Microwire electrode structure, its preparation method and its implantation method

Abstract

This application discloses a microfilament electrode structure, its fabrication method, and its implantation method. The microfilament electrode structure includes: a substrate having a microfilament region and a bonding region; multiple electrode filament layers, each layer comprising multiple microfilament structures located on the microfilament region and a limiting structure, each microfilament structure having an electrode site on one side surface; any adjacent electrode filament layers being connected in the bonding region and relatively independent in the microfilament region; the limiting structure being fixed to one side surface of the microfilament structure; and bonding pads located in the bonding region and electrically connected to the electrode sites one-to-one. This microfilament electrode structure solves the problems of folding and breakage risks and low wafer area utilization in planar microfilament electrode structures of related technologies during implantation.

Description

Technical Field

[0001] This application relates to the field of electrode technology, and more specifically, to a microwire electrode structure, its preparation method, and its implantation method. Background Technology

[0002] In the field of existing microfilament electrode technology, microfilament electrode structures are widely used as important tools in neuroscience and biomedical engineering for recording nerve signals and stimulating neurons. Currently, common microfilament electrode structure designs typically arrange all electrode wires on the same plane. While this layout is simple and straightforward, it faces a series of challenges in practical applications.

[0003] First, when it is necessary to implant a dense array of electrodes within a limited area, such as implanting 3×4, 4×4, or more electrode wires within a 3×3cm area, traditional planar layouts often require additional twisting or folding of the electrode wires to precisely locate the target implantation site. However, the diameter of microfilament electrode structures is typically only a few micrometers to tens of micrometers, and their materials are relatively fragile. This makes the twisting and folding process extremely prone to causing electrode wire breakage, increasing surgical risks and operational difficulty.

[0004] Secondly, planar microfilament electrode structures occupy a significant amount of wafer area during manufacturing. Since microfilament electrode structures are typically manufactured on wafers, the number of electrodes that can be fabricated per unit area directly impacts wafer yield and cost. The excessive area occupied by planar microfilament regions leads to low wafer utilization, thereby increasing the overall production cost of microfilament electrode structures.

[0005] With the development of neural interface technology, a single microfilament electrode structure needs to accommodate more electrode sites to achieve more precise neural signal acquisition and stimulation. How to safely and efficiently implant multiple layers of electrode wires within a limited space, while ensuring the relative independence and non-interference between each layer, has become a problem that current technologies struggle to solve. Summary of the Invention

[0006] This application provides a microfilament electrode structure, its preparation method, and its implantation method to solve the problems of folding and breakage risk and low effective utilization of wafer area in the implantation process of planar microfilament electrode structures in related technologies.

[0007] According to one aspect of this application, a microfilament electrode structure is provided, comprising: a substrate having a microfilament region and a bonding region; a multilayer electrode filament layer, each of the electrode filament layers comprising multiple microfilament structures and a limiting structure located on the microfilament region, each microfilament structure having an electrode site on one side surface, any adjacent electrode filament layers being connected on the bonding region and relatively independent on the microfilament region, the limiting structure being fixed to one side surface of the microfilament structure; and a bonding pad located on the bonding region and electrically connected to each of the electrode sites.

[0008] Optionally, the microfilament electrode structure has a first state and a second state, wherein: when the microfilament electrode structure has the first state, each layer of the electrode filament extends along the same horizontal direction; when the microfilament electrode structure has the second state, at least one layer of the electrode filament is in a bent state under the action of the limiting structure.

[0009] Optionally, the limiting structure has a first hollow portion, and the limiting structure is fixed to the side surface of the microfilament structure having the electrode sites. The first hollow portion corresponds one-to-one with the electrode sites, and exposes the electrode sites.

[0010] Optionally, the limiting structure is fixed to one side surface of the microfilament structure by intermolecular forces or van der Waals forces.

[0011] Optionally, the limiting structure comprises a biocompatible organic flexible material.

[0012] Optionally, the plurality of electrode wire layers have a stepped structure on the welding area. The stepped structure has a plurality of stepped surfaces that correspond one-to-one with the plurality of electrode wire layers. The pads are located on the stepped surfaces, and the pads corresponding to the same stepped surface are electrically connected to the electrode sites in the electrode wire layers one-to-one.

[0013] Optionally, the microfilament structure includes a first flexible layer and a second flexible layer, the second flexible layer covers a portion of the first surface of the first flexible layer and has a second hollow portion, the electrode sites are correspondingly covered on the first surface in the second hollow portion, the first surface has the stepped surface in the welding area, and the limiting structure is fixed on a portion of the second surface of the second flexible layer.

[0014] Optionally, the electrode wire layer may further include a surface modification layer located on the surface of the electrode site.

[0015] According to another aspect of this application, a method for fabricating the above-mentioned microfilament electrode structure is provided, comprising: step S10, providing a substrate having a microfilament region and a bonding region; step S20, disposing a flexible layer and a bonding pad on one side of the substrate, the flexible layer having multiple microfilament structures located on the microfilament region, each microfilament structure having an electrode site on one side surface, the bonding pad being located on the bonding region and corresponding one-to-one with the electrode site; step S30, fixing a limiting structure on the microfilament structure, the limiting structure and the microfilament structure forming an electrode filament layer; and step S40, repeating step S20 and step S30 at least once to obtain multiple layers of the electrode filament layer.

