Implantable electrical contact assembly

Abstract

An implantable electrical contact assembly is described having at least one electrode body assembly completely surrounded by a biocompatible electrically insulating material, the electrode body assembly having at least one electrode surface indirectly or directly surrounded by a biocompatible electrically insulating material, the electrode body assembly having a stacked layer composite, the layer composite has a metallization layer at least on the ceramic substrate by means of an adhesive layer. The invention is characterized in that the stacked layer composite is connected to the passivation layer by forming a covalent bond, and the stacked layer composite is completely surrounded by the passivation layer except for at least one surface region of the metallization layer facing away from the layer composite, the passivation layer having a passivation layer surface facing away from the stacked layer composite, a biocompatible electrically insulating material is indirectly or directly adjacent to the surface, and a passivation layer is deposited on the stacked layer composite by plasma enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD) or a wet chemical coating process.

Description

Technical Field

[0001] The present invention describes an implantable electrical contact component having at least one electrode body component that is completely surrounded by a biocompatible electrically insulating material, the electrode body component having at least one electrode surface that is indirectly or directly surrounded by the biocompatible electrically insulating material, wherein the electrode body component has a stacked layer composite that has a metallization layer at least on a ceramic substrate via an adhesive layer.

[0002] A special requirement in the manufacture and design of implantable electrical contact components is to avoid the ingress and / or penetration of water or moisture into and / or through the material interfaces contained in the electrical contact component, via which the electrical conductors or conductor structures are in electrical contact with one another. Water coming into contact with the electrically conductive wires and electrode structures, which are usually made of metallic materials, can lead to irreversible degradation phenomena and to associated impairments of the electrical energy and signal transmission properties. In addition, a long-term humid environment can lead to delamination phenomena between the metallic structures contained in the electrical contact component and the immediately surrounding surfaces, which are usually made of polymer materials, thereby ultimately shortening the service life of such contact components. Background Art

[0003] From the article "Metallurgical Design of Metallurgical Materials" published by Patrick Kiele et al. in IEEE Transactions on Components, Packaging and Manufacturing Technology, Vol. 10, No. 11, 2020 It is known from the publication "Keramic Basis for Active Implantate" that when manufacturing medical implants with electrical connections or contact structures, the electrical connections or contact structures are manufactured on a ceramic substrate, preferably in the form of an Al2O3 substrate, by a conventional metal vapor deposition process, such as a sputtering process, and better results can be achieved in terms of adhesion compared to the use of a screen printing process with a metal paste and a subsequent high-temperature treatment. In particular, when manufacturing such electrical contact structures, the adhesion on the aluminum oxide substrate can be improved by a metallization process in which platinum is sputtered on an adhesion layer made of tungsten-titanium, thereby achieving good results. The contact component manufactured in this way is subsequently potted with a biocompatible electrically insulating material to protect the internal contact component from the influence of the humid environment in the body.

[0004] Document DE 10 2016 222 710 A1 discloses an implantable electrical contact component having at least one electrode body component which is otherwise completely surrounded by a biocompatible electrically insulating material and which has at least one freely accessible electrode surface which is indirectly or directly surrounded by the biocompatible electrically insulating material. Summary of the invention

[0005] The object of the present invention is to improve an implantable electrical contact component, which has at least one electrode body component completely surrounded by a biocompatible electrically insulating material, and the electrode body component has at least one electrode surface indirectly or directly surrounded by the biocompatible electrically insulating material, wherein the electrode body component has a stacked layer composite, which has a metallization layer at least on a ceramic substrate via an adhesive layer, so that the resistance of the implantable electrical contact component surrounded by the biocompatible electrically insulating material to moisture or water from the humid environment in the body should be significantly improved, so as to extend the service life of the medical implant and the maximum operating time in the body specified by the manufacturer in this way.

[0006] The solution to the problem on which the invention is based is specified in claim 1. Further developments of the subject matter of the invention are characterized by the dependent claims and by the further description, with reference in particular to the drawings.

[0007] The implantable electrical contact assembly according to the invention according to the features of the preamble of claim 1 is characterized in that the stacked layer composite of the electrode body assembly is connected to the passivation layer by forming covalent bonds and, with the exception of at least one surface region of the metallization layer facing away from the layer composite, the stacked layer composite is completely enclosed by the passivation layer. In addition, the passivation layer has a passivation layer surface facing away from the stacked layer composite, to which the biocompatible electrically insulating material is indirectly or directly adjacent and on which covalent bonds are formed with the biocompatible electrically insulating material in a similar manner to the side surfaces of the layer composite.

[0008] Due to the covalent or chemical bonds formed between the surface of the stacked layer composite and the passivation layer, and preferably also between the passivation layer and the biocompatible electrically insulating material, which are based on the interaction of the outer electrons of atoms and / or molecules, the penetration of moisture or water is at least almost completely excluded, at least in the region of the electrical contact component encapsulated by the biocompatible electrically insulating material. In this way, delamination between the interfaces of two adjacent material layers, for example, interfaces within the stacked layer composite, and interfaces between the passivation layer and the stacked layer composite, and also interfaces between the passivation layer and a shell consisting of the biocompatible electrically insulating material surrounding the passivation layer, can be largely avoided.

