Microelectrode array

Abstract

The utility model relates to the technical field of biomedical engineering, in particular to a microelectrode array. According to the microelectrode array provided by the invention, the flexible microwire electrodes are adopted, the flexible microwire electrodes have the bending rigidity equivalent to that of neuronal axons, immunoreactions possibly caused by implantation of the microelectrodes are reduced, and the protrusions which are obliquely arranged in the direction deviating from the extension direction of the insulating media are arranged on the insulating media wrapping the wires in the flexible microwire electrodes, so that the microelectrodes are more flexible. After the flexible microwire electrode enters the biological tissue, the flexible microwire electrode and the biological tissue can be kept relatively fixed through the protrusions, and relative displacement between the microwire electrode and the tissue caused by rhythmic physiological activities such as breathing, heartbeat and the like is reduced. Meanwhile, according to the microelectrode array provided by the invention, the capacitors are intensively wrapped in the insulating medium in an array manner, and the large-area capacitors required for processing the neuron pulse signals are arranged in the insulating medium, so that the layout area of a signal processing chip is saved, and the communication rate of a brain-computer interface system is further improved.

Description

Technical Field

[0001] The present disclosure relates to the field of biomedical engineering technology, and particularly to a microelectrode array. Background Art

[0002] Brain-computer interface systems need to use electrodes of various forms to collect electrical signals of neuronal activities at different scales. Brain-computer interface systems are divided into invasive brain-computer interface systems and non-invasive brain-computer interface systems. Among them, invasive brain-computer interfaces have become a current research hotspot due to advantages such as high spatio-temporal resolution and high accuracy.

[0003] Traditional invasive brain-computer interface systems are accustomed to using 96-lead Utah arrays to collect and process neural signals. Considering that the number of nerve cells in the human brain is roughly on the order of 10 11 order of magnitude, relative to the complexity of the human brain, the number of channels provided by the Utah array is small, and the number of nerve cells that can be collected in real time is insufficient to support a complex brain-computer interface system. In addition, the commonly used sampling electrodes in the Utah array have a relatively large bending stiffness compared to neuronal axons, and their mechanical properties do not match those of the nervous system. When the biological nervous system moves rhythmically with breathing, heartbeat, etc., the rigid sampling electrodes will have relative displacement with the surrounding nerve cells, thereby causing mechanical damage to the target neurons and other tissues that collect signals around, and this damage is considered to be an important reason for causing an immune response and resulting in the failure of the implanted sampling electrodes.

[0004] In view of the above situation, in the relevant prior art, there is no technical solution that effectively solves the above problems, and this technical problem has always been an important factor hindering the development of brain-computer interface systems. Summary of the Invention

[0005] The present disclosure provides a microelectrode array, which can effectively solve the above or other potential technical problems.

[0006] A first aspect of the present disclosure is to provide a microelectrode array, which includes a plurality of flexible microfilament electrodes arranged in an array for collecting neural signals; the flexible microfilament electrodes include an insulating medium, a wire, an electrode contact, and a protrusion; the insulating medium wraps the wire, and protrusions are formed on the side surface of the insulating medium, and the protrusions are inclined in a direction away from the extending direction of the insulating medium; the electrode contact is embedded in the insulating medium and connected to the wire, and at least a part of the electrode contact is exposed outside the insulating medium.

[0007] In an optional embodiment according to the first aspect, a plurality of spaced protrusions are formed on the side surface of the insulating medium.

[0008] In an alternative embodiment according to the first aspect, the plurality of protrusions are respectively disposed on two opposite sides of the insulating medium.

[0009] In an alternative embodiment according to the first aspect, a plurality of the electrode contacts are disposed on the insulating medium, and a part of the electrode contacts among the plurality of electrode contacts are acquisition electrode contacts for acquiring nerve signals, and another part of the electrode contacts are stimulation electrode contacts for stimulating nerve cells; each of the acquisition electrode contacts is spaced along the extending direction of the insulating medium on a first side of the insulating medium, each of the stimulation electrode contacts is spaced along the extending direction of the insulating medium on a second side of the insulating medium, the second side being opposite to the first side; and along the extending direction of the insulating medium, each of the acquisition electrode contacts and each of the stimulation electrode contacts are arranged alternately; protrusions are disposed on opposite sides of each of the acquisition electrode contacts and the stimulation electrode contacts.

[0010] In an alternative embodiment according to the first aspect, the acquisition electrode contacts and / or the stimulation contacts are also inclined along a direction away from the extending direction of the insulating medium.

[0011] In an alternative embodiment according to the first aspect, an angle between each of the acquisition electrode contacts and the insulating medium, an angle between each of the stimulation electrode contacts and the insulating medium, and an angle between each of the protrusions and the insulating medium are all equal.

[0012] In an alternative embodiment according to the first aspect, the insulating medium is a flexible medium material, and the insulating medium is a biocompatible insulating layer composed of one or several thin film materials of parylene, epoxy resin, acrylate, polyimide.

[0013] In an alternative embodiment according to the first aspect, a circular ring structure or a hook-like structure is disposed at an implantation end of the insulating medium, and the circular ring structure or the hook-like structure is used for implanting the flexible microfilament electrode into biological tissue.

[0014] In an alternative embodiment according to the first aspect, the wire includes a first wire and a second wire;

[0015] The capacitor includes a lower electrode plate, a dielectric layer, and an upper electrode plate stacked in the insulating medium. The lower electrode plate is connected to the acquisition electrode contact through the first wire, and the upper electrode plate is used for connecting to an external signal processing chip; a stimulation contact is also embedded in the insulating medium, and the stimulation contact is connected to the stimulation electrode contact through the second wire. The stimulation contact is connected to the external signal processing chip, and the stimulation electrode contact stimulates surrounding neurons.

[0016] In an optional embodiment according to the first aspect, the wire includes a first wire and a second wire; the capacitor includes a lower electrode plate, a dielectric layer, and an upper electrode plate laminated in the insulating medium, and the lower electrode plate is connected to the acquisition electrode contact through the first wire; a connection contact connected to the upper electrode plate is also embedded in the insulating medium, and the connection contact is used to connect to an external signal processing chip; a stimulation contact is also embedded in the insulating medium, the second wire is connected to the stimulation contact, and a stimulation contact is also embedded in the insulating medium, the second wire is connected to the stimulation contact, and the stimulation contact is connected to the external signal processing chip, so that the stimulation electrode contact stimulates the surrounding neurons.

[0017] The second aspect of the present disclosure also provides a method for manufacturing a microelectrode array, including: sequentially growing a silicon dioxide thin film, a sacrificial layer, a bottom insulating layer, and a patterned metal layer on a substrate, and the patterned metal layer includes wires; sequentially growing a middle insulating layer and a top insulating layer on the patterned metal layer and the bottom insulating layer; forming electrode contacts penetrating through the top insulating layer and the middle insulating layer and connected to the wires; performing mask etching according to the contour of the microelectrode array; peeling off the sacrificial layer, the silicon dioxide thin film, and the substrate from the bottom insulating layer to form the microelectrode array, wherein the side surface of the insulating medium wrapping the wires in the microelectrode array has protrusions, and the protrusions are inclined to the extending direction of the insulating medium wrapping the wires.

