body is to be formed. A first step of subjecting the silicon wafer to isotropic etching, a second step of subjecting the silicon wafer to anisotropic etching having selective etching properties in the thickness direction in the form of providing the mask, And a third step of performing isotropic etching on the silicon wafer in a manner in which a mask is provided. In the second step, the etching step and the deposition step are alternately repeated by switching the reaction gas. An anisotropic etching is performed .
[0011]
The method for manufacturing a needle-like body according to claim 2 has a tapered distal end portion that is reduced in diameter toward the distal end and a proximal end portion having the same diameter in the longitudinal direction continuous to the distal end portion. A method of manufacturing a silicon needle-like body having a through-hole formed from the base end toward the base end by etching a silicon wafer, wherein a first mask is provided in addition to the portion where the through-hole is to be formed A first step of subjecting the silicon wafer to anisotropic etching having selective etching properties in a thickness direction thereof, and a second mask provided in a portion where the needle-like body is to be formed, thereby isolating the silicon wafer. A second step of performing etching, a third step of performing anisotropic etching having selective etching properties in the thickness direction on the silicon wafer in a form in which the second mask is provided, and the second mask. state In a fourth step of applying isotropic etching to the silicon wafer, characterized by having in this order.
[0012]
The method for manufacturing a needle-like body according to claim 3 has a tapered distal end portion that is reduced in diameter toward the distal end and a proximal end portion having the same diameter in the longitudinal direction continuous to the distal end portion. A method of manufacturing a silicon needle-like body having a through-hole formed from the base end toward the base end by etching a silicon wafer, wherein a first mask is provided in addition to the portion where the through-hole is to be formed A first step of subjecting the silicon wafer to anisotropic etching having selective etching properties in a thickness direction thereof, and a second mask provided in a portion where the needle-like body is to be formed, thereby isolating the silicon wafer. A second step of performing etching, a third step of performing anisotropic etching having selective etching properties in the thickness direction on the silicon wafer in a form in which the second mask is provided, and the second mask. state In which a fourth step of applying isotropic etching to the silicon wafer, in the first step and / or the third step, repeating the deposition step and etch step alternately switching the reactive gas And anisotropic etching is performed.
[0013]
In the first invention, isotropic etching, anisotropic etching, and isotropic etching are performed in this order on the silicon wafer to manufacture a silicon needle having a predetermined taper angle at the tip. That is, a certain degree of needle shape is created by isotropic etching in the first step, and then, the anisotropic etching in the second step is selectively performed in the thickness direction by the necessary length as a needle-like body. Finally, the tip is sharpened to achieve a predetermined taper angle by isotropic etching in the third step. The needle-shaped body manufactured in the first invention is composed of a cylindrical base end portion made by anisotropic etching and a conical tip portion made by isotropic etching. .
[0014]
In the second invention, the silicon wafer is subjected to anisotropic etching, isotropic etching, anisotropic etching, and isotropic etching in this order, and has a predetermined taper angle at the tip and a through hole in the longitudinal direction. A silicon needle-like body having the following is manufactured. That is, through holes are formed by anisotropic etching in the first step, then a certain needle shape is created by isotropic etching in the second step, and then anisotropic in the third step. By etching, the length necessary for the needle-like body is selectively etched in the thickness direction, and finally, the tip is sharpened by the isotropic etching in the fourth step to realize a predetermined taper angle. The needle-like body manufactured according to the second invention is a needle-like body manufactured according to the first invention in which a through hole is further formed.
[0015]
In the manufacturing method of the present invention, since the tapered shape of the tip is created by isotropic etching with stable process treatment, a desired taper angle can be easily realized. In addition, since the needle-like body of the present invention has only a tapered tip, the density of the needle-like body that can be manufactured is higher than that of a conventional needle-like body that is entirely tapered. This leads to improved manufacturing efficiency.
[0016]
Further, in the second step of the first invention or the first and third steps of the second invention for performing anisotropic etching, the reaction gas is switched and the etching step and the deposition step are alternately repeated, thereby achieving higher accuracy. Anisotropic etching can be performed.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
FIG. 1 is a configuration diagram of an inductively coupled plasma apparatus (ICP (Inductively Coupled Plasma) apparatus) for carrying out the needle-shaped body manufacturing method (isotropic etching and anisotropic etching of silicon) according to the present invention. is there.
[0018]
In this ICP device, AC power is applied to the coil to generate low-pressure reactive gas plasma, AC power is applied to the substrate electrode on which the sample is placed, the generated plasma is drawn, and etching is performed by the drawn plasma. I do. Further, when this ICP apparatus is used, in order to increase the anisotropy of etching, an etching gas (for example, SF ₆ ) and a deposition gas (for example, C ₄ F ₈ ) are alternately introduced as a reaction gas to be converted into plasma. Then, an ASE ^™ (Advanced Silicon Etching) method is performed in which the etching step and the deposition step are repeated.
