A microelectrode structure and a manufacturing method thereof

Abstract

The present invention relates to the field of microelectrode technology, and specifically relates to a microelectrode structure and a manufacturing method thereof, including a hard needle and a soft needle disposed above the hard needle; the hard needle and the soft needle are separated by micro-columns, and at least one micro-column is provided on the front surface of the tail of the hard needle or at least one micro-column is provided on the back surface of the tail of the soft needle. When the hard needle of the microelectrode structure of the present invention is implanted into nerve tissue, the soft needle is brought into the tissue through the hard needle and the soft needle guide on the hard needle, and then the hard needle is pulled out, leaving the soft needle in the tissue, which can avoid the defects of using a single hard needle or a single soft needle, and at least one micro-column is provided on the front surface of the tail of the hard needle or the back surface of the tail of the soft needle, which can effectively prevent adhesion between the hard needle and the soft needle, and reduce the difficulty of pulling out the hard needle after implantation into the tissue.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical engineering and brain-computer interface neuro-microelectrode technology, and particularly relates to a microelectrode structure and a manufacturing method thereof. Background Art

[0002] A microelectrode refers to an electrode with at least one dimension in the micron or nanometer scale (i.e., <100 microns). It has been widely used in fields such as analytical chemistry and medical engineering. All kinds of physiological functions of humans and animals are directly or indirectly regulated by the neural network in the brain. Recording the change in the discharge frequency of a single neuron requires the microelectrode to collect a strong electrical signal and conduct long-term observation and research. Among them, microelectrodes that can be implanted into the central nervous system (CNS) for a long time have a wide range of applications.

[0003] Common microelectrodes are divided into two categories: metal and glass. Metal microelectrodes are high-strength metal fine needles, and the part outside the tip is insulated with paint or glass. The metal electrode wire is formed by electrolytic corrosion of stainless steel, platinum-iridium alloy or tungsten carbide wire in an acidic solution, and there are various finished products to choose from. Its disadvantage is that it is difficult to maintain the consistency of the geometric shape and insulation state of the microelectrode. Glass microelectrodes are drawn by users from hard capillary tubes according to needs. When used to measure the intracellular resting potential and action potential, the tip needs to be less than 0.5 microns; when used to measure the potential of non-active points in the extracellular active region, the tip can be 1 - 5 microns.

[0004] The micro needles of the above two types of microelectrodes both use rigid micro needles, which cannot adaptively deform as the blood vessels expand and contract during implantation, and thus are likely to cause damage to human or animal tissues. If the micro needles of the microelectrode are completely made of flexible materials, the micro needles are prone to deformation during the process of implanting into tissues, which is not convenient for the operator to implant the micro needle body into the tissues. Summary of the Invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a microelectrode structure and a manufacturing method thereof. By bringing a soft needle into the tissue with a hard needle and then pulling out the hard needle, it can not only avoid the defects of using a single hard needle or soft needle, but also avoid adhesion between the hard needle and the soft needle, and reduce the difficulty of pulling out the hard needle after implanting into the tissue.

[0006] To achieve the above purpose, the technical solution of the present invention is a microelectrode structure, including a hard needle and a soft needle arranged above the hard needle; the hard needle and the soft needle are separated by micro-columns, and at least one micro-column is arranged on the front surface of the tail of the hard needle or at least one micro-column is arranged on the back surface of the tail of the soft needle.

[0007] Further, the number of the micro-columns is multiple, and the micro-columns are arranged in multiple rows and multiple columns at a preset interval.

[0008] Further, the height of the micro-columns is 0.2 μm - 1.5 μm.

[0009] Further, the micro-columns are made of any one of silicon, polysilicon, silicon nitride, and silicon dioxide.

[0010] Further, a soft needle guide is provided on the hard needle.

[0011] Still further, the soft needle guide includes an inverted L-shaped hook, and the inverted L-shaped hook includes a vertical portion and a horizontal portion; a guiding window is provided at the head of the soft needle, one end of the vertical portion is connected to the head of the hard needle, the other end penetrates upward through the guiding window and is connected to the horizontal portion, and the size of the guiding window is larger than the size of the horizontal portion.

[0012] Further, an integrated circuit chip is included, and the integrated circuit chip is electrically connected to the soft needle.

[0013] The present invention also provides a manufacturing method of the above microelectrode structure, including the following steps:

[0014] S1. Provide a substrate;

[0015] S2. Grow a micro-column layer on the surface of the substrate, then etch the micro-column layer to form at least one micro-column, and then grow a sacrificial layer on the surface;

[0016] Or grow a sacrificial layer on the surface of the substrate first, then grow a micro-column layer, then etch the micro-column layer to form at least one micro-column, and then grow a sacrificial layer on the surface of the substrate, wherein the sacrificial layer grown for the second time is flush with the micro-columns;

[0017] S3. Grow a soft needle structure layer on the structure completed in step S2 to form a soft needle;

[0018] S4. Etch or thin the back of the substrate to form a hard needle;

[0019] S5. Release the sacrificial layer between the hard needle and the soft needle.