[0018] In an optional embodiment according to the second aspect, the patterned metal layer further includes a lower electrode plate of a capacitor; the sequentially growing a middle insulating layer and a top insulating layer on the patterned metal layer and the bottom insulating layer specifically includes: growing a middle insulating layer on the patterned metal layer and the bottom insulating layer; removing the middle insulating layer on the lower electrode plate; sequentially growing a dielectric layer and an upper electrode plate on the lower electrode plate; growing a top insulating layer on the middle insulating layer and the upper electrode plate; the manufacturing method further includes: forming a connection contact penetrating through the top insulating layer and connected to the upper electrode plate.

[0019] In an optional embodiment according to the second aspect, the patterned metal layer further includes a lower electrode plate of a capacitor; the sequentially growing a middle insulating layer and a top insulating layer on the patterned metal layer and the bottom insulating layer specifically includes: growing a middle insulating layer on the patterned metal layer and the bottom insulating layer; removing the middle insulating layer on the lower electrode plate; sequentially growing a dielectric layer and an upper electrode plate on the lower electrode plate; growing a top insulating layer on the middle insulating layer and the upper electrode plate; removing the top insulating layer on the upper electrode plate.

[0020] In an optional embodiment according to the second aspect, the patterned metal layer includes multiple wires and a plurality of capacitors arranged in an array, and the lower electrode plate of each capacitor is connected to one of the wires.

[0021] In an optional embodiment according to the second aspect, forming the electrode contacts that penetrate through the top insulating layer and the middle insulating layer and are connected to the wire specifically includes: forming a plurality of first through-holes and a plurality of second through-holes in the formation of the top insulating layer and the middle insulating layer; forming electrode contacts in the first through-holes; and forming stimulation contacts in the second through-holes.

[0022] The third aspect of the present disclosure further provides a microelectrode array, which includes an electrode substrate for connecting to an external signal processing chip; the electrode substrate includes an insulating medium and a capacitor, at least a part of the capacitor is wrapped in the insulating medium, and the capacitor is used for connecting to a flexible microfilament electrode and an external signal processing chip.

[0023] In an optional embodiment according to the third aspect, the capacitor includes a lower electrode plate, a dielectric layer, and an upper electrode plate arranged in a stacked manner; the lower electrode plate is used for connecting to a flexible microfilament electrode; the upper electrode plate is exposed outside the insulating medium, and the upper electrode plate is used for connecting to an external signal processing chip; or, the upper electrode plate is wrapped in the insulating medium and connected to a connection contact embedded in the insulating medium, and the connection contact is used for connecting to an external signal processing chip.

[0024] In an optional embodiment according to the third aspect, a stimulation contact is also embedded in the insulating medium, the stimulation contact is spaced from the upper electrode plate, and the stimulation contact is used for stimulating surrounding neurons; the flexible microfilament electrode includes a first wire connected to the lower electrode plate and a second wire connected to the stimulation contact.

[0025] In an optional embodiment according to the third aspect, a plurality of capacitors arranged in an array are wrapped in the insulating medium.

[0026] A microelectrode array provided by the present disclosure has at least the following beneficial effects compared with the prior art:

[0027] The microelectrode array provided by the first aspect of the present disclosure includes a plurality of flexible microfilament electrodes arranged in an array for collecting nerve signals, and the flexible microfilament electrodes include an insulating medium, a wire, an electrode contact, and a protrusion. The protrusion is inclined in a direction away from the extension direction of the insulating medium.

[0028] In the present disclosure, a flexible microfilament electrode is adopted, which has a bending stiffness equivalent to that of a neuron axon, reduces the immune response that may be caused by an implantable microelectrode, extends the service life of the microfilament electrode, greatly prolongs the time during which the electrode can work effectively, and improves the long-term stability of the invasive brain-computer interface system. At the same time, in the present disclosure, a protrusion inclined in a direction away from the extension direction of the insulating medium is included, and the protrusion is arranged in a barbed shape on the insulating medium, so that the flexible microfilament electrode is convenient to enter biological tissue, and after entering the biological tissue, the inclined protrusion assists in connecting to the biological tissue, making it not easy to fall off, keeping the flexible microfilament electrode relatively fixed to the biological tissue, and reducing the relative displacement between the microfilament electrode and the tissue caused by rhythmic physiological activities such as breathing and heartbeat.

[0029] The preparation method provided in the second aspect of the present disclosure also has the above-mentioned beneficial effects because it is based on the above-mentioned microelectrode array.

[0030] The microelectrode array provided in the third aspect of the present disclosure. In this embodiment, the microelectrode array wraps the capacitor in the insulating medium, the capacitor is connected to the acquisition electrode contact through the wire, and the capacitor is also used to connect to an external signal processing chip. The large-area capacitor required for processing neuron pulse signals is arranged in the insulating medium, thereby saving the layout area of the signal processing chip, enabling more sampling channels of neuron pulse signals to be processed on the same-sized chip, and further improving the communication rate of the brain-computer interface system.

[0031] Advantages of additional aspects of the present disclosure will be partially given in the following description, partially will become apparent from the following description, or will be learned through the practice of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of the overall structure of the microelectrode array provided in an embodiment of the present disclosure;

[0033] Figure 2 is Figure 1 an enlarged view of part I in

[0034] Figure 3 is Figure 1 an enlarged view of part II in

[0035] Figure 4 is Figure 1 an enlarged view of part III in

[0036] Figure 5 is a schematic diagram of the overall structure of the microelectrode array provided in an embodiment of the present disclosure without including electrical stimulation contacts and stimulation electrode contacts;

[0037] Figure 6 is Figure 5Middle edge AA ’ sectional view of

[0038] Figure 7 for Figure 5 Middle edge BB ’ sectional view of

[0039] Figure 8 A schematic diagram of a portion of the structure having stimulation contacts in an embodiment of the present disclosure;

[0040] Figure 9 for Figure 8 Zhongyan CC ’ sectional view of

[0041] Figures 10 to 20 The present invention provides a schematic flow chart of a method for preparing a microelectrode array according to an embodiment of the present invention.

[0042] In the attached figure:

[0043] 11: flexible microwire electrode; 111: insulating medium;

[0044] 112: wire; 113: electrode contact;

[0045] 1131: acquisition electrode contact; 1133: stimulation electrode contact;

[0046] 114: bulge; 115: ring structure;

[0047] 13: electrode base; 133: capacitor; 1331: lower plate;

[0048] 1333: upper plate; 1335: dielectric layer;

[0049] 135: connection contact; 137: stimulation contact;

[0050] 15: substrate; 151: silicon dioxide film;

[0051] 152: sacrificial layer; 153: bottom insulating layer;

[0052] 157: middle insulation layer; 162: top insulation layer. DETAILED DESCRIPTION

[0053] The following describes in detail embodiments of the present disclosure, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present disclosure, and should not be construed as limiting the present disclosure.

