KR100384283B1 - Single crystal silicon micro needle and method for manufacturing the same - Google Patents

Abstract

The present invention discloses a single crystal silicon microneedle and a method of manufacturing the same. According to this, at least one trench is formed in a predetermined region of the single crystal silicon substrate, a circular fluid passage is formed in the single crystal silicon substrate under the trench bottom portion, and the trench corresponding to the upper opening of the fluid passage is sealed with a film. Then, fluid elements such as micro valves and micro pumps are integrated with the fluid passage so as to control the flow of the micro fluid. Subsequently, another trench having a desired depth is formed in the single crystal silicon substrate between the predetermined regions, an insulating film is formed in both side surfaces of the trench, and the single crystal silicon substrate under the trench is etched to the rear surface thereof. The single crystal silicon substrate is etched back with a basic aqueous solution so that the single crystal silicon substrate having a thickness corresponding to the depth of the trench is suspended.

Therefore, the present invention achieves a process simplification and high reproducibility, thereby improving yield in mass production. In addition, the durability of the fluid passage can be increased to accurately acquire the microfluidic sample from the biological tissue and to accurately inject the microfluidic sample into the biological tissue.

Description

Single crystal silicon microneedle and its manufacturing method {SINGLE CRYSTAL SILICON MICRO NEEDLE AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a microneedle, and more particularly, micromachining manufacturing technology using (111) single crystal silicon to accurately acquire and inject a microfluidic sample while providing excellent reproducibility and fluid passage. The present invention relates to a single crystal silicon microneedle and a method of manufacturing the same to achieve durability.

In general, a needle is used to obtain a sample from a living tissue or to inject a medicine into the living tissue. Most needles in use today are macroneedles that have diameters that are very large in millimeters compared to blood cells. The large diameter of the macroneedle shaft has the disadvantage of seriously damaging the biological tissue during its penetration. In addition, tissue penetration by the needle often suffers from the patient because of the relatively large needle diameter.

A kind of spring-powered macroneedle penetrates tissue and drops blood into the measuring chemistry tester. The needle is still quite large and causes damage to biological tissues, despite much less pain in the patient because the penetration is quite short. Moreover, the macroneedle does not provide real time blood analysis.

As an alternative to such macroneedles, microneedles with micrometer-level diameters have many different applications. For example, microneedles may be used as accurate infusion / extraction needles in cell biology, or as injection / extraction heads in drug delivery systems or microchemical plants. In addition, small size needles are advantageous because the small size reduces discomfort and pain for the patient. This has been demonstrated in research on electrical microprobes made of silicon. The study demonstrated that silicon microprobes with cross-sectional areas on the order of tens of micrometers can penetrate living tissue without causing serious trauma.

In the past, microneedles having an inner diameter of about 20 μm have been used. These microneedles are formed by heating the ends of the glass pipettes and stretching the ends until the diameter is reduced to about 20 μm. In animals such as humans, most cells have a size of 10-20 μm. Thus, these glass microneedles can be used to inject and obtain liquids or gases from a single cell, but are difficult to control while manufacturing the size of the needle shaft. In addition, the resulting needle is not robust and real-time blood analysis is not possible. Another disadvantage of the glass pipette needle is that it is difficult to integrate the needle and the electronic device.

Various new microneedles have been proposed as a solution to the drawbacks of such microneedles. US Patent 5,855,801 entitled "IC-processed Microneedle," and Journal of Microelectrochemical Systems, Vol. A new microneedle was proposed in a paper entitled "Silicon-processed Microneedles", published in 8, No. 1, March 1999. See also Transaction on Biomedical Engineering, Vol. 44, No. 8, Aug. A multichannel neural probe was proposed in 1997, in a paper entitled "A Multichannel Neural Probe for Selective Chemical Deliverly at the Cellular Level." And Proceeding of Engineering in Medicine and Biology Society, Vol. A microneedle using palladium (Pd) plating was proposed in a paper entitled "Micromachined Pipette Array (MPA)", published in 5, chicago, USA, 1997.

U.S. Patent 5,855,801 and Journal of Microelectrochemical Systems, Vol. 8, No. 1, March 1999, according to the paper, microneedle is formed of a low stress silicon nitride film deposited by a low pressure chemical vapor deposition method. At this time, a thin film of a phosphosilicate glass (PSG) film and a low temperature oxide (LTO) film is used as a sacrificial layer to form a fluid path of the microneedle, and a P ++ type etch stop layer is formed on the back side to float the microneedle. Until then, use the method of etching the silicon body. In this method, it is not easy to properly control the physical properties of the thin film because low pressure chemical vapor deposition is mainly used because the characteristics of the thin film are affected by the manufacturing process conditions. There is a high possibility of deformation of the structure due to stress. In addition, the wet etching process on the back of the silicon body using the P ++ type etchstop layer, which is a process for floating the microneedles, is limited in the thickness of the structure, and has the disadvantage of increasing the time and pattern size for the structure floating. have. This drawback is a great limitation in the manufacture of microneedles or integrating multiple microneedles using a silicon batch process.

