3D Printed Ceramic Metal Feedthroughs for Implantable Devices
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Solution Overview
Problem
The challenge in creating a hermetic seal for implantable medical devices, such as cochlear implants, lies in the difficulty of bonding dissimilar materials like ceramics and metals, which results in poor adhesion and thermal stress due to differences in material properties and expansion coefficients.
Innovation Solution
A 3D printing process is used to create a hermetic electrical feedthrough assembly with a sintered structure of ceramic insulator material and metallized conductive vias, forming a gradient transition interface for a mechanical bond, and the assembly is sealed within a metallic ferrule, reducing the number of joining steps and facilitating miniaturization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional bonding techniques are used to join ceramic and metal feedthrough components, then the hermetic seal is achieved, but the adhesion is poor and thermal stress occurs due to mismatched expansion coefficients
Solution Approach 1:
The patent employs a composite material structure consisting of a ceramic feedthrough body with an integrated metallized layer. This composite construction combines the electrical insulation properties of ceramic with the electrical conductivity and mechanical bonding capabilities of metal, creating a unified structure that eliminates traditional bonding interfaces and their associated adhesion and thermal stress problems.
Solution Approach 2:
The patent utilizes a metallization process that changes the physical and chemical parameters of the ceramic surface by depositing a metallic layer. This parameter change enables the ceramic to be directly bonded to metal components through conventional metal-to-metal bonding techniques, resolving the incompatibility between ceramic and metal bonding.
2Reliability
If multiple separate components are assembled to form the feedthrough, then the hermetic seal can be achieved, but the manufacturing complexity and number of joining steps increase
Solution Approach 1:
The patent merges the ceramic insulator and metal conductor into a single integrated feedthrough component through metallization. The ceramic body with embedded metallized traces forms a unified structure that combines insulation and conduction functions, eliminating the need for separate ceramic-to-metal bonding operations and reducing manufacturing complexity.
Solution Approach 2:
The metallized ceramic feedthrough serves multiple functions simultaneously: it provides electrical insulation through the ceramic matrix, electrical conduction through the metallized traces, mechanical support through the ceramic body, and bonding surfaces for metal components. This multi-functionality reduces the number of separate components and joining steps required.
3Reliability
If conventional feedthrough designs are used, then basic electrical insulation is provided, but miniaturization and integration of complex circuit components are limited
Solution Approach 1:
The patent transitions from planar circuit traces to three-dimensional embedded conductive pathways within the ceramic structure. Complex circuit components such as capacitors, inductors, and multi-layer trace patterns are integrated within the volumetric ceramic body, enabling miniaturization while maintaining electrical insulation performance through the ceramic matrix.
Solution Approach 2:
The patent implements nested structures where conductive elements, circuit components, and bonding interfaces are embedded within the ceramic feedthrough body. Multiple functional layers are nested within the ceramic matrix, allowing complex circuitry to be contained within a compact volume while maintaining electrical insulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a robust, hermetic seal that minimizes moisture and fluid ingress, enhances bonding between ceramic and metal components, and allows for complex geometries and embedded circuit components, improving the reliability and functionality of implantable medical devices.
Implementation Method 1
A 3D printing process is used to create a hermetic electrical feedthrough assembly with a sintered structure of ceramic insulator material and metallized conductive vias
Implementation Method 2
A 3D printing process is used to create a hermetic electrical feedthrough assembly with a sintered structure of ceramic insulator material and metallized conductive vias
Data Source
AI summary
An electrical feedthrough assembly for an implantable medical device includes an outer ferrule of metallic material having an outer surface hermetically sealed to an implantable device housing. There is an inner feedthrough assembly which is hermetically sealed within the ferrule and which has a structure of sintered layers that include: i. an electrical insulator of ceramic insulator material, ii. one or more electrically conductive vias of metallized conductive material embedded within and extending through the electrical insulator, and iii. a transition interface region around each of the conductive vias comprising a gradient mixture of the ceramic insulator material and the metallized conductive material forming a gradual transition and a mechanical bond between the electrical insulator and the conductive via.