[0054] It should be understood that the following embodiments do not limit the execution order of the steps in the method protected by the present disclosure. Each step of the method of the present disclosure can be executed in any possible order and in a cyclic manner without contradiction.

[0055] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure 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 cannot be understood as a limitation of the present disclosure.

[0056] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present disclosure, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0057] In the present disclosure, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0058] In the present disclosure, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "under" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0059] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0060] As described in the background art, traditional invasive brain-computer interface systems are accustomed to using 96-channel Utah arrays to collect and process neural signals. Considering that the number of nerve cells in the human brain is roughly on the order of 10 11 orders of magnitude, relative to the complexity of the human brain, the number of channels that the Utah array can provide is small, and the number of nerve cells that can be collected in real time is insufficient to support a complex brain-computer interface system. In addition, the commonly used sampling electrodes in the Utah array have a relatively large bending stiffness compared to neuron axons, and their mechanical properties do not match those of the nervous system. When the biological nervous system moves rhythmically with breathing, heartbeat, etc., the rigid sampling electrodes will have relative displacement with the surrounding nerve cells, thereby causing mechanical damage to the target neurons and other tissues that collect signals around. This damage is considered to be an important reason for causing an immune response, resulting in a decrease in the long-term stability of the implanted electrodes and ultimately causing the implanted electrodes to fail.

[0061] In view of this, in the present disclosure, flexible microfilament electrodes are used, which have a bending stiffness equivalent to that of neuron axons, can effectively reduce the immune response that may be caused by implanted microelectrodes, extend the service life of the microfilament electrodes, greatly extend the time during which the electrodes can work effectively, and improve the long-term stability of the invasive brain-computer interface system. At the same time, the present disclosure includes protrusions that are inclined in a direction away from the extension direction of the insulating medium. The protrusions are arranged in a barbed shape on the insulating medium, so that the flexible microfilament electrodes are convenient to enter biological tissues, and after entering the biological tissues, the inclined protrusions assist in connecting to the biological tissues, making it not easy to fall off, keeping the flexible microfilament electrodes relatively fixed with the biological tissues, and reducing the relative displacement between the microfilament electrodes and the tissues caused by rhythmic physiological activities such as breathing and heartbeat.

[0062] Figure 1 It is a schematic diagram of the overall structure of the microelectrode array provided in the embodiment of the present disclosure. Figure 3 is Figure 1 the enlarged view of part II in Figure 7 is Figure 5 the cross-sectional view along B-B in ’ Please refer toFigure 1 , Figure 3 and Figure 7 . The microelectrode array provided in this embodiment includes a plurality of flexible microfilament electrodes 11 arranged in an array for collecting nerve signals; the flexible microfilament electrode 11 includes an insulating medium 111, a wire 112, an electrode contact 113, and a protrusion 114; the insulating medium 111 wraps the wire 112, and a protrusion 114 is formed on the side of the insulating medium 111, and the protrusion 114 is inclined in a direction away from the extending direction of the insulating medium 111; the electrode contact 113 is embedded in the insulating medium 111 and connected to the wire 112, and at least a part of it is exposed outside the insulating medium 111.

[0063] The insulating medium 111 is a flexible dielectric material, and the insulating medium 111 is a biocompatible insulating layer composed of one or several thin film materials among parylene, epoxy resin, acrylate, and polyimide. It should be noted that specifically, in this embodiment, the insulating medium 111 is a flexible dielectric material, and the insulating medium 111 is a biocompatible insulating layer composed of one or several thin film materials among parylene, epoxy resin, acrylate, and polyimide. The biocompatible insulating layer composed of the above materials further enables the microfilament electrode to have a smaller geometric size and a bending stiffness equivalent to that of a neuron axon, thereby reducing the immune response that may be caused by the implantable microelectrode and extending the service life of the microfilament electrode. At the same time, it can be understood that the material of the insulating medium 111 is not limited to one or several of the above parylene, epoxy resin, acrylate, and polyimide, and other suitable materials can be used according to the actual needs of the user.

[0064] It should be noted that the insulating medium 111 is made of a biocompatible flexible dielectric material processed by photolithography technology. The microelectrode array has a smaller geometric size and a bending stiffness equivalent to that of a neuron axon, thereby reducing the immune response that may be caused by the implantable microelectrode and extending the service life of the electrode.

[0065] Specifically, the insulating medium 111 on the outside of the wire 112 is an insulating bracket, and the shape of the insulating bracket is set to be one or a combination of a linear shape, a branched shape, or a mesh shape. The insulating medium 111 being an insulating bracket can provide support for the wire 112 and the electrode contact 113. It can be understood that the specific shape of the insulating medium 111 is not limited here, and the insulating medium 111 can be set to other shapes according to the needs of the user.

[0066] The wire 112 is a metal wire 112 or a non-metal wire 112. Exemplarily, the material of the metal wire 112 includes an alloy composed of one or several of gold, silver, copper, platinum, aluminum, and tungsten; the material of the non-metal wire 112 is polysilicon. Making the wire 112 from the above materials can effectively achieve the conduction function of the wire 112. It should be noted that the specific material of the wire 112 is not limited here. In other specific embodiments, the wire 112 can be made of other suitable materials according to the user's needs. Exemplarily, the material of the wire 112 is gold.

[0067] Please continue to refer to Figure 3 , the electrode contact 113, and the electrode contact 113 is embedded in the insulating medium 111 and connected to the wire 112, and at least a part of the electrode contact 113 is exposed outside the insulating medium 111. Exposing a part of the electrode contact 113 outside the insulating medium 111 to obtain the corresponding bioelectric signal. The electrode contact 113 is inclined along the direction away from the extension direction of the insulating medium 111; an angle is formed between the electrode contact 113 and the insulating medium 111. Such a setting facilitates the flexible microfilament electrode 11 to easily enter the biological tissue and is not easy to fall off after entering the biological tissue.

[0068] Exemplarily, the material of the electrode contact 113 includes an alloy composed of one or several of gold, silver, copper, platinum, aluminum, and tungsten. Exemplarily, the material of the electrode contact 113 is gold. It should be noted that it can better collect the neuron signals of biological tissues.