Transaction on Biomedical Engineering, Vol. 44, No. 8, Aug. According to a paper published in 1997, nerve probes are formed with a structure with microfluidic passages for localized chemical stimulation of nerve cells. An etch stop layer of P ++ type is used as a mask to dope the portion where the fluid passage is to be formed into P ++ type. After doping the part where the fluid passage is to be formed in P ++ type, the pattern is defined in the shape of a seagull wing and the fluid passage is formed by using the anisotropic etching characteristic of ethylene-diamine pyrocatechol (EDP). In order to form a P ++ type etchstop layer for floating the neural probe, a composite film having a laminated structure of a thermal oxide film and a silicon oxide film / silicon nitride film / silicon oxide film is used as a method for sealing the open portion of the upper surface. In this method, since the anisotropic etching characteristic according to the crystal surface of the silicon is used, the direction of the fluid passage should be in the <100> direction, and there is a disadvantage in that only the fluid passages that meet vertically can be formed. This is because the flow of fluid is disturbed when the fluid passage is bent vertically. The depth at which the fluid passage is formed is limited to a few micrometers because it is limited by the thickness of the P ++ type etchstop layer used as a mask.

Proceeding of Engineering in Medicine and Biology Society, Vol. According to a paper published in 5, Chicago, USA, 1997, the microneedle used a thick film photoresist as a sacrificial layer to form a fluid passageway and forms the body of the microneedle by palladium plating. The microneedle is suspended by removing the silicon thin film by etching the silicon body from the backside of the silicon to the P ++ type etchstop layer. In this method, a silicon body is processed to form a thin silicon thin film, and there is a high risk of breakage during the manufacturing process in order to proceed with the manufacture of the microneedle. Thick film photosensitizers, which also determine the size of the fluid passageways, are limited in controlling the deposition thickness.

Accordingly, it is an object of the present invention to provide a single crystal silicon microneedle and a method of manufacturing the same to improve reliability by accurately obtaining a microfluidic sample from biological tissue and injecting a microfluidic sample into biological tissue.

It is another object of the present invention to provide a single crystal silicon microneedle and a method for manufacturing the same, which achieves a simplified production process and a high reproducibility to improve the yield in mass production.

It is still another object of the present invention to provide a single crystal silicon microneedle and a method of manufacturing the same to increase the durability of the fluid passage.

1 is a schematic diagram showing a single crystal silicon microneedle according to the present invention.

2 is a view showing a single crystal silicon microneedle according to an embodiment of the present invention, Figure 2a is a plan view showing a fluid passage and the storage portion of the single crystal silicon microneedle according to an embodiment of the present invention, Figure 2b is Figure 2a 2A-2A is a cross-sectional view taken along a line, and FIG. 2C is a cross-sectional view taken along a line 2B-2B in FIG. 2A.

3 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention, Figure 3a is a plan view showing a fluid passage of the single crystal silicon microneedle according to another embodiment of the present invention, Figure 3b Sectional drawing cut along the line 3A-3A of FIG. 3C is sectional drawing cut along the line 3B-3B of FIG. 3A.

4 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention, Figure 4a is a plan view showing a fluid passage of the single crystal silicon microneedle according to another embodiment of the present invention, Figure 4b 4A is a cross-sectional view taken along the line 4A-4A, and FIG. 4C is a cross-sectional view taken along the line 4B-4B of FIG. 4A.

5 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention, Figure 5a is a plan view showing a fluid passage of the single crystal silicon microneedle according to another embodiment of the present invention, Figure 5b 5A is a cross-sectional view taken along line 5A-5A, and FIG. 5C is a cross-sectional view taken along line 5B-5B of FIG. 5A.

6 to 11 are process flowcharts showing a method for manufacturing single crystal silicon microneedle according to the present invention.

Single crystal silicon microneedle according to the present invention for achieving the above object

A body portion made of a single crystal silicon substrate; An extension portion formed of a single crystal silicon substrate and integrally connected to a portion of the body portion, the extension portion including at least one fluid passageway; A fluid element connected to the fluid passage so as to flow fluid through the fluid passages and formed on one surface of the body portion; And a cap part joined to one surface of the body part to provide a path for collecting the fluid.