[0019]
In FIG. 1, reference numeral 1 denotes a reactor, and an upper plasma generation chamber 2 a that generates plasma by energizing the coil 3, and a lower reaction that draws the generated plasma and performs an etching process on the sample 20. Chamber 2b.
[0020]
The plasma generation chamber 2a has a shape of a ceramic hollow cylinder, and a coil 3 is concentrically surrounded on the peripheral surface thereof. A power supply 8 having a predetermined frequency is connected to the coil 3 via a matching unit 7 so that AC power having a desired magnitude is applied to the coil 3. A gas introduction pipe 4 for introducing a reaction gas (SF ₆ or C ₄ F ₈ ) into the reactor 1 is connected to the center of the upper wall of the plasma generation chamber 2a so as to penetrate therethrough. A reactive gas plasma is generated in the plasma generation chamber 2 a by applying AC power to the coil 3.
[0021]
An exhaust port 5 connected to an exhaust device (not shown) is opened on the side wall of the reaction chamber 2b. A platen 6 having a substrate electrode 11 on which a sample 20 to be etched is placed is disposed at the bottom of the reaction chamber 2b. A power source 10 having a predetermined frequency is connected to the platen 6 via a matching unit 9 so that AC power having a desired magnitude is applied to the substrate electrode 11. The plasma generated in the plasma generation chamber 2a is drawn into the reaction chamber 2b by the application of AC power to the substrate electrode 11, and the sample 20 is etched by the drawn plasma.
[0022]
(First embodiment)
2A is a perspective view showing a plurality of needle-like bodies 31 in the first embodiment, FIG. 2B is a cross-sectional view of one needle-like body 31, and each needle-like body 31 is A tapered conical tip 31a (maximum diameter: 75 μm, height: 50 μm) and a cylindrical base end 31b (diameter: 75 μm, height) connected to the tip 31a are tapered toward the tip. : 100 μm).
[0023]
When the needle-like body 31 having such a configuration is used, the needle-like body 31 in which the tip 31a is immersed in a chemical solution or a medicine is applied around the tip 31a is inserted into the skin of the subject from the tip 31a. These drugs can be injected into the body. It is also possible to measure the body potential by inserting a needle having a large number of needles 31 into the skin of the subject.
[0024]
The manufacturing process of the needle-shaped body 31 having such a configuration will be described below. FIG. 3 is a diagram showing the transition of the shape of the sample (silicon wafer) 20 in the manufacturing process of the first embodiment.
[0025]
First, a sample (silicon wafer) 20 provided with a mask 21 at a portion where the needle-like body 31 is to be formed is placed on the platen 6 (FIG. 3A). Note that the thickness of the sample (silicon wafer) 20 is about 200 μm. Then, according to the following conditions, isotropic etching (first step) from the surface of the sample (silicon wafer) 20 to a depth of about 50 μm is performed to create a certain shape of the tip (FIG. 3B). .
[0026]
(Etching conditions)
Flow rate of reaction gas to be introduced: SF ₆ 130 sccm
Gas pressure: 1.47 Pa Etching time: 20 minutes Applied power to coil 3: 800 W Applied power to substrate electrode 11: 20 W
[0027]
Next, anisotropic etching (second process) having etching selectivity in the thickness direction is performed by alternately repeating the etching step and the deposition step according to the following conditions, and a hole having a depth of about 100 μm is formed. Create (FIG. 3C). At this time, the etching step (13 seconds per time) and the deposition step (5 seconds per time) are alternately repeated to perform anisotropic etching for a total of 15 minutes. Since the tip of the sample (silicon wafer) 20 is covered with the mask 21, no deposited film for inhibiting etching is formed in this second step.
[0028]
(Etching step conditions)
Flow rate of reaction gas to be introduced: SF ₆ 130 sccm
Gas pressure: 1.47 Pa Processing time per time: 13 seconds Applied power to the coil 3: 600 W Applied power to the substrate electrode 11: 15 W
(Deposition step conditions)
Flow rate of reaction gas to be introduced: 50 sccm of C ₄ F ₈
Gas pressure: 1.60 Pa Processing time per time: 5 seconds Applied power to coil 3: 600 W Applied power to substrate electrode 11: 0 W
[0029]
Finally, isotropic etching (third step) is performed again under the same conditions as in the first step, and a conical tip portion 31a having a predetermined taper shape and a cylindrical portion 31b connected thereto are formed. A needle-like body 31 is prepared. (FIG. 3 (d)).
[0030]
(Second Embodiment)
FIG. 4 is a cross-sectional view showing the needle-like body 41 in the second embodiment, and the needle-like body 41 is similar to the distal end portion 31a and the proximal end portion 31b of the needle-like body 31. And a through hole 42 (diameter: 15 μm) penetrating in the longitudinal direction is formed at the center in the radial direction.
