Method for preparing sealing structure

Abstract

The present disclosure describes a method for preparing a sealing structure, which includes: preparing a ceramic substrate with multiple feedthrough holes, filling the multiple feedthrough holes with feedthrough electrodes; preparing a metal ring and brazing the metal ring to the ceramic substrate; covering the multiple feedthrough electrodes with a solderable coating; and preparing a circuit board with a pad, and welding the pad to the coating. According to the present disclosure, a method for preparing a sealing structure that can improve the reliability of the feedthrough electrode can be provided.

Description

[0001] This application is filed on October 12, 2019 、Application No. 201910970197.4 、The name of the invention is Implantation Sealing method for type device A divisional application for a patent application. Technical Field

[0002] The present disclosure relates to a method for preparing a sealing structure. Background Art

[0003] Currently, implantable devices have been widely used in various fields such as restoring body functions, improving life quality or saving lives, etc. Such implantable devices include, for example, cardiac pacemakers, deep brain stimulators, cochlear implants, retinal stimulators, etc. that can be implanted into the body.

[0004] Since implantable devices need to be implanted in the body and remain in the body for a long time, implantable devices implanted in the body need to face the complex physiological environment in the body. This physiological environment condition is often harsh. After long-term implantation, implantable devices may interact with tissues and organs around the implantation site. For example, the materials of implantable devices will undergo physical or chemical reactions such as aging, degradation, cracking, and re-crosslinking, thereby causing negative effects on the implanted object, such as causing adverse biological reactions such as inflammation. Therefore, for implantable devices, the requirements for biosafety and long-term implantation reliability are very high. Usually, in order to ensure the biosafety and long-term implantation reliability of implantable devices, on the one hand, it is necessary to use a sealed shell with good biosafety and long-term implantation reliability to isolate non-biosafety components in the implantable device, such as silicon-based chips, printed circuit boards (PCBs), etc. from the implanted site (such as blood, tissues or bones); on the other hand, it is also necessary to lead out from the sealed shell, for example, functional wires that interact with the stimulation components for signals.

[0005] In the current feedthrough ceramic manufacturing process, the chip or printed circuit board is usually connected to the feedthrough electrode in the ceramic substrate by bonding or the like, and then the metal and the ceramic are brazed. However, in the above-mentioned ceramic manufacturing process, the brazing temperature is often high, so the connection between the chip or printed circuit board and the feedthrough electrode is easily damaged during the brazing process, thereby reducing the reliability of the feedthrough electrode. Summary of the invention

[0006] In the existing sealing method of implantable devices, after the ceramic substrate is manufactured, the chip or printed circuit board is usually connected to the feedthrough electrode in the ceramic substrate by bonding or the like, and then the metal ring and the ceramic substrate are brazed. However, in the above-mentioned ceramic manufacturing process, the brazing temperature is often high, so the connection between the chip or printed circuit board and the feedthrough electrode is easily damaged during the brazing process, thereby reducing the reliability of the feedthrough electrode.

[0007] In view of this, the present disclosure proposes a sealing method for an implantable device that can improve the reliability of a feedthrough electrode in the implantable device.

[0008] To achieve the above-mentioned objectives, the present disclosure proposes a sealing method for an implantable device, comprising: preparing a ceramic substrate having a plurality of feedthrough holes, wherein the plurality of feedthrough holes are filled with feedthrough electrodes; preparing a metal ring, and brazing the metal ring to the ceramic substrate; covering the plurality of feedthrough electrodes with a solderable plating layer; and preparing a circuit board with electronic components and solder pads, and wire-bonding the circuit board to the plating layer via the solder pads.

[0009] In the present disclosure, the ceramic substrate is first brazed with the metal ring, and then the circuit board composed of circuit elements such as chips is connected to the circuit board by plating (electroplated, chemically plated, etc.) a solderable coating on the feed-through electrode, thereby enhancing the reliability of the connection between the ceramic substrate and the circuit.

[0010] In addition, in the sealing method of the implantable device involved in the present disclosure, optionally, the feedthrough electrode is composed of at least one selected from platinum, iridium, niobium, tantalum, and gold. Thus, the performance parameters of the feedthrough electrode and the ceramic substrate can be more matched, the strength of the connection structure can be improved, and not only the electrical performance of the ceramic substrate can be improved, but also the long-term reliability of the ceramic substrate can be further improved.