Preferably, the one fluid passage is formed in the extension portion, the reservoir portion communicating with the fluid passage of the extension portion and the upper opening is open may be formed in the body portion. In addition, one fluid passage may be formed in the extension portion, and at least one fluid passage in common communication with the fluid passage of the extension portion may be formed in the body portion. In addition, a plurality of fluid passages may be formed in the extension portion and the body portion in the same quantity.

Meanwhile, the upper opening of the fluid passage of the extension part and the body part may be sealed with a predetermined film, and the film may be formed of at least one of a polysilicon film, a silicon oxide film, and a silicon nitride film. In addition, in order to visually check the fluid flowing through the fluid passage, the cap portion may be made of a transparent material, for example, a glass material.

In addition, the method for producing a single crystal silicon microneedle according to the present invention

Forming at least one fluid passageway each having an upper opening in defined portions of the single crystal silicon substrate; Sealing the upper openings of the fluid passages with a predetermined membrane; Integrating a fluid element with the fluid passage in another portion of the single crystal silicon substrate to control the flow of fluid flowing through the closed fluid passages; And floating the structure of the single crystal silicon substrate including the fluid passages.

Preferably, forming the fluid passage

Forming at least one trench each having a desired depth in a predetermined partial region of the single crystal silicon substrate; Forming a protective film only on the side portions of each of the trenches and exposing a single crystal silicon substrate below the bottom portions of the trenches; And isotropically etching the exposed single crystal silicon substrate to form circular fluid passages having the upper opening.

In addition, the single crystal silicon substrate may be isotropically etched by dry etching using SF ₆ plasma and XeF ₂ gas, or isotropically etched by wet etching using hydrofluoric acid / nitric acid / acetic acid.

In addition, the upper opening may be sealed with at least one of a polysilicon film, a silicon oxide film, and a silicon nitride film using a low pressure chemical vapor deposition method, or the upper opening may be closed with a coating using a biocompatible organic thin film such as perylene. In addition, after the upper opening is formed, the upper opening may be sealed by heat treating the single crystal silicon substrate in a predetermined gas atmosphere to generate recombination of crystals.

Preferably, the step of floating the structure of the single crystal silicon substrate comprising the fluid passages

Selectively forming a pattern of a photoresist film on the predetermined partial regions; forming a trench of a desired depth in a single crystal silicon substrate between the predetermined partial regions using the pattern of the photoresist film as a masking layer; Forming an insulating film to protect the side portions of the trench and exposing a single crystal silicon substrate under the trench; Etching the exposed single crystal silicon substrate in the trench to the backside of the single crystal silicon substrate; And etching the back surface of the single crystal silicon substrate in the predetermined partial region to float the structure of the single crystal silicon substrate including the fluid passages.

In this case, the thickness of the extension including the fluid passage may be determined by the depth of the trench, and the width of the extension including the fluid passage may be determined by the width of the pattern of the photosensitive film.

On the other hand, it is preferable to further include the step of anisotropically etching the terminal portion of the structure of the single crystal silicon substrate with a basic aqueous solution to form a sharp shape. The method may further include bonding a cap of a transparent material covering the fluid element to collect the fluid flowing through the fluid passage in a predetermined region of the single crystal silicon substrate.

Therefore, according to the present invention, by producing a microneedle using a single crystal silicon substrate, the production process is simplified and high reproducibility is achieved, thereby achieving a yield improvement in mass production. In addition, the durability of the fluid passage can be increased to accurately acquire the microfluidic sample from the biological tissue and to accurately inject the microfluidic sample into the biological tissue.

Hereinafter, a single crystal silicon microneedle according to the present invention and a manufacturing method thereof will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram showing a single crystal silicon microneedle according to the present invention. As shown in FIG. 1, the microneedle 100 includes a body portion 10 and an extension portion 20. The body portion 10 and the extension portion 20 are made of a single crystal silicon material and are integrally connected. The body portion 10 is thick enough to allow installation of on-chip elements for real time analysis. The extension 20 is inserted into a living tissue (not shown) so that fluid (including gas) can be administered to or inhaled from the patient, and has a relatively thin thickness, a narrow width, and a predetermined length. The distal end 21 of the extension 20 has a sharp shape that is easy to insert. The fluid passage 23 is formed inside the extension 20 along the length of the extension 20. In addition, the first groove 11 communicates with the fluid passage 23 and is formed in the body portion 10, and the second groove portion 13 is spaced apart from the first groove portion 11 at a predetermined interval and the body portion 10. Is formed.