[0031]
When the needle-like body 41 having such a configuration is used, the drug solution sucked into the through-hole 42 can be injected into the subject's skin without waste similarly to a general injection needle.
[0032]
The manufacturing process of the needle-shaped body 41 having such a configuration will be described below. 5 and 6 are diagrams showing the transition of the shape of the sample 20 in the manufacturing process of the first example of the second embodiment.
[0033]
The sample 20 to be used has a configuration in which a silicon wafer 20a (thickness: 150 μm) to be etched and a carrier wafer 20b are attached with a resist 20c. The sample 20 provided with the mask 22 in a region other than the portion where the through hole 42 is to be formed on the silicon wafer 20a side is placed on the platen 6 (FIG. 5A).
[0034]
Then, anisotropic etching (first step) having etching selectivity in the thickness direction is performed by alternately repeating the etching step and the deposition step according to the following conditions, and a depth of 150 μm at which the through hole 42 is formed. Are made through the silicon wafer 20a (FIG. 5B). At this time, since the etching rate of the hole having a diameter of 15 μm is 2.3 μm / min under the following conditions, in order to form a hole having a depth of 150 μm, an etching step (8 seconds per time) and a deposition step (1 The anisotropic etching is repeated for a total of 65 minutes.
[0035]
(Etching step conditions)
Flow rate of reaction gas to be introduced: 110 sccm for SF ₆ and 5 sccm for C ₄ F ₈
Gas pressure: 4 Pa Processing time per time: 8 seconds Applied power to the coil 3: 600 W Applied power to the substrate electrode 11: 25 W
(Deposition step conditions)
Flow rate of reaction gas to be introduced: 5 sccm for SF ₆ and 90 sccm for C ₄ F ₈
Gas pressure: 3 Pa Processing time per time: 5 seconds,
Applied power to the coil 3: 600 W Applied power to the substrate electrode 11: 3 W
[0036]
Next, as in the first step of the first embodiment, a mask 23 is provided in a portion where the needle-like body 41 is to be formed by a resist spin coating method (FIG. 5C). Isotropic etching (second step) over a depth of about 50 μm from the surface is performed to create a certain shape of the tip (FIG. 6D). The etching conditions at this time are the same as those in the first step of the first embodiment described above.
[0037]
Next, similarly to the second step of the first embodiment, anisotropic etching (third step) is performed to create a hole having a depth of about 100 μm reaching the resist 20c in the silicon wafer 20a (FIG. 6 ( e)). The etching conditions at this time are the same as those in the second process of the first embodiment described above.
[0038]
Finally, similarly to the third step of the first embodiment, isotropic etching (fourth step) is performed again, and the conical tip portion 41a having a predetermined taper shape and the cylindrical portion 41b connected thereto are formed. A needle-like body 41 having a through-hole 42 in the longitudinal direction is prepared (FIG. 6F). The etching conditions at this time are the same as those in the third step of the first embodiment described above, in other words, in the second step of the second embodiment. In order to obtain a single needle-like body 41, the resist 20c may be dissolved with acetone.
[0039]
FIG. 7 is a diagram showing another example of the sample 20 that can be used in the second embodiment. The sample 20 includes a base silicon body 20d, an SiO ₂ film 21e as an insulator, and a silicon film to be etched. 20f (thickness: 150 μm) is laminated.
[0040]
Also in the sample 20 having such a configuration, the needle-like body 41 can be manufactured by performing the same etching process as the silicon wafer 20a of the above example on the silicon film 20f. In this example, when it is desired to obtain a single needle-like body 41, the SiO ₂ film 21e may be removed with hydrofluoric acid.
[0041]
FIG. 8 is a diagram showing the transition of the shape of the sample 20 in the manufacturing process of the second example of the second embodiment. In the first example, when the mask 23 is provided, if the spin coating conditions of the resist used as the material are poor, there is a possibility that the resist flows into the through holes 42 that have already been formed and plugs it. . The second example below is a technique that prevents the occurrence of such a possibility.
[0042]
The same mask 22 as in the first example is provided and anisotropic etching (first step) is performed under the same conditions. However, as in the first example, the through hole 42 that completely penetrates the silicon wafer 20a is formed. Instead, the formation of the hole 24 is finished when the etching time is adjusted to leave 20 to 30 μm (FIG. 8A). Then, the silicon wafer 20a is removed from the resist 20c, and the sample 20 ′ is prepared by attaching the silicon wafer 20a to the other carrier wafer 20b ′ in the reverse direction with the resist 20c ′ (FIG. 8B).