[0016] Optionally, the flexible layer includes a first flexible layer and a second flexible layer. Step S20 includes: setting the first flexible layer on the substrate, wherein the first flexible layer set for the first time is in contact with the substrate, the first flexible layer set for the nth time is in contact with the second flexible layer set for the (n-1)th time, and n>1; setting the electrode sites and the pads on a first surface of the first flexible layer; covering a portion of the first surface with the second flexible layer, the second flexible layer having a second cutout and a third cutout, the first surface having a stepped surface located in the third cutout, the electrode sites being located one-to-one in the second cutout, and the pads being located one-to-one in the third cutout; and in step S30, fixing the limiting structure on a portion of the second surface of the second flexible layer.

[0017] Optionally, step S30 executed for the (n-1)th time includes: fixing a limiting structure on the microfilament structure; covering the surface of the electrode wire layer located in the microfilament region with a sacrificial layer; in step S20 executed for the nth time, providing the flexible layer on the surface of the electrode wire layer located in the welding region and the surface of the sacrificial layer, where n > 1; after the last execution of step S30, the preparation method further includes: removing the sacrificial layer so that any adjacent electrode wire layers are connected in the welding region and relatively independent in the microfilament region.

[0018] Optionally, before step S30, the fabrication method further includes: a preset region via in the flexible layer, wherein the preset region is a region in the flexible layer located on the side of the electrode site away from the pad; and after step S40, the via in each electrode wire layer is formed in one step.

[0019] According to another aspect of this application, a method for implanting a microfilament electrode structure is also provided, comprising the following steps: providing the microfilament electrode structure, wherein each electrode filament layer in the microfilament electrode structure includes multiple microfilament structures and a limiting structure; causing the limiting structure to cause at least one layer of the electrode filament layer to be in a bent state, and implanting an electrode site in at least one microfilament structure in the target electrode filament layer into a target object, wherein the target electrode filament layer is the electrode filament layer outside the bent state.

[0020] This application discloses a microfilament electrode structure employing multiple electrode filament layers. Each electrode filament layer includes multiple microfilament structures and a limiting structure located on the microfilament region. Any adjacent electrode filament layers are connected in the welding area but relatively independent in the microfilament region. The introduction of the limiting structure allows the microfilament structure to remain stable and orderly within a specific area, preventing accidental movement or damage to the microfilament structure when processing other layers. When implanting a certain layer of microfilament structure, the microfilament structures of other layers can be gently flipped to one side with the support of the limiting structure, thus not hindering the implantation of the current layer. This ensures that multiple layers of microfilament structures can be implanted sequentially without increasing the difficulty of operation or causing damage due to their mutual presence. Specifically, the electrode filament layers with limiting structures ensure the independence and safety of each microfilament structure during implantation. Even with multiple layers stacked together, it ensures that the operation of each layer does not affect other layers, thus avoiding mutual interference and unnecessary stress. This significantly reduces the risk of microfilament structure folding and breakage, improving the efficiency and success rate of the implantation process. Furthermore, by vertically stacking multiple microfilament structures, the area occupied by the electrodes on the wafer is greatly reduced. Traditional single-layer electrode arrays occupy a large planar space due to the limited number of microfilament structures, limiting the electrode density and yield on the wafer. In contrast, multi-layer microfilament structures can provide more microfilament structures within the same wafer area, increasing electrode density and thus increasing the number of electrodes that can be produced per wafer. Therefore, the aforementioned microfilament electrode structure solves the problems of folding and breakage risk and low wafer area utilization in planar microfilament electrode structures in related technologies during implantation. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a three-dimensional structural schematic diagram of a microwire electrode structure provided according to an embodiment of this application;

[0023] Figure 2 yes Figure 1 The diagram shows a three-dimensional structural schematic of the microfilament electrode structure in the microfilament region.

[0024] Figure 3 This is a process flow diagram of a method for preparing a microwire electrode structure according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the substrate structure after a first flexible layer, electrode sites, and pads are formed on a substrate in a method for fabricating a microwire electrode structure provided in this application embodiment.

[0026] Figure 5 Is Figure 4 A schematic diagram of the structure of the substrate after a second flexible layer is covered on a portion of the first surface is shown.

[0027] Figure 6 Is Figure 5 The diagram shows a structural schematic of the substrate after the limiting structure is fixed on a portion of the second surface of the second flexible layer.

[0028] Figure 7 Is Figure 6 The diagram shows the structure of the substrate after the surface of the electrode wire layer located on the microfilament region is covered with a sacrificial layer;

[0029] Figure 8 It is to combine the first flexible layer with Figure 7 The diagram shows the structure of the substrate after the target second flexible layer is placed in contact with the welding area.

[0030] Figure 9 Is Figure 8 The diagram shows the structure of the substrate after the flexible layer, pads and limiting structure are repeatedly applied to the substrate.

[0031] Figure 10 It is to remove Figure 9 The diagram shows the structure of the substrate after the sacrificial layer.

[0032] The above figures include the following reference numerals:

[0033] 20. Pad; 100. Limiting structure; 101. Electrode wire layer; 102. First hollow part; 110. Microfilament structure; 111. Electrode site; 112. Through hole; 301. Substrate; 302. First flexible layer; 303. Second flexible layer; 304. Sacrificial layer. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] As described in the background section, with the development of neural interface technology, a single microfilament electrode structure needs to accommodate more electrode sites to achieve more precise neural signal acquisition and stimulation. How to safely and efficiently implant multiple layers of electrode wires within a limited space, while ensuring the relative independence and non-interference between each layer, has become a problem that existing technologies struggle to solve. To address the above technical problems, embodiments of this application provide a microfilament electrode structure and its fabrication method.

[0038] According to embodiments of this application, a microfilament electrode structure is provided, such as... Figure 1 and Figure 2 As shown, the microfilament electrode structure includes:

[0039] The substrate has a bonding region and a microfilament region, wherein the bonding region is the area on the substrate surface used to support the bonding pad 20, and the microfilament region is the area on the substrate surface used to support the electrode filament layer 101.