[0069] Exemplarily, in this embodiment, a plurality of electrode contacts 113 are provided. A part of the electrode contacts 113 among the plurality of electrode contacts 113 are acquisition electrode contacts 1131 for collecting nerve signals, and the other part of the electrode contacts 113 are stimulation electrode contacts 1133 for stimulating nerve cells; each acquisition electrode contact 1131 is arranged at intervals along the extension direction of the insulating medium 111 on the first side of the insulating medium 111, and each stimulation electrode contact 1133 is arranged at intervals along the extension direction of the insulating medium 111 on the second side of the insulating medium 111, and the second side is opposite to the first side; and along the extension direction of the insulating medium 111, each acquisition electrode contact 1131 and each stimulation electrode contact 1133 are arranged in an alternating manner. Since the bidirectional brain-machine interface system needs to stimulate the neurons to generate action potentials while collecting neuron pulse signals, the acquisition electrode contacts 1131 and the stimulation electrode contacts 1133 are provided in this disclosure, and the acquisition electrode contacts 1131 are used to stimulate nerve cells and the acquisition electrode contacts 1131 are used to collect nerve signals. At the same time, along the extension direction of the insulating medium 111, each acquisition electrode contact 1131 and each stimulation electrode contact 1133 are arranged in an alternating manner; the alternating arrangement can increase the distance between the two and minimize the interference of the electrical stimulation of the system itself on the sampling signal.

[0070] Exemplarily, the collection electrode contacts 1131 and / or the stimulation contacts 1133 are also arranged obliquely along the extension direction away from the insulating medium 111, so that after entering the biological tissue, they are in a barbed shape, and according to their structural characteristics, they are easy to enter the biological tissue, and after entering the biological tissue, they are not easy to separate from the biological tissue, thereby ensuring the stability of the collection work or the implementation of the stimulation work.

[0071] In an optional exemplary embodiment, the surface coating material of the electrode contact 113 is one or more of titanium nitride, tantalum, iridium oxide, or the conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS). Exemplarily, one or a combination of titanium nitride, iridium oxide thin film, or PEDOT coating is sputtered on the surface of the electrode contact 113 to effectively increase the current driving capability. Exemplarily, in this embodiment, the surface of the electrode contact 113 is coated with a thin layer of the conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS).

[0072] In an optional exemplary embodiment, the microelectrode array includes at least two flexible microwire electrodes 11; wherein each flexible microwire electrode 11 includes 40 electrode contacts 113, and the 40 electrode contacts 113 are staggered and arranged on both sides along the extension direction of the insulating medium 111, with 20 acquisition electrode contacts 1131 on one side and 20 stimulation electrode contacts 1133 on the other side. It should be noted that the provision of 40 electrode contacts can effectively meet the needs of collecting signals and implementing stimulation without causing unnecessary waste. It is understandable that the specific number of electrode contacts 113 is not limited here. In other specific embodiments, the number of electrode contacts 113 can be set to other appropriate values according to the actual needs of the user.

[0073] Further, in an optionally exemplary embodiment, 40 electrode contacts 113 are evenly distributed within a 2-mm length range at the end of the insulating medium 111 close to the biological tissue to be accessed; the distance between adjacent acquisition electrode contacts 1131 on the same side is 100 microns, the distance between adjacent stimulation electrode contacts 1133 on the same side is 100 microns, and the distance between adjacent acquisition electrode contacts 1131 and stimulation electrode contacts 1133 on different sides is 50 microns; the thickness of the insulating medium 111 does not exceed 4 microns, and the width is less than 10 microns. Such a spacing setting can effectively ensure the distance between the acquisition electrode contacts 1131 and the stimulation electrode contacts 1133, and minimize the interference of the electrical stimulation of the system itself on the sampling signal. It should be noted that the arrangement and mutual spacing of the acquisition electrode contacts 1131 and the stimulation electrode contacts 1133 can also be adjusted according to the actual needs of the user, and only the acquisition electrode contacts 1131 or the stimulation electrode contacts 1133 can be placed separately on one microfilament electrode 11.

[0074] In an optionally exemplary embodiment, the shape of the electrode contact 113 is circular or oval. Specifically, in this embodiment, the electrode contact 113 is a circle with a radius of 6 microns. It should be noted that the electrode contact 113 includes but is not limited to circular and oval shapes. It can be understood that in other specific embodiments, the electrode contact 113 can be set to other suitable shapes and sizes according to the needs of the user.

[0075] It should also be noted that the electrode contact 113 can be composed of a metal material that is the same as or different from that of the wire 112.

[0076] It should be pointed out that the protrusion 114 can be made of the same material as the insulating medium 111, which will become obvious in the preparation method described below. Of course, in some other examples, the protrusion 114 can also be made of different materials. The protrusion 114 is provided on the side of the insulating medium 111 and is inclined in a direction away from the extending direction of the insulating medium 111. In other words, the protrusion 114 is arranged in a barbed shape on the insulating medium 111, so that the flexible microfilament electrode 11 is convenient to enter the biological tissue, and after entering the biological tissue, the inclined protrusion 114 assists in connecting to the biological tissue, making it not easy to fall off, keeping the flexible microfilament electrode 11 relatively fixed to the biological tissue, reducing the relative displacement between the microfilament electrode and the tissue caused by rhythmic physiological activities such as breathing and heartbeat, and thus ensuring the stability of the connection of the microfilament electrode 11.

[0077] Exemplarily, a plurality of protrusions 114 are formed on the side surface of the insulating medium 111 at intervals. The arrangement of the plurality of protrusions 114 on the side surface of the insulating medium 111 further ensures the stability of the connection of the microfilament electrode 11. Exemplarily, the plurality of protrusions 114 are respectively arranged on two opposite side surfaces of the insulating medium 111. That is, the protrusions 114 arranged in a barbed shape are connected to the biological substance in multiple directions and at multiple positions, further ensuring the stability of the connection.

[0078] Specifically, the protrusions 114 are respectively arranged on the opposite sides of the acquisition electrode contact 1131 and the stimulation electrode contact 1133. With this structure, the protrusions 114 and the acquisition electrode contact 1131, and the protrusions 114 and the stimulation electrode contact 1133 are structurally relatively stable, ensuring the stability of the acquisition electrode contact 1131 and the stimulation electrode contact 1133 during the implementation of the acquisition work and the stimulation work, and reducing the relative displacement between the flexible microfilament electrode 11 and the tissue caused by rhythmic physiological activities such as breathing and heartbeat.

[0079] In an optionally exemplary embodiment, the angles between the acquisition electrode contact 1131 and the insulating medium 111, the angles between the stimulation electrode contact 1133 and the insulating medium 111, and the angles between the protrusions 114 and the insulating medium 111 are all equal. It should be noted that with this structural arrangement, the acquisition electrode contact 1131 and the protrusions 114 maintain symmetry in structure, and the stimulation electrode contact 1133 and the protrusions 114 also maintain symmetry in structure. Further, it is not easy to displace and then fall off after entering the biological tissue, and at the same time, the symmetric setting of its structure itself also has stability, further ensuring the stability of the acquisition work and the stimulation work.

