An integrated electrode feedthrough structure for a brain-computer interface and a method of making the same

Abstract

The application provides an integrated electrode feedthrough structure for a brain-computer interface and a preparation method thereof, comprising an integrally formed electrode array and a pin-surface heterogeneous integrated feedthrough. The integrally formed electrode array comprises an electrode point array, a connecting wire and a plurality of circular ring pads. Two ends of the connecting wire are respectively electrically connected with the electrode point array and the circular ring pads. The pin-surface heterogeneous integrated feedthrough is integrated with a feedthrough substrate, a metal feedthrough pin, a redistribution pad, a redistribution conductive layer and a thermal barrier structure. The redistribution conductive layer and the thermal barrier structure are arranged inside the feedthrough substrate. The metal feedthrough pin is arranged on one side of the feedthrough substrate and is connected with the circular ring pads one by one. The redistribution pad is arranged on the other side of the feedthrough substrate and is electrically connected with the metal feedthrough pin through the redistribution conductive layer. The application can reduce the internal connection level and the packaging volume of the integrated electrode feedthrough structure, improve the space utilization, the overall packaging integration and the long-term implantation reliability of the integrated electrode feedthrough structure.

Description

Technical Field

[0001] This application relates to the field of implantable brain-computer interface technology, specifically to an integrated electrode feedthrough structure for brain-computer interfaces and its fabrication method. Background Technology

[0002] Implantable brain-computer interface systems typically require feedthrough structures to ensure reliable transmission of electrical signals between the inside and outside of a sealed cavity. With the development of neural interfaces, implantable medical electronics, and miniaturized electronic packaging technologies, the number of system channels is constantly increasing, placing higher demands on the interconnect density, space utilization, and long-term reliability of feedthrough structures.

[0003] Current implantable brain-computer interface (BCI) systems widely employ needle-type feedthrough structures to achieve signal transmission within and outside the sealed cavity. The needle-like structure facilitates reliable interconnection using methods such as tubing, wire winding, or direct laser welding. Furthermore, the needle-like structure provides excellent mechanical anchoring during encapsulation with polyurethane, silicone, and other encapsulation materials, exhibiting strong pull-out resistance and long-term connection stability. However, feedthrough pins typically need to penetrate the PCB (Printed Circuit Board) and connect to internal electronic circuits, thus requiring via areas on the PCB. This limits the layout space for peripheral circuits, resulting in low system space utilization. To address these issues, planar feedthrough structures are increasingly being applied to high-density implantable systems. Planar structures can be directly bonded to the PCB or chip, significantly reducing package height and improving space utilization. Additionally, planar pads can form high-density metal bonding areas, facilitating high-channel-count, ultra-fine-pitch signal connections using interconnection processes such as flip-chip packaging. However, planar feedthrough structures also have drawbacks; their connection reliability is highly dependent on mounting accuracy and interface flatness. As the number of channels increases, the pad spacing decreases, placing extremely high demands on the alignment accuracy in the XY directions and the coplanarity in the Z direction of the placement equipment. Even minute height errors can lead to unreliable connections at local solder joints, resulting in problems such as cold solder joints, open circuits, or stress concentrations. Simultaneously, it is difficult to maintain consistent solder volume and solder joint morphology in high-density arrays, easily leading to decreased connection uniformity and affecting stability and reliability in long-term implantation environments. Furthermore, planar pad structures rely primarily on solder connections, and their mechanical anchoring capability is relatively weak, posing a risk of connection failure under long-term mechanical loads.

[0004] A literature search of existing technologies revealed a Chinese invention patent with publication number CN119792809A, which discloses an implantable device and its formation method, a neural signal acquisition device, and a neurostimulator. This patent application proposes an implantable device structure comprising an electrode assembly, a feedthrough assembly, and a packaging shell. The feedthrough assembly includes a ceramic component and a metal component, with multiple conductive posts penetrating the ceramic component to achieve electrical connection between the electrode assembly and the internal circuitry. However, this patent application only optimizes the connection structure between the electrodes and the ceramic feedthrough assembly and the hermetically sealed packaging of the implantable device. Its feedthrough assembly essentially still uses a traditional through-wall interconnection structure of ceramic conductive posts, failing to achieve integrated design of the feedthrough structure and the peripheral circuitry. Furthermore, the electrode assembly in the aforementioned application still uses an independent electrode support plate and a connection point structure, making it difficult to further improve system integration.

[0005] Therefore, there is an urgent need in this field for a novel feedthrough structure and its fabrication method that combines the high reliability of the pin-type feedthrough structure with the high integration of the planar feedthrough structure, thereby solving the technical defects of the existing pin-type feedthrough and planar feedthrough structures. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this application is to provide an integrated electrode feedthrough structure for brain-computer interfaces and its fabrication method.

[0007] According to one aspect of this application, an integrated electrode feedthrough structure for a brain-computer interface is provided, comprising: An integrally molded electrode array includes an electrode point array, connecting wires, and several circular pads, wherein the two ends of the connecting wires are electrically connected to the electrode point array and the circular pads, respectively. The integrated feedthrough with heterogeneous pin surface integrates a feedthrough substrate, metal feedthrough pins, redistribution pads, a redistribution conductive layer, and a thermal barrier structure. The redistribution conductive layer and thermal barrier structure are disposed inside the feedthrough substrate. The metal feedthrough pins are disposed on one side of the feedthrough substrate and are connected to the annular pads one by one. The redistribution pads are disposed on the other side of the feedthrough substrate and are electrically connected to the metal feedthrough pins through the redistribution conductive layer.

[0008] Optionally, the feedthrough substrate is any one of a ceramic feedthrough substrate, a glass feedthrough substrate, and a silicon-based feedthrough substrate; the feedthrough substrate has a conductive path structure inside, the redistribution conductive layer is disposed inside the conductive path structure, the conductive path structure passes through both sides of the feedthrough substrate, so that the two ends of the redistribution conductive layer are respectively connected to the redistribution pad and the metal feedthrough pin.