[0040] The multilayer electrode wire layer 101 includes multiple microwire structures 110 and limiting structures 100 located on the microwire region. Each microwire structure 110 has an electrode site 111 on one side surface. Any adjacent electrode wire layers 101 are connected in the welding area and relatively independent in the microwire region. The limiting structure 100 is fixed on one side surface of the microwire structure 110.

[0041] The pad 20 is located on the soldering area and is electrically connected to the electrode sites 111 in a one-to-one correspondence.

[0042] In the microfilament electrode structure provided in this application embodiment, a multilayer electrode filament layer 101 is adopted. Each electrode filament layer 101 includes multiple microfilament structures 110 located on the microfilament region and a limiting structure 100. Any adjacent electrode filament layers 101 are connected in the welding area and relatively independent in the microfilament region. The introduction of the limiting structure 100 allows the microfilament structure 110 to remain stable and orderly in a specific area, preventing accidental movement or damage to the microfilament structure 110 when processing other layers. When implanting a certain layer of microfilament structure 110, the microfilament structures 110 of other layers can be gently flipped to one side with the support of the limiting structure 100, so as not to hinder the implantation of the current layer, thereby ensuring that the multilayer microfilament structures 110 can be implanted sequentially without increasing the difficulty of operation or causing damage due to their existence.

[0043] Specifically, the microfilament electrode structure has a first state and a second state, wherein: when the microfilament electrode structure has the first state, each electrode filament layer 101 extends along the same horizontal direction; when the microfilament electrode structure has the second state, at least one electrode filament layer 101 is in a bent state under the action of the limiting structure 100.

[0044] Therefore, the electrode filament layer 101 with the limiting structure 100 ensures the independence and safety of each microfilament structure 110 during implantation. Even with multiple layers stacked together, it ensures that the operation of each layer will not affect other layers, thereby avoiding mutual interference and unnecessary stress, significantly reducing the risk of folding and breakage of the microfilament structure 110, and improving the efficiency and success rate of the implantation process. Furthermore, by vertically stacking multiple layers of microfilament structures 110, the area occupied by the electrodes on the wafer is greatly reduced. Traditional single-layer electrode arrays occupy a large planar space due to the limited number of microfilament structures 110, limiting the electrode density and yield on the wafer. In contrast, multiple layers of microfilament structures 110 can provide more microfilament structures 110 within the same wafer area, increasing the electrode density and thus increasing the number of electrodes that can be produced per wafer. Therefore, the above-mentioned microfilament electrode structure solves the problems of folding and breakage risk of microfilament structures 110 during implantation and low effective utilization of wafer area in related technologies.

[0045] Specifically, the substrate of the microfilament electrode structure is typically made of silicon, quartz, ceramic, or other rigid materials. The role of the substrate is to provide stable support and carrier, enabling the microfilament structure to maintain its structural integrity and stability during fabrication, processing, and implantation.

[0046] The substrate has a soldering area and a microfilament area. The soldering area is used to set the part of the microfilament electrode structure that establishes an electrical connection with an external electronic device. This part includes multiple solder pads 20. Each solder pad 20 is used to connect one or more electrode sites 111 in the electrode filament layer 101 through thin metal traces. The microfilament area is used to set the part of the microfilament electrode structure that directly contacts biological tissue. It includes multiple microfilament structures 110. Each microfilament structure 110 is provided with electrode sites 111 for collecting or stimulating nerve signals.

[0047] Specifically, the aforementioned microfilament structure 110 is the core component of the microfilament electrode structure, made of conductive materials and flexible or stretchable insulating materials, such as polyimide, silicone, Parylene, PMMA, SU-8, etc., typically possessing high tensile strength and biocompatibility. The diameter and length of the microfilament structure 110 vary depending on different application requirements, and its surface may undergo special treatments, such as nanostructuring or coating, to enhance interfacial performance with the target object (such as neural tissue). The front end of the microfilament structure 110 serves as the implantation end of the microfilament electrode structure, used for implantation into the target object. For example, the implantation end can be inserted into neural tissue and directly contact bioelectrically active units such as neurons or cells. The implantation end is typically very small, with a diameter possibly on the micrometer scale, to reduce damage to the target object and improve the resolution of signal acquisition. The implantation end includes electrode sites 111, which can be exposed metal regions (such as gold, platinum, iridium, etc.) used to capture neural electrical activity signals or apply stimulation.

[0048] Specifically, the electrode site 111 is the part that directly contacts the target biological tissue (such as brain neurons), and its material directly affects the quality of electrophysiological signal acquisition and stimulation effect. The electrode site 111 is usually made of materials with good biocompatibility and conductivity. Such materials include, but are not limited to: platinum (Pt), iridium (Ir), tungsten (W), gold (Au), platinum-iridium alloys, and graphite. The selection of these materials is based on their stability, low toxicity, and non-degradability in biological environments, thereby ensuring the safety and functional effectiveness of long-term implantation.

[0049] Specifically, the pad 20 in the microfilament electrode structure is a key component, serving as an interface for electrically connecting the microfilament electrode structure to external electronic devices (such as amplifiers, signal processors, or recording devices). The pad 20 is typically made of materials with good biocompatibility and conductivity, such as platinum (Pt), iridium (Ir), tungsten (W), gold (Au), or platinum-iridium alloys. The selection of these materials ensures good conductivity, which is beneficial for the acquisition and transmission of electrophysiological signals.