[0080] In the present disclosure, the flexible microfilament electrode 11 is adopted, which has a bending stiffness equivalent to that of a neuron axon, reduces the immune response that may be caused by implantable microelectrodes, extends the service life of the microfilament electrode, greatly extends the time during which the electrode can work effectively, and improves the long-term stability of the invasive brain-computer interface system. At the same time, in the present disclosure, the protrusions 114 are arranged on the insulating medium 111 and are oppositely arranged with the electrode contacts 113 on both sides of the insulating medium 111. The protrusions 114 are arranged on the insulating medium 111, and the protrusions 114 assist the flexible microfilament electrode 11 to be connected to the biological tissue, keeping the flexible microfilament electrode 11 relatively fixed with the biological tissue, and reducing the relative displacement between the microfilament electrode and the tissue caused by rhythmic physiological activities such as breathing and heartbeat.

[0081] Figure 4 For Figure 1 the enlarged view at III, please refer to Figure 4, in an optionally exemplary embodiment, a circular ring structure 115 or a hook-shaped structure is provided at the implantation end of the insulating medium 111. The circular ring structure 115 or the hook-shaped structure is used to implant the flexible microfilament electrode 11 into biological tissue. It should be noted that, in this embodiment, a circular ring structure 115 or a hook-shaped structure is provided at the implantation end of the insulating medium 111, and the circular ring structure 115 or the hook-shaped structure is used to assist in implanting the flexible microfilament electrode 11 into biological tissue. Specifically, the circular ring structure 115 can be formed by etching a circular through-hole at the end of the insulating medium 111. The hook-shaped structure is formed by etching the corresponding shape at the end of the insulating medium 111. It should be noted that the circular ring structure 115 is shown in the drawings of the present disclosure, but is not limited to the circular ring structure 115. Specifically, the circular ring structure 115 or the hook-shaped structure is made of polyimide material, that is, made of the same material as the insulating medium 111, that is, one or several of parylene, epoxy resin, acrylate, and polyimide.

[0082] It should be noted that, in order to be able to process the neural signals collected by the microfilament electrode in real time and further construct a bidirectional real-time invasive brain-computer interface system, the microfilament electrode is generally connected to a dedicated integrated circuit responsible for processing neural signals in various ways; since the neural signals collected by the electrode usually have a large DC offset and the peak value of the extracellular neuron pulse signal is small, a large DC-blocking capacitor 133 is usually added at the front end of the low-noise amplifier in the analog circuit part responsible for processing neural signals. This capacitor 133 usually occupies a relatively large layout area in the analog circuit design part, thereby reducing the number of sampling channels that can be integrated per unit area and restricting the improvement of the communication rate of the invasive brain-computer interface system.

[0083] Figure 5 This is a schematic diagram of the overall structure of the microelectrode array provided in the embodiment of the present disclosure, excluding the electrical stimulation contact and the stimulation electrode contact. Please refer to Figure 5, in an optionally exemplary embodiment, the microelectrode array further includes a plurality of capacitances 133 arranged in an array. The capacitances 133 are wrapped in an insulating medium 111. The capacitances 133 are connected to the acquisition electrode contacts 1131 through wires 112, and the capacitances 133 are also used to connect to an external signal processing chip. It should also be noted that in the present disclosure, the insulating medium 111 wrapping the wires 112 and the insulating medium 111 wrapping the capacitances 133 are made of the same material, but the structural shapes of the insulating medium 111 wrapping the capacitances 133 and the insulating medium 111 wrapping the wires 112 are not the same, and it adopts a plate-like structure. This facilitates the centralized setting of the plurality of capacitances 133 arranged in an array therein. The present disclosure centrally arranges the large-area capacitances 133 required for processing neuron pulse signals in the insulating medium 111, thereby saving the layout area of the signal processing chip, enabling more sampling channels of neuron pulse signals to be processed on the same-sized chip, and further improving the communication rate of the brain-computer interface system.

[0084] Figure 6 is Figure 5 in the A-A ’ cross-sectional view of, Figure 9 is Figure 8 in the C-C ’ cross-sectional view of, please refer to Figure 6 and Figure 9 , the capacitance 133, uses a capacitance array to replace the large-area MIM DC-blocking capacitance 133 in the signal processing end low-noise amplifier, thereby saving the layout area of the signal processing chip, enabling more sampling channels of neuron pulse signals to be processed on the same-sized chip. Exemplarily, the capacitance 133 is a parallel plate capacitor. The parallel plate capacitor is composed of two parallel metal conductor plates, separated by a dielectric material in the middle. When there is a certain potential difference between the two plates, an electrostatic field distribution will exist between the plates. There is a uniform electric field distribution in the part between the two plates. Due to the edge effect, the electric field lines at the edge of the capacitor are curved and divergent. It should be noted that the upper plate of the capacitor can be used as the connection contact, thereby saving the manufacturing process. It can be understood that the specific form of the capacitance 133 is not limited here. In other specific embodiments, the capacitance 133 can also be set in other forms according to the specific needs of the user.

[0085] A plurality of capacitors 133 arranged in an array are disposed within an insulating dielectric 111. The plurality of capacitors 133 form a capacitor array. The capacitor 133 includes a lower electrode 1331, a dielectric layer 1335, and an upper electrode 1333 stacked within the insulating dielectric 111. Exemplarily, in the present embodiment, the materials of the upper electrode 1333 and the lower electrode 1331 are an alloy composed of one or several of gold, silver, platinum, copper, aluminum, and tungsten. Exemplarily, in the present embodiment, the materials of the upper electrode 1333 and the lower electrode 1331 are gold. It can be understood that the specific materials of the upper electrode 1333 and the lower electrode 1331 are not limited herein. In other specific embodiments, the upper electrode 1333 and the lower electrode 1331 can be made of other suitable materials according to user requirements. The material of the intermediate dielectric layer 1335 is silicon dioxide or a high-K dielectric material. Exemplarily, it is hafnium dioxide (HfO2). It can be understood that the specific materials of the upper electrode 1333, the lower electrode 1331, and the dielectric layer 1335 are not limited herein. In other specific embodiments, the upper electrode 1333, the lower electrode 1331, and the dielectric layer 1335 can also be made of other materials according to user requirements.

[0086] In an optionally exemplary embodiment, the wire 112 includes a first wire and a second wire; the lower electrode 1331 is connected to the acquisition electrode contact 1131 through the first wire, and the upper electrode 1333 is used to connect to an external signal processing chip; a stimulation contact 137 is also embedded in the insulating dielectric 111. The stimulation contact 137 is connected to the stimulation electrode contact 1133 through the second wire. The stimulation contact 137 is connected to the external signal processing chip, and the stimulation electrode contact 1133 stimulates the surrounding neurons. With such an arrangement, the upper electrode 1333 of the capacitor 133 is directly connected to the external signal processing chip, eliminating the need to separately fabricate connection contacts and saving the manufacturing process.