[0020] Further, the soft needle structure layer is made of any one of silicon carbide, silicon nitride, and polysilicon.

[0021] Further, the substrate is made of any one of Si, SOI, and Si / SiO2, and the sacrificial layer is made of any one of PI, silicon nitride, and oxide.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) When the microelectrode structure of the present invention is implanted into nerve tissue with a hard needle, the soft needle is brought into the tissue through the hard needle, and then the hard needle is pulled out, leaving the soft needle in the tissue. This can avoid the damage to the tissue caused by the inability to adaptively deform with the blood vessels during implantation when using a single hard needle, and also avoid the difficulty of implanting the soft needle well into the tissue due to the easy deformation of the single soft needle during implantation. At least one microcolumn is provided on the front of the tail of the hard needle or the back of the tail of the soft needle, which can effectively prevent adhesion between the hard needle and the soft needle and reduce the difficulty of pulling out the hard needle after implantation into the tissue.

[0024] (2) The preparation process of the present invention is simple and only requires one more layout on the original preparation basis to complete the preparation. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0026] Figure 1 Schematic diagram of the microelectrode structure provided in Embodiment 1 of the present invention;

[0027] Figure 2 Flow chart of the preparation method of the microelectrode structure provided in Embodiment 1 of the present invention;

[0028] Figure 3 Schematic diagram of the microelectrode structure provided in Embodiment 2 of the present invention;

[0029] Figure 4 Flow chart of the preparation method of the microelectrode structure provided in Embodiment 2 of the present invention;

[0030] Figure 5 Three-dimensional diagram of the microelectrode structure provided in the embodiment of the present invention;

[0031] Figure 6 Overall structure diagram of the microelectrode structure provided in Embodiment 1 of the present invention;

[0032] In the figure: 1, hard needle; 2, soft needle; 3, microcolumn; 4, guiding window; 5, inverted L-shaped hook; 6, substrate; 7, microcolumn layer; 8, sacrificial layer; 9, soft needle structure layer. Detailed Embodiments

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0035] The terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features; in the description of the present invention, unless otherwise specified, the meaning of "several" is two or more.

[0036] Embodiment 1

[0037] As Figure 1 、 Figure 3 and Figure 5 shown, this embodiment provides a microelectrode structure, including a hard needle 1 and a soft needle 2 disposed above the hard needle 1; a micro-column 3 separates the tail of the hard needle 1 from the tail of the soft needle 2. As an implementation manner, at least one micro-column 3 is disposed on the front surface of the tail of the hard needle 1, and the upper surface of each micro-column 3 contacts the soft needle 2; as another implementation manner, at least one micro-column 3 is disposed on the back surface of the tail of the soft needle 2, and the lower surface of each micro-column 3 contacts the hard needle 1. The hard needle 1 brings the soft needle 2 into the nerve tissue. Since there may be a risk of adhesion between the hard needle 1 and the soft needle 2, resulting in difficult extraction of the hard needle 1, in this embodiment, at least one micro-column 3 is disposed on the front surface of the tail of the hard needle 1 or the back surface of the tail of the soft needle 2. The micro-column 3 plays a supporting role, and on the other hand, reduces the contact area between the soft needle 2 and the hard needle 3, which can effectively prevent adhesion between the hard needle 1 and the soft needle 2 and reduce the extraction difficulty of the hard needle 1 after implantation into the tissue.

[0038] In this embodiment, the number of the micro-columns 3 is multiple, and the micro-columns 3 are arranged in multiple rows and columns at a preset interval. The specific number and spacing of the micro-columns 3 can be designed according to actual requirements.

[0039] In this embodiment, the height of the micro-column 3 is 0.2 μm - 1.5 μm. Optimally, the height of the micro-column 3 is about 1 μm. The cross-sectional size and shape of the micro-column 3 can be designed according to actual requirements.

[0040] Preferably, the micro-column 3 is made of any one of silicon, polysilicon, silicon nitride, and silicon dioxide, and the sacrificial layer release will not affect it. The soft needle 2 is made of a flexible material, which facilitates the adaptive deformation of the soft needle 2 as the blood vessel expands and contracts, reducing the damage to human or animal tissues during implantation. The hard needle 1 is made of Si, SOI, or Si / SiO2, etc., and has a certain hardness, so that the operator can bring the soft needle 2 into the soft tissue of a human or animal through the hard needle 1.

