Airtight feed-through packaging method based on composite micropore array and airtight feed-through device

Abstract

The invention discloses an airtight feed-through packaging method based on a composite micropore array and an airtight feed-through device, and relates to the technical field of implantable medical electrical connection.The airtight feed-through packaging method comprises the following steps that a base body layer is prepared; a micro through hole array is formed based on processing of the base body layer; the micro through hole array corresponding to the substrate layer is filled with glass slurry; and local heating is carried out on the through hole position of the micro through hole array, so that the glass slurry is refluxed and cured to form the glass plug body. According to the method and the device, a foundation can be established for the airtight feed-through device through a core combined structure of the base body layer and the glass plug body, stable support can be effectively provided by relying on the base body layer, the flexible requirement can be met, the glass plug body fills the micro through hole array to form reliable sealing, meanwhile, a conductive path is configured, and the sealing performance of the airtight feed-through device is improved. Cooperative application of airtight protection and electric connection functions is further achieved, the problem of airtight electric connection between in-vivo and in-vitro electronic systems in implantable medical equipment is solved, and core structure support is provided for subsequent performance optimization.

Description

Technical Field

[0001] This invention relates to the field of implantable medical electrical connection technology, and more specifically, to a hermetically sealed feedthrough packaging method and hermetically sealed feedthrough device based on a composite microporous array. Background Technology

[0002] Currently, in modern medical technology, the application of implantable brain-computer interfaces (BCI), pacemakers, cochlear implants, neurostimulators and other medical devices is becoming increasingly widespread. These devices require a long-term, airtight, reliable and low-crosstalk electrical connection between a high-density electrode array in the body and an external or internal electronic system, namely the "feedthrough" function. The performance of this function directly affects the effectiveness and lifespan of the device.

[0003] For implantable brain-computer interfaces (BCIs), as technology advances, the requirements for channel density continue to increase, and thousand-channel-level signal transmission has become a trend. At the same time, the device needs to adapt to the curved surface of the skull and the micro-motion environment of tissues, which places more stringent requirements on the flexibility and fit of the feedthrough device. In addition, since implantable devices need to be implanted in the body for a long time, they must have extremely high airtightness to prevent the infiltration of body fluids from causing failure of internal electronic components, and to avoid adverse effects on human tissues, while meeting the medical standards for biocompatibility and compatibility with external medical devices such as magnetic resonance imaging (MRI) equipment.

[0004] In existing technologies, there are two main types of solutions for feedthrough devices in implantable medical devices: One type is the traditional ceramic / glass-metal sealed feedthrough solution. This solution forms an airtight feedthrough by combining a titanium alloy shell with a ceramic platinum through-hole or a glass-metal seal. Its airtightness is relatively reliable and can meet the basic airtightness requirements of some medical devices. However, this solution still has the following significant drawbacks: In other words, the manufacturing process of ceramic / glass-metal sealed feedthroughs requires high-temperature sintering or brazing at 400–1000°C. The high-temperature environment can easily cause changes in material properties and consumes a lot of energy. At the same time, the overall structure is rigid and cannot achieve a good stress transition with the flexible electrode cable. Under the environment of micro-movement of human tissue, stress concentration can easily lead to structural cracking or loosening of the connection. Furthermore, the processing of its micron-level high-density through holes is difficult, costly, and has a limited yield, making it difficult to meet the needs of thousand-channel-level high-density connections.

[0005] Another type is the pure polymer thermal welding feedthrough scheme developed in recent years, such as the polymer thermal welding scheme with PCTFE (polytrifluoroethylene) as the shell. This scheme improves MRI compatibility and structural flexibility, and can adapt to tissue micro-movement to a certain extent. However, this scheme also has at least the following drawbacks: In other words, the wires in pure polymer thermally welded feedthroughs rely on polymer coating for sealing. However, polymer materials are prone to moisture penetration during long-term use, making it difficult to meet the long-term airtightness requirements for medical-grade applications and thus failing to meet the 10⁻ standard. 8 The leakage rate standard of atm・cc / s seriously affects the long-term reliability of the equipment; at the same time, the pure polymer structure is insufficient in mechanical strength and wear resistance. After long-term implantation, the structure may be damaged due to friction, stress and other factors, which will affect the stability of electrical connection and overall device function.

[0006] In summary, while existing feedthrough devices meet certain application requirements, they still struggle to simultaneously satisfy multiple performance demands such as long-term airtightness, flexible fit, low-temperature manufacturing, high channel density, and low crosstalk. This hinders the further development and application of implantable medical devices, especially invasive BCI devices. Therefore, developing a feedthrough device that takes into account all of the above performance requirements has significant practical implications and application value. Summary of the Invention

[0007] To address these issues, the present invention provides a hermetically sealed feedthrough packaging method and a hermetically sealed feedthrough device based on a composite microporous array, thereby resolving the aforementioned technical problems existing in feedthrough devices for implantable brain-computer interfaces in the prior art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A hermetic feedthrough packaging method based on a composite micropore array includes the following steps: Preparation of the substrate layer; Micro-hole arrays are formed based on substrate layer processing; A glass slurry is filled with a micro-pore array corresponding to the substrate layer; Local heating is applied to the via locations of the micro-via array to cause the glass slurry to reflow and solidify, forming a glass plug.

[0009] Based on the above technical solution, the present invention is further described as follows: As a further aspect of the present invention, The preparation of the substrate layer specifically includes: Preparation of PCTFE matrix layer; The micro-via array formed based on substrate layer processing specifically includes: Micro-via arrays are formed based on PCTFE substrate layer.