[0009] Optionally, the integrated heterogeneous feeder also includes a flange, a welding ring, and an insulator. The flange is disposed on the periphery of the feeder substrate, the welding ring is disposed at the connection interface between each metal feeder needle and the feeder substrate, and the insulator is disposed between adjacent metal feeder needles.

[0010] Optionally, a semi-buried feed hole is provided on the side of the feed board near the metal feed pin, and the metal feed pin is fixedly connected in the semi-buried feed hole.

[0011] Optionally, the metal feed pin has a bent anchoring structure on the side away from the feed board. The bent anchoring structure is L-shaped and includes a horizontal part and a vertical part that are perpendicularly connected to each other. The horizontal part is connected to the end of the metal feed pin, and the end of the metal feed pin is connected to the bent anchoring structure to form a U-shaped structure. The annular pad is sleeved on the outer periphery of the metal feed pin and located at the opening of the U-shaped structure. The annular pad is mechanically fixed to the bent anchoring structure.

[0012] Optionally, the material of the thermal barrier structure is any one of alumina, zirconium oxide, and silicon nitride.

[0013] Optionally, the redistributed conductive layer includes a plurality of conductive paths, the first end of the conductive path being arranged at a first spacing on the side where the metal feed pin is located, and the second end of the conductive path being arranged at a second spacing on the side where the redistributed pad is located, wherein the first spacing is greater than the second spacing.

[0014] Optionally, an external functional module and a data acquisition chip for a brain-computer interface are also provided on the side of the feedthrough substrate near the redistribution pad, and both the external functional module and the data acquisition chip are electrically connected to the redistribution pad.

[0015] Optionally, the integrated electrode feedthrough structure further includes a flexible insulating layer and a flexible insulating substrate. The electrode point array, connecting wires, and circular pads are laser micro-processed to form an integrally molded electrode array. The integrally molded electrode array is encapsulated between the flexible insulating layer and the flexible insulating substrate. Windows are opened on the flexible insulating layer corresponding to the positions of the electrode point array and the circular pads, so that the electrode point array and the circular pads are exposed.

[0016] According to another aspect of this application, a method for fabricating an integrated electrode feedthrough structure for a brain-computer interface is provided, comprising: An integral electrode array comprising an electrode point array, connecting wires, and several annular pads is formed by integral processing of a conductive substrate; wherein, the two ends of the connecting wires are electrically connected to the electrode point array and the annular pads, respectively. The integrally molded electrode array is transferred to a flexible insulating substrate and insulated with a flexible insulating layer. Then, the electrode point array and circular pads in the integrally molded electrode array are exposed to obtain the encapsulated integrally molded electrode array. A feedthrough substrate with a redistribution conductive layer is prepared. A semi-buried feedthrough hole is processed on one side of the feedthrough substrate. A metal feedthrough pin is connected to the semi-buried feedthrough hole and made to be conductive with one end of the redistribution conductive layer. On the other side of the feedthrough substrate, a redistribution pad, an external functional module, and a data acquisition chip are arranged and made to be conductive with the other end of the redistribution conductive layer. The external functional module and the data acquisition chip are electrically connected to the redistribution pad. The metal feed pins are connected one-to-one with the annular pads in the packaged integral electrode array.

[0017] This application provides an integrated electrode feedthrough structure for brain-computer interfaces, which adopts a heterogeneous integrated feedthrough with pins and surfaces. Pin-type interconnect structures and planar redistributed pad structures are respectively set on both sides of the feedthrough substrate. This combines the advantages of high reliability and easy laser welding of pin-type feedthrough with the advantages of high space utilization and easy high-density integration of planar feedthrough. The integrally molded electrode array adopts an integrally molded structure, realizing the integrated fabrication of electrode point array, connecting wires and pad structures, reducing intermediate connection nodes, improving the packaging reliability and long-term stability of the system, and meeting the miniaturization and high stability application requirements of brain-computer interface systems.

[0018] Other technical effects resulting from the additional features will be further illustrated in the corresponding embodiments. Attached Figure Description

[0019] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of an integrated electrode feedthrough structure in one embodiment of this application. Figure 1 ; Figure 2 This is a schematic diagram of an integrated electrode feedthrough structure in one embodiment of this application. Figure 2 Among them, (a) is a schematic diagram of the heterogeneous integrated feedthrough between the electrode and the pad side pin surface; (b) is a schematic diagram of the connection between the electrode and the metal feedthrough pin side. Figure 3 This is a schematic diagram of a molded electrode array in one embodiment of the present application; wherein, (a) is a planar schematic diagram of the molded electrode array; and (b) is a three-dimensional schematic diagram of the molded electrode array. Figure 4This is a schematic diagram of the integrated feedthrough with heterogeneous pin and surface in one embodiment of the present application; wherein, (a) is a schematic diagram of the integrated feedthrough with heterogeneous pin and surface before and after mounting the acquisition chip on the redistribution pad side; (b) is a schematic diagram of the metal feedthrough pin side and its tail end bending and anchoring structure. Figure 5 This is a schematic diagram of the cross-sectional structure of the integrated feedthrough with heterogeneous needle and surface in one embodiment of this application; Figure 6 This is a flowchart of a method for fabricating an integrated electrode feedthrough structure in one embodiment of this application; Figure 7 This is a flowchart of a method for fabricating an integrally formed electrode array according to one embodiment of this application; Figure 8 This is a flowchart illustrating the preparation method of the integrated feedthrough with heterogeneous needle and surface in one embodiment of this application.