[0009] Similar to the deposition of the adhesion layer on the ceramic substrate and the deposition of the metallization layer on the adhesion layer, plasma enhanced chemical vapor deposition (PECVD) is suitable for depositing the passivation layer on the stacked layer composite and, if necessary, on existing surface areas of the ceramic substrate. Alternatively, physical vapor deposition (PVD) or wet chemical coating of the passivation layer on the stacked layer composite and, if applicable, adjacent surface areas of the ceramic substrate is also suitable.

[0010] The passivation layer is arranged all over the surface of the stacked layer composite, with the exception of at least one surface area of ​​the metallization layer which is provided for electrical contact with an electrical conductor structure, preferably in the form of a wire, one wire end of which is permanently and firmly electrically contacted with the surface area of ​​the metallization layer provided for contact by means of a welding, bonding or adhesive connection.

[0011] After the corresponding electrical contacts have been established on the freely accessible surface areas of the metallization layer, the stacked layer composite, which is completely coated with the passivation layer except for the above-mentioned areas, together with the ceramic substrate is surrounded by a biocompatible electrically insulating material, which preferably consists of a polymer and which, during the casting process, can seamlessly surround the stacked layer composite and the ceramic substrate in a viscous state, and which is then converted into a solid state by curing. Particularly preferred are polymers of the following types: silicone rubber, polyimide, liquid crystal polymer (LCP) or parylene.

[0012] The encapsulation formed by curing of the biocompatible electrically insulating material likewise surrounds the electrical conductor structure which is in electrical contact with the stacked layer composite.

[0013] The electrical conductor structure which is electrically conductively connected to at least one surface area of ​​the metallization layer can in principle have any function and form. For example, the electrical conductor structure represents an independent electrical component which is connected to the metallization layer via at least one electrical connection and is also coated by the passivation layer apart from its electrical connection.

[0014] The stacked layer composite is preferably realized in a manner corresponding to the construction described by Kiele et al. in the above-cited publication, i.e. a titanium or tungsten-titanium layer is applied as an adhesion layer to an aluminum oxide layer as a ceramic substrate, and a platinum or gold layer is then applied to the adhesion layer in the form of a metallized layer.

[0015] In principle, one of the following compounds is suitable for the passivation layer: silicon oxide, silicon carbide, silicon nitride or silicon oxynitride. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be described exemplarily below by way of examples and with reference to the accompanying drawings, but the general concept of the present invention is not limited thereto. The accompanying drawings show:

[0017] Figure 1a perspective top view of an implantable electrical contact assembly; and

[0018] Figure 2 Longitudinal section through an implantable electrical contact assembly in the region of contact with an electrical conductor structure. DETAILED DESCRIPTION

[0019] Figure 1 A stereoscopic view of an implantable electrical contact structure constructed according to the present invention is schematically shown, which electrical contact structure is used for the electrical connection between an electrical conductor 1 leading to a medical active implant (not shown) and a corresponding electrical input / output conductor 2 leading to an implantable power supply unit (not shown), which provides electrical energy and control signals for the operation of the medical implant.

[0020] For the one-to-one contacting between the electrical conductor 1 and the electrical input / output conductor 2, two (preferably identically constructed) electrical contact components 3 are used, each of which has a layered structure. Figure 2 The cross-sectional view is schematically shown.

[0021] On the one hand, electrical contacts 11 are used for electrical contacting of electrical conductors 1, and electrical contacts 12 are used for electrical contacting of electrical input / output conductors 2. The individual electrical contacts 11 and 12 are each electrically connected to one another in pairs via metallization layers in the form of conductor tracks 13.

[0022] On a ceramic substrate 4, preferably made of Al2O3, an adhesion layer 5, preferably made of WTi or Ti, is deposited by physical vapor deposition (PVD), on the surface of which a metallization layer 6, preferably in the form of platinum or gold, is likewise deposited using a PVD coating process.

[0023] The deposition processes for structuring the metallization layer 6 are each carried out using a suitable structured mask in order to be able to carry out a minimally dimensioned and geometrically restricted layer deposition on the Al 2 O 3 substrate 4 in this way.

[0024] Furthermore, a passivation layer 7 is applied to the surface of the metallization layer 6 and to the surrounding surface area of ​​the ceramic substrate 4, likewise by means of PVD coating. Silicon oxide is preferably suitable as the passivation layer 7, which can form covalent bonds with the metallization layer 6 and the ceramic layer 4, respectively. Only the surface area of ​​the metallization layer 6, which is subsequently provided for electrical contacting with the corresponding input / output line 2 or electrical line 1, remains uncoated with the passivation layer 7.

[0025] exist Figure 2In the embodiment, the surface area 8 of the metallization layer 6 provided for making electrical contact with the input / output conductor 2 is not covered by the passivation layer 7. The end of the input / output conductor 2 is directly in contact with the surface area 8 of the metallization layer 6 provided for making contact and is electrically and mechanically firmly connected to the surface area via a soldering, bonding or adhesive connection 9.