In addition, a microfluidic element is formed in the body portion 10 so that the microfluid of the biological tissue can be sucked through the fluid passage 21 or the drug can be administered to the biological tissue. That is, the body portion 10 is provided with a micro pump 15 to provide a driving force through which the fluid sample can flow, and a micro valve 17 for controlling the flow of the micro fluid sample is installed. The metal electrode 19 is formed in the predetermined region of the body portion 10. The operation of the micropump 15 uses a drive using a flat plate electrode, a drive using bubbles formed by electrical heating, and the like. In addition, the cap portion 30, which is a plate of transparent material such as glass, is joined along the upper edge of the body portion 10 so that the flow of the fluid sample may be smoothly observed and visually observed. The bottom of the cap portion 30 is formed so that the first groove portion 31 overlaps the groove portion 11 and the microvalve 17 together, and the second groove portion 33 is spaced apart from the first groove portion 31 at a predetermined interval. It is formed spaced apart, the third groove portion 35 is formed so as to overlap the outlet of the groove portion (13).

On the other hand, the arrow shown in the drawing is the fluid through the fluid passageway 23 of the extension portion 20, the groove portion 11 of the body portion 10, the groove portion 31 of the cap portion 30, the groove portion of the body portion 10 13 shows a process of sequentially passing through the groove portion 35 of the cap portion 30. In addition, although only one fluid passage is inherent in the extension portion 20 in the drawings for the convenience of description, two or more fluid passages may be included as necessary, and the purpose and characteristics of use. Various types of fluid passages can be formed to suit the requirements.

2 is a view showing a single crystal silicon microneedle according to an embodiment of the present invention. FIG. 2A is a plan view illustrating a fluid passage and a storage part of a single crystal silicon microneedle according to an exemplary embodiment of the present invention, FIG. 2B is a cross-sectional view taken along the line 2A-2A of FIG. 2A, and FIG. It is sectional drawing cut along the 2B line.

As shown in FIG. 2A, the body portion 110 and the extension portion 120 of the microneedle are made of a single crystal silicon substrate 1 and are integrally connected to each other. The width of the extension part 120 is narrower than the width of the body part 110. In the extension part 120, one fluid passage 133 is formed to go straight along the longitudinal direction of the extension part 120. The distal end 135 has a sharp shape for easy insertion. In the body portion 110, the groove portion 131 is formed in a circular shape and communicates with the fluid passage 133. In addition, the upper opening 132 of the groove portion 131 has a smaller diameter than the groove portion 131.

As shown in FIGS. 2B and 2C, an insulating film 137 is deposited on the inner surface of the groove 131 and the opening 132 of the body 110 and the surface of the silicon substrate 1 by chemical vapor deposition. . In addition, an insulating film 137 is laminated on the inner surface of the fluid passage 133 of the extension part 120, the inner surface of the upper opening of the fluid passage 133, and the surface of the silicon substrate 1 by chemical vapor deposition. At this time, the circular upper opening 132 of the groove 131 is opened, but the upper opening of the fluid passage 133 is sealed with the insulating film 137, which is larger in diameter than the width of the groove 131. Because of the size. Both the groove 131 and the fluid passage 133 have a circular shape, and the groove 131 has a larger diameter than the fluid passage 133. The thickness of the silicon substrate 1 of the body portion 110 is much thicker than the thickness of the silicon substrate 1 of the extension 120.

In the case of the microneedle configured as described above, the groove portion 131 having the upper opening 132 may be used as a reservoir capable of forming an input / output port connectable with an external device (not shown).

3 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention. 3A is a plan view illustrating a fluid passage of a single crystal silicon microneedle according to another embodiment of the present invention, FIG. 3B is a cross-sectional view taken along the line 3A-3A of FIG. 3A, and FIG. 3C is 3B-3B of FIG. 3A. Sectional view cut along the line.

As shown in FIG. 3A, the body portion 110 and the extension portion 120 of the microneedle are made of a single crystal silicon substrate 1 and are integrally connected to each other. The width of the extension part 120 is narrower than the width of the body part 110. In the extension part 120, one fluid passage 143 is formed to go straight along the longitudinal direction of the extension part 120. The distal end 145 of the extension 120 has a sharp shape for easy insertion. In the body portion 110, for example, three spaced fluid passages 141 are brought together as they approach close to the extension 120 side and communicate with the fluid passage 143 in common.

As shown in FIGS. 3B and 3C, the chemical vapor deposition method is performed on the inner surface of the fluid passage 141 of the body portion 110, the inner surface of the upper opening of the fluid passage 141, and the upper surface of the silicon substrate 1. By this, the insulating film 147 is laminated. In addition, an insulating film 147 is laminated on the inner surface of the fluid passage 143 of the extension part 120, the inner surface of the upper opening of the fluid passage 143, and the upper surface of the silicon substrate 1 by chemical vapor deposition. . At this time, since the upper openings of the fluid passages 141 and 143 have the same size, they are all sealed by the insulating film 147. The fluid passages 141, 143 form a circular shape of the same diameter. The thickness of the silicon substrate 1 of the body part 110 is thicker than the thickness of the silicon substrate 1 of the extension part 120.

