Hermetic Feedthrough via Double Drilling and CRMC

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Solution Overview

Problem

Current hermetic terminal designs for active implantable medical devices face challenges in maintaining biocompatibility, resisting degradation under bias current or voltage