[0010] As a further aspect of the present invention, before filling the glass slurry into the micro-pore array corresponding to the substrate layer, the following steps are also included: Plasma activation treatment was performed on the micro-hole array formed during processing.

[0011] As a further aspect of the present invention, before filling the glass slurry into the micro-pore array corresponding to the substrate layer, the following steps are also included: Metallization is performed on the activated microvia array to form a conductive continuous metal film uniformly adhered to the walls of the microvia array.

[0012] As a further aspect of the present invention, before filling the glass slurry into the micro-pore array corresponding to the substrate layer, the following steps are also included: An adaptive force-releasing layer is applied to a metallized micro-via array. After applying the adaptive force-releasing layer, fill with glass slurry.

[0013] As a further aspect of the present invention, The micro-pore array-filled glass slurry corresponding to the substrate layer specifically includes: The functionally graded glass slurry is filled in layers with micro-pore arrays corresponding to the matrix layer, and then pre-baked sequentially. The layered filled functional gradient glass paste specifically includes: First, an inner layer of low-melting-point glass slurry is injected into the through-holes of the micro-via array; Then, high-strength glass slurry is injected into the through-holes of the micro-via array to fill the remaining space of the through-holes.

[0014] As a further aspect of the present invention, The localized heating of the via locations in the micro-via array to reflow and solidify the glass slurry to form a glass plug specifically includes: Localized layered reflow heating is performed focusing on the via area of ​​the micro-via array; The process involves first heating the inner layer of low-melting glass slurry to soften it and fully wet and fuse it with the adaptive force-releasing layer, and then heating the outer layer of high-strength glass slurry to partially reflow and solidify it to form high-hardness glass.

[0015] As a further aspect of the present invention, the following steps are also included: Based on the functionally graded glass plug, electrode metal layers are formed corresponding to the inner and outer feedthrough layers, respectively; This enables an electrical connection between the electrode metal layer and the conductive continuous metal film layer. Flexible circuit boards are connected based on electrode metal layers.

[0016] As a further aspect of the present invention, the following steps are also included: The titanium alloy shell is welded to the PCTFE substrate layer.

[0017] A hermetic feedthrough device fabricated according to the hermetic feedthrough packaging method based on a composite micropore array.

[0018] The present invention has the following beneficial effects: 1. This hermetic feedthrough device establishes a foundation for hermetic feedthrough devices through the core combination structure of the substrate layer and the glass plug. At the same time, it can effectively provide stable support and adapt to flexibility requirements by relying on the substrate layer. The reliable seal formed by the glass plug filling the micro-hole array, along with the configuration of conductive paths, further realizes the synergistic application of hermetic protection and electrical connection functions. It solves the basic hermetic electrical connection problem between the internal and external electronic systems in implantable medical devices, and provides core structural support for subsequent performance optimization.

[0019] 2. By adopting a functional gradient design for the glass plug, the inner layer of low-melting glass has a reflow melting point lower than that of the substrate layer, and can be fused with the substrate through a low-temperature process to achieve a tight seal. The outer layer of high-strength glass ensures the mechanical stability and wear resistance of the structure. This effectively solves the defects of material performance changes, high energy consumption and insufficient air tightness and poor mechanical strength of pure polymer structures caused by traditional high-temperature sintering processes, and improves the overall functional adaptability.

[0020] 3. By incorporating a microphase that can migrate / redeposit twice into the inner low-melting glass to form a self-healing glass system, it can automatically repair any microcracks that may occur during long-term use, continuously ensuring airtight performance, significantly reducing the risk of airtight failure caused by microcracks in the glass plug, and improving the reliability of long-term device implantation.

[0021] 4. By using perforated metal wires pre-filled inside the glass plug to create conductive pathways, the metal wires possess excellent conductivity, enabling them to stably adapt to the transmission requirements of the main signal channel. Furthermore, during the glass reflow process, they are tightly encased by low-melting glass, forming a gapless three-phase airtight interface. This design balances high conductivity efficiency with airtight protection, thereby more effectively supporting high-density signal transmission performance at the thousand-channel level.

[0022] 5. An adaptive force-relieving layer is set between the inner wall of each through hole of the micro-hole array and the glass plug, which can effectively absorb the stress caused by the mismatch of thermal expansion coefficients between the substrate layer and the glass plug, avoid the interface cracking due to stress concentration, and reduce the risk of damage to traditional rigid feedthrough structures in micro-movement or thermal cycling environments.

[0023] 6. An embedded water-blocking shielding layer is set inside the substrate layer around the micro-via array area. On the one hand, it can block water vapor from migrating laterally, further enhancing the airtight protection effect. On the other hand, it has EMI shielding function, which can reduce signal crosstalk and external electromagnetic interference. Combined with the low dielectric properties of the substrate layer, it significantly improves the stability and accuracy of signal transmission.

[0024] 7. Two sets of annular electrode pads are respectively set at both ends of the inner and outer layers of the glass plug to provide a stable and reliable electrical interface for the flexible FPC, ensuring the connection contact area and accuracy, improving the conductivity reliability, and at the same time, the flexible circuit board can flexibly adapt to the micro-movement of the organization, avoiding the breakage of the connection part due to stress concentration.