In the case of the microneedle configured as described above, the same or different types of fluids may be injected into the fluid passage 143 via the respective fluid passages 141 while controlling the flow rate.

4 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention. 4A is a plan view illustrating a fluid passage of a single crystal silicon microneedle according to another embodiment of the present invention, FIG. 4B is a cross-sectional view taken along the line 4A-4A of FIG. 4A, and FIG. 4C is the 4B- 4A of FIG. 4A. It is sectional drawing cut along the 4B line.

As shown in FIG. 4A, the body portion 110 and the extension portion 120 of the microneedle are made of a single crystal silicon substrate 1 and are integrally connected to each other. The width of the extension part 120 is narrower than the width of the body part 110. In the extension part 120, one fluid passage 153 is formed to go straight along the longitudinal direction of the extension part 120. The distal end 155 of the extension 120 has a sharp shape for easy insertion. In the body portion 110, for example, two spaced fluid passages 151 merge into one fluid passageway 152 while approaching the extension portion 120 side to communicate with the fluid passageway 153. In addition, the fluid passage 152 may be formed in various free forms.

As shown in FIGS. 4B and 4C, the insulating layer 157 is formed by the chemical vapor deposition method on the fluid passage 151 of the body 110, the upper opening of the fluid passage 151, and the upper surface of the silicon substrate 1. This is laminated. An insulating film 157 is deposited on the fluid passage 153 of the extension part 120, the inner surface of the fluid passage 153, and the upper surface of the silicon substrate 1 by chemical vapor deposition. At this time, since the upper openings of the fluid passages 123 and 143 have the same size, they are all sealed by the insulating film 157. The fluid passages 151, 152, and 153 form a circular shape of the same diameter. The thickness of the silicon substrate 1 of the body part 110 is thicker than the thickness of the silicon substrate 1 of the extension part 120.

In the case of the microneedle configured as described above, different reagents may be mixed or reacted to be injected.

5 is a view showing a single crystal silicon microneedle according to another embodiment of the present invention. Figure 5a is a plan view showing a fluid passage of a single crystal silicon microneedle according to another embodiment of the present invention, Figure 5b is a cross-sectional view taken along the line 5A-5A of Figure 5a, Figure 5c is a 5B- 5B- Sectional drawing cut along line 5B.

As shown in FIG. 5A, the body portion 110 and the extension portion 120 of the microneedle are made of single crystal silicon and are integrally connected to each other. The width of the extension part 120 is narrower than the width of the body part 110. In the extension 120, for example, three fluid passages 163 are spaced apart from each other and are formed to go straight along the longitudinal direction of the extension 120. The distal end 165 of the extension 120 has a sharp shape for easy insertion. In the body part 110, three fluid passages 161 communicate with each other and correspond to the fluid passages 163 in a 1: 1 manner, and are spaced apart from each other.

As shown in FIGS. 5B and 5C, the chemical vapor deposition method is applied to the upper surface of the silicon substrate 1 of the body 110 and the inner surface of the fluid passage 161 and the inner surface of the upper opening of the fluid passage 161. The insulating film 167 is deposited by this. An insulating film 167 is deposited on the upper surface of the silicon substrate 1 of the extension part 120, the inner surface of the fluid passage 163 and the inner surface of the upper opening of the fluid passage 163 by chemical vapor deposition.

At this time, since the upper openings of the fluid passages 161 and 163 have the same size, they are all sealed by the insulating film 167. The fluid passages 161, 163 form a circular shape of the same diameter. The thickness of the silicon substrate 1 of the body part 110 is thicker than the thickness of the silicon substrate 1 of the extension part 120.

In the case of the microneedle configured as described above, it is possible to inject or inject various different types of fluids to different places.

Meanwhile, in addition to the microneedle illustrated in FIGS. 2 to 5, a fluid passage having a free shape may be formed according to the purpose and characteristics of use. In addition, the insulating films 137, 147, 157, and 167 of FIGS. 2 to 5 may be deposited using a low pressure chemical vapor deposition method, for example, at least one of a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film. It can be done as one. In addition, instead of the low pressure chemical vapor deposition method, it may be made of a biocompatible organic thin film such as a parylene thin film. Further, if the silicon substrate 1 is heat-treated at a temperature of 1100 ° C. with a hydrogen atmosphere after formation of the fluid passage, It is also possible to form the shape of the complete fluid passage by taking advantage of the phenomenon that the recombination of the crystals occurs so that the upper opening of the fluid passage is closed.