[0087] Figure 2 For Figure 1 the enlarged view at I, please refer to Figure 2 In an optionally exemplary embodiment, the wire 112 includes a first wire and a second wire; the lower electrode 1331 is connected to the acquisition electrode contact 1131 through the first wire; a connection contact 135 connected to the upper electrode is also embedded in the insulating dielectric 111. The connection contact 135 is used to connect to an external signal processing chip; a stimulation contact 137 is also embedded in the insulating dielectric 111. The second wire connects the stimulation contact 137. The stimulation contact 137 is connected to the external signal processing chip, and the stimulation electrode contact 1133 stimulates the surrounding neurons.

[0088] It should be noted that the connection contact 135 is used to connect the flexible microelectrode array to the signal processing module. Exemplarily, the connection contact 135 is connected to the upper plate 1333 of the capacitor 133 and is connected to an external dedicated signal processing chip through flip chip soldering.

[0089] The stimulation contact 137. It should be noted that the stimulation contact 137 is arranged at an interval from the capacitor 133. And it is wrapped in the insulating medium 111. The connection contact 135 is connected to the upper plate 1333 of the capacitor 133. The capacitor 133 is connected to the acquisition electrode contact 1131 through the wire 112, and then the neuron signals are acquired through the acquisition electrode contact 1131. And are transmitted to the connection contact 135 through the first wire and the capacitor 133, and then transmitted to the external signal processing chip. The stimulation contact 137 is wrapped in the insulating medium 111 and is connected to the stimulation electrode contact 1133 through the second wire. Through the stimulation contact 137, the second wire transmits stimulation signals to the stimulation electrode contact 1133 and is used to stimulate the surrounding neurons. Since a bidirectional real-time brain-computer interface needs to be able to stimulate the surrounding neurons to generate action potentials while acquiring neuron pulse signals, the stimulation contact 137 for electrical stimulation is provided beside the capacitor 133. The stimulation contact 137 is directly connected to the wire 112 to stimulate the neurons in the target biological tissue to generate action potentials through a charge-balanced current waveform.

[0090] Figure 8 This is a partial structural schematic diagram with a stimulation contact in the embodiment of the present disclosure. Please refer to Figure 8 , in an optional example, the area of the capacitor array composed of multiple capacitors 133 is 5500 square micrometers, providing an input capacitance 133 of approximately 16 pF. The capacitor arrays are spaced 100 micrometers apart from each other, and a single column contains 20 independent parallel plate capacitors 133, corresponding to 20 sampling contacts of a single microfilament electrode. It can be understood that the overall area of the capacitor array is not limited here, nor is the spacing dimension between the capacitors 133 from each other. In other specific embodiments, according to the specific needs of the user, the specific dimensions of the capacitor array and the spacing between the capacitors 133 from each other can be set to other appropriate dimensions.

[0091] Figures 10 to 20 A preparation method of a microelectrode array provided by the present disclosure will be schematically introduced below in conjunction with the attached Figures 10 to 20 drawings.

[0092] S101: A silicon dioxide thin film 151, a sacrificial layer 152, a bottom insulating layer 153, and a patterned metal layer are sequentially grown on the substrate 15, wherein the patterned metal layer includes the wire 112 and the lower plate 1331 of the capacitor 133.

[0093] Figure 10Schematically shows the substrate 15 and the silicon dioxide thin film 151 grown on the substrate 15. During preparation, a silicon substrate or the like can be placed in an oxidation furnace for oxidation to form the silicon dioxide thin film 151 on the surface of the silicon substrate.

[0094] Optionally, the surface of the wafer can be cleaned before placing the wafer in the thermal oxidation furnace to remove impurities on the surface of the wafer. Of course, in some other examples, the silicon dioxide thin film 151 can also be formed on the surface of the sapphire substrate by physical or chemical means.

[0095] It should be noted that in order for the lithography machine to align better, the silicon dioxide thin film 151 can also be patterned to form an alignment mark for the lithography machine to align. For example, during preparation, a layer of photoresist is first spin-coated on the surface of the silicon dioxide thin film 151; then pre-baking is carried out to volatilize the organic solvent in the photoresist and cure the photoresist; then a step-and-repeat lithography machine is used to expose and develop the wafer, and the developed photoresist is rinsed with a solvent and hard-baked to strengthen the etching resistance of the photoresist; finally, a reactive ion is used to etch an alignment pattern on the wafer so that the subsequent lithography machine can align through this alignment pattern.

[0096] Figure 11 Schematically shows a structure in which a sacrificial layer 152 is grown on the surface of the silicon dioxide thin film 151. The sacrificial layer can be a nickel sacrificial layer, which can be formed on the surface of the silicon dioxide thin film by vapor phase or chemical physical deposition. It should be noted that this sacrificial layer will be stripped in subsequent processes to form the final electrode array product.

[0097] Figure 12 Schematically shows a structure in which a bottom insulating layer 153 is grown on the surface of the sacrificial layer 152. The material of the bottom insulating layer 153 can be one or several of parylene, epoxy resin, acrylate, polyimide. During preparation, a layer of the bottom insulating layer 153 can be spin-coated on the sacrificial layer 152, and then pre-baked to volatilize the organic solvent in the bottom insulating layer 153; finally, hard baking is carried out using a hot plate to further cure the bottom insulating layer 153.

[0098] Figure 13Schematically shows a structure in which a patterned metal layer is grown on the surface of the underlying insulating layer 153, and the patterned metal layer includes a wire 112 for forming a microfilament electrode. The material of the patterned metal layer can be one or several alloys composed of gold, silver, copper, platinum, aluminum, tungsten, etc. During preparation, a layer of lift-off glue can be spin-coated on the underlying insulating layer 153 first; then, a first layer of photoresist is spin-coated on the surface of the lift-off glue; next, pre-baking is carried out to volatilize the organic solvent in the first layer of photoresist; then, exposure is carried out using a stepper, followed by post-baking and development to obtain an undercut structure, and then rinsing and residue removal of the photoresist are carried out; next, a metal film is deposited by electron beam evaporation; then, the metal film is stripped using a stripping solution to obtain a patterned metal layer; finally, the remaining photoresist is removed.

[0099] It should be noted that other methods can also be used to prepare the patterned metal layer. For example, first, a metal layer is evaporated on the underlying insulating layer, and then mask etching is carried out to form a patterned metal layer.

[0100] S102: The middle insulating layer 157 and the top insulating layer 162 are sequentially grown on the patterned metal layer and the underlying insulating layer 153.

[0101] Figure 14 Schematically shows a structure in which when the patterned metal layer only includes the wire 112, the middle insulating layer 157 and the top insulating layer 162 are sequentially grown on the patterned metal layer and the underlying insulating layer 153.

[0102] The material of the middle insulating layer can be one or several of parylene, epoxy resin, acrylate, polyimide, etc. During preparation, a layer of the middle insulating layer 157 can be spin-coated on the surface of the wire 112 and the underlying insulating layer 153 first, then pre-baking is carried out to volatilize the organic solvent in the middle insulating layer 157, and then hard-baking is carried out to further cure the middle insulating layer 157.