[0020] In the figure: 1. Integrated electrode array; 101. Electrode point array; 102. Connecting wire; 103. Circular pad; 104. Flexible insulating layer; 2. Heterogeneous integrated feedthrough; 201. Feedthrough substrate; 202. Metal feedthrough pin; 203. Redistribution pad; 204. Flange; 205. Weld ring; 206. Weld strip; 207. External functional module; 208. Acquisition chip; 209. Redistribution conductive layer; 210. Thermal barrier structure; 2021. Bending anchoring structure. Detailed Implementation

[0021] The present application will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all fall within the protection scope of the present application. Parts not described in detail in the following embodiments can be implemented using existing technology.

[0022] It should be noted that all information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with relevant regulations.

[0023] Implantable brain-computer interface (BCI) systems typically require feedthrough structures to ensure reliable transmission of electrical signals within and outside a sealed cavity. With the development of neural interfaces, implantable medical electronics, and miniaturized electronic packaging technologies, the number of system channels is constantly increasing, placing higher demands on the interconnect density, space utilization, and long-term reliability of feedthrough structures. Existing implantable BCI systems mostly employ pin-type or planar feedthrough structures to achieve signal transmission within and outside the cavity. However, pin-type structures usually require penetrating the PCB and reserving through-holes, limiting the layout of peripheral circuits and reducing space utilization. The connection reliability of planar feedthroughs is highly dependent on mounting accuracy and interface flatness; even minute height errors can lead to unreliable connections at local solder joints, resulting in problems such as cold solder joints, open circuits, or stress concentration. Simultaneously, the consistency of solder volume and solder joint morphology in high-density arrays is poor, resulting in weak mechanical anchoring capabilities and limited long-term stability. Based on the above problems, this application provides an integrated electrode feedthrough structure for brain-computer interfaces to solve these issues.

[0024] Reference Figure 1 and Figure 2 As shown, this application provides an integrated electrode feedthrough structure for a brain-computer interface, including a monolithic electrode array 1 and a needle-surface heterogeneous integrated feedthrough 2. The monolithic electrode array 1 adopts a monolithic structure, including an electrode point array 101, connecting wires 102 and several circular pads 103. The two ends of the connecting wires 102 are electrically connected to the electrode point array 101 and the circular pads 103 respectively to realize the output of electrical signals. The needle-surface heterogeneous integrated feedthrough 2 integrates a feedthrough substrate 201, a metal feedthrough needle 202, a redistribution pad 203, a redistribution conductive layer 209 and a thermal barrier structure 210. The redistribution conductive layer 209 and the thermal barrier structure 210 are disposed inside the feedthrough substrate 201. The metal feedthrough needle 202 is disposed on one side of the feedthrough substrate 201 and is connected to the circular pads 103 one by one. The redistribution pad 203 is disposed on the other side of the feedthrough substrate 201 and is electrically connected to the metal feedthrough needle 202 through the redistribution conductive layer 209.

[0025] In the embodiments described above, metal feedthrough pins as pin-type interconnects and redistribution pads as planar structures are respectively disposed on both sides of the feedthrough substrate. This combines the advantages of high reliability and ease of laser welding of pin-type feedthrough connections with the advantages of high space utilization and ease of high-density integration of planar feedthroughs. The fixed connection between the metal feedthrough pins and the annular pads improves the connection stability between the integrated electrode array and the heterogeneous integrated feedthrough. The redistribution conductive layer enables reliable signal communication between the redistribution pads and the integrated electrode array. The integrated electrode array adopts a one-piece structure, improving the packaging reliability and long-term stability of the integrated electrode array, meeting the miniaturization and high stability requirements of brain-computer interface systems. This application can reduce the internal connection layers and packaging volume of the integrated electrode feedthrough structure, improving the space utilization, overall packaging integration, and long-term implantation reliability of the integrated electrode feedthrough structure.

[0026] In some specific embodiments of this application, an external functional module 207 and a data acquisition chip 208 for a brain-computer interface are also provided on the side of the feedthrough substrate 201 near the redistribution pad 203. Both the external functional module 207 and the data acquisition chip 208 are electrically connected to the redistribution pad 203.

[0027] For example, the integrally molded electrode array 1 is fabricated using a laser cutting integral molding process, with a circular pad 103 at the end, and the entire array is encapsulated by a flexible insulating layer 104; see reference. Figure 4 As shown, the needle-surface heterogeneous integrated feedthrough 2 adopts a highly integrated needle-surface heterogeneous integrated feedthrough. The metal feedthrough needle 202 is disposed on one side of the feedthrough substrate 201 and corresponds one-to-one with the annular pad 103 of the integrally formed electrode array 1 and is directly nested and connected. The redistribution pad 203 is disposed on the other side of the feedthrough substrate 201 and is electrically connected to the metal feedthrough needle 202 through the redistribution conductive layer 209. The redistribution pad 203 is used to connect with the acquisition chip 208 and / or the external functional module 207. The redistribution pad 203 occupies a part of the other side of the feedthrough substrate 201. The remaining area on the other side of the feedthrough substrate 201 is used to integrate the external functional module 207. The external functional module 207 includes at least one of peripheral circuits and auxiliary devices. The acquisition chip 208 can be directly soldered onto the redistribution pad 203.

[0028] In some specific embodiments of this application, the feedthrough substrate 201 is any one of a ceramic feedthrough substrate, a glass feedthrough substrate, and a silicon-based feedthrough substrate; the feedthrough substrate 201 has a conductive path structure inside, and the redistribution conductive layer 209 is disposed inside the conductive path structure. The conductive path structure penetrates both sides of the feedthrough substrate 201, so that the two ends of the redistribution conductive layer 209 are respectively connected to the redistribution pad 203 and the metal feedthrough pin 202.

[0029] In the embodiments described above, the feedthrough substrate 201 serves as the main support structure for the entire heterogeneous integrated feedthrough, and its material may include any one of ceramic, glass, or silicon-based materials. In some embodiments, the feedthrough substrate 201 is made of a ceramic substrate to obtain good hermeticity, insulation, and mechanical strength. The conductive path structure includes one or more of blind vias, through-vias, and redistribution wiring structures, serving as an electrical signal transmission path that passes through both sides of the feedthrough substrate 201.