[0025] 8. The titanium alloy shell and the substrate layer are connected in a closed manner, forming a triple airtight barrier to further prevent the erosion of body fluids and protect the internal structure from damage. In addition, the titanium alloy has good biocompatibility, mechanical strength and corrosion resistance, making it suitable for long-term implantation in the body. At the same time, all materials in contact with tissues meet medical-grade standards, have good biocompatibility and MRI compatibility, ensuring the safety of long-term implantation and effectively adapting to the application needs of various medical devices such as implantable brain-computer interfaces and pacemakers. Attached Figure Description

[0026] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The structures, proportions, sizes, etc., drawn in this specification are only used to complement the content disclosed in the specification, so that those skilled in the art can understand and read them. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0027] Figure 1 This is a schematic diagram of the overall process of the hermetic feedthrough packaging method based on a composite micropore array provided in an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the overall application state structure of the hermetic feedthrough device based on a composite micropore array provided in an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of an embodiment of the internal assembly structure and conductive path of a micro-via array for a hermetically sealed feedthrough device based on a composite micro-via array, provided by an embodiment of the present invention.

[0030] Figure 4 This is a schematic diagram of another embodiment of the hermetic feedthrough device based on a composite micropore array provided in this invention, corresponding to the conductive path.

[0031] Figure 5 This is a schematic diagram of another embodiment of the hermetic feedthrough device based on a composite micropore array provided in this invention, corresponding to the conductive path.

[0032] Figure 6This is a schematic diagram of the assembly structure of the airtight feedthrough device based on a composite micropore array corresponding to the embedded water-blocking shielding layer provided in the embodiments of the present invention.

[0033] Figure 7 The schematic diagram of the cross-sectional structure of the airtight feedthrough device based on the composite micropore array provided in the embodiment of the present invention, corresponding to the embedded water-blocking shielding layer.

[0034] Figure 8 This is a schematic diagram of the assembly structure of the hermetic feedthrough device based on a composite micropore array corresponding to the annular electrode pad and the flexible circuit board provided in the embodiments of the present invention.

[0035] Figure 9 This is a schematic diagram illustrating the functional principle of the selective laser reflow process corresponding to the hermetic feedthrough device based on a composite micropore array provided in an embodiment of the present invention.

[0036] The attached diagram lists the components represented by each number as follows: PCTFE substrate layer 1; Micro-via array 2; Functionally graded glass stopper 3: inner layer low-melting glass 31, outer layer high-strength glass 32; Conductive path 4: Hole wall metallization layer 41, perforated metal wire 42, conductive glass plug 43; 5. Adaptive force-relieving layer; 6. Embedded water-blocking shielding layer; 7. Ring electrode pad; 8. Flexible circuit board; 9. Titanium alloy shell; Feedthrough inner layer a; feedthrough outer layer b. Detailed Implementation

[0037] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The terms "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and are not intended to limit the scope of the invention. Any changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0039] like Figures 2 to 8As shown, this embodiment of the invention provides a hermetically tight feedthrough device based on a composite micropore array, including a PCTFE substrate layer 1, a micropore array 2, a functionally graded glass plug 3, a conductive path 4, an adaptive force-relieving layer 5, and an embedded water-blocking shielding layer 6. Based on the PCTFE substrate layer 1 as a substrate for flexible bonding, the micropore array 2 formed in the PCTFE substrate layer 1 can further coordinate the functionally graded glass plug 3 and the conductive path 4. Furthermore, selective laser reflow can be used to achieve localized hermetically tight bonding of the functionally graded glass plug 3 at a specific low-temperature window, thereby effectively achieving long-term hermetically tight protection. It also possesses the thousand-channel capability achieved by the conductive path 4 in conjunction with the micropore array 2. High-density signal transmission performance; simultaneously, the adaptive force-relieving layer 5 effectively absorbs the mismatch stress of the functionally graded glass plug 3 to achieve stress buffering and reduce damage, and further introduces a self-healing glass system to continuously self-heal and seal long-term microcracks in the functionally graded glass plug 3, further ensuring the overall airtight performance of the corresponding area of ​​the micro-via array 2; in addition, the embedded water-blocking shielding layer 6, located outside the micro-via array 2 and insulated from the conductive path 4, effectively blocks the lateral migration of surface moisture through the PCTFE substrate layer 1, and further provides EMI (internal and external electromagnetic wave) shielding, reducing crosstalk and external interference, significantly improving the overall airtight feedthrough functional stability and practicality. Specific settings are as follows: Please refer to Figure 2 The PCTFE substrate layer 1 is configured as a PCTFE (polyvinyl chloride trifluoroethylene) thin plate structure with a thickness range of 0.3~1.0mm. It serves as the assembly base layer for the airtight feedthrough device, which can ensure structural strength while taking into account flexible support performance, so that its bending radius meets the adaptation requirements of the cranial surface. It also has the characteristics of low moisture permeability, low dielectric constant (ε_r≈2.1) and non-magnetic properties, which can meet the MRI compatibility requirements of implantable devices and environmental adaptability for long-term use.

[0040] The micro-via array 2 is configured as an array structure formed by a number of uniformly distributed vias. Each via is a straight through-hole formed by laser / ultrasonic processing on the PCTFE substrate layer 1, with a diameter ranging from Φ30 to 100µm. This is used to accommodate the functionally graded glass plug 3 and the conductive path 4, providing a channel basis for electrical connection. The spacing between the vias is set to a range of 100 to 200µm to achieve a sufficient number of vias in the limited area of ​​the PCTFE substrate layer 1, thereby realizing a high-density feedthrough connection at the thousand-channel level, while avoiding signal interference and structural interference between adjacent vias.