[0043]
Next, as in the first example, a mask 23 is provided on the surface side of the silicon wafer 20a where the holes 24 are not formed (FIG. 8C). At this time, since the hole 24 does not reach the surface, there is no possibility that the resist enters the hole 24. Then, isotropic etching (second step), anisotropic etching (third step), and isotropic etching (fourth step) similar to those in the first example are sequentially performed. As a result, the remaining portion having a thickness of 20 to 30 μm is also tapered, and finally the through hole 42 is formed (FIG. 8D).
[0044]
In the first embodiment described above, the case where a needle-like body is manufactured by etching a sample of silicon alone has been described. However, as in the second embodiment, a base body such as a SiO ₂ film is used. Of course, the same can be applied to a sample formed with a silicon film.
[0045]
【The invention's effect】
As described above in detail, in the present invention, a silicon needle having a predetermined taper angle at the tip is manufactured by combining isotropic etching and anisotropic etching for a silicon wafer. Therefore, a needle-like body having a predetermined taper shape can be easily manufactured with a high yield.
[0046]
In the present invention, since only the necessary portion of the needle-like body is tapered, the needle-shaped body can be manufactured at a higher density and the manufacturing efficiency can be improved as compared with the case where the entire needle-like body is tapered. can do.
[0047]
Furthermore, in the present invention, the anisotropic etching is performed by switching the reaction gas and alternately repeating the etching step and the deposition step, so that highly accurate anisotropic etching can be performed.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of an inductively coupled plasma apparatus (ICP apparatus) for carrying out a method for manufacturing a needle-shaped body according to the present invention.
FIGS. 2A and 2B are a perspective view and a cross-sectional view showing a needle-like body in the first embodiment. FIGS.
FIG. 3 is a diagram showing a transition of the shape of a sample in the manufacturing process of the needle-like body in the first embodiment.
FIG. 4 is a cross-sectional view showing a needle-like body in a second embodiment.
FIG. 5 is a diagram showing the transition of the shape of a sample in the manufacturing process of the needle-like body in the first example of the second embodiment.
FIG. 6 is a diagram showing a transition of the shape of a sample in the manufacturing process of the needle-like body in the first example of the second embodiment.
FIG. 7 is a diagram showing another example of a sample that can be used in the second embodiment.
FIG. 8 is a diagram showing a transition of the shape of a sample in a manufacturing process of a needle-like body in a second example of the second embodiment.
FIG. 9 is a perspective view showing a needle-like body in a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reactor 3 Coil 4 Gas introduction pipe 6 Platen 11 Substrate electrode 20 Sample 31,41 Needle-like body 31a, 41a Tip part 31b, 41b Base end part 42 Through-hole

Claims (3)

In a method of manufacturing a silicon needle having a predetermined taper shape by etching a silicon wafer, a mask is provided at a portion where the needle is to be formed, and isotropic etching is performed on the silicon wafer. A second step of performing anisotropic etching having selective etching properties in the thickness direction on the silicon wafer in a mode in which the mask is provided, and isotropic on the silicon wafer in a mode in which the mask is provided And a third step of performing etching, and in the second step, the anisotropic etching is performed by switching the reaction gas and alternately repeating the etching step and the deposition step. Body manufacturing method. It has a tapered tip that is tapered toward the tip, and a base end that has the same diameter in the longitudinal direction continuous to the tip, and a through hole is formed from the tip toward the base. A silicon needle-like body is manufactured by etching a silicon wafer, and a first mask is provided in addition to the portion where the through hole is to be formed, and the silicon wafer is selectively etched in the thickness direction. A first step of performing anisotropic etching having a property, a second step of applying isotropic etching to the silicon wafer by providing a second mask at a portion where the needle-like body is to be formed, and the second mask. A third step of performing anisotropic etching having selective etching properties in the thickness direction on the silicon wafer in the provided mode; and an isotropic etch on the silicon wafer in a mode of providing the second mask. The fourth a step, the production method of the needle body, characterized in that it comprises in this order to perform the ring. It has a tapered tip that is tapered toward the tip, and a base end that has the same diameter in the longitudinal direction continuous to the tip, and a through hole is formed from the tip toward the base. A silicon needle-like body is manufactured by etching a silicon wafer, and a first mask is provided in addition to the portion where the through hole is to be formed, and the silicon wafer is selectively etched in the thickness direction. A first step of performing anisotropic etching having a property, a second step of applying isotropic etching to the silicon wafer by providing a second mask at a portion where the needle-like body is to be formed, and the second mask. A third step of performing anisotropic etching having selective etching properties in the thickness direction on the silicon wafer in the provided mode; and an isotropic etch on the silicon wafer in a mode of providing the second mask. And a fourth step of performing ring, in the first step and / or the third step, is subjected to anisotropic etching by repeating the deposition step and etch step alternately switching the reactive gas A method for producing a needle-like body characterized by the above .

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