[0011] In addition, in the sealing method of the implantable device involved in the present disclosure, optionally, the solderable coating includes a stacked first coating and a second coating, the material of the first coating is selected from one of gold, copper, silver or tin, and the material of the second coating is selected from one of gold, tungsten, molybdenum manganese, silver, platinum or nickel. More preferably, the first coating is plated with gold by electroplating, the second coating is plated with nickel by electroplating, or both the first coating and the second coating are gold, thereby enabling reflow soldering or FC (Flip-chip) between the ceramic substrate and the circuit board, and enhancing the connection strength between the circuit board and the ceramic substrate.

[0012] In addition, in the sealing method of the implantable device disclosed herein, optionally, the ceramic of the ceramic substrate is composed of more than 99% alumina. In this case, the biosafety of the manufactured ceramic substrate and the airtightness of the formed sealing device are better.

[0013] In addition, in the method for sealing an implantable device according to the present disclosure, the ceramic substrate is optionally formed by stacking and firing a plurality of ceramic sheets, thereby making it easier to fire the ceramic substrate.

[0014] In addition, in the sealing method of the implantable device involved in the present disclosure, optionally, a patterned wiring conductor is arranged between the ceramic sheets of adjacent layers. Combined with the ceramic substrate being formed by stacking and firing multiple layers of ceramic sheets, the bonding force between the feedthrough electrode, the patterned wiring and the ceramic substrate can also be improved, thereby reducing the sintering temperature and improving the airtightness of the ceramic substrate.

[0015] In addition, in the sealing method of the implantable device disclosed herein, optionally, the feedthrough holes in adjacent rows or columns and the feedthrough electrodes filled in the feedthrough holes are arranged in a staggered manner, thereby effectively blocking or extending the path of airtight leakage and effectively improving the airtightness of the ceramic substrate.

[0016] In addition, in the sealing method of the implantable device involved in the present disclosure, optionally, the coating is formed by at least one of electroplating, chemical plating, ion plating, hot dip plating, spray plating, infiltration plating, and cathode sputtering. The coating method of the present disclosure is preferably electroplating, but is not limited to electroplating. For example, in other embodiments, with the aid of a suitable reducing agent, without the need for an external current, the coating can be more conveniently deposited on the surface of the ceramic substrate by chemical plating, which can simplify the process steps.

[0017] In addition, in the sealing method of the implantable device involved in the present disclosure, optionally, it also includes preparing a metal cover that matches the metal ring, and joining the metal cover to the metal ring. In this way, the implantable device can form a sealed structure, and when used for implantation in a biological organism, it can avoid the environment in the biological organism from affecting the circuit and other components in the implantable device, thereby improving the biological safety and long-term implantation reliability of the implantable device.

[0018] In addition, in the sealing method of the implantable device of the present disclosure, optionally, the metal ring is arranged along the edge of the ceramic substrate, so as to improve the space utilization inside the implantable device.

[0019] Compared with the manufacturing process of the traditional sealing structure, the sealing method of the implantable device disclosed in the present invention can enhance the reliability of the connection between the ceramic substrate and the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a schematic flow chart showing a method for sealing an implantable device according to an embodiment of the present disclosure.

[0021] Figure 2 1 is a three-dimensional structural diagram showing a sealing structure of an implantable device according to an embodiment of the present disclosure.

[0022] Figure 3 It shows Figure 2 A cross-sectional view of the sealing structure of the implantable device is shown.

[0023] Figure 4 Schematic diagram showing the structure of the ceramic substrate of the present invention.

[0024] Figure 5 It shows Figure 4 A partial enlarged view of the middle feed-through electrode.

[0025] Figure 6 It shows Figure 4 A partially enlarged view of Modification 1 of the middle feed-through electrode.

[0026] Figure 7 It shows Figure 2 A partial cross-sectional schematic diagram of Modification 1 of the sealing structure of the implantable device is shown.

[0027] Figure 8 It shows Figure 2 A partial cross-sectional schematic diagram of a second variation of the sealing structure of the implantable device is shown.