[0041] Please refer to Figure 2 and Figure 3The functionally graded glass plug 3 is filled in each of the through holes of the micro-via array 2. Specifically, the functionally graded glass plug 3 includes an inner low-melting glass 31 and an outer high-strength glass 32. The inner low-melting glass 31 and the outer high-strength glass 32 are sequentially filled in the through holes of the micro-via array 2. The inner low-melting glass 31 is located inside the through hole near the feedthrough inner layer a, i.e., the human body fluid side. The outer high-strength glass 32 is located inside the through hole near the feedthrough outer layer b, i.e., the external device side. This is to achieve low-temperature fusion sealing with the PCTFE substrate layer 1 through the inner low-melting glass 31, and to enhance the mechanical stability and wear resistance of the structure through the outer high-strength glass 32, thereby synergistically ensuring the airtight performance and structural strength of the feedthrough device.

[0042] As a preferred embodiment, a surface activation-coupling-slow-release composite interface structure is further provided between the PCTFE matrix layer 1 and the functionally graded glass stopper 3. This composite interface structure includes a plasma activation layer and a chemical anchoring layer, which further enhance the interfacial adhesion between the glass stopper and the PCTFE matrix layer 1, improving the adhesion and long-term airtightness of the polymer-glass interface. The plasma activation layer is formed by plasma activation treatment of the pore walls of the PCTFE matrix layer 1. This activation process generates polar groups, significantly increasing the surface energy of the PCTFE surface from 20m². The J / m² level is increased from a lower level to a higher level of ≥60mJ / m², enhancing the bonding ability with the subsequent chemical anchoring layer. The chemical anchoring layer is a fluorosilane coupling agent or fluorosilicone copolymer coated on the surface of the plasma activation layer. It can chemically react with the polar groups of the plasma activation layer and bond with the Si–O⁻ groups in the glass during the reflow process of the functionally graded glass plug 3. After cooling, it forms an interface bridge that combines chemical bonding and elastic buffering, so that the bonding between the PCTFE matrix layer 1 and the functionally graded glass plug 3 changes from physical adsorption to chemical bonding, thereby significantly improving the bonding strength and long-term stability of the interface.

[0043] As another preferred embodiment, please refer to [the relevant documentation]. Figure 3 The adaptive force relief layer 5 is disposed between the inner wall of each through hole of the micro-perforation array 2 and the outer wall of the functionally graded glass plug 3, so as to effectively absorb the thermal expansion coefficient (CTE) mismatch stress between the PCTFE matrix layer 1 and the functionally graded glass plug 3, thereby avoiding interface cracking leading to airtight failure.

[0044] Specifically, the adaptive force-relieving layer 5 is configured as a curable elastic intermediate layer with a thickness ranging from 2 to 5 µm. The materials selected include, but are not limited to, fluorosilicone copolymers, fluorosilicone elastomers, acrylate-fluoropolymer copolymers, and photocurable fluorinated para-xylene (Parylene-F). These materials have good elastic buffering performance and chemical inertness, which can meet the requirements of interfacial stress relief. They also have the characteristics of being flowable when heated and curable when cooled. In the subsequent selective laser reflow process, they can adaptively flow with the fusion and softening process of the inner low-melting glass 31, further filling the interfacial gaps, and curing after cooling to form an elastic buffer layer. When the feedthrough device is in a thermal cycling environment or subjected to external forces, the adaptive force-relieving layer 5 can also generate elastic deformation, disperse stress concentration, prevent cracks from forming between the PCTFE matrix layer 1 and the functionally graded glass plug 3, and effectively ensure the long-term bonding stability and hermetic performance of the interface.

[0045] Please continue to refer to this. Figure 3 The inner low-melting glass 31 uses a low-melting glass material with a specific formulation, specifically a fluorine-containing low-melting glass (BaO–B2O3–SiO2–F), with a reflow temperature range of 180~210℃, which matches the temperature window of the subsequent selective laser reflow process. It can soften at low temperatures and fully wet and fuse with the PCTFE substrate layer 1 or the adaptive force-releasing layer 5 to form a tight airtight interface. The outer high-strength glass 32 uses a glass material with high mechanical strength and good wear resistance, specifically a high-strength silicate glass, with a reflow temperature range of 210~230℃. After curing, it can resist external friction and stress impact, effectively reduce internal damage, and further block the water vapor permeation path.

[0046] The dual-layer structure of the functionally graded glass stopper 3 utilizes a layered filling and step-by-step reflow process. Specifically, precise heating transforms the glass slurry from a solid state to a molten / semi-molten state, enabling it to fully wet the surface of the PCTFE matrix layer 1 or the adaptive force-releasing layer 5 and fill tiny gaps. After cooling, it solidifies to form a dense, airtight, and structurally stable glass stopper, effectively ensuring the overall airtightness.

[0047] In an optional implementation, the PCTFE matrix layer 1 can be replaced with other low-permeability, medical-grade polymer materials, including but not limited to ETFE, PFA, FEP, and PEEK. These materials also have good biocompatibility and environmental stability, and can be flexibly selected according to the needs of actual application scenarios. When replacing different matrix materials, the reflow temperature of the subsequent functionally graded glass plug 3 and the material formulation of the adaptive force-releasing layer 5 are adjusted accordingly to ensure the compatibility and connection reliability between the various structures.

[0048] In another optional implementation, the glass system of the functionally graded glass plug 3 can be replaced with other low-melting-point formulation materials, including but not limited to Bi2O3–B2O3–ZnO and P2O5–Na2O–CaO glass materials. These materials also have the characteristic of low-temperature reflow, which can flexibly meet different process conditions and performance requirements. When replacing the glass system, ensure that the reflow temperature of the inner low-melting glass 31 does not exceed the melting point of the PCTFE matrix layer 1, and that it has good compatibility with the outer high-strength glass 32, without causing chemical reactions or delamination.