[0030] In some specific embodiments of this application, the needle-surface heterogeneous integrated feeder 2 further includes a flange 204, a welding ring 205 and an insulator. The flange 204 is disposed on the periphery of the feeder substrate 201, the welding ring 205 is disposed at the connection interface between each metal feeder needle 202 and the feeder substrate 201, and the insulator is disposed between adjacent metal feeder needles 202.

[0031] For example, the needle-surface heterogeneous integrated feedthrough 2 also includes a flange 204, a welding ring 205, a welding strip 206, and an insulator. The flange 204 is connected to the periphery of the feedthrough substrate 201 and is used to achieve mechanical fixation and sealing connection between the entire needle-surface heterogeneous integrated feedthrough and the external package, thereby achieving mechanical fixation and sealing of the entire brain-computer interface system. An insulator is provided between adjacent metal feedthrough needles 202 to achieve electrical isolation between adjacent metal feedthrough needles 202. The welding ring 205 is disposed at the connection interface between each metal feedthrough needle 202 and the feedthrough substrate 201 to weld and fix the metal feedthrough needle 202 to the feedthrough substrate 201 and achieve electrical conduction between the two, thereby buffering thermal and mechanical stress. The welding strip 206 is disposed in the peripheral area of ​​the needle-surface heterogeneous integrated feedthrough to achieve overall package connection and electromagnetic shielding.

[0032] In some specific embodiments of this application, a semi-buried feed hole is provided on the side of the feed substrate 201 near the metal feed pin 202, and the metal feed pin 202 is fixedly connected in the semi-buried feed hole.

[0033] In the above embodiments of this application, the metal feed pin 202 is disposed on one side of the feed substrate 201 and fixed in the pre-made semi-buried feed hole in the feed substrate 201 by a brazing process. The conduction between the feed pin and the redistribution pad 203 is achieved through the through-hole structure inside the feed substrate 201.

[0034] In some specific embodiments of this application, the material of the metal feed needle 202 includes any one of platinum-iridium alloy, gold, nickel and stainless steel; the structure of the metal feed needle 202 adopts any one of straight needle type, tapered needle or hollow needle structure.

[0035] For example, the metal feed pin 202 can be a straight pin, a tapered pin, or a hollow pin, and its material includes any one of conductive metal materials such as platinum-iridium alloy, gold, nickel, or stainless steel. The straight pin metal feed pin is a straight rod of uniform diameter, the tapered pin metal feed pin gradually reduces in diameter from the tail to the tip, and the hollow pin metal feed pin is a tubular structure with a through-cavity, to adapt to different packaging and connection requirements.

[0036] In some specific embodiments of this application, a bent anchoring structure 2021 is provided on the side of the metal feed needle 202 away from the feed substrate 201. The bent anchoring structure 2021 has an L-shaped structure, including a transverse part and a longitudinal part that are perpendicularly connected to each other. The longitudinal part is parallel to the metal feed needle 202, and the transverse part is connected to the end of the metal feed needle 202. The end of the metal feed needle 202 is connected to the bent anchoring structure 2021 to form a U-shaped structure. The annular pad 103 is sleeved on the outer periphery of the metal feed needle 202 and located at the opening of the U-shaped structure. The annular pad 103 is mechanically fixedly connected to the bent anchoring structure 2021.

[0037] In the above embodiments of this application, after the annular pad 103 at the tail end of the integrally molded electrode array 1 is sleeved on the outer periphery of the corresponding metal feedthrough pin 202, the annular pad 103 is located at the opening of the U-shaped structure, so that the annular pad 103 forms a mechanical self-locking connection through the bending anchoring structure 2021, and further achieves electrical connection and permanent fixation by at least one of laser welding, brazing, resistance welding or conductive adhesive curing, thus constructing a signal transmission path with high mechanical strength, high connection reliability and high integration. The bending anchoring structure 2021 is used to form a mechanical self-locking connection with the annular pad 103, improving pull-out resistance and long-term stability. This application improves the connection stability between the electrode and the feedthrough by forming a mechanical anchoring connection between the metal feedthrough pin 202 and the annular pad and cooperating with laser welding.

[0038] In some specific embodiments of this application, the inner diameter of the annular pad 103 matches the outer diameter of the metal feed needle 202, and the metal feed needle 202 is embedded in the inner hole of the annular pad 103.

[0039] In the embodiments described above, the inner diameter of the annular pad 103 at the end of the integrally molded electrode array 1 is precisely matched with the outer diameter of the metal feed pin 202. Initial mechanical fixation is achieved through a bending anchoring structure 2021, and a permanent electrical connection is further achieved using laser welding, brazing, resistance welding, or conductive adhesive curing. This forms a stable, integrated electrical connection structure, constructing a highly reliable signal path. Compared to traditional wire bonding or connector methods, this structure effectively reduces the number of connection nodes and intermediate transition structures, improving mechanical stability and long-term electrical connection reliability under high-density channels.

[0040] In some specific embodiments of this application, the feedthrough substrate 201 is further provided with a thermal barrier structure 210, and the material of the thermal barrier structure 210 is any one of alumina, zirconium oxide, and silicon nitride.

[0041] For example, the thermal barrier structure 210 is located inside the feedthrough substrate 201 and is disposed parallel to the upper surface of the feedthrough substrate 201. It is used to isolate the heat generated during the soldering process on the metal feedthrough pin 202 side from being conducted to the other side of the feedthrough substrate 201, preventing solder melting on the redistribution pad 203 side or thermal damage to the electronic devices of the mounted external functional module 207, thereby improving the thermal stability and reliability of the package structure. The thermal barrier structure 210 can be a locally low thermal conductivity insulating layer or a multilayer composite structure. The material of the thermal barrier structure 210 includes alumina, zirconium oxide, silicon nitride, or other electrically insulating and low thermal conductivity materials. This structure is used to block or weaken the propagation of heat to the redistribution pad 203 and the external functional module 207 side during soldering or high-temperature packaging processes on the metal feedthrough pin 202 side, preventing solder remelting or thermal damage to electronic devices, and improving the system packaging stability. This application reduces the impact of soldering heat on mounted devices by setting a thermal barrier structure. The materials used in thermal barrier structures include, but are not limited to, any one of the following low thermal conductivity materials: porous alumina, porous aluminum nitride, low-temperature co-fired glass ceramics, etc.