[0028] Explanation of symbols:

[0029] 1…sealing structure, 10…ceramic substrate, 20…metal ring, 30…metal cover, 40…plating, 50…circuit board, 11, 12, 13, 14…ceramic sheet, 41…first plating, 42…second plating, 110 (111, 112, 113, 114)…feedthrough electrode, 120 (121, 122, 123)…patterned wiring conductor, 130…feedthrough hole. DETAILED DESCRIPTION

[0030] The technical solution of the present disclosure will be described clearly and completely below in conjunction with the accompanying drawings of the present disclosure. Obviously, the described implementation is only a part of the implementation of the present disclosure, not all of the implementation. Based on the implementation in the present disclosure, all other implementations obtained by ordinary technicians in the field without creative work are within the scope of protection of the present disclosure.

[0031] It should be noted that if the present disclosure involves directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0032] In addition, if the present disclosure contains descriptions involving "first", "second", etc., the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various implementation methods can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present disclosure.

[0033] The sealing structure 1 of the present disclosure can be applied to implantable devices such as cardiac pacemakers, deep brain stimulators, cochlear implants, retinal stimulators, etc. In addition, the sealing structure 1 of the present embodiment is also particularly suitable for high-density ceramic packaging technology.

[0034] In addition, since the sealing structure 1 involved in the present embodiment needs to be placed in the body of the implant object, it is easy for those skilled in the art to understand that the external materials of the sealing structure 1 involved in the present disclosure that come into contact with blood, tissue or bone (including the ceramic substrate 10, metal ring 20, metal cover 30 described later, and the constituent materials of the feedthrough electrode 110 filling the feedthrough hole 130 of the ceramic substrate 10, etc.) need to meet the prescribed standards (such as ISO10993 (international standard), GB / T16886 (Chinese standard)) for biosafety and long-term implantation reliability.

[0035] Figure 1 1 is a schematic flow chart showing a method for sealing an implantable device according to an embodiment of the present disclosure. Figure 2 1 is a three-dimensional structural diagram showing a sealing structure of an implantable device according to an embodiment of the present disclosure. Figure 3 It shows Figure 2 A cross-sectional view of the sealing structure of the implantable device is shown.

[0036] In this embodiment, if Figures 1 to 3As shown, the sealing structure 1 of the implantable device involved in this embodiment includes a ceramic substrate 10, a metal ring 20 and a metal cover 30. First, the ceramic substrate 10 is prepared, and the ceramic substrate 10 serves as the bottom of the sealing structure 1. The feedthrough hole 130 inside the sealing structure 1 is filled with a feedthrough electrode 110 or a feedthrough electrode array that is electrically connected to the outside of the sealing structure 1 (for example, for electrical stimulation); then the prepared metal ring 20 is welded to the ceramic substrate 10 by brazing; then the feedthrough electrode 110 is covered with a solderable coating 40 to join the circuit board 50 with electronic components and pads to the solderable coating 40; finally, the metal cover 30 is welded (such as laser welding, etc.) to the metal ring 20. In this way, the sealing structure 1 can be formed into a sealed body having a accommodating space for accommodating the circuit board 50 by arranging (for example, welding) the metal ring 20 and the metal cover 30 on the ceramic substrate 10.

[0037] In the conventional manufacturing process of the sealing structure 1, the circuit board 50 with electronic components and pads is connected to the feedthrough electrode 110 in the ceramic substrate 10 by bonding or laser welding, and then the metal ring 20 and the ceramic substrate 10 are brazed. However, since the brazing temperature of the metal ring 20 and the ceramic substrate 10 is too high, the structure of the connected circuit board 50 and the ceramic substrate 10 will be destroyed during brazing, thereby affecting the function of the sealing structure 1.

[0038] It can be understood that in the sealing method of the implantable device involved in the present disclosure, the ceramic substrate 10 and the metal ring 20 are first brazed, and then the circuit board 50 composed of circuit elements such as chips is connected to the circuit board 50 by plating (electroplated, chemically plated, etc.) the solderable coating 40 on the feed-through electrode 110, thereby cleverly avoiding the problem of poor connection reliability in traditional methods.

[0039] The sealing method of the implantable device disclosed in the present invention is described in detail below with reference to the accompanying drawings.