[0050] Specifically, the electrode sites 111 on each microfilament structure 110 are electrically connected to the pads 20 via metal traces. This connection is typically achieved through fine metal lines, which can be fabricated using processes such as physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplating, transfer printing, or inkjet printing, ensuring the efficiency and accuracy of signal transmission.

[0051] To improve the electrochemical performance of electrode site 111 and enhance its signal acquisition capability and stimulation effect, the surface of electrode site 111 can be specially modified to form a surface modification layer. This surface modification layer can include, but is not limited to, coatings formed from the following materials: iridium oxide (IrOx), titanium nitride (TiN), gold nanoparticles (Au), carbon nanotubes (CNTs), and poly(3,4-ethylenedioxythiophene) (PEDOT). These types of coatings can reduce electrochemical impedance, improve charge injection capability, reduce signal attenuation, and provide a more stable interface, thus reducing damage to biological tissues.

[0052] It should be noted that other embodiments of this application may further improve the electrochemical performance and biocompatibility of the microfilament structure 110 by using other types of surface modification materials, such as biodegradable materials or coatings with specific functions. The embodiments of this application are not specifically limited.

[0053] Specifically, such as Figure 2 As shown, each microfilament structure 110 also has a through-hole 112 (sometimes also called a pinhole), which is located on the side of the electrode site 111 away from the pad 20 and in the region near the tip of the microfilament structure 110. The main function of the through-hole 112 is to provide a guide channel for the auxiliary implantation needle during implantation, ensuring that the microfilament structure 110 can be accurately and non-damagingly implanted into the target biological tissue.

[0054] In some alternative embodiments, the aforementioned restraining structure 100 is fixed to one side surface of the microfilament structure by intermolecular forces or van der Waals forces. In this embodiment, by selecting materials with appropriate intermolecular or van der Waals forces, the restraining structure 100 can be firmly fixed to the microfilament structure 110, while being easily detachable when needed. Intermolecular or van der Waals forces provide a fixation method that does not require chemical bonding, which is particularly important during implantation because it avoids additional damage to the microfilament structure 110 or brain tissue, thereby ensuring the stability of the microfilament structure 110 during implantation. Furthermore, it allows for easy detachment from the restraining structure 100 after implantation without damaging the microfilament structure 110, improving the implantation success rate and the lifespan of the microfilament structure 110.

[0055] In this embodiment, the limiting structure 100 may include a biocompatible organic flexible material. Biocompatible materials can reduce the rejection reaction between the implant and the body, improving the long-term stability and safety of the implant. To generate the required intermolecular forces or van der Waals forces, the aforementioned organic flexible material may include, but is not limited to: polyimide, silicone rubber, parylene, polymethyl methacrylate (PMMA), and SU-8.

[0056] Specifically, the polyimide molecular chain contains polar groups, such as imide rings, which gives the polyimide film surface a certain degree of polarity, enabling it to form a relatively strong bond with the microfilament structure 110 through intermolecular attraction (i.e., van der Waals forces). Silicone rubber is a biocompatible elastomer material with low surface energy, but under appropriate conditions, such as surface modification or pretreatment (e.g., corona treatment), the silicone rubber surface can generate weak polarity, thereby enhancing the intermolecular attraction between it and the microfilament structure 110. Parylene is a polymer thin film material deposited under vacuum conditions. It has extremely high barrier properties and biocompatibility. There are weak van der Waals forces between the Parylene molecular layers, which makes it an effective confinement structure 100 material. It is not likely to cause permanent adhesion of the microfilament structure 110, but can provide the necessary fixation during implantation. PMMA can also be modified by chemical modification or physical treatment (such as plasma treatment) to enhance the intermolecular forces between it and the microfilament structure 110. SU-8 is an epoxy resin photoresist. The polarity of SU-8 can be optimized by formulation adjustment and surface treatment to ensure good bonding between the confinement structure 100 and the microfilament structure 110.

[0057] The aforementioned materials all possess different physical and chemical properties. By precisely controlling these properties, appropriate intermolecular forces or van der Waals forces can be established between the microfilament structure 110 and the limiting structure 100. These forces are sufficient to hold the microfilament structure 110 in its designated position under normal operating conditions, while allowing the microfilament structure 110 to detach smoothly from the limiting structure 100 under slight external forces, thus reducing the complexity and risk of the implantation process. In practical applications, depending on the specific requirements of the electrode and the usage environment, one or more of these materials may be selected or modified. This application does not impose specific limitations on these materials.

[0058] In this embodiment of the application, the aforementioned limiting structure 100 is fixed on any side surface of the microfilament structure 110, for example, as shown below. Figure 1 and Figure 2As shown, the limiting structure 100 can be fixed to the side surface of the microfilament structure 110 with the electrode site 111. Since it is located on the same side of the microfilament structure 110 as the electrode site 111, the limiting structure 100 has a first hollow portion 102 that exposes the electrode site 111. In another example, the limiting structure 100 can also be fixed to the side surface of the microfilament structure 110 opposite to the electrode site 111. This embodiment does not specifically limit the specific application.

[0059] like Figure 1 and Figure 2 As shown, when the limiting structure 100 is fixed on the side surface of the microfilament structure 110 away from the electrode site 111, the limiting structure 100 has a first hollow portion 102. The limiting structure 100 is fixed on the side surface of the microfilament structure 110 with the electrode site 111. The first hollow portion 102 corresponds one-to-one with the electrode site 111, and exposes the electrode site 111.

[0060] It should be noted that in other embodiments of this application, the fixation problem of the microfilament structure 110 during implantation can also be solved by using other types of physical fixation methods, such as micromechanical structures or electrostatic adsorption.

