Hermetic Feedthrough via Controlled Oxidation of Titanium Substrate
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Solution Overview
Problem
Existing methods for manufacturing hermetic and electrically isolated feedthroughs in metal casings, particularly for implantable medical devices, face challenges such as complexity, high cost, and difficulty in reducing the center-to-center pitch between adjacent feedthroughs, due to the need for thick isolating layers that can cause mechanical stress and deformation, and may compromise hermeticity and electrical isolation over time.
Innovation Solution
A method involving a metallic substrate thinning and controlled oxidation to create a monolithically integrated feedthrough with lateral vertical isolation, allowing for reduced substrate thickness and enabling the production of multiple, closely spaced feedthroughs with enhanced mechanical holding and hermeticity, without the need for final substrate thinning, and allowing for additional components like capacitors to be integrated simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick isolating layers are used to provide electrical isolation and hermeticity, then electrical isolation and hermeticity are improved, but mechanical stress and deformation increase, and device complexity increases
Solution Approach 1:
The patent changes the physical-chemical state of the isolating material by using controlled oxidation to convert metallic substrate material into oxide layers in-situ. This transformation provides electrical isolation and hermeticity without requiring thick deposited layers, thereby reducing mechanical stress and deformation while maintaining reliability.
Solution Approach 2:
The patent replaces the mechanical deposition of thick isolating layers with a chemical oxidation process. Instead of physically depositing thick insulating material that causes mechanical stress, the method uses controlled oxidation to grow oxide layers in-situ, substituting a chemical process for a mechanical one and eliminating the associated mechanical problems.
2Reliability
If thick isolating layers are used to ensure hermeticity, then hermeticity is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functions of electrical isolation and hermeticity into a single integrated oxide layer formed by controlled oxidation. Instead of requiring separate thick isolating layers and additional hermetic sealing structures, the oxidation process creates a unified structure that provides both functions simultaneously, reducing device complexity and manufacturing steps.
Solution Approach 2:
The patent employs self-service by using the substrate material itself as the source of the isolating material through oxidation. The metallic substrate is converted in-situ into oxide layers that provide both electrical isolation and hermeticity, eliminating the need for separate isolating material deposition and reducing manufacturing complexity.
3Manufacturing precision
If traditional feedthrough manufacturing methods are used, then electrical isolation is achieved, but the center-to-center pitch between adjacent feedthroughs cannot be reduced
Solution Approach 1:
The patent applies local quality by performing controlled oxidation in specific localized regions where feedthroughs are required. The oxidation is confined to precise areas around through-elements, creating isolating oxide layers only where needed. This localized approach enables reduced center-to-center pitch between adjacent feedthroughs while maintaining electrical isolation, as each feedthrough's isolating layer is formed independently in its specific location without requiring extensive spacing.
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 enables the production of robust, miniaturized feedthroughs with reduced center-to-center pitch, ensuring mechanical stability and hermeticity, while allowing for the integration of additional components like capacitors, thereby reducing manufacturing complexity and cost.
Implementation Method 1
performing a controlled oxidation of the substrate material, including an oxidation of the lateral walls of the trench up to i) complete filling of the free inner volume of the trench by growth of the oxide in this free inner volume
Data Source
AI summary
A device casing includes a wall having a metallic substrate and electrical connection of a feedthrough that includes a metal through-element made at least in a zone of isolation of the area of the feedthrough from the substrate material, in the form of an islet of closed contour, physically and electrically isolated from the substrate. An interface for coupling the through-element to the substrate provides the mechanical securing of the through-element to the substrate and the electrical isolation thereof and includes a peripheral lateral layer made of an electrically isolating material that surrounds the through-element over the whole periphery thereof and extends transversally through the thickness of the thinned area of the substrate. The substrate, the through-element and the lateral layer form a monolithically integrated unit, and the lateral layer provides essentially and directly both the mechanical securing and the electrical isolation between through-element and substrate.