Laser-Bonded Feedthrough Assemblies for Hermetic Sealing
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Solution Overview
Problem
Existing feedthrough assemblies for hermetically sealed enclosures, such as those in implantable medical devices, face challenges in maintaining electrical coupling stability under various environmental conditions without using high-temperature processes or ferrules, which can introduce material stresses and require complex sealing methods.
Innovation Solution
A feedthrough assembly is formed using a non-conductive substrate with a via and a conductive material, where an external contact is laser-bonded to the substrate, creating a hermetic seal without ferrules or high-temperature brazing, allowing for low-stress assembly and internal metallization for electronic device integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass or ceramic insulators are used with high-temperature sealing processes, then hermetic sealing is achieved, but material stress and process complexity increase
Solution Approach 1:
The patent removes the ferrule component and high-temperature sealing process from the feedthrough assembly. Instead of using traditional glass or ceramic insulators requiring brazing or wetting processes, the invention uses a substrate with a via and conductive material that can be sealed at lower temperatures, eliminating the complex high-temperature sealing step while maintaining hermetic sealing.
Solution Approach 2:
The patent changes the sealing temperature parameter from high-temperature processes (required for glass/ceramic insulators) to low-temperature processes. This is achieved by using alternative materials and sealing methods that can form hermetic seals at lower temperatures, reducing material stress and process complexity.
2Reliability
If high-temperature brazing or wetting processes are used, then feedthroughs are sealed, but material stress increases
Solution Approach 1:
The patent changes the sealing temperature parameter from high-temperature processes to low-temperature processes. By using alternative sealing methods that operate at lower temperatures, the invention reduces thermal stress on the materials while still achieving reliable hermetic sealing of the feedthrough.
Solution Approach 2:
The patent uses a composite structure consisting of a substrate, via, and conductive material that can be sealed together at lower temperatures. This composite approach allows for thermal expansion coefficient matching and reduced stress compared to traditional dissimilar material joints requiring high-temperature brazing.
3Reliability
If ferrules are used in feedthrough assemblies, then electrical isolation is achieved, but assembly complexity increases
Solution Approach 1:
The patent removes the ferrule component from the feedthrough assembly. Instead of using a separate ferrule for electrical isolation and mechanical support, the invention integrates these functions into the substrate and via structure, simplifying the overall assembly while maintaining electrical isolation.
Solution Approach 2:
The patent merges the functions of the ferrule, insulator, and mechanical support structure into a single integrated substrate assembly. The substrate with via and conductive material combines electrical isolation, structural support, and sealing functions that were previously distributed across multiple components including the ferrule.
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 solution provides a stable, low-temperature method for forming hermetically sealed feedthroughs that reduce material stress and enable efficient electrical coupling, facilitating the integration of electronic devices within implantable medical devices while maintaining environmental integrity.
Implementation Method 1
attaching the external contact to the outer surface of the non-conductive substrate by a laser bond that surrounds the via and hermetically seals the external contact to the outer surface of the non-conductive substrate
Data Source
Figure 1A
Figure 1B~2
Figure 3~4
AI summary
Various embodiments of a feedthrough assembly and methods of forming such assemblies are disclosed. In one or more embodiments, the feedthrough assembly can include a non-conductive substrate and a feedthrough. The feedthrough can include a via from an outer surface to an inner surface of the non-conductive substrate, a conductive material disposed in the via, and an external contact disposed over the via on the outer surface of the non-conductive substrate. The external contact can be electrically coupled to the conductive material disposed in the via. And the external contact can be hermetically sealed to the outer surface of the non-conductive substrate by a bond surrounding the via. In one or more embodiments, the bond can be a laser bond.