[0103] Similarly, the top insulating layer 162 can be fabricated on the middle insulating layer 157. Among them, the material of the top insulating layer 162 can be the same as or different from that of the middle insulating layer 157. For example, the material of the top insulating layer 162 is parylene and the middle insulating layer 157 is epoxy resin.

[0104] Figure 15 Schematically shows a structure when the patterned metal layer includes the wire 112 and the lower plate 1331 of the capacitor 133.

[0105] Figure 16It is illustrated that a patterned metal layer includes a conductive line 112 and a middle insulating layer 157 is spin-coated on the lower plate 1331 of the capacitor 133. After spin-coating the middle insulating layer 157, pre-baking is performed to volatilize the organic solvents in the middle insulating layer 157, and then hard-baking is carried out to further cure the middle insulating layer 157; next, the middle insulating layer 157 on the lower plate 1331 is removed. For example, the middle insulating layer 157 on the lower plate 1331 can be removed by etching or by planarization. Figure 17 It shows the structure after removing the middle insulating layer 157 on the lower plate 1331.

[0106] Specifically, when removing the middle insulating layer 157 on the lower plate 1331 by etching, a layer of photoresist can be spin-coated on the middle insulating layer 157 first; then pre-baking is carried out to volatilize the organic solvents in the photoresist, so as to cure the photoresist; then a stepper is used for exposure and development, and the developed photoresist is rinsed with a solvent; then hard baking is carried out to enhance the etching resistance of the photoresist; finally, the middle insulating layer 157 above the lower plate 1331 is removed by reactive ion etching to expose the lower plate 1331. Of course, the middle insulating layer 157 on the lower plate 1331 can also be removed by planarization methods such as chemical mechanical polishing to expose the lower plate 1331.

[0107] Next, a silicon dioxide thin film is grown as the dielectric layer 1335 of the capacitor on the lower plate 1331 and the middle insulating layer covering the conductive line by plasma enhanced chemical vapor deposition (PECVD).

[0108] Subsequently, a metal layer is grown on the dielectric layer 1335 by electron beam evaporation; then, a layer of photoresist is spin-coated on the metal layer; then pre-baking is carried out to volatilize the organic solvents in the photoresist, so as to cure the photoresist; then a stepper is used for exposure and development, and the developed photoresist is rinsed with a solvent, and then hard baking is carried out to enhance the etching resistance of the photoresist; next, dry etching is used to remove the metal layer above the middle insulating layer and the dielectric layer 1335.

[0109] Finally, a top insulating layer 162 is spin-coated on the upper plate 1333 and the middle insulating layer, and then pre-baking is carried out to volatilize the organic solvents in the top insulating layer 162, and then hard baking is carried out to further cure the top insulating layer 162, as Figure 18 shown.

[0110] It should be noted that in some other examples, when the upper electrode plate 1333 is directly connected to an external signal processing chip, a top insulating layer 162 can be spin-coated only on the middle insulating layer 157 and the upper electrode plate 1333, and then the top insulating layer 162 on the upper electrode plate 1333 can be removed so that the upper electrode plate 1333 protrudes from the top insulating layer 162 or is flush with the surface of the top insulating layer 162. As mentioned above, the top insulating layer 162 on the upper electrode plate 1333 can be removed by etching or planarization.

[0111] In some examples, the patterned metal layer includes a plurality of wires 112 and a plurality of capacitors 133 arranged in an array, and the lower electrode plate 1331 of each capacitor 133 is connected to a wire 112.

[0112] S103: Form an electrode contact 113 that penetrates the top insulating layer 162 and the middle insulating layer 157 and is connected to the wire 112.

[0113] During preparation, a layer of photoresist can be spin-coated on the top insulating layer 162 first; then pre-baked to volatilize the organic solvent in the photoresist, so that the photoresist is cured; then exposed and developed using a stepper, and the developed photoresist is rinsed with a solvent, and then hard-baked to enhance the etching resistance of the photoresist; then the top insulating layer 162 and the middle insulating layer 157 are etched by reactive ion etching to form a first through hole exposing the wire; then the photoresist is decomposed by oxygen plasma and wet-cleaned to remove the photoresist; next, the first through hole is filled by electron beam evaporation; finally, planarization is performed to remove the metal on the surface of the top insulating layer 162 to form the electrode contact 113. Figure 19 Schematically shows the structure with the electrode contact 113 formed.

[0114] Exemplarily, in combination with Figure 19 and Figure 20 , when etching the first through hole exposing the wire, at least one first through hole is provided in the wire connected to the lower electrode plate 1331; at least one first through hole is provided at each end of the wire not connected to the lower electrode plate 1331. After depositing metal in the first through hole, the electrode contact formed by the first through hole connected to the lower electrode plate 1331 is called the acquisition electrode contact 113, and the electrode contacts formed by the first through holes at both ends of the wire not connected to the lower electrode plate 1331 are called the stimulation contact 137 and the stimulation electrode contact 113 respectively.

[0115] It should be pointed out that as Figure 20As shown, when the patterned metal layer includes a capacitor and the upper electrode 1333 in the capacitor is covered with the top insulating layer 162, a connection contact 135 that penetrates the top insulating layer 162 and is connected to the upper electrode 1333 can also be formed by the method of forming the electrode contact 113 as described above for etching. Specifically, a second via 165 that penetrates the top insulating layer 162 and reaches the upper electrode 1333 is formed by etching, and metal is deposited in the second via 165 to form the connection contact 135.

[0116] It should be understood that when multiple capacitances arranged in an array, multiple wires, and multiple contacts need to be arranged on the wires need to be encapsulated in the insulating medium, these first vias 164 and second vias 165 can be fabricated simultaneously or sequentially, so as to obtain the required number of acquisition electrode contacts 113, stimulation contacts 137, stimulation electrode contacts 113, and connection contacts 135.

[0117] Finally, after forming the acquisition electrode contacts 113, stimulation contacts 137, stimulation electrode contacts 113, and connection contacts 135, the metal remaining on the surface is removed by chemical mechanical polishing.

[0118] S104: Perform mask etching according to the contour of the microelectrode array.

[0119] Exemplarily, the structure formed with the above electrode contacts 113 and / or connection contacts 135 is cleaned, and then a hard mask layer is deposited by PECVD; PECVD (Plasma Enhanced Chemical Vapor Deposition) refers to plasma-enhanced chemical vapor deposition. There are many advantages to using this method, such as good film formation quality. Then a layer of photoresist is spin-coated and pre-baked to volatilize the organic solvent in the photoresist, thereby curing the photoresist; then a step-and-repeat lithography machine is used for exposure and development, and then the developed photoresist is rinsed with a solvent; next, dry etching is performed using the hard mask layer, and the etching stops at the sacrificial layer 152 to form the contour of the microelectrode array; finally, the photoresist is removed.