[0061] In some optional embodiments, multiple electrode wire layers have a stepped structure in the welding area. The stepped structure has multiple stepped surfaces corresponding one-to-one with the multiple electrode wire layers. Pads are located on the stepped surfaces, and pads corresponding to the same stepped surface are electrically connected to electrode sites in the electrode wire layers. This embodiment of the application achieves electrical connection and spatial isolation between multiple electrode wire layers by setting a stepped structure in the welding area. The stepped structure design allows pads to correspond to electrode sites, while different stepped surfaces spatially separate the electrode wire layers, avoiding electrical interference between layers. Thus, the stepped structure achieves efficient electrical connection of multiple electrode wire layers while ensuring the independence of each electrode wire layer in the microfilament region, improving the density of implanted microfilament structures and the accuracy of signal acquisition.

[0062] In some alternative embodiments, the microfilament structure 110 includes a first flexible layer and a second flexible layer. The second flexible layer covers a portion of the first surface of the first flexible layer and has a second hollow portion. The electrode sites 111 are correspondingly covered on the first surface in the second hollow portion. The first surface has a stepped surface in the welding area. The limiting structure 100 is fixed to a portion of the second surface of the second flexible layer.

[0063] In the above optional embodiments, by providing a first flexible layer and a second flexible layer in the microfilament structure 110, the arrangement of electrode sites 111 and the fixation of the limiting structure 100 are achieved. The second hollow portion of the second flexible layer ensures that the electrode sites 111 can directly contact brain tissue, while the limiting structure 100, by being fixed to the second surface of the second flexible layer, provides stability for the microfilament structure 110 during implantation. In this embodiment, the layered structure of the first and second flexible layers achieves a high-density arrangement of the microfilament structure 110, while ensuring the stability of the microfilament structure 110 during implantation, thereby improving the implantation success rate and signal acquisition effect.

[0064] According to embodiments of this application, a method for fabricating a microfilament electrode structure is also provided. Figure 3 This is a flowchart based on an embodiment of this application. For example... Figure 3 As shown, the preparation method includes:

[0065] Step S10: Provide a substrate having a bonding region and a microfilament region;

[0066] Step S20: A flexible layer and a pad are disposed on one side of the substrate. The flexible layer has multiple microfilament structures located on the microfilament region. Each microfilament structure has an electrode site on one side surface. The pad is located on the welding area and corresponds one-to-one with the electrode site.

[0067] Step S30: Fix the limiting structure on the microfilament structure, and the limiting structure and the microfilament structure form an electrode wire layer.

[0068] Step S40: Repeat steps S20 and S30 at least once to obtain a multilayer electrode wire layer.

[0069] In the method for preparing the microfilament electrode structure provided in this application embodiment, a multilayer electrode filament layer is formed. Each electrode filament layer includes multiple microfilament structures and a limiting structure located on the microfilament region. Any adjacent electrode filament layers are connected in the welding area and are relatively independent in the microfilament region. The introduction of the limiting structure allows the microfilament structure to remain stable and orderly in a specific area, preventing accidental movement or damage to the microfilament structure when processing other layers. When implanting a certain layer of microfilament structure, the microfilament structures of other layers can be gently flipped to one side with the support of the limiting structure, so as not to hinder the implantation of the current layer. This process does not introduce folding and torsional tearing forces, thereby ensuring that the multilayer microfilament structure can be implanted sequentially without increasing the difficulty of operation or causing damage due to their existence.

[0070] Exemplary embodiments of the fabrication method of the microfilament electrode structure provided in this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0071] First, proceed to step S10: (e.g.) Figure 4 As shown, a substrate 301 is provided, having a welding region A and a microfilament region B.

[0072] In the aforementioned substrate 301, the soldering region A is used to set the part of the microfilament electrode structure that establishes an electrical connection with external electronic devices. This part includes multiple solder pads 20, each solder pad 20 being used to connect one or more electrode sites 111 in the electrode filament layer through thin metal traces. The microfilament region B is used to set the part of the microfilament electrode structure that directly contacts biological tissue. It includes multiple microfilament structures, each microfilament structure having an electrode site 111 for collecting or stimulating nerve signals.

[0073] After the step of providing substrate 301, step S20 is performed: as follows Figure 4 and Figure 5 As shown, a flexible layer and a pad 20 are disposed on one side of the substrate 301. The flexible layer has multiple microfilament structures 110 located on the microfilament region B. Each microfilament structure has an electrode site 111 on one side surface. The pad 20 is located on the welding region A and corresponds one-to-one with the electrode site 111.

[0074] Specifically, on one side of the substrate 301, a flexible material is deposited to form a flexible material layer through spin coating, spraying, or other processes, providing a foundation for the subsequent formation of the microfilament structure. This flexible material (such as polyimide, silicone, Parylene, etc.) has excellent biocompatibility and flexibility, and can withstand deformation during the implantation process without damaging the electrode structure. The flexible layer formed by the above-mentioned flexible material not only provides support for the electrode site 111 and the pad 20, but also protects the electrode site 111 and the pad 20 from the influence of the external environment to a certain extent.

[0075] To form the aforementioned flexible layer, photolithography and patterning processes, such as lift-off, dry etching, wet etching, and laser cutting, can be used to process the flexible material into multiple strands, such as... Figure 2 The microfilament structures 110 shown are located on microfilament region B. For example... Figure 2As shown, the diameter of the microfilament structure 110 is typically very fine to minimize trauma to biological tissue. Each microfilament structure 110 has an electrode site 111 and an exposed area on one side surface. The electrode site 111 is used to contact biological tissue, while the exposed area is used for subsequent fixation and restraint structure 100.