[0040] In this embodiment, if Figure 1 As shown, the sealing method of the implantable device may include: preparing a ceramic substrate 10 having a plurality of feedthrough holes 130, and filling the plurality of feedthrough holes 130 with feedthrough electrodes 110 (step S10); preparing a metal ring 20, and soldering the metal ring 20 to the ceramic substrate 10 (step S20); covering the plurality of feedthrough electrodes 110 with a solderable coating 40 (step S30); preparing a circuit board 50 with electronic components and pads, and wire bonding the circuit board 50 to the coating 40 via the pads (step S40); preparing a metal cover 30, and bonding the metal cover 30 to the metal ring 20 (step S50).

[0041] In this embodiment, the ceramic substrate 10 in step S10 can be composed of at least one of aluminum oxide (chemical formula Al2O3, including single crystal sapphire and ruby, or polycrystalline α-Al2O3), zirconium oxide (chemical formula ZrO2, including magnesium oxide partially stabilized zirconium oxide (Mg-PSZ)), yttria stabilized tetragonal zirconia polycrystalline (Y-TZP), or cerium oxide stabilized tetragonal zirconia polycrystalline (Ce-TZP). Thus, the requirements of implantable medical devices for material biocompatibility can be met.

[0042] In this embodiment, the ceramic substrate 10 may be composed of 96% or more (unless otherwise specified, the percentages here all represent mass fractions) of aluminum oxide (Al2O3). In addition, the ceramic substrate 10 may preferably be composed of 99% or more of aluminum oxide. Furthermore, the ceramic substrate 10 may more preferably be composed of 99.99% or more of aluminum oxide.

[0043] Generally speaking, in the ceramic substrate 10, as the mass fraction of aluminum oxide (Al2O3) increases, the main crystalline phase increases, and the physical properties of the ceramic substrate 10 gradually improve. For example, the compressive strength (MPa), flexural strength (MPa), and elastic modulus (GPa) also increase accordingly. Therefore, it can be considered that it will present better biosafety and long-term reliability.

[0044] In addition, in this embodiment, in some examples, such as Figure 2 As shown, the ceramic substrate 10 may be in a substantially cylindrical shape. In this embodiment, the shape of the ceramic substrate 10 is not particularly limited, and it may also be other regular shapes such as a cube, an elliptical cylinder, a triangular cylinder, etc., or an irregular shape (including a shape formed by combining a regular shape and an irregular shape). Thus, the requirements of different implantable medical devices for the shape of the ceramic substrate 10 can be met.

[0045] Figure 4 Schematic diagram showing the structure of the ceramic substrate of the present disclosure. Figure 4 , the ceramic substrate 10 may be formed by stacking and firing multiple layers of ceramic sheets. In this embodiment, the ceramic substrate 10 may include multiple ceramic sheets having multiple feedthrough holes 130, and the multiple ceramic sheets are stacked in sequence. In some examples, the ceramic substrate 10 may be composed of, for example, four layers of ceramic sheets (e.g., ceramic sheets 11, 12, 13, 14). Figure 4As shown, ceramic sheets 11, 12, 13 and 14 are stacked in sequence to form a ceramic substrate 10. However, the present embodiment is not limited thereto, and the number of ceramic sheets constituting the ceramic substrate 10 is not particularly limited, and for example, the ceramic substrate 10 may be composed of two, three, or more than five layers of ceramic sheets. Therefore, according to different application requirements, a ceramic sheet layer less than or greater than four layers may be provided, so as to meet the requirements of different implantable medical devices for the structure of the ceramic substrate 10.

[0046] In this embodiment, as described above, the ceramic substrate 10 can be formed by stacking and firing multiple ceramic sheets. However, this embodiment is not limited thereto, and it can of course be prepared in other ways, for example, it can be formed by pressing multiple ceramic sheets. Thus, process requirements under different conditions can be met.

[0047] In addition, in the present embodiment, the thickness of each ceramic sheet 11 to ceramic sheet 14 is not particularly limited. In some examples, the thickness of the ceramic sheets 11 to ceramic sheets 14 can be greater than 0.05 mm and less than 0.35 mm, so as to be easy to process and have a good punching effect. Generally, when the thickness of the ceramic sheet is too small, for example, less than 0.05 mm, it is inconvenient to process due to its small thickness; when the thickness of the ceramic sheet is too large, for example, greater than 0.35 mm, the punching effect is poor due to its large thickness.