Hereinafter, a method of manufacturing a single crystal silicon microneedle according to the present invention will be described in detail with reference to FIGS. 6 to 11.

6 to 11 are process flowcharts showing a method for manufacturing single crystal silicon microneedle according to the present invention.

Referring to FIG. 6, first, an insulating film 3 is formed on the entire surface of the single crystal silicon substrate 1 as an etching masking layer of the silicon substrate 1. In more detail, a silicon oxide film (not shown) is grown on the front surface of the silicon substrate 1 by thermal oxidation, and then a low stress silicon nitride film (not shown) is formed on the silicon oxide film by low pressure chemical vapor deposition. By laminating, an insulating film 3 made of a composite layer of a silicon oxide film and a silicon nitride film is formed. Here, the silicon oxide film acts as a thermal barrier and also as an electrical insulating layer.

The photographic process is then used to define certain areas in which fluid passageways are to be formed. That is, after coating a photoresist film (not shown) as an etch masking layer on the insulating film 3, the photoresist film of a predetermined partial region where fluid passages are to be formed is selectively removed until the insulating film 3 below it is exposed. . Therefore, the pattern of the photosensitive film remains only on the insulating film 3 in the region where the fluid passages are not formed.

Then, by using the remaining photoresist pattern as an etching mask layer, the exposed portion of the insulating film 3 is etched until the silicon substrate 1 below is exposed, thereby forming a pattern of the insulating film 3. Subsequently, the pattern of the photosensitive film remaining on the pattern of the insulating film 3 is completely removed.

Subsequently, using the pattern of the insulating film 3 as an etching masking layer, the exposed silicon substrate 1 is anisotropically etched to a desired depth, for example, by a chlorine series plasma etching process or a Bosch process. At this time, the etching depth of the silicon substrate 1 is determined according to the position where the fluid passage is to be formed. Thus, a narrow deep rectangular trench 41 is formed in the single crystal silicon substrate 1 in the predetermined partial region where the fluid passage is to be formed.

Of course, although not shown in the drawings, it is obvious that the trench 41 should be formed to be elongated straight in the forward direction to have a shape similar to the fluid passage 23 of FIG. 1. In addition, the direction of the fluid passage 23 is determined from the structure of the trench 41 using dry etching, so that when it is necessary to change the direction of the fluid passage, the trench is provided so as not to disturb the fluid flow in the fluid passage 23. It is preferable to change the pattern of (41) into a curved shape at the design stage.

Meanwhile, although one trench 41 is formed in each of a predetermined region of the single crystal silicon substrate 1 in the drawing, as shown in FIG. 5, the single crystal silicon is included to include a plurality of fluid passages in the extension portion. It is apparent that a plurality of trenches may be formed in predetermined portions of the substrate 1, respectively.

Referring to FIG. 7, after the trench 41 is formed, the passivation layer 5 having good step coverage is formed on the side surface of the trench 41. In more detail, the silicon oxide film (not shown) and the silicon nitride film (not shown) having good step coverage, for example, are formed on the insulating film 3 outside the trench 41 together with the bottom and side portions of the trench 41. ) Are sequentially laminated by low pressure chemical vapor deposition. This is to protect the etching damage of the side part of the trench 41 in the etching step of the silicon substrate 1 for the subsequent formation of the fluid passage.

Subsequently, the protective film 5 is etched by using an etch back process having an anisotropic etching characteristic until the silicon substrate 1 of the bottom portion of the trench 41 is exposed, thereby protecting the protective film 5 only on the side surface of the trench 31. Leaves. At this time, the protective film 5 outside the trench 41 is also etched and the pattern of the insulating film 3 is exposed.

Thereafter, the exposed silicon substrate 1 in the trench 41 isotropically etched to form a circular fluid passage 45 under the trench 41. In this case, any one of dry etching using SF ₆ plasma, XeF ₂ gas, or wet etching using hydrofluoric acid / nitric acid / acetic acid may be used for isotropic etching. According to this method, it is possible to accurately adjust the diameter of the fluid passage 45.

Referring to FIG. 8, after the fluid passage 45 is formed, the trenches 41 may be formed by simultaneously stacking the same films 47 and 48 on the front and rear surfaces of the silicon substrate 1 of the resulting structure, respectively. ) Is completely sealed to form a complete fluid passage 45 inside the silicon substrate 1. In more detail, the film 47, for example, a polysilicon film, a silicon oxide film, a silicon nitride film, and the like, may be uniformly laminated to the deep portion of the trench 41 by a low pressure chemical vapor deposition method, and at the same time the fluid passage 45 may be formed. The film 47 is also laminated on the inner surface of the substrate. At this time, when the film 47 is gradually thickened from both inner surfaces of the trench 41 toward the center of the trench 41, and the films 47 on both inner surfaces are interviewed with each other, the trench 41 is formed by the film 47. It is completely sealed by). Thus, the shape of the complete fluid passage 45 is completed.