[0076] Multiple pads 20 are set on the welding area A. The pads 20 are typically made of metal materials with good conductivity and biocompatibility, such as platinum (Pt), iridium (Ir), tungsten (W), gold (Au), or platinum-iridium alloys. Each pad 20 is electrically connected to the electrode site 111 in the microfilament area B through metal traces (such as Pt, Ir, W, Au, platinum-iridium alloys, graphite, etc.), ensuring that electrophysiological signals can be transmitted from the electrode site 111 to the pad 20, and then further transmitted to external electronic devices.

[0077] After setting up the microfilament structure 110 and the pads 20, proceed to step S30: as follows Figure 6 As shown, a limiting structure 100 is fixed on the microfilament structure 110, and the limiting structure 100 and the microfilament structure 110 constitute an electrode wire layer. After completing step S20, the basic structure of the electrode wire layer has been formed. The above step S30 is to fix the limiting structure 100 on each microfilament structure 110 to ensure the stability of the microfilament structure 110 during the implantation process.

[0078] In some alternative embodiments, each microfilament structure 110 has an electrode site 111 and an exposed area on one side surface. A limiting structure 100 is fixed on the exposed area to fix the limiting structure 100 to the side surface of the microfilament structure 110 with the electrode site 111. In this case, the limiting structure 100 has a first hollow portion that exposes the electrode site 111.

[0079] It should be noted that, in this embodiment, the limiting structure is not limited to fixing the limiting structure on the side surface of the microfilament structure with the electrode site. The limiting structure can also be fixed on the side surface of the microfilament structure away from the electrode site. In this case, the first hollow part does not need to be provided in the limiting structure. The fixed position of the limiting structure is not specifically limited in this embodiment.

[0080] Specifically, the aforementioned limiting structure 100 is also made of a flexible material with good biocompatibility, such as polyimide, silicone, Parylene, PMMA, SU-8, etc. Through photolithography and patterning, the limiting structure 100 is processed into a specific shape, which may include a first hollow portion. The first hollow portion allows the electrode site 111 to be exposed to facilitate contact with biological tissue, while providing space for the microfilament structure 110 to flip during the implantation process.

[0081] Specifically, the limiting structure 100 covers a portion of the microfilament structure 110 and is fixed to the microfilament structure 110 by intermolecular forces or van der Waals forces. In this way, the limiting structure 100 can not only maintain the stability of the microfilament structure 110, but also allow the microfilament structure 110 to detach from the limiting structure 100 by a slight external force when needed (such as during implantation), reducing the risk of folding and breakage during implantation.

[0082] Through step S30, the combination of the limiting structure 100 and the microfilament structure 110 forms a complete electrode wire layer. This electrode wire layer will become the basis for the subsequent multilayer structure. Then, step S40 is executed, and steps S20 and S30 are repeated at least once to obtain a multilayer electrode wire layer. After each electrode wire layer is completed, steps S20 and S30 can be repeated in a similar process until all the required number of electrode wire layers are prepared.

[0083] In some alternative implementations, such as Figure 4 , Figure 5 , Figure 8 and Figure 9 As shown, the flexible layer includes a first flexible layer 302 and a second flexible layer 303. Step S20 includes: setting the first flexible layer 302 on the substrate 301, wherein the first flexible layer 302 set for the first time covers the substrate 301, and the first flexible layer 302 set for the nth time is in contact with the second flexible layer 303 set for the (n-1)th time on the welding area A, where n>1; setting electrode sites 111 and pads 20 on the first surface of the first flexible layer 302, wherein the electrode sites 111 are located on the microfilament area B, and the pads 20 are located on the welding area A; covering a portion of the first surface with the second flexible layer 303, the second flexible layer 303 having a second hollow portion and a third hollow portion, the first surface having a stepped surface located in the third hollow portion, the electrode sites 111 being located one-to-one in the second hollow portion, and the pads 20 being located one-to-one in the third hollow portion; in step S30, fixing a limiting structure 100 on a portion of the second surface of the second flexible layer 303.

[0084] It should be noted that the second flexible layer 303 can be made of the same material as the first flexible layer 302, but is not limited to the same material.

[0085] For example, the step of forming the first electrode wire layer includes: as Figure 4 As shown, the first flexible layer 302 is disposed in contact with the substrate 301, and electrode sites 111 and pads 20 are disposed on the first surface of the first flexible layer 302; as Figure 5As shown, a second flexible layer 303 covers a portion of the first surface. The second flexible layer 303 has a second hollow portion and a third hollow portion. The first surface has a stepped surface located in the third hollow portion. Electrode sites 111 are located in the second hollow portion, and pads 20 are located in the third hollow portion. Through-holes 112 are located in a predetermined region in the flexible layer. The predetermined region is the area in the flexible layer located on the side of the electrode sites 111 away from the pads 20. Figure 6 As shown, a limiting structure 100 is fixed on a portion of the second surface of the second flexible layer 303.

[0086] Furthermore, after forming the first electrode wire layer, as... Figures 7 to 10 As shown, in step S20 of the second execution, the first flexible layer 302 is brought into contact with the target second flexible layer located on the welding area A. The target second flexible layer is the second flexible layer 303 set in step S20 of the first execution. Electrode sites 111 and pads 20 are set on the first surface of the first flexible layer 302. The second flexible layer 303 is covered on a portion of the first surface. The second flexible layer 303 has a second hollow portion and a third hollow portion. The first surface has a stepped surface located in the third hollow portion. The electrode sites 111 are located in the second hollow portion one by one, and the pads 20 are located in the third hollow portion one by one. A through hole 112 is formed in a preset area in the flexible layer. The preset area is the area in the flexible layer located on the side of the electrode site 111 away from the pad 20. In step S30, a limiting structure 100 is fixed on a portion of the second surface of the second flexible layer 303 to form a second electrode wire layer.