[0049] As another preferred embodiment, the inner low-melting glass 31 is doped with a microphase that can migrate / redeposit twice to form a self-healing glass system. The microphase includes, but is not limited to, B2O3 particles and microencapsulated fluorosilicone oil, which are used to self-heal and seal microcracks that may occur in the glass plug under long-term body temperature conditions, ensuring the stability of long-term airtight performance. When microcracks appear in the glass plug, the microphase can migrate under the influence of ambient temperature and humidity, fill the crack gaps and re-solidify, so that the airtight performance of the glass plug is restored. Its long-term airtight recovery rate can reach a high level, significantly reducing the possibility of airtight failure caused by microcracks in the glass plug during long-term use of the device in the body, and enhancing the overall functional stability.

[0050] Please refer to Figures 3 to 5 The conductive path 4 is disposed inside the functionally graded glass plug 3, and / or between the functionally graded glass plug 3 or the adaptive force-relieving layer 5 and the inner wall of the through-hole of the micro-hole array 2, so as to provide a path for electrical signal transmission through the conductive path 4; specifically, the conductive path 4 is configured as one or more combinations of the hole wall metallization layer 41, the perforated metal wire 42 or the conductive glass plug 43, so as to flexibly adapt to different signal transmission requirements and processing conditions.

[0051] More specifically, the hole wall metallization layer 41 is configured as a continuous metal film layer formed on the hole wall by sputtering or electroplating. The material of the continuous metal film layer can be selected from specific metal combinations, including but not limited to Ti / Au or Ti / Pt / Au, so as to achieve higher channel density and good adaptability to automated processing. At the same time, its synergy with the functionally graded glass plug 3 can provide insulation and better mechanical support for the conductive path 4, thereby effectively avoiding signal short circuits.

[0052] In another optional implementation, the metallization system of the pore wall metallization layer 41 can be replaced with other combinations, including but not limited to Ti / Pt / Au, Cr / Au, and Ni / Au. The above metal combinations all have good conductivity, corrosion resistance, and biocompatibility, and can be selected according to the needs of the actual application scenario. When replacing the metallization system of the pore wall metallization layer 41, ensure that the adhesion between the metal film and the pore wall and the functionally graded glass plug 3 is good, and that it will not fall off or peel off due to thermal cycling or stress.

[0053] The perforated metal wire 42 is pre-filled sequentially inside the inner low-melting glass 31 and the outer high-strength glass 32. The perforated metal wire 42 is made of a precious metal wire, including but not limited to Pt, Au, PtIr, and Ti / Au. The diameter of the perforated metal wire 42 is set to 20~50µm. This is to make the perforated metal wire 42 more suitable for the transmission of the main signal channel by taking advantage of its low resistance and excellent conductivity. At the same time, the perforated metal wire 42 can be covered by the inner low-melting glass 31 during the glass reflow process. That is, after the low-melting glass slurry melts, it can uniformly wrap the perforated metal wire 42 due to its fluidity and wetting properties. Thus, after cooling, the inner low-melting glass 31 forms a tight bond with the perforated metal wire 42 without gaps. This can form a three-phase airtight interface between the perforated metal wire 42, the inner low-melting glass 31, and the PCTFE matrix layer 1 or the adaptive force-relieving layer 5, further ensuring the dual functions of conductivity and airtightness.

[0054] The conductive glass plug 43 is formed directly from the functionally graded glass plug 3. Specifically, the conductive glass plug 43 is set as an Ag⁺ / ITO doped conductive glass material to directly form conductive properties based on the glass plug. It is suitable for the transmission of low current reference signals, shielded signals or sensing auxiliary channels. It can be used in combination with the perforated metal wire 42 or the metallization layer 41 on the hole wall to realize the classified transmission of multiple types of signals.

[0055] Please refer to Figures 6 to 7The embedded water-blocking shielding layer 6 is disposed inside the PCTFE substrate layer 1 and surrounds the outer part of several via areas of the micro-via array 2. It is pre-embedded by the PCTFE substrate layer 1 through its own melting or lamination process to ensure a tight and gapless bond with the PCTFE substrate layer 1. The embedded water-blocking shielding layer 6 is a thin metal mesh layer, and its material is selected from a combination of metals with good conductivity and corrosion resistance, specifically including but not limited to Au-Ti mesh or Pt film. The embedded water-blocking shielding layer 6 is electrically insulated from the conductive path 4 to effectively suppress the lateral diffusion of water vapor along the feedthrough inner and outer layer connection direction. It also has EMI shielding function to reduce signal crosstalk and external interference. That is, it can block the interference of external electromagnetic signals to the internal conductive path 4 and prevent internal signals from radiating outward, thereby reducing crosstalk between channels and ensuring the stability and accuracy of signal transmission.

[0056] Please refer to Figure 3 and Figure 8 The annular electrode pads 7 are provided in two sets. The two sets of annular electrode pads 7 are respectively fixedly disposed at the outer edges of the two ends of the corresponding feedthrough inner and outer layers of the functionally graded glass plug 3. The material of the pads includes, but is not limited to, the Ti / Au annular metal layer. The two sets of annular electrode pads 7 are electrically connected to the two ends of the corresponding feedthrough inner and outer layers of the conductive path 4, so as to effectively serve as the interface for subsequent flexible circuit boards 8 to be soldered / laminated corresponding to the feedthrough inner and outer layers. The annular electrode pads 7 are formed into a clear annular structure by laser selective film removal or re-sputtering process, so as to further ensure the contact area and connection accuracy with the subsequent flexible circuit board 8, and improve the overall conductive connection reliability.

[0057] The flexible circuit board 8 is provided in two sets. The materials of the two sets of flexible circuit boards 8 are including but not limited to PI+Cu or PI+Au. The two sets of flexible circuit boards 8 are respectively electrically connected to the two sets of annular electrode pads 7 to realize the flexible connection between the conductive path 4 and the external electronic system and to transmit electrical signals.