[0026] In order to preferably completely surround or encapsulate the implantable electrical contact component 3, the biocompatible electrically insulating material 10 is preferably applied to the surface of the passivation layer 7 by a casting process and forms a covalent bond with the passivation layer. In addition, the biocompatible electrically insulating material 10 also surrounds the electrical contact area 3 and, at least in the case of the electrical contacts 12, the electrical input / output conductors 2, similar to the matrix directly surrounding the electrical input / output conductors 2, which are electrically insulated from each other by the biocompatible electrically insulating material 10 and are also supported mechanically stably.

[0027] The metallization layer 6 is used for the electrical connection between the electrical contacts 11 and 12. The metallization layer is respectively configured in the form of individual printed conductors between the contact points and locally connects the contact points 11 and 12 in pairs. With the exception of the surface areas 8 of the metallization layer 6 provided at the electrical contacts 11 and 12 for contacting the electrical wires 1 and the electrical input / output wires 2, the passivation layer 7 is completely deposited on the upper and lower surfaces of the ceramic substrate 4 and the printed conductors 13, thereby forming a uniform surface for forming a covalent bond with the biocompatible electrically insulating material layer 10 composed of a polymer material applied thereon.

[0028] Reference numerals list

[0029] 1-Electrical wire

[0030] 2-Electrical input / output wires

[0031] 3-Electrical contact components

[0032] 4-Ceramic substrate

[0033] 5- Adhesion layer

[0034] 6-Metalization layer

[0035] 7-Passivation layer

[0036] 8-Surface area of ​​metallization layer

[0037] 9- Welding, bonding or adhesive connection

[0038] 10-Biocompatible electrical insulating materials

[0039] 11-Electrical contacts

[0040] 12-Electrical contacts

[0041] 13-Printed conductor

Claims

1. An implantable electrical contact component (3), comprising at least one electrode body component completely surrounded by a biocompatible electrically insulating material (10), the electrode body component having at least one electrode surface indirectly or directly surrounded by the biocompatible electrically insulating material (10), wherein: The electrode body assembly comprises a stacked layer composite which comprises a metallization layer (6) at least on a ceramic substrate (4) via an adhesive layer (5). characterised in that the stacked layer composite is connected to the passivation layer (7) by forming covalent bonds and that, with the exception of at least one surface region (8) of the metallization layer (6) facing away from the layer composite, the stacked layer composite is completely surrounded by the passivation layer, The passivation layer (7) has a passivation layer surface facing away from the stacked layer composite, the biocompatible electrically insulating material (10) being directly or indirectly adjacent to the passivation layer surface, and The passivation layer (7) is deposited on the stacked layer composite by plasma enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD) or wet chemical coating.

2. The contact assembly according to claim 1, It is characterized in that At least one surface area (8) of the metallization layer (6) not covered by the passivation layer (7) corresponds to at least one electrode surface, on which the electrical conductor (1) or the electrical input / output conductor (2) makes contact.

3. The contact assembly according to claim 1 or 2, It is characterized in that The metallization layer (6) is a platinum layer or a gold layer.

4. The contact assembly according to any one of claims 1 to 3, It is characterized in that The adhesion layer (5) is a WTi layer or a titanium layer.

5. The contact assembly according to any one of claims 1 to 4, It is characterized in that The passivation layer (7) is a silicon oxide layer, a silicon carbide layer, a silicon nitride layer or a silicon oxynitride layer.

6. The contact assembly according to any one of claims 1 to 5, It is characterized in that The biocompatible electrically insulating material (10) is composed of a polymer.

7. The contact assembly according to claim 6, It is characterized in that The polymer is one of the following polymers: silicone rubber, polyimide, liquid crystal polymer (LCP), parylene.

8. The contact assembly according to any one of claims 1 to 7, It is characterized in that The biocompatible electrically insulating material (10) is selected such that it is connected to the passivation layer (7) at least via covalent bonds.

9. The contact assembly according to any one of claims 1 to 8, It is characterized in that The electrical component is connected to the metallization layer (6) via at least one electrical connection (129), and the electrical component is coated by the passivation layer (7) except for its electrical connection.

10. The contact assembly according to any one of claims 1 to 9, It is characterized in that The stacked layer composite is connected to the passivation layer (7) exclusively by forming covalent bonds.

11. The contact assembly according to any one of claims 1 to 10, It is characterized in that The surface of the passivation layer is connected to the biocompatible electrical insulating material (10) only by forming a covalent bond.

12. The contact assembly according to any one of claims 2 to 11, It is characterized in that The electrical contacting of the electrical line (1) or the electrical input / output line (2) is achieved by means of a soldered, bonded or adhesive connection (9).

13. The contact assembly according to any one of claims 1 to 12, It is characterized in that The ceramic substrate (4) comprises oxide ceramic.

14. The contact assembly according to claim 13, It is characterized in that The oxide ceramic is Al2O3 or ZrO2.

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