[0041] Furthermore, a soft needle guide is provided at the head of the hard needle. The hard needle 1 can bring the soft needle 2 into the nerve tissue together through the soft needle guide, and the soft needle guide can be separated from the soft needle 2 when the hard needle 1 is withdrawn.

[0042] As one of the implementation manners, the soft needle guide includes an inverted L-shaped hook 5, and the inverted L-shaped hook 5 includes a vertical portion and a horizontal portion; a guiding window 4 is provided at the head of the soft needle 2, one end of the vertical portion is connected to the head of the hard needle 1, the other end penetrates upward through the guiding window 4 and is connected to the horizontal portion, and the size of the guiding window 4 is larger than the size of the horizontal portion. Taking the implementation manner in which at least one micro-column 3 is provided on the front surface of the tail of the hard needle 1 as an example for illustration, as Figure 3 shown, when the hard needle 1 is implanted into the nerve tissue, the vertical portion of the inverted L-shaped hook 5 contacts the front edge of the guiding window 4 and drives the soft needle 2 to be implanted into the nerve tissue together. When the hard needle 2 is withdrawn, the inverted L-shaped hook 5 retreats in the guiding window 4. Since the size of the horizontal portion of the inverted L-shaped hook 5 is smaller than that of the guiding window 4, when the inverted L-shaped hook 5 is completely within the range of the guiding window 4, the head of the hard needle 1 can be first moved downward out of the guiding window 4 and then withdrawn, so as to leave the soft needle 2 in the tissue.

[0043] Furthermore, at least one body electrode point is provided at the head of the soft needle 2 for collecting nerve signals and transmitting the collected nerve signals to the integrated circuit chip. The body electrode point is connected to the corresponding solder joint at the tail of the soft needle 2 through a connecting wire. When at least one body electrode point is provided at the head of the soft needle 2, the at least one body electrode point can be arranged in a staggered or array pattern along the length direction of the soft needle 2, and the size and spacing of the body electrode points can be designed according to actual requirements.

[0044] Further, it further includes an integrated circuit chip, and the integrated circuit chip is electrically connected to the soft needle 2. Specifically, there is at least one solder joint on the integrated circuit chip, and there is at least one solder joint at the tail of the soft needle 2. Conductive materials are provided on the solder joints of the integrated circuit chip and the soft needle 2 so that the solder joints on the integrated circuit chip are bonded to the corresponding solder joints on the soft needle 2. Among them, the conductive materials include indium, gold, silver, platinum, etc.

[0045] Embodiment 2

[0046] As Figure 2 shown, this embodiment provides a Figure 1 manufacturing method of the microelectrode structure shown, including the following steps:

[0047] S1. Provide a substrate 6; among them, the substrate 6 adopts a Si substrate, an SOI substrate, a Si / SiO2 substrate, etc.;

[0048] S2. Grow a microcolumn layer 7 with a certain thickness on the surface of the substrate 6; among them, the microcolumn layer 7 adopts silicon, polysilicon, silicon nitride, or silicon dioxide, and the thickness of the microcolumn layer 7 is 0.2 μm - 1.5 μm;

[0049] S3. Etch the microcolumn layer 7 to form at least one microcolumn 3; preferably, there are multiple microcolumns 3, and the microcolumns 3 are arranged in multiple rows and columns at a certain interval at the tail of the substrate 6 needle;

[0050] S4. Grow a sacrificial layer 8 with a certain thickness on the surface of the substrate 6, and the thickness of the sacrificial layer 8 is greater than the height of the microcolumn 3; among them, the sacrificial layer 8 adopts PI, silicon nitride, or oxide, etc., and the oxide can adopt SiO2, etc.;

[0051] S5. Grow a soft needle structure layer 9 on the surface of the sacrificial layer 8 and pattern it to form the soft needle 2; among them, the soft needle structure layer 9 adopts silicon carbide, silicon nitride, polysilicon, etc., and there is also a metal electrode layer inside the soft needle structure layer 9, and the metal electrode layer mainly adopts aluminum, gold, copper, silver, etc.;

[0052] S6. Etch or thin the back of the substrate 6 to form the hard needle 1;

[0053] S7. Release the sacrificial layer 8 between the hard needle 1 and the soft needle 2.

[0054] Preferably, between step S5 and step S6, a window is opened on the soft needle 2, then the vertical part of the inverted L-shaped hook 5 is regrown, and finally the horizontal part of the inverted L-shaped hook 5 is regrown.

[0055] The processes such as growth, etching, thinning, and release in the preparation method of this embodiment all adopt the conventional process methods in the art.