[0048] In this embodiment, each ceramic sheet is preferably composed of more than 96% (mass fraction, the same below) of aluminum oxide (Al2O3). More preferably, each ceramic sheet is composed of more than 99% aluminum oxide (Al2O3). In some examples, each ceramic sheet 11 to 14 is composed of more than 99.99% aluminum oxide (Al2O3). Generally speaking, in each ceramic sheet, as the mass fraction of aluminum oxide (Al2O3) increases, the main crystal phase increases, and the physical properties of each ceramic sheet gradually improve, such as compressive strength, flexural strength, and elastic modulus. It can be considered that aluminum oxide (Al2O3) with a higher mass fraction will present better biosafety and long-term reliability.

[0049] In addition, in this embodiment, each ceramic sheet can be composed of alumina ceramics with the same component content. In some examples, the ceramic sheets 11 to 14 are preferably composed of more than 99.99% alumina (Al2O3). However, this embodiment is not limited to this, and each ceramic sheet can be composed of different types of ceramics, or can be composed of the same type of ceramics with different component contents. Therefore, it can be adjusted according to actual needs to meet different requirements for the ceramic substrate 10 under different environmental conditions.

[0050] In this embodiment, if Figure 4As shown, each ceramic sheet constituting the ceramic substrate 10 has a plurality of feedthrough holes 130 .

[0051] In this embodiment, the arrangement of each feedthrough hole 130 on each ceramic sheet can be the same. In some examples, each feedthrough hole 130 between adjacent ceramic sheets can be aligned. Thus, each feedthrough electrode 110 filling each through hole between adjacent ceramic sheets can be aligned, so that the feedthrough electrode 110 passes through each ceramic sheet.

[0052] In addition, in this embodiment, the arrangement of each feedthrough hole 130 on each ceramic sheet can be different. In some examples, each feedthrough hole 130 between adjacent ceramic sheets can be arranged in a staggered manner. Thus, each feedthrough electrode 110 filling each through hole between adjacent ceramic sheets can be arranged in a staggered manner, thereby effectively blocking or extending the walking path of the airtightness leakage, and effectively improving the airtightness performance of the ceramic substrate 10.

[0053] In addition, in this embodiment, the arrangement shape of the feedthrough holes 130 is not particularly limited. Figure 4 As shown, the feedthrough holes 130 can be arranged in a regular shape such as a rectangular array. In other examples, the feedthrough holes 130 can also be arranged in other regular shapes, such as squares, circles, etc., and can also be arranged in irregular shapes (including shapes formed by combining regular shapes and irregular shapes).

[0054] In addition, in the present embodiment, there is no particular limitation on the aperture and the hole spacing of the feedthrough hole 130. In some examples, the aperture of the feedthrough hole 130 may be 50 μm to 500 μm, and the spacing (hole spacing) between the feedthrough holes 130 may be not less than 25 μm to 500 μm. In this case, the manufactured ceramic substrate 10 can meet the requirements of miniaturization and high integration density, for example, it can be used in a ceramic substrate for implantable medical devices.

[0055] In addition, the number of the feedthrough holes 130 is not particularly limited and can be determined according to specific needs. For example, the number of the feedthrough holes can be 1 or more than 2.

[0056] Figure 5 It shows Figure 4 A partial enlarged view of the middle feed-through electrode. Figure 6 It shows Figure 4 A partially enlarged view of Modification 1 of the middle feed-through electrode.

[0057] In this embodiment, if Figure 5 and Figure 6 As shown, the feed-through holes 130 provided on each ceramic sheet can be filled with feed-through electrodes 110. Specifically, as Figure 6 As described above, the feed-through electrode 110 may include a feed-through electrode 111 in the ceramic sheet 11, a feed-through electrode 112 in the ceramic sheet 12, a feed-through electrode 113 in the ceramic sheet 13, and a feed-through electrode 114 in the ceramic sheet 14. In some examples, the feed-through electrode 110 may pass through the upper and lower surfaces of each ceramic sheet. Specifically, as Figure 4 As described above, the feedthrough electrode 111 may penetrate the upper and lower surfaces of the ceramic sheet 11. The feedthrough electrode 112 may penetrate the upper and lower surfaces of the ceramic sheet 12. The feedthrough electrode 113 may penetrate the upper and lower surfaces of the ceramic sheet 13. The feedthrough electrode 114 may penetrate the upper and lower surfaces of the ceramic sheet 14.