[0042] In some specific embodiments of this application, the redistribution conductive layer 209 includes a plurality of conductive paths. The first end of the conductive path corresponds to the side where the metal feed pin 202 is located and is arranged at a first spacing. The second end of the conductive path corresponds to the side where the redistribution pad 203 is located and is arranged at a second spacing. The first spacing is greater than the second spacing.

[0043] For example, refer to Figure 5As shown, the redistribution conductive layer 209 is disposed inside the feedthrough substrate 201. The redistribution conductive layer includes several redistribution layers and microvia interconnect structures. Adjacent redistribution layers are connected by microvia interconnect structures. Through the redistribution layers RDL and microvia interconnect structures, the redistribution conductive layer redistributes the input signal on one side of the metal feedthrough pin 202 to the redistribution pad 203 area on the other side of the feedthrough substrate 201 to achieve high-density transfer and spatial rearrangement of signal channels. It converts the input channels with larger spacing on the side of the metal feedthrough pin 202 into output channels with smaller spacing on the side of the redistribution pad 203, thereby rearranging the large-area input channels on the side of the metal feedthrough pin 202 to the redistribution pad 203 in a smaller area, realizing the spatial rearrangement and transfer of high-density signal channels, and improving the area utilization and system integration within the limited package space. Since the redistribution pad 203 occupies only a portion of the other side of the feedthrough substrate 201, the remaining area of ​​the feedthrough substrate 201 can be further integrated with peripheral circuits or auxiliary devices, such as amplifier circuits, filter circuits, wireless communication modules, or power supply modules. This achieves integrated pin-to-surface heterogeneous feedthrough and peripheral circuitry, improving overall system space utilization and package integration. This application achieves signal redistribution between large-pitch electrode interconnects and small-pitch chip interconnects through a redistribution conductive layer within the feedthrough substrate, improving space utilization and system integration under high-density channel conditions.

[0044] In the embodiments described above, the redistribution pad 203 is electrically connected to the metal feedthrough pin 202 via the redistribution conductive layer 209, for adapting to ball grid array (BGA) packages or other high-density interconnect interfaces, thereby achieving electrical connection between the heterogeneous feedthrough pin and external circuitry. Specifically, the redistribution pad 203 is disposed on the other side of the feedthrough substrate 201, for connecting to the ball grid array (BGA) package or other high-density interconnect interface on the feedthrough substrate 201, thereby achieving electrical connection between the feedthrough substrate and the acquisition chip 208 and peripheral circuitry.

[0045] In some specific embodiments of this application, the integrally molded electrode array 1 is electrically connected to the external functional module 207 and the acquisition chip 208 respectively through the redistribution pads 203.

[0046] In some specific embodiments of this application, the integrated electrode feedthrough structure further includes a flexible insulating layer 104 and a flexible insulating substrate. The electrode point array 101, the connecting wire 102, and the annular pad 103 are formed into an integrally molded electrode array 1 by laser micromachining of a conductive substrate. The integrally molded electrode array 1 is encapsulated between the flexible insulating layer 104 and the flexible insulating substrate. Windows are opened on the flexible insulating layer 104 at positions corresponding to the electrode point array 101 and the annular pad 103, so that the electrode point array 101 and the annular pad 103 are exposed.

[0047] For example, refer to Figure 3 As shown, the integrated electrode array 1 is fabricated using a metal thin-film laser micromachining process. It includes an electrode array 101, connecting wires 102, and a ring pad 103. All structures are continuous and integrated, requiring no additional intermediate connectors or splicing structures. The electrode array 101 consists of several electrode points arranged in a matrix. The electrode array 101 is used to contact brain tissue and collect neural electrical signals. Multiple electrode points are integratedly connected to the ring pad 103 at the tail end via connecting wires 102. Each electrode point is connected to a ring pad 103 via a connecting wire 102, ensuring a one-to-one correspondence between each electrode point and each ring pad 103. The ring pad 103 is used to connect one-to-one with the metal feed needles 202 in the highly integrated needle-surface heterogeneous integrated feedthrough 2. The flexible insulating layer 104 is used to achieve wire insulation encapsulation and improve the overall flexibility and biocompatibility of the electrode. Furthermore, the integrally formed electrode array 1 is transferred to a flexible insulating substrate by a transfer process and encapsulated with a flexible insulating layer 104. Finally, the electrode points and circular pads 103 are exposed by a laser micromachining process.

[0048] In the embodiments described above, the integrally molded electrode array 1 is used to acquire neural electrical signals and transmit the acquired signals to a highly integrated needle-surface heterogeneous feedthrough 2. The needle-surface heterogeneous feedthrough 2 is used to achieve high-density signal transfer, redistribution interconnection, and peripheral circuit integration. Compared to the traditional discrete connection structure of "flexible electrode-ceramic feedthrough-PCB," this application integrates the feedthrough substrate, redistribution pads, and peripheral circuits into the same high-density needle-surface heterogeneous feedthrough, significantly reducing the internal connection layers and intermediate transfer structures, shortening the signal transmission path, and improving the space utilization and overall packaging integration of the brain-computer interface system. Simultaneously, the integrally molded electrode array structure reduces the mechanically weak areas caused by traditional multi-segment splicing or wire bonding connections, improving the connection stability and reliability under long-term implantation conditions.