[0058] The flexible circuit board 8 is laminated to the annular electrode pad 7 via hot pressing or ultrasonic welding. Temperature, pressure, and time parameters are controlled during the welding process to ensure the conductivity and mechanical strength of the connection. The flexible circuit board 8 has good flexibility and bending performance, which can effectively adapt to the micro-movement of the organization and avoid the connection from breaking due to stress concentration. At the same time, the pre-laid circuit of the flexible circuit board 8 makes it easier to realize the orderly transmission of multi-channel signals, which is compatible with the thousand-channel density of the micro-via array 2.

[0059] Please continue to refer to this. Figure 2The titanium alloy housing 9 is welded to the PCTFE substrate layer 1 to further encapsulate and protect the entire feedthrough device, protecting the internal structure from fluid corrosion. At the same time, the signal output terminal of the flexible circuit board 8 can be brought out separately to connect to the internal electrode array or external device.

[0060] Specifically, the titanium alloy shell 9 is welded to the PCTFE matrix layer 1 via laser welding or low-temperature brazing. The low-temperature brazing can use, but is not limited to, Au-Sn80 / 20 low-temperature variant brazing filler metal. During the welding process, a structural stress transition design is incorporated to prevent damage to the PCTFE matrix layer 1 or the functionally graded glass plug 3 due to welding stress. The welded area forms a local weld seam, and a desiccant is placed inside the titanium alloy shell 9 to further absorb any residual moisture, ensuring an airtight internal environment. This synergistically forms a triple airtight barrier consisting of the PCTFE matrix layer 1, the functionally graded glass plug 3, and the titanium alloy shell 9, significantly improving the overall long-term airtight performance. Furthermore, the titanium alloy shell 9 possesses good biocompatibility, mechanical strength, and corrosion resistance, enabling it to stably adapt to the internal environment. Long-term use will not result in corrosion or the leaching of harmful substances, and it can further provide structural support to ensure stress transition.

[0061] As another preferred embodiment, the micro-via array 2 is provided with conductive holes and insulating holes in a mixed arrangement. The conductive holes are provided with functionally graded glass plugs 3 and conductive paths 4 inside, which are responsible for signal extraction. The type of conductive path 4 inside is selected according to the signal transmission requirements. The insulating holes are provided with only functionally graded glass plugs 3 inside, which are used to realize the integration of stress buffering and passive sensing functions.

[0062] Specifically, the insulating hole forms a stress buffer region, which can disperse stress through its own structural characteristics when the feedthrough device is subjected to external force or thermal stress, thus preventing damage to the conductive hole area due to stress concentration. More preferably, a miniature temperature or stress-sensitive material is embedded in the insulating hole to achieve a passive sensing function, which monitors the ambient temperature or stress state of the feedthrough device in real time, providing data support for the evaluation of the device's operating status. The mixed layout of the conductive holes and insulating holes is reasonably planned, which does not affect the density requirements of thousand-channel signal transmission, and can give full play to the stress buffering and sensing functions, significantly improving the overall performance and reliability of the feedthrough device and enhancing its overall functionality and practicality.

[0063] In a further optional implementation, the array formed by the functionally graded glass plug 3 is directly replaced by an all-metal microneedle array, and a local reflow seal is further completed based on the PCTFE substrate layer 1, so as to ensure conductivity and mechanical strength protection while forming an airtight effect.

[0064] The array formed by the functionally graded glass plug 3 can be directly replaced by a fully conductive glass array. At the same time, based on the outer surface coating of the PCTFE substrate layer 1, the manufacturing process is simplified by sacrificing some conductivity.

[0065] A thin ceramic sheet with a thickness ranging from 80 to 150 µm is embedded in a local area of ​​the PCTFE matrix layer 1, and several through holes are formed corresponding to the thin ceramic sheet. Then, the functionally graded glass plug 3 is used for laser reflow sealing, thereby obtaining a higher hardness local insert that can be used in different scenarios.