[0087] Then, according to the required number of electrode wire layers, steps S20 and S30 are repeated: the first flexible layer 302 is brought into contact with the previously formed second flexible layer 303 located on the welding area A; electrode sites 111 and pads 20 are provided on the first surface of the first flexible layer 302; the second flexible layer 303 is covered on a portion of the first surface, the second flexible layer 303 having a second cutout and a third cutout, the first surface having a stepped surface located in the third cutout, the electrode sites 111 being located one-to-one in the second cutout, and the pads 20 being located one-to-one in the third cutout; in step S30, a limiting structure 100 is fixed on a portion of the second surface of the second flexible layer 303. If the required number of electrode wire layers is N, the repetition stops when the number of repetitions of steps S20 and S30 reaches N-1, ultimately forming through holes 112 in each electrode wire layer.

[0088] In some alternative implementations, step S30, executed for the (n-1)th time, includes: as follows Figure 6 As shown, a limiting structure 100 is fixed on the microfilament structure 110; as Figure 7As shown, a sacrificial layer 304 is applied to the surface of the electrode wire layer located in the microfilament region B; in step S20 executed for the nth time, as... Figure 8 and Figure 9 As shown, flexible layers (including a first flexible layer 302 and a second flexible layer 303) are disposed on the surface of the electrode wire layer and the surface of the sacrificial layer 304 located in the welding area A, where n > 1. Figure 9 The flexible layer shown also includes a first flexible layer 302 and a second flexible layer 303 formed after the (n+1)th execution of step S20, and Figure 9 The diagram also shows the sacrificial layer 304 formed before the nth execution of step S20. After the last execution of step S30, as shown... Figure 10 As shown, the sacrificial layer 304 is removed so that any adjacent electrode wire layers are connected on the welding area A and relatively independent on the microwire area B.

[0089] In the above optional embodiments, spatial isolation and electrical connection between the electrode wire layers are achieved by covering the surface of the electrode wire layers with a sacrificial layer 304. The sacrificial layer 304 serves as a separator and protector during the fabrication process, and is removed by etching with a specific solution before implantation. This allows the electrode wire layers to be connected in welding area A, while remaining independent in microwire area B, ensuring the electrical connection and spatial isolation of the electrode wires. The sacrificial layer 304 can be made of soluble materials such as Al, Cr, or SiO2.

[0090] It should be noted that in other embodiments, the preparation efficiency and precision of the electrode wire layer, as well as the electrochemical performance and biocompatibility of the electrode wire, can be further improved by using other types of sacrificial materials, such as biodegradable materials.

[0091] The preparation method of the microwire electrode structure described above in this application will be explained below with reference to specific embodiments.

[0092] This embodiment provides a method for fabricating a microwire electrode structure, including the following steps:

[0093] S1: A first flexible layer 302 is fabricated on a substrate 301, and a conductive layer is fabricated on the first flexible layer 302. Electrode sites 111, pads 20, and metal traces connecting the electrode sites 111 and pads 20 are obtained through photolithography and patterning. Figure 4The structure is shown. The substrate 301 is made of at least one of silicon and quartz, and the conductive layer is made of at least one of Pt, Ir, W, Au, platinum-iridium alloy and graphite. The preparation method includes one of the following processes: physical vapor deposition, chemical vapor deposition, electroplating, transfer printing and inkjet printing; the material used for the first flexible layer 302 is at least one of polyimide, silicone, Parylene, PMMA and SU-8, and the preparation method includes one of the following: spin coating and spray coating; the patterning method of the conductive layer includes one of the following: peeling, dry etching, wet etching and laser cutting.

[0094] S2: On the structure obtained in step S1 above, a second flexible layer 303 is prepared to form an insulating separator layer. Holes are then created at the electrode sites 111 and pads 20 through photolithography and patterning to expose them. Simultaneously, a first electrode wire layer is formed for through-holes 112 through which the implantation needle passes, resulting in the structure shown above. Figure 5 The structure shown.

[0095] S3: A limiting flexible layer is fabricated on the second flexible layer 303, and the limiting structure 100 of the first electrode wire is formed by photolithography and patterning, resulting in the following... Figure 6 The structure shown, the limiting structure 100 is made of at least one of polyimide, silicone, Parylene, PMMA and SU-8.

[0096] S4: A sacrificial layer is prepared on the structure obtained in step S3 above, and a sacrificial layer 304 capable of separating each electrode wire layer 101 is formed in the microfilament region B by photolithography and patterning, resulting in the structure shown above. Figure 7 The structure shown has a sacrificial layer made of at least one of Al, Cr and SiO2.

[0097] S5: Repeat steps S1 to S4 to prepare the second electrode wire layer; further repeat steps S1 to S4 to prepare the third top electrode wire layer, as shown below. Figure 9 The structure shown.

[0098] S6: Immerse the structure in a solution capable of corroding and dissolving the sacrificial layer without affecting other materials. The sacrificial layer is then removed by etching, yielding a microwire electrode structure with multiple electrode wire layers, such as... Figure 10 As shown.

[0099] According to an embodiment of this application, a method for implanting a microwire electrode structure is also provided, comprising the following steps:

[0100] The microfilament electrode structure in the above embodiments is provided, wherein each electrode filament layer in the microfilament electrode structure includes multiple microfilament structures and a limiting structure.