[0120] S105: Peel the sacrificial layer 152, the silicon dioxide thin film 151, and the substrate 15 from the bottom insulating layer 153 to form a microelectrode array, wherein the side surface of the insulating medium 111 that wraps the wire 112 in the microelectrode array has a protrusion 114, and the protrusion 114 is inclined to the extending direction of the insulating medium 111 that wraps the wire 112. Exemplarily, a solution of 40% FeCl3: 39% HCl: H2O of 1:1:20 is used for peeling to obtain the microelectrode array.

[0121] It should be noted that the above text illustrates a solution where the patterned metal layer includes a wire and the lower plate of a capacitor. However, in other examples, the patterned metal layer can also include only the wire or only the lower plate of the capacitor. During fabrication, only minor adjustments to the above preparation method are required.

[0122] Please refer to Figure 5 , this disclosure also provides a microelectrode array, which is different from the microelectrode array in Embodiment 1. In this embodiment, the microelectrode array includes an electrode substrate 13 for connecting to an external signal processing chip; the electrode substrate 13 includes an insulating medium 111 and a capacitor 133, at least a part of the capacitor 133 is wrapped within the insulating medium 111, and the capacitor 133 is used for connecting to the flexible microfilament electrode 11 and to the external signal processing chip.

[0123] It should be noted that the insulating medium 111 wrapping the capacitor 133 has a plate-like structure, which facilitates concentrating the capacitances 133 arranged in an array within the plate-like structure. Furthermore, the large-area capacitor 133 required for processing neuron pulse signals is arranged within the insulating medium 111 having a plate-like structure, thereby saving the layout area of the signal processing chip and enabling more sampling channels of neuron pulse signals to be processed on a chip of the same size. The insulating medium 111 wrapping the capacitor 133 is composed of one or several thin film materials such as polyimide, parylene, epoxy resin, and acrylate.

[0124] Please refer to Figure 6 , the capacitor 133, the capacitor 133 includes a lower plate 1331, a dielectric layer 1335, and an upper plate 1333 which are stacked; the lower plate is used for connecting to the flexible microfilament electrode 11; the upper plate 1333 is exposed outside the insulating medium 111 and is used for connecting to the external signal processing chip; alternatively, the upper plate 1333 is wrapped within the insulating medium 111 and is connected to a connection contact 135 embedded within the insulating medium 111, and the connection contact 135 is used for connecting to the external signal processing chip.

[0125] Figure 9 For Figure 8 the cross-sectional view along C-C ’ ; Please refer to Figure 9 Combined with the figure, a stimulation contact 137 is also embedded within the insulating medium 111 wrapping the capacitor 133. The stimulation contact 137 is spaced apart from the upper plate 1333, and the stimulation contact 137 is used for stimulating surrounding neurons; the flexible microfilament electrode 11 includes a first wire connected to the lower plate 1331 and a second wire connected to the stimulation contact 137. Exemplarily, multiple capacitors 133 arranged in an array are wrapped within the insulating medium 111.

[0126] Exemplarily, in this embodiment, the electrode substrate 13 includes a support layer for enhancing the overall strength of the substrate 131. The support layer can be made of one or several materials among parylene, epoxy resin, acrylate, and polyimide.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them; although the present disclosure has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present disclosure.

[0128] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

Claims

1. A microelectrode array, characterized in that, The microelectrode array includes a plurality of flexible microfilament electrodes arranged in an array for collecting nerve signals; The flexible microfilament electrode includes an insulating medium, a wire, an electrode contact, and a protrusion; The insulating medium wraps the wire, and protrusions are formed on the side surface of the insulating medium, and the protrusions are inclined in a direction away from the extending direction of the insulating medium; The electrode contact is embedded in the insulating medium and connected to the wire, and at least a part of it is exposed outside the insulating medium; A plurality of electrode contacts are provided on the insulating medium, and a part of the plurality of electrode contacts are acquisition electrode contacts for collecting nerve signals, and another part of the electrode contacts are stimulation electrode contacts for stimulating nerve cells; Each of the acquisition electrode contacts is arranged at intervals along the extending direction of the insulating medium on the first side of the insulating medium, and each of the stimulation electrode contacts is arranged at intervals along the extending direction of the insulating medium on the second side of the insulating medium, and the second side is opposite to the first side; and along the extending direction of the insulating medium, each of the acquisition electrode contacts and each of the stimulation electrode contacts are arranged in an alternating manner; Protrusions are provided on the opposite sides of the acquisition electrode contact and the stimulation electrode contact; 2. The microelectrode array according to claim 1, characterized in that, A plurality of spaced protrusions are formed on the side surface of the insulating medium; 3. The microelectrode array according to claim 1, wherein The plurality of protrusions are respectively provided on two opposite side surfaces of the insulating medium; 4. The microelectrode array according to claim 1, characterized in that, The acquisition electrode contact and / or the stimulation contact are also inclined in a direction away from the extending direction of the insulating medium; 5. The microelectrode array according to claim 4, wherein, The angles between the acquisition electrode contact and the insulating medium, the angles between the stimulation electrode contact and the insulating medium, and the angles between the protrusions and the insulating medium are all equal; 6. The microelectrode array according to any one of claims 1-5, characterized in that, The insulating medium is a flexible dielectric material, and the insulating medium is a biocompatible insulating layer composed of one or several thin film materials such as parylene, epoxy resin, acrylate, and polyimide; 7. The microelectrode array according to any one of claims 1-5, characterized in that, A circular ring structure or a hook-like structure is provided at the implantation end of the insulating medium, and the circular ring structure or the hook-like structure is used to implant the flexible microfilament electrode into biological tissue; 8. The microelectrode array according to any one of claims 1-5, characterized in that, The microelectrode array further includes a plurality of capacitances arranged in an array, the capacitances are wrapped in the insulating medium, the capacitances are connected to the acquisition electrode contacts through the wires, and the capacitances are also used to be connected to an external signal processing chip; 9. The microelectrode array according to claim 8, wherein The wire includes a first wire and a second wire; The capacitance includes a lower electrode plate, a dielectric layer, and an upper electrode plate stacked in the insulating medium, the lower electrode plate is connected to the acquisition electrode contact through the first wire, and the upper electrode plate is used to be connected to an external signal processing chip; A stimulation contact is also embedded in the insulating medium, the stimulation contact is connected to the stimulation electrode contact through the second wire, and the stimulation contact is connected to an external signal processing chip, so that the stimulation electrode contact stimulates surrounding neurons; 10. The microelectrode array according to claim 8, characterized in that, The wire includes a first wire and a second wire; The capacitance includes a lower electrode plate, a dielectric layer, and an upper electrode plate stacked in the insulating medium, and the lower electrode plate is connected to the acquisition electrode contact through the first wire; A connection contact connected to the upper electrode plate is also embedded in the insulating medium, and the connection contact is used to connect to an external signal processing chip; A stimulation contact is also embedded in the insulating medium, the second wire is connected to the stimulation contact, the stimulation contact is connected to an external signal processing chip, and the stimulation electrode contact stimulates surrounding neurons.

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