[0066] like Figure 1 As shown, this embodiment of the invention also provides a hermetically tight feedthrough packaging method for a hermetically tight feedthrough device based on the above-described glass composite micro-via array, specifically including the following steps: S1: Prepare PCTFE matrix layer 1 and clean and dry it; The specific process is as follows: According to the design dimensions and thickness requirements of 0.3~1.0mm, a PCTFE matrix layer 1 is prepared as the flexible base for subsequent processing. After preparation, the PCTFE matrix layer 1 is cleaned to remove surface oil, dust and impurities. The cleaning method can be ultrasonic cleaning or plasma cleaning. After cleaning, the PCTFE matrix layer 1 is placed in a drying equipment for drying to remove internal and surface moisture and avoid moisture affecting subsequent processing and airtightness. S2: Micro-via array 2 is formed based on PCTFE substrate layer 1; The specific process is as follows: Several through holes are formed on the dried PCTFE substrate layer 1 by laser or ultrasonic processing. During the processing, the roundness and diameter of the through holes are ensured to meet the design requirements within the range of Φ30~100µm by precise control of equipment parameters. Several through holes are evenly distributed according to a preset arrangement to form a micro-through hole array 2 with thousands of channels. The hole spacing is set to 100~200µm to achieve both channel density and structural stability. After processing, the micro-through hole array 2 is inspected to remove processing debris from the holes and ensure that the hole walls are smooth and burr-free. S3: Perform plasma activation treatment on the micro-via array 2; The specific process is as follows: Plasma activation treatment is performed on the walls of several through holes in the micro-hole array 2; Optionally, the PCTFE substrate layer 1 with the micro-via array 2 is placed in a plasma activation device to perform plasma activation treatment on the pore walls. During the activation process, high-energy particles generated by the plasma bombard the pore wall surface, causing polar groups to be generated on the pore wall surface, increasing the pore wall surface energy, and enhancing the subsequent bonding ability with the functionally graded glass plug 3, the conductive pathway 4, or the adaptive force-releasing layer 5. S4: Metallize the activated micro-via array 2; The specific process is as follows: If the hole wall metallization layer 41 is selected as the conductive path 4, then after the plasma activation treatment, the hole wall of the micro-hole array 2 is metallized. Metallization is performed using sputtering or electroplating processes. First, an adhesion layer is deposited by sputtering, followed by a conductive layer. Alternatively, the conductive layer can be thickened by electroplating, ultimately forming a conductive continuous metal film uniformly adhered to the walls of the micro-via array 2. S5: Continue to coat the metallized micro-via array 2 with an adaptive force-releasing layer 5; The specific process is as follows: Using a precision coating device, the material selected for the adaptive force release layer 5 is further coated on the inner wall region of the conductive continuous metal film layer of the micro-hole array 2, and the coating thickness is controlled within a preset range of 2~5µm. During the coating process, ensure that the material evenly covers the pore walls without any omissions or accumulations. After coating, pre-curing treatment is carried out according to the material characteristics to improve the stability of the coating and provide basic conditions for subsequent glass slurry filling of functionally graded glass plug 3. S6: Corresponding to the micro-hole array 2-layer filling functional gradient glass slurry, which is pre-baked sequentially; The specific process is as follows: First, an inner layer of low-melting glass slurry, such as BaO–B2O2–SiO2–F, is injected into the through-holes of the micro-via array 2. The filling amount is controlled to be 50% of the volume at the bottom of the hole, with an error range of less than 1%. The PCTFE matrix layer 1 was placed in a drying equipment for the first pre-drying treatment. The pre-drying temperature was set to 120°C. The purpose was to remove the solvent in the glass slurry and prevent bubbles from being generated during the subsequent reflow process. After the first pre-baking is completed, the outer layer of high-strength glass slurry is injected into the through holes of the micro-hole array 2 to fill the remaining space and perform a second pre-baking treatment to further remove the solvent and ensure the density of the glass slurry. The above-mentioned double-layer glass slurry injection method can be, but is not limited to, two-layer sequential injection or inkjet printing; As a preferred embodiment, the particle size of the inner low-melting glass slurry is set to be less than 1µm, thereby ensuring uniform filling and reflow effect; S7: Please refer to Figure 9 By selective laser reflow process, local heating is applied to the through-hole positions of the micro-hole array 2, causing the functionally graded glass slurry to reflow and solidify to form a functionally graded glass plug 3; The specific process is as follows: The pre-baked PCTFE substrate layer 1 is placed in a selective laser reflow apparatus, and the laser beam is modulated using a spatial light modulator or a mask so that the laser energy is focused only on the via area of ​​the micro-via array 2 for local reflow heating; more specifically, the inner low-melting glass slurry is first heated to 190°C to soften it and fully wet and fuse it with the adaptive force-relieving layer 5, and then the outer high-strength glass slurry is heated to 210~230°C to locally reflow and solidify it to form high-hardness glass; The temperature window range of the entire reflow process is controlled at 180~210°C, which is lower than the melting point of PCTFE matrix layer 1, i.e., 215°C, to ensure that PCTFE matrix layer 1 does not melt and collapse during the reflow process; Meanwhile, the reflow pressure range is set to 0.5~1.0MPa to ensure bubble removal and compaction, and to ensure sufficient wetting of the contact interface; the reflow time is controlled to 2~5min to limit heat retention and control stress generation. After reflow, the glass is cooled at a rate of 2~5°C / s to effectively suppress glass microcracks and ultimately form a continuous and dense double-layer functional gradient glass plug 3. As another preferred embodiment, the laser source for the selective laser reflow process can be a CO2 laser, a near-infrared laser, or a femtosecond laser, etc. The selection of the laser source is determined according to the absorption characteristics of the glass slurry and the processing accuracy requirements. Spatial light modulators or mask projections can be used to modulate the laser beam to ensure that the laser energy is accurately applied to the hole area and to avoid thermal damage to other parts of the PCTFE substrate layer 1. S8: Based on the functionally graded glass plug 3, a ring electrode metal layer is formed in the corresponding feedthrough inner and outer layers; The specific process is as follows: A Ti / Au annular metal layer is prepared on the outer edge of the functionally graded glass plug 3 corresponding to the inner and outer feedthrough layers using laser selective film removal or re-sputtering processes. If re-sputtering is used, a Ti layer is first sputtered as an adhesion layer, and an Au layer is then sputtered as a conductive and bonding layer. If laser selective film removal is used, a complete Ti / Au metal film is first sputtered on the upper and lower surfaces of the PCTFE substrate layer 1, and then the metal film outside the outer edge of the functionally graded glass plug 3 is selectively removed by laser to obtain a clear annular electrode pad 7. Clean the annular electrode pad 7 to remove the oxide layer or impurities on the surface and ensure welding performance; S9: Laminate the flexible circuit board 8 to the annular electrode pad 7; The specific process is as follows: The flexible circuit board 8 is laminated to the corresponding positions of the annular electrode pads 7 in the inner and outer layers of the feedthrough, i.e., lamination is performed using hot pressing or ultrasonic welding processes. During hot pressing, the temperature, pressure, and time parameters are controlled to ensure that the Au layer of the annular electrode pad 7 and the conductive layer of the flexible circuit board 8 are fully fused to form a stable electrical and mechanical connection. During ultrasonic welding, the vibration energy of ultrasonic waves causes plastic deformation and atomic diffusion at the connection interface, achieving metallurgical bonding. S10: Weld the titanium alloy shell 9 to the PCTFE substrate layer 1 to complete the encapsulation; The specific process is as follows: The PCTFE substrate layer 1, on which the flexible circuit board 8 is laminated, is aligned and assembled with the titanium alloy shell 9, and then sealed using laser welding or low-temperature brazing. During the welding process, the welding energy and weld width are controlled to form local welds, ensuring the airtightness of the seal. At the same time, a desiccant is placed inside the titanium alloy shell to absorb any residual moisture. After welding, a series of tests are performed on the entire package structure, including He leak detection, electrical testing, EIS testing, stress testing, and immersion aging testing. After passing the tests, the package is stored for future use. As another preferred embodiment, during the encapsulation process, the cleanliness of the process is strictly controlled to ensure that the processing environment meets the cleanliness requirements of ISO14644-1 Class 7 or better, so as to avoid impurities entering the interior of the structure and affecting the airtightness and conductivity. All materials that may come into contact with tissues meet medical implant-grade standards (USP Class VI or equivalent) and pass the ISO10993 series of biocompatibility tests to ensure the safety of long-term implantation. The entire encapsulation structure ensures that the whole system is non-ferromagnetic and meets the conditional requirements of MRI.