[0049] In some specific embodiments of this application, the materials of the flexible insulating layer 104 and the flexible insulating substrate include any one of imide, polyester, parylene, polyurethane and silicone.

[0050] In the embodiments described above, the integrally molded electrode array 1 is transferred to a flexible insulating substrate via a transfer process and encapsulated using a flexible insulating layer 104. Subsequently, the electrode dot array 101 and the annular pads 103 are exposed using a laser micromachining process. The flexible insulating layer 104 and the flexible insulating substrate are made of any one of flexible insulating materials such as polyimide (PI), polyester (PET), parylene, polyurethane (PU), or silicone. Among them, polyimide has good flexibility, insulation, and high-temperature resistance, making it suitable for high-density flexible electrode encapsulation.

[0051] In some specific embodiments of this application, the material of the integrally formed electrode array 1 includes any one of gold, copper, platinum-iridium alloy and stainless steel.

[0052] In the embodiments described above, the flexible high-density integrally molded electrode array 1 is fabricated using laser micromachining technology. By laser cutting a conductive substrate (such as a metal thin film), an integral structure including an electrode array 101, connecting wires 102, and circular bonding pads 103 is formed, thus avoiding the connection instability problems caused by traditional multi-component splicing or independent welding. The material of the integrally molded electrode array 1 can include any one of conductive materials such as gold (Au), copper (Cu), platinum-iridium alloy (PtIr), and stainless steel. Among these, platinum-iridium alloy, due to its excellent conductivity, biocompatibility, and corrosion resistance, is more suitable for long-term implantable brain-computer interface applications.

[0053] The metal feedthrough pins 202 of this application are disposed on one side of the feedthrough substrate 201 for connection to the integrally formed electrode array 1; the redistribution pads 203 are disposed on the other side of the feedthrough substrate 201 for connection to the acquisition chip 208 or peripheral electronic devices; the redistribution conductive layer 209 is disposed inside the feedthrough substrate 201, which can redistribute the signal channels corresponding to the large-pitch feedthrough pin array into a small-pitch pad array, realizing the spatial rearrangement and transfer of high-density signal channels; the thermal barrier structure 210 is disposed inside the feedthrough substrate 201 to reduce the heat generated during the welding process on the metal feedthrough pin 202 side from the electronic devices on the other side; a bent anchoring structure 2021 is also provided at the end of the metal feedthrough pin 202 away from the feedthrough substrate 201. The integrally formed electrode array is fabricated using a laser micromachining integral forming process, including an electrode point array 101, connecting wires 102 and several annular pads 103, and is encapsulated by a flexible insulating layer. This application enables stable extraction and reliable interconnection of high-throughput neural signals, reduces the number of internal connection layers and packaging volume, and improves the space utilization, overall packaging integration and long-term implantation reliability of the system.

[0054] The embodiments described above utilize laser micromachining to create a monolithic electrode array structure, achieving integrated fabrication of electrode points, connecting wires, and pad structures, thus reducing intermediate connection nodes. Simultaneously, pin-type interconnect structures and planar redistributed pad structures are employed on both sides of the feedthrough substrate, balancing the requirements for high-reliability connections and high-density integration. An internal redistributed conductive layer facilitates signal redistribution between large-pitch electrode terminals and small-pitch chip terminals, improving system space utilization and integration. Furthermore, the combination of monolithic electrodes, bent anchoring structures, and thermal barrier structures enhances connection reliability, packaging stability, and long-term implantation performance. This application addresses the problems in existing brain-computer interface systems, such as numerous connection nodes between electrodes and feedthroughs, large structural volume, limited high-density interconnection, low integration of peripheral circuits, insufficient packaging space utilization, and poor long-term implantation connection reliability.

[0055] This application, by employing metal feedthrough pins and redistributed pads, combines the high reliability of pin-type feedthrough structures with the high integration of planar feedthrough structures in terms of mechanical connection capability. It can ensure reliable transmission of high-density channels while achieving efficient utilization within a limited package space, and can also take into account the integration of peripheral electronic devices, thermal management, and long-term implantation reliability, thereby solving the technical defects of existing pin-type and planar feedthrough structures.

[0056] Reference Figure 6 As shown, based on the same inventive concept, another embodiment of this application provides a method for fabricating an integrated electrode feedthrough structure for a brain-computer interface, comprising: M1. The conductive substrate is integrally processed to form an integrally formed electrode array including an electrode point array, connecting wires and several circular pads; wherein, the two ends of the connecting wires are electrically connected to the electrode point array and the circular pads respectively. M2. The integral molded electrode array is transferred to a flexible insulating substrate and insulated with a flexible insulating layer. Then, the electrode point array and circular pads in the integral molded electrode array are exposed to obtain the encapsulated integral molded electrode array. M3. Prepare a feedthrough substrate with a redistribution conductive layer inside. Process a semi-buried feedthrough hole on one side of the feedthrough substrate. Connect a metal feedthrough pin to the semi-buried feedthrough hole and make the metal feedthrough pin conductive with one end of the redistribution conductive layer. Arrange a redistribution pad, an external functional module and a data acquisition chip on the other side of the feedthrough substrate and make the redistribution pad conductive with the other end of the redistribution conductive layer. Electrically connect the external functional module and the data acquisition chip to the redistribution pad. M4. Connect the metal feedthrough pins to the corresponding circular pads in the packaged integral electrode array.

[0057] For example, the integrated electrode feedthrough structure also includes a flexible insulating layer and a flexible insulating substrate. The conductive substrate is integrally processed using laser micromachining technology to obtain an integrally formed electrode array. The integrally formed electrode array is transferred to the flexible insulating substrate and insulated and encapsulated, and then the electrode points and annular pads are exposed. The feedthrough substrate 201 is internally provided with a redistribution conductive layer 209, blind holes and through-hole structures. The metal feedthrough needle 202 is mechanically embedded in a semi-buried feedthrough hole on one side and fixed by brazing in a vacuum or inert atmosphere. A redistribution pad 203 is formed on the other side of the feedthrough substrate 201. The annular pad 103 is sleeved with the metal feedthrough needle 202 and mechanically locked by a bending anchoring structure. The final fixation is completed by laser welding, constructing a brain-computer interface signal transmission path composed of an integrally formed electrode array, a needle-surface heterogeneous integrated feedthrough, and peripheral electronic circuits.