The film 47 may be formed of at least one of a film that can be deposited using a low pressure chemical vapor deposition method, for example, a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film. In addition, a coating using a biocompatible organic thin film, such as a parylene thin film, may be used instead of the low pressure chemical vapor deposition for sealing the trench 41. In addition, apart from the processes mentioned in FIGS. 7 and 8, when the silicon substrate 1 is heat-treated at a temperature of 1100 ° C. with a hydrogen atmosphere after the formation of the trench 41, crystal recombination occurs to form the trench 41. It is also possible to form the shape of the complete fluid passage 45 by using the phenomenon that the upper side is sealed.

After the formation of the complete fluid passage 45, the planarization process of planarizing the surface of the silicon substrate 1 of the resultant structure may be further performed to smoothly carry out the subsequent photographic process. If the width of 41 is small, the planarization step may not be performed.

A fluid element (not shown), such as a microvalve or micropump, is then formed and integrated with the fluid passage 45 to control the flow of fluid flowing through the sealed fluid passage 45.

Referring to FIG. 9, after the formation of the fluid passages 45 in the single crystal silicon substrate 1 of the predetermined partial region is completed, the width W is formed on the film 47 of the predetermined partial region using a photographic process. The pattern (not shown) of the photosensitive film which has () is selectively formed. Here, the width W determines the width of the extension of the microneedle to be formed, for example, the extension 20 of FIG. 1.

Subsequently, using the pattern of the photoresist film as an etching mask, the exposed portions of the films 47 and 3 are etched until the single crystal silicon substrate 1 below is exposed and the pattern of the photoresist film is removed.

Then, the trench 49 is formed by anisotropically etching the exposed single crystal silicon substrate 1 by using a reactive ion etching process by using the patterns of the film 47 and the insulating film 3 that remain unetched as the etching masking layer. At this time, the depth D of the trench 49 determines the thickness of the extension of the microneedle to be formed, for example, the extension 21 of FIG. 1.

In order to protect the sidewalls of the trench 49, an insulating layer 51 is stacked on the inner surface of the trench 49 and the upper surface of the film 47 as an etch masking layer of the single crystal silicon substrate 1. Here, the insulating film 51 is shown as one layer, but may be formed of a composite layer of a silicon oxide film and a silicon nitride film. Next, the insulating film 51 on the bottom portion of the trench 49 is etched until the single crystal silicon substrate 1 below it is exposed.

Referring to FIG. 10, after the silicon substrate 1 of the bottom portion of the trench 49 is exposed, the single crystal silicon substrate 1 exposed by using the insulating layer 51 as an etch masking layer and the film 48 thereunder. ) Is anisotropically etched by a reactive ion etching process. Thus, a through hole 53 penetrating the single crystal silicon substrate 1 completely vertically is formed.

Referring to FIG. 11, after the through hole 53 is formed, the single crystal silicon substrate 1 of the predetermined partial region has a thickness corresponding to the depth D of the trench 49 of FIG. 9. By wet etching the back surface of the silicon substrate 1 with a basic aqueous solution, for example, the shape of the microneedles as shown in FIG. 1 is formed and these microneedles are separated from the single crystal silicon substrate 1.

Therefore, the present invention uses only one photo process for forming the fluid passage and defining the shape of the microneedles, so that the precise thickness and width of the microneedles can be determined and the accumulation of alignment errors can be avoided. Since the direction of the fluid passage is determined from the structure of the trench using dry etching, the fluid passage may be formed in a curved structure so as not to disturb the fluid flow in the fluid passage. In addition, the present invention provides a simple and accurate microneedle using the SBM process technology, compared to the manufacturing method using a conventional (100) silicon substrate or a manufacturing method using a silicon on insulator (SOI) substrate, yield in mass production Can improve.

As described above, the single crystal silicon microneedle and the method of manufacturing the same according to the present invention use a single crystal silicon substrate as a material of the structure to ensure excellent reproducibility. In addition, the present invention can improve the yield during mass production by improving the process reliability by reducing the number of photographic processes to simplify the process and the accumulation of alignment errors. In addition, the present invention can prevent deformation of the fluid passage due to the stress of the thin film to enhance durability, and furthermore, it is possible to accurately acquire the microfluidic sample from the biological tissue and to inject the microfluidic sample into the biological tissue.

In addition, a fluid passage having any path can be used as a separate element for suction and injection of a sample when manufactured integrating with a microfluidic element, as well as for use with a surgical tool such as an endoscope.