[0056] Embodiment 3

[0057] As shown Figure 4 in the figure, this embodiment provides a Figure 3 method for fabricating the microelectrode structure shown, including the following steps:

[0058] S1. Provide a substrate 6; wherein, the substrate 6 is a Si substrate, an SOI substrate or a Si / SiO2 substrate;

[0059] S2. First grow a sacrificial layer 8 with a certain thickness on the surface of the substrate 6,

[0060] S3. Then grow a microcolumn layer 7 with a certain thickness on the surface of the sacrificial layer 8; wherein, the microcolumn layer 7 is made of silicon, polysilicon, silicon nitride or silicon dioxide, and the thickness of the microcolumn layer 7 is 0.2 μm - 1.5 μm;

[0061] S4. Then etch the microcolumn layer 7 to form at least one microcolumn 3; preferably, there are multiple microcolumns 3, and the microcolumns 3 are arranged in multiple rows and columns at a certain interval at the tail of the substrate 6;

[0062] S5. Grow another sacrificial layer 8 with a certain thickness on the surface of the sacrificial layer 8 fabricated in step S2, wherein the second-grown sacrificial layer is flush with the microcolumns; both sacrificial layers 8 can be made of PI, silicon nitride or oxide, etc., the oxide can be SiO2, etc., and the sum of the thicknesses of the two sacrificial layers 8 is about 2 μm;

[0063] S6. Grow a soft needle structure layer 9 on the surface of the structure fabricated in step S5 and pattern it to form soft needles 2; wherein, the soft needle structure layer 9 is made of silicon carbide, silicon nitride, polysilicon, etc., and there is also a metal electrode layer inside the soft needle structure layer 9, and the metal electrode layer is mainly made of aluminum, gold, copper, silver, etc.;

[0064] S7. Etch or thin the back of the substrate 6 to form a hard needle 1;

[0065] S8. Release the sacrificial layer 8 between the hard needle 1 and the soft needle 2.

[0066] Preferably, between step S6 and step S7, a window is opened for the soft needle 2, then the vertical part of the inverted L-shaped hook 5 is regrown, and finally the horizontal part of the inverted L-shaped hook 5 is regrown.

[0067] The processes such as growth, etching, thinning, and release in the preparation method of this embodiment are all conventional process methods in the art.

[0068] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A microelectrode structure, characterized in that: It includes a hard needle and a soft needle disposed above the hard needle; the hard needle and the soft needle are separated by micro-columns, and at least one micro-column is provided on the front surface of the tail of the hard needle or at least one micro-column is provided on the back surface of the tail of the soft needle; a soft needle guide is provided on the hard needle, and the hard needle can bring the soft needle into the nerve tissue together through the soft needle guide, and the soft needle guide can be separated from the soft needle when the hard needle is pulled out.

2. The microelectrode structure according to claim 1, wherein: The number of the micro-columns is multiple, and the micro-columns are arranged in multiple rows and multiple columns at a preset interval.

3. The microelectrode structure according to claim 1, wherein: The height of the micro-column is 0.2μm - 1.5μm.

4. The microelectrode structure according to claim 1, characterized in that: The micro-column is prepared from any one of silicon, polysilicon, silicon nitride, and silicon dioxide.

5. The microelectrode structure according to claim 1, characterized in that: The soft needle guide includes an inverted L-shaped hook, and the inverted L-shaped hook includes a vertical portion and a horizontal portion; a guiding window is provided at the head of the soft needle, one end of the vertical portion is connected to the head of the hard needle, the other end penetrates upward through the guiding window and is connected to the horizontal portion, and the size of the guiding window is larger than the size of the horizontal portion.

6. The microelectrode structure according to claim 1, characterized in that: It further includes an integrated circuit chip, and the integrated circuit chip is electrically connected to the soft needle.

7. A method for manufacturing a microelectrode structure according to any one of claims 1-6, characterized in that, It includes the following steps: S1. Provide a substrate; S2. Grow a micro-column layer on the surface of the substrate, then etch the micro-column layer to form at least one micro-column, and then grow a sacrificial layer on the surface; Or first grow a sacrificial layer on the surface of the substrate, then grow a micro-column layer, then etch the micro-column layer to form at least one micro-column, and then grow a sacrificial layer on the surface of the substrate, wherein the sacrificial layer grown for the second time is flush with the micro-column; S3. Grow a soft needle structure layer on the structure made in step S2 to form a soft needle; S4. Etch or thin the back of the substrate to form a hard needle; S5. Release the sacrificial layer between the hard needle and the soft needle.

8. The manufacturing method of the microelectrode structure according to claim 7, characterized in that: The soft needle structure layer is made of any one of silicon carbide, silicon nitride, and polysilicon.

9. The manufacturing method of the microelectrode structure according to claim 7, characterized in that: The substrate is made of any one of Si, SOI, and Si / SiO2, and the sacrificial layer is made of any one of PI, silicon nitride, and oxide.

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