[0058] The present application will be further described below with reference to specific embodiments in order to better understand the above technical solutions of the present application. It should be understood that the following are only some examples and are not intended to limit the present application.

[0059] Example 1: A method for fabricating a flexible high-density electrode array integrally based on laser micromachining, comprising the following steps: Step 1: The conductive substrate is processed in an integrated manner using laser micromachining technology to form an integrated pattern structure including an electrode dot array 101, connecting wires 102 and annular pads 103, which serves as an integrated electrode array; the integrated pattern structure is transferred to a flexible insulating substrate and encapsulated using a flexible insulating layer 104, and then the electrode dot array 101 and annular pads 103 are exposed to obtain the encapsulated integrated electrode array 1; Step 2: Prepare a feedthrough substrate 201 with an internal redistribution conductive layer based on high temperature co-fired ceramic (HTCC) technology. Process redistribution pads 203 on one side of the feedthrough substrate 201 to form a redistribution pad area, and process feedthrough holes on the other side. Mechanically embed metal feedthrough pins 202 into the feedthrough holes of the feedthrough substrate 201 and fix them. Perform brazing and curing treatment in a vacuum or inert atmosphere to form a metal feedthrough pin connection area, thus obtaining a heterogeneous integrated feedthrough 2. Step 3: Connect the circular pad 103 to the metal feed needle 202 to construct a conduction signal path from the integrally formed electrode array 1 through the needle surface heterogeneous integrated feed needle 2 to the external functional module, and finally obtain the brain-computer interface system.

[0060] Furthermore, refer to Figure 7 As shown, the fabrication method of the encapsulated monolithic electrode array in step one is as follows: T1: Prepare a conductive metal sheet material with a thickness of 0.01-0.1mm, and use a laser micromachining device to cut the metal sheet with high precision to form a metal pattern structure including an electrode dot array 101, a connecting wire 102 and a tail ring pad 103. T2: The cut metal pattern structure is transferred to a flexible insulating substrate through a transfer process to form the main structure of the flexible electrode; T3: A flexible insulating layer 104 is covered on the surface of the metal pattern structure to achieve overall encapsulation; T4: The flexible insulating layer 104 after encapsulation is partially windowed using laser micromachining technology to expose the electrode point array 101 and the annular pad 103 area, so as to form a functional area that can be used for neural signal acquisition and feedthrough connection. T5: Cleaning, surface treatment, and electrical performance testing are performed on the processed flexible high-density integrally molded electrode array to improve the cleanliness of the electrode surface and its long-term stability.

[0061] Furthermore, refer to Figure 8 As shown, the preparation and installation method of the needle-surface heterogeneous integrated feedthrough in step two is as follows: S1: Select alumina ceramic, aluminum nitride ceramic or other high insulating ceramic materials as the substrate of feedthrough substrate 201, and process them to the predetermined size and surface finish through cutting, grinding and polishing processes; S2: Based on the integrated feedthrough design of the pin-surface heterogeneous structure, through-hole processing is performed on the ceramic green ceramic strip (i.e., feedthrough substrate), and conductive circuit patterns and redistribution layer structures are formed on the ceramic layer surface of the ceramic green ceramic strip using screen printing, sputtering, electroplating or other metallization processes. S3: Construct a conductive layer (i.e., redistribution layer) and microvia structure inside the ceramic layer for signal redistribution, and fill the vias with conductive paste to achieve electrical connection between different conductive layers; S4: A thermal barrier structure 210 is preset inside the feedthrough substrate 201. In some embodiments, alumina, zirconium oxide, silicon nitride, porous ceramics or other low thermal conductivity insulating materials can be used to form a local thermal barrier layer to reduce the conduction of heat to the device side during subsequent welding. S5: The multi-layer ceramic structure is laminated and stacked according to a predetermined line, and sintered through a high-temperature co-firing process to form an integral feedthrough substrate 201, so that the redistribution conductive layer 209, the micro-via structure and the thermal barrier structure 210 are integrated into the feedthrough substrate. S6: A feedthrough hole structure is formed on one side of the feedthrough substrate 201, a redistribution pad 203 is formed at the feedthrough hole structure, and a metallization layer is formed on the hole wall of the feedthrough hole structure and the surface of the redistribution pad 203 to improve conductivity and welding reliability. S7: The metal feed pin 202 is prepared using stamping, precision forming die bending, or micromachining processes, and a bent anchoring structure 2021 is pre-formed at the end of the metal feed pin 202 away from the feed substrate 201; then the metal feed pin 202 is embedded into the semi-buried feed hole of the feed substrate 201 and fixed by brazing. In some embodiments, gold-based brazing alloy, silver-based brazing alloy, or platinum-based brazing alloy can be used, and the welding is completed in a vacuum or inert atmosphere environment to form a stable hermetically tight electrical connection structure; S8: A packaging structure such as flange 205, solder ring 206 and solder strip 207 is formed in the peripheral area of ​​feedthrough substrate 201. External functional module 207 is integrated in the remaining area of ​​substrate. Acquisition chip 208 is integrated on redistribution pad 203. S9: The annular pad 103 at the tail end of the flexible high-density integrally molded electrode array is sleeved on the outer periphery of the corresponding metal feed needle 202, so that the annular pad 103 passes over the bending anchoring structure 2021; since the bending anchoring structure 2021 forms an axial limit, the annular pad 103 is locked on the feed needle 202, thereby forming a mechanical self-locking connection. S10: The circular pad 103 and the metal feed pin 202 are fixed by laser welding, brazing, resistance welding or conductive adhesive curing process to achieve permanent electrical and mechanical connection, thereby constructing a high-density signal transmission path composed of flexible high-density electrodes, heterogeneous integrated feed pins and peripheral electronic circuits.