[0101] The limiting structure causes at least one layer of electrode wires to be in a bent state, and the electrode site of at least one microfilament in the target electrode wire layer is implanted into the target object, wherein the target electrode wire layer is the electrode wire layer that is not in a bent state.

[0102] The implantation method provided in this application uses a microfilament electrode structure comprising multiple layers of electrode wires. Each layer of electrode wires includes multiple microfilament structures and a limiting structure located on the microfilament region. Any adjacent electrode wire layers are connected in the welding area and are relatively independent in the microfilament region. The introduction of the limiting structure allows the microfilament structure to remain stable and orderly in a specific area, preventing accidental movement or damage to the microfilament structure when processing other layers. When implanting a certain layer of microfilament structure, the microfilament structures of other layers can be gently flipped to one side with the support of the limiting structure, so as not to hinder the implantation of the current layer. This process does not introduce folding, torsional, or tearing forces, thereby ensuring that multiple layers of microfilament structures can be implanted sequentially without increasing the difficulty of operation or causing damage due to their existence.

[0103] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0104] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A microwire electrode structure, characterized in that, include: The substrate has microfilament regions and bonding regions; A multilayer electrode wire layer, each of which includes multiple microfilament structures and a limiting structure located on the microfilament region. Each microfilament structure has an electrode site on one side surface. Any adjacent electrode wire layers are connected on the welding area and are relatively independent on the microfilament region. The limiting structure is fixed on one side surface of the microfilament structure to support the microfilament structures of other layers when one layer of the microfilament structure is implanted, so as to flip it to one side. The solder pads are located on the soldering area and are electrically connected to the electrode sites one by one.

2. The microfilament electrode structure according to claim 1, characterized in that, The microfilament electrode structure has a first state and a second state, wherein: When the microfilament electrode structure is in the first state, each layer of the electrode filament extends along the same horizontal direction. When the microfilament electrode structure is in the second state, at least one layer of the electrode filament is in a bent state under the action of the limiting structure.

3. The microfilament electrode structure according to claim 1, characterized in that, The limiting structure has a first hollow portion, and the limiting structure is fixed to the side surface of the microfilament structure with the electrode sites. The first hollow portion corresponds one-to-one with the electrode sites and exposes the electrode sites.

4. The microfilament electrode structure according to claim 1, characterized in that, The limiting structure is fixed to one side surface of the microfilament structure by intermolecular forces or van der Waals forces.

5. The microfilament electrode structure according to claim 3, characterized in that, The limiting structure comprises a biocompatible organic flexible material.

6. The microfilament electrode structure according to claim 1, characterized in that, The plurality of electrode wire layers have a stepped structure on the welding area. The stepped structure has a plurality of stepped surfaces that correspond one-to-one with the plurality of electrode wire layers. The pads are located on the stepped surfaces, and the pads corresponding to the same stepped surface are electrically connected to the electrode sites in the electrode wire layers one-to-one.

7. The microfilament electrode structure according to claim 6, characterized in that, The microfilament structure includes a first flexible layer and a second flexible layer. The second flexible layer covers a portion of the first surface of the first flexible layer and has a second hollow portion. The electrode sites are correspondingly covered on the first surface in the second hollow portion. The first surface has the stepped surface in the welding area. The limiting structure is fixed on a portion of the second surface of the second flexible layer.

8. The microfilament electrode structure according to any one of claims 1 to 7, characterized in that, The electrode wire layer also includes a surface modification layer located on the surface of the electrode site.

9. A method for preparing a microwire electrode structure according to any one of claims 1 to 8, characterized in that, include: Step S10: Provide a substrate having a microfilament region and a bonding region; Step S20: A flexible layer and a pad are disposed on one side of the substrate. The flexible layer has multiple microfilament structures located on the microfilament region. Each microfilament structure has an electrode site on one side surface. The pad is located on the welding area and corresponds one-to-one with the electrode site. Step S30: Fix a limiting structure on the microfilament structure, wherein the limiting structure and the microfilament structure constitute an electrode wire layer; Step S40: Repeat steps S20 and S30 at least once to obtain multiple layers of the electrode wire.

10. The preparation method according to claim 9, characterized in that, The flexible layer includes a first flexible layer and a second flexible layer, and step S20 includes: A first flexible layer is disposed on the substrate, wherein the first flexible layer disposed for the first time is in contact with the substrate, and the first flexible layer disposed for the nth time is in contact with the second flexible layer disposed for the (n-1)th time, where n>1; The electrode sites and the pads are disposed on the first surface of the first flexible layer; A second flexible layer is covered on a portion of the first surface. The second flexible layer has a second cutout and a third cutout. The first surface has a stepped surface located in the third cutout. The electrode sites are located in the second cutout, and the pads are located in the third cutout. In step S30, the limiting structure is fixed on a portion of the second surface of the second flexible layer.

11. The preparation method according to claim 9, characterized in that, The step S30 executed in the (n-1)th time includes: A limiting structure is fixed on the microfilament structure; A sacrificial layer is covered on the surface of the electrode filament layer located in the microfilament region; In step S20 executed for the nth time, the flexible layer is provided on the surface of the electrode wire layer and the surface of the sacrificial layer located in the welding area, where n > 1; After performing step S30 for the last time, the preparation method further includes removing the sacrificial layer so that any adjacent electrode wire layers are connected on the welding area and relatively independent on the microwire region.

12. The preparation method according to claim 11, characterized in that, Prior to step S30, the preparation method further includes: A through-hole is formed in a predetermined region in the flexible layer, wherein the predetermined region is the area in the flexible layer located on the side of the electrode site away from the pad; After step S40, the through holes in each layer of electrode wires are connected.

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