[0058] In some examples, the feedthrough electrode 110 may be composed of at least one selected from platinum, iridium, niobium, tantalum, and gold. From the perspective of biosafety and long-term implant reliability, the feedthrough electrode 110 may be composed of platinum. In some examples, the feedthrough electrode 110 may be composed of more than 99% platinum. In other examples, the feedthrough electrode 110 may be composed of more than 99.99% platinum.

[0059] In some examples, the shape of the feedthrough holes 130 in each ceramic sheet is not particularly limited. In some examples, the feedthrough holes 130 may be rectangular or trapezoidal, and the feedthrough electrodes 110 filled therein may also be rectangular or trapezoidal. In other examples, the feedthrough holes 130 may be cylindrical, and the feedthrough electrodes 110 filled therein may also be cylindrical. After the feedthrough holes 130 on each ceramic sheet are filled with the feedthrough electrodes 110, a complete ceramic sheet is formed.

[0060] In this embodiment, the feed-through electrode 110 can be co-fired with the ceramic sheets 11 to 14 at a temperature of 1450° C. to 1600° C. Thus, the feed-through electrode 110 formed by firing can be bonded to the ceramic substrate 10 as a whole, avoiding the welding technology of ceramic and metal, simplifying the process, and further improving the airtightness and long-term reliability of the ceramic substrate 10.

[0061] In addition, in some examples, such as Figure 5 As shown, the arrangement of each feedthrough hole 130 on each ceramic sheet can be the same. In this case, the ceramic sheets that have been filled with the feedthrough electrodes 110 can be bonded together, so that the feedthrough electrodes 110 can pass through each ceramic sheet. In addition, since the arrangement of each feedthrough hole 130 on each ceramic sheet is the same, the ceramic sheets can also be bonded together, and the feedthrough electrodes 110 are filled between the aligned feedthrough holes 130, so that the process steps can be simplified. In this case, the feedthrough electrode 110 can realize the electrical connection between the upper surface 10a and the lower surface 10b of the ceramic substrate 10.

[0062] In addition, in some examples, such as Figure 6 As shown, the arrangement of the feedthrough holes 130 on each ceramic sheet may be different. In this case, in order to electrically connect the upper surface 10a and the lower surface 10b of the ceramic substrate 10, a patterned wiring conductor 120 may be formed between each ceramic sheet.

[0063] In some examples, such as Figure 6 As shown, patterned wiring conductors 120 (including patterned wiring conductors 121, 122, and 123 stacked sequentially from top to bottom of the ceramic substrate 10) are arranged between adjacent layers of ceramic sheets. In some examples, each feedthrough electrode 110 (including feedthrough electrodes 111, 112, 113, and 114) can penetrate the upper and lower surfaces of the ceramic sheet 11 to the ceramic sheet 14, respectively, and communicate through the patterned wiring conductors 120 to form a conductive electrical connection. As a result, the electrical performance of the ceramic substrate 10 can be improved.

[0064] In some examples, the patterned wiring conductor 120 may be composed of one or more materials selected from tungsten, molybdenum manganese, silver, gold, platinum and alloys thereof. Preferably, the patterned wiring conductor 120 may be composed of platinum slurry. Thus, the patterned wiring conductor 120 may have a smaller resistance and better match the performance parameters of the ceramic substrate 10, thereby making the connection strength between the patterned wiring conductor 120 and the ceramic substrate 10 higher, which can effectively improve the long-term reliability of the ceramic substrate 10.

[0065] In addition, in this embodiment, the shape of the wiring conductor pattern is not particularly limited. In some examples, the wiring conductor pattern can be a regular shape such as a straight line, an S shape, a U shape, etc., or an irregular shape (including a shape formed by combining a regular shape and an irregular shape). Thus, different requirements of different application environments can be met.

[0066] In this embodiment, the feed-through electrode 110 can be co-fired with the patterned wiring conductor 120 and the ceramic sheets 11 to 14 at a temperature of 1450° C. to 1600° C. Thus, the feed-through electrode 110 formed by firing can be bonded to the patterned wiring conductor 120 and the ceramic substrate 10 as a whole, avoiding the welding technology between ceramic and metal, simplifying the process, and further improving the airtightness and long-term reliability of the ceramic substrate 10.