On the other hand, the present invention is not limited to the contents described in the drawings and detailed description, it is obvious to those skilled in the art that various modifications can be made without departing from the spirit of the invention. .

Claims (25)

A body portion made of a single crystal silicon substrate; An extension portion formed of a single crystal silicon substrate and integrally connected to a portion of the body portion, the extension portion including at least one fluid passageway; A fluid element connected to the fluid passage so as to flow fluid through the fluid passages and formed on one surface of the body portion; And And a cap portion bonded to one surface of the body portion to provide a path for collecting the fluid. The single crystal silicon microneedle according to claim 1, wherein one of the fluid passages is formed in the extension part, and a groove part for communicating with the fluid passage of the extension part and the upper opening is opened. The single crystal silicon microneedle according to claim 1, wherein the one fluid passage is formed in the extension portion, and at least one fluid passage in common communication with the fluid passage of the extension portion is formed in the body portion. The single crystal silicon microneedle according to claim 1, wherein a plurality of fluid passages are formed in the extension portion and the body portion in the same quantity. The single crystal silicon microneedle according to any one of claims 1 to 4, wherein an upper opening of the fluid passage of the extension portion and the body portion is sealed with a predetermined film. 6. The single crystal silicon microneedle according to claim 5, wherein the film is made of at least one of a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film. The single crystal silicon microneedle according to claim 1, wherein the cap part is made of a transparent material to visually check the fluid flowing through the fluid passage. 5. The single crystal silicon microneedle according to claim 4, wherein the cap portion is made of glass material. Forming at least one fluid passageway each having an upper opening in defined portions of the single crystal silicon substrate; Sealing the upper openings of the fluid passages with a predetermined membrane; Integrating a fluid element with the fluid passage in another portion of the single crystal silicon substrate to control the flow of fluid flowing through the sealed fluid passages; And And suspending the structure of the single crystal silicon substrate including the fluid passages. 10. The method of claim 9, wherein forming the fluid passage Forming at least one trench each having a desired depth in a predetermined partial region of the single crystal silicon substrate; Forming a protective film only on the side portions of each of the trenches and exposing a single crystal silicon substrate below the bottom portions of the trenches; And Isotropically etching the exposed single crystal silicon substrate to form circular fluid passages having the upper opening. 10. The method of claim 9, wherein the single crystal silicon substrate is isotropically etched by dry etching. The method of claim 11, wherein the single crystal silicon substrate is isotropically etched by dry etching using SF ₆ plasma and XeF ₂ gas. 10. The method of claim 9, wherein the single crystal silicon substrate is isotropically etched by wet etching. The method of claim 13, wherein the single crystal silicon substrate is isotropically etched by wet etching using hydrofluoric acid / nitric acid / acetic acid. 10. The method of claim 9, wherein the upper opening is sealed by at least one of a polycrystalline silicon film, a silicon oxide film, and a silicon nitride film using a low pressure chemical vapor deposition method. 10. The method of claim 9, wherein the upper opening is sealed with a coating using a biocompatible organic thin film. 17. The method for producing a single crystal silicon microneedle according to claim 16, wherein a perylene thin film is used as the organic thin film. 10. The method of claim 9, wherein after forming the upper opening, the single crystal silicon substrate is heat-treated in a predetermined gas atmosphere to seal the upper opening to seal the upper opening. 10. The method of claim 9, wherein floating the structure of the single crystal silicon substrate including the fluid passages comprises Selectively forming a pattern of the photoresist on the predetermined partial regions; Forming a trench having a desired depth in a single crystal silicon substrate between the predetermined partial regions using the pattern of the photoresist layer as a masking layer; Forming an insulating film to protect the side portions of the trench and exposing a single crystal silicon substrate under the trench; Etching the exposed single crystal silicon substrate in the trench to the backside of the single crystal silicon substrate; And Etching the back surface of the single crystal silicon substrate of the predetermined partial region to float the structure of the single crystal silicon substrate including the fluid passages. 20. The method of claim 19, wherein the depth of the trench determines the thickness of the extension including the fluid passageway. 20. The method of claim 19, wherein the width of the extension portion including the fluid passage is determined by the width of the pattern of the photosensitive film. 10. The method of claim 9, comprising anisotropically etching the terminal portions of the structure of the single crystal silicon substrate with a basic aqueous solution to form a sharp shape. 10. The method of claim 9, comprising bonding a cap portion covering the fluid element to collect fluid flowing through the fluid passage in a predetermined region of the single crystal silicon substrate. 24. The method of claim 23, wherein the cap portion is formed of a transparent material. 25. The method of claim 24, wherein the cap portion is formed of glass.