[0062] The embodiments described above in this application can achieve high-density interconnection, spatial redistribution, and peripheral circuit integration of high-throughput neural signals, reduce the internal connection levels and packaging volume of the system, improve the space utilization, overall packaging integration, and long-term implantation reliability of the brain-computer interface system, and are suitable for brain-computer interface systems with high channel count, miniaturization, and high stability.

[0063] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0064] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0065] In the description of the embodiments in this application, "multiple" means two or more, unless otherwise explicitly specified. In this application, unless otherwise explicitly specified and limited, the terms "installed," "connected," "linked," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0066] The terms "comprising" and "having," and any variations thereof, in the embodiments of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or devices.

[0067] The preferred features in the above embodiments can be used individually in any embodiment, or in any combination thereof, provided they do not conflict with each other. Furthermore, parts not described in detail in the embodiments can be implemented using existing technologies.

[0068] The foregoing has described some specific embodiments of this application. It should be understood that this application is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the substantive content of this application. The above-described preferred features can be used in any combination without conflict.

Claims

1. An integrated electrode feedthrough structure for brain-computer interfaces, characterized in that, include: An integrally molded electrode array includes an electrode point array, connecting wires, and several circular pads, wherein the two ends of the connecting wires are electrically connected to the electrode point array and the circular pads, respectively. The integrated feedthrough with heterogeneous pin surface integrates a feedthrough substrate, metal feedthrough pins, redistribution pads, a redistribution conductive layer, and a thermal barrier structure. The redistribution conductive layer and thermal barrier structure are disposed inside the feedthrough substrate. The metal feedthrough pins are disposed on one side of the feedthrough substrate and are connected to the annular pads one by one. The redistribution pads are disposed on the other side of the feedthrough substrate and are electrically connected to the metal feedthrough pins through the redistribution conductive layer.

2. The integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The feedthrough substrate is any one of a ceramic feedthrough substrate, a glass feedthrough substrate, and a silicon-based feedthrough substrate; the feedthrough substrate has a conductive path structure inside, the redistribution conductive layer is disposed inside the conductive path structure, the conductive path structure passes through both sides of the feedthrough substrate, so that the two ends of the redistribution conductive layer are respectively connected to the redistribution pad and the metal feedthrough pin.

3. The integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The integrated feeder with heterogeneous pin surface also includes a flange, a welding ring, and an insulator. The flange is disposed on the periphery of the feeder substrate, the welding ring is disposed at the connection interface between each metal feeder pin and the feeder substrate, and the insulator is disposed between adjacent metal feeder pins.

4. The integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The feedthrough substrate has a semi-buried feedthrough hole on the side near the metal feedthrough pin, and the metal feedthrough pin is fixedly connected in the semi-buried feedthrough hole.

5. An integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The metal feed pin has a bent anchoring structure on the side away from the feed board. The bent anchoring structure is L-shaped and includes a horizontal part and a vertical part that are perpendicularly connected to each other. The horizontal part is connected to the end of the metal feed pin. The end of the metal feed pin is connected to the bent anchoring structure to form a U-shaped structure. The annular pad is sleeved on the outer periphery of the metal feed pin and located at the opening of the U-shaped structure. The annular pad is mechanically fixed to the bent anchoring structure.

6. The integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The material of the thermal barrier structure is any one of alumina, zirconium oxide, and silicon nitride.

7. An integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The redistributed conductive layer includes a plurality of conductive paths. The first end of the conductive path is arranged at a first spacing on the side where the metal feed pin is located, and the second end of the conductive path is arranged at a second spacing on the side where the redistributed pad is located. The first spacing is greater than the second spacing.

8. An integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, An external functional module and a data acquisition chip for a brain-computer interface are also provided on the side of the feedthrough substrate near the redistribution pad. Both the external functional module and the data acquisition chip are electrically connected to the redistribution pad.

9. An integrated electrode feedthrough structure for a brain-computer interface according to claim 1, characterized in that, The integrated electrode feedthrough structure further includes a flexible insulating layer and a flexible insulating substrate. The electrode point array, connecting wires, and circular pads are laser micro-processed to form an integrally molded electrode array. The integrally molded electrode array is encapsulated between the flexible insulating layer and the flexible insulating substrate. Windows are opened on the flexible insulating layer corresponding to the positions of the electrode point array and the circular pads, so that the electrode point array and the circular pads are exposed.

10. A method for fabricating an integrated electrode feedthrough structure for a brain-computer interface as described in any one of claims 1-9, characterized in that, include: An integral electrode array comprising an electrode point array, connecting wires, and several annular pads is formed by integral processing of a conductive substrate; wherein, the two ends of the connecting wires are electrically connected to the electrode point array and the annular pads, respectively. The integrally molded electrode array is transferred to a flexible insulating substrate and insulated with a flexible insulating layer. Then, the electrode point array and circular pads in the integrally molded electrode array are exposed to obtain the encapsulated integrally molded electrode array. A feedthrough substrate with a redistribution conductive layer is prepared. A semi-buried feedthrough hole is processed on one side of the feedthrough substrate. A metal feedthrough pin is connected to the semi-buried feedthrough hole and made to be conductive with one end of the redistribution conductive layer. On the other side of the feedthrough substrate, a redistribution pad, an external functional module, and a data acquisition chip are arranged and made to be conductive with the other end of the redistribution conductive layer. The external functional module and the data acquisition chip are electrically connected to the redistribution pad. The metal feed pins are connected one-to-one with the annular pads in the packaged integral electrode array.

Images