[0067] During use, the high-density electrode array inside the device is connected to the annular electrode pad 7 via the flexible circuit board 8. Electrical signals are transmitted to electronic devices inside or outside the body via the conductive path 4, effectively achieving bidirectional signal transmission. At the same time, the functionally graded glass plug 3 and the embedded water-blocking shielding layer 6 form a double anti-seepage barrier, which can effectively block the penetration of body fluids and ensure the long-term stable operation of internal electronic components. Moreover, the flexible characteristics of the adaptive force-relieving layer 5 and the PCTFE matrix layer 1 enable the device to adapt to the curvature of the skull and the micro-movement of tissues, avoiding structural damage caused by stress concentration. In addition, the self-healing glass plug can automatically repair micro-cracks during long-term use, further improving structural reliability and service life.

[0068] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A hermetic feedthrough packaging method based on a composite microporous array, characterized in that, Includes the following steps: Preparation of the matrix layer; Micro-hole arrays are formed based on substrate layer processing; A glass slurry is filled with a micro-pore array corresponding to the substrate layer; Local heating is applied to the via locations of the micro-via array to cause the glass slurry to reflow and solidify, forming a glass plug.

2. The hermetic feedthrough packaging method based on a composite microporous array according to claim 1, characterized in that, The preparation of the substrate layer specifically includes: Preparation of PCTFE matrix layer; The micro-via array formed based on substrate layer processing specifically includes: Micro-via arrays are formed based on PCTFE substrate layer.

3. The hermetic feedthrough packaging method based on a composite microporous array according to claim 2, characterized in that, Before filling the micro-pore array corresponding to the substrate layer with glass slurry, the following steps are also included: Plasma activation treatment was performed on the micro-hole array formed during processing.

4. The hermetic feedthrough packaging method based on a composite microporous array according to claim 3, characterized in that, Before filling the micro-pore array corresponding to the substrate layer with glass slurry, the following steps are also included: Metallization is performed on the activated microvia array to form a conductive continuous metal film uniformly adhered to the walls of the microvia array.

5. The hermetic feedthrough packaging method based on a composite microporous array according to claim 4, characterized in that, Before filling the micro-pore array corresponding to the substrate layer with glass slurry, the following steps are also included: An adaptive force-releasing layer is applied to a metallized micro-via array. After applying the adaptive force-releasing layer, fill with glass slurry.

6. The hermetic feedthrough packaging method based on a composite microporous array according to claim 5, characterized in that, The micro-pore array-filled glass slurry corresponding to the substrate layer specifically includes: The functionally graded glass slurry is filled in layers with micro-pore arrays corresponding to the matrix layer, and then pre-baked sequentially. The layered filled functional gradient glass paste specifically includes: First, an inner layer of low-melting-point glass slurry is injected into the through-holes of the micro-via array; Then, high-strength glass slurry is injected into the through-holes of the micro-via array to fill the remaining space of the through-holes.

7. The hermetic feedthrough packaging method based on a composite microporous array according to claim 6, characterized in that, The localized heating of the via locations in the micro-via array to reflow and solidify the glass slurry to form a glass plug specifically includes: Localized layered reflow heating is performed focusing on the via area of ​​the micro-via array; The process involves first heating the inner layer of low-melting glass slurry to soften it and fully wet and fuse it with the adaptive force-releasing layer, and then heating the outer layer of high-strength glass slurry to partially reflow and solidify it to form high-hardness glass.

8. The hermetic feedthrough packaging method based on a composite microporous array according to claim 7, characterized in that, It also includes the following steps: Based on the functionally graded glass plug, electrode metal layers are formed corresponding to the inner and outer feedthrough layers, respectively; This enables an electrical connection between the electrode metal layer and the conductive continuous metal film layer. Flexible circuit boards are connected based on electrode metal layers.

9. The hermetic feedthrough packaging method based on a composite microporous array according to claim 8, characterized in that, It also includes the following steps: The titanium alloy shell is welded to the PCTFE substrate layer.

10. A hermetic feedthrough device fabricated according to the hermetic feedthrough packaging method based on a composite micropore array as described in any one of claims 1-9.

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