[0067] In the present embodiment, in step S20 , the metal ring 20 is prepared and the metal ring 20 is brazed to the ceramic substrate 10 .

[0068] In some examples, the metal ring 20 may be arranged along the edge of the ceramic substrate 10. Of course, the brazing position of the metal ring 20 may be appropriately adjusted for specific application scenarios and the appearance of the sealing structure 1, and is not limited here.

[0069] In some examples, the metal ring 20 may be made of titanium and its alloys, noble metals (including gold, silver and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum)) and their alloys, medical grade (biograde) stainless steel, tantalum, niobium, Nitinol, or nickel cobalt chromium molybdenum alloy (MP35N), etc. In addition, in this embodiment, the metal ring 20 may be made of the same metal material or different metal materials. In addition, the metal ring 20 is preferably made of titanium or titanium alloy material.

[0070] In this embodiment, in step S30 , the plurality of feed-through electrodes 110 are covered with a solderable plating layer 40 .

[0071] Figure 7 It shows Figure 2 A partial cross-sectional schematic diagram of a modified example 1 of the sealing structure of the implantable device is shown. Figure 8 It shows Figure 2 A partial cross-sectional schematic diagram of a second variation of the sealing structure of the implantable device is shown.

[0072] In addition, in this embodiment, if Figure 7 and Figure 8 As shown, the cross-sectional area of ​​the solderable coating 40 can be larger than the cross-sectional area of ​​the feedthrough hole 130, thereby increasing the metal body area of ​​the solderable coating 40 exposed on the ceramic substrate 10 to enhance the airtightness of the ceramic substrate 10 and the connection reliability between the solderable coating 40 and the circuit board 50.

[0073] In some examples, such as Figure 7 and Figure 8 As shown, the solderable coating 40 may include a stacked first coating 41 and a second coating 42. The material of the first coating 41 may be selected from one of gold, copper, silver or tin, and the material of the second coating 42 may be selected from one of gold, tungsten, molybdenum manganese, silver, platinum or nickel. Here, the selection of the coating is based on biocompatibility. By using the coating composed of the above materials, the performance parameters of the ceramic substrate 10 are matched, and the connection structure strength with the ceramic substrate 10 is high. In particular, the first coating 41 and the second coating 42 can be composed of two layers of gold, and more preferably, the second coating 42 is made of nickel, and then a first coating 41 composed of gold is plated on the nickel.

[0074] In addition, the weldable coating 40 may be formed by at least one of electroplating, chemical plating, ion plating, hot dip plating, spray plating, infiltration plating, and cathode sputtering. In some examples, the weldable coating 40 may be formed by electroplating. The examples disclosed herein are not limited thereto, and for example, chemical plating or ion plating may be used, which is not limited here.

[0075] In the present embodiment, in step S40 , a circuit board 50 with electronic components and pads is prepared, and the circuit board 50 is wire-bonded to the solderable plating layer 40 via the pads.

[0076] After the metal ring 20 is brazed to the ceramic substrate 10 along the edge of the ceramic substrate 10 , the gap or other parts between the circuit board 50 and the ceramic substrate 10 are then filled with resin such as silicone, epoxy resin, etc. This setting method can fully utilize the space inside the sealing structure 1.

[0077] Among them, Figure 7 As shown, the circuit board 50 can be a PCB. The surface of the PCB contains pins. For example, in some examples, the second plating layer 42 is made of nickel and the first plating layer 41 is made of gold. After the solderable plating layer 40 is made, it can be connected to the pins of the PCB through the first plating layer 41, and then through reflow soldering, the nickel is melted by heating to fuse the ceramic substrate 10 with the PCB pad through the pins, and then the nickel is cooled by cooling the reflow soldering to solidify the ceramic substrate 10 and the PCB together, so as to achieve the connection between the PCB and the ceramic substrate 10.

[0078] In some examples, such as Figure 8 As shown, the circuit board 50 may be an integrated circuit board or a chip, which is a pinless structure. At this time, an appropriate number of solder balls on the surface of the integrated circuit board or the chip may be connected to the solderable plating layer 40 to achieve FC (Flip-chip) of the chip.

[0079] Compared with the traditional method of connecting metal to metal (here referring to the feedthrough electrode 110 and the pins on the circuit board 50) by laser welding or bonding, the present disclosure can more conveniently connect the ceramic substrate 10 and the circuit board 50 by coating a layer of weldable coating 40 on the feedthrough electrode 110, and its connection reliability is higher than that of laser welding or bonding.

[0080] In step S50, the metal cover 30 is prepared and bonded to the metal ring 20. In this embodiment, the metal cover 30 may be welded (eg, by laser) to the metal ring 20 on the ceramic substrate 10, thereby obtaining the sealing structure 1 according to this embodiment.

[0081] In this embodiment, the metal cover 30 can be made of titanium and its alloys, precious metals (including gold, silver and platinum group metals (ruthenium, rhodium, palladium, osmium, iridium, platinum) and their alloys, medical grade (biograde) stainless steel, tantalum, niobium, Nitinol, or nickel cobalt chromium molybdenum alloy (MP35N). The metal cover 30 can also be made of titanium or titanium alloy material.

[0082] In addition, if Figure 2 As shown, the sealing structure 1 is roughly cylindrical in shape. In the present embodiment, the dimensions of the cylinder of the typical sealing structure 1 are that the diameter of the bottom surface is about 5 mm to 40 mm, and the height is about 5 mm to 40 mm. Although the sealing structure 1 is shown here as a cylindrical structure, the shape of the sealing structure 1 is not particularly limited, and it may also be other shapes. For example, the sealing structure 1 may also be roughly rectangular in shape, and the dimensions of a typical rectangular shape are, for example, length 10 mm × width 10 mm × height 10 mm. In addition, the sealing structure 1 may also be other regular shapes such as cylindrical, elliptical, triangular, etc., or may be an irregular shape (including a shape formed by combining regular and irregular shapes).

[0083] The above description is only a preferred embodiment of the present disclosure, and does not limit the patent scope of the present disclosure. All equivalent structural changes made by using the contents of the present disclosure and the drawings under the inventive concept of the present disclosure, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present disclosure.

Claims

1. A method for preparing a sealing structure, characterized in that: include: preparing a ceramic substrate having a plurality of feedthrough holes, wherein the plurality of feedthrough holes are filled with feedthrough electrodes; preparing a metal ring, and brazing the metal ring to the ceramic substrate; Covering the plurality of feed-through electrodes with a solderable plating layer; and A circuit board with a solder pad is prepared; the plating layer includes a first plating layer and a second plating layer stacked in sequence, the solder pad is wire-bonded to the first plating layer, and the second plating layer is melted by reflow heating so that the solder pad is fused and welded to the ceramic substrate, wherein the material of the first plating layer is selected from one of gold, copper, silver, and tin, the material of the second plating layer is selected from one of gold, tungsten, molybdenum, manganese, silver, platinum, and nickel, and the material of the second plating layer is different from the material of the feed-through electrode.

2. The preparation method according to claim 1, characterized in that: The feed-through electrode is co-fired with the ceramic substrate at a temperature of 1450° C. to 1600° C. and bonded to the ceramic substrate as a whole.

3. The preparation method according to claim 1, characterized in that: After the second coating layer is cooled, the ceramic substrate and the circuit board are solidified together and connected to the feed-through electrode.

4. The preparation method according to claim 1, characterized in that: The ceramic substrate is formed by stacking and firing multiple layers of ceramic sheets, and patterned wiring conductors are arranged between the ceramic sheets of adjacent layers.

5. The preparation method according to claim 4, characterized in that: The feed-through holes of each ceramic sheet are filled with the feed-through electrodes penetrating the upper and lower surfaces of each ceramic sheet. The feed-through electrodes of each ceramic sheet are arranged differently, and the feed-through electrodes are electrically connected via wiring conductors.

6. The preparation method according to claim 4, characterized in that: The wiring conductor is made of one or more materials selected from tungsten, molybdenum, manganese, silver, gold, and platinum.

7. The preparation method according to claim 1, characterized in that: The invention also comprises a metal cover which is prepared to match with the metal ring, and the metal cover is welded to the metal ring.

8. The preparation method according to claim 1, characterized in that: The brazing temperature of the metal ring is higher than the melting point of the coating.

9. The preparation method according to claim 1, characterized in that: The metal ring is made of titanium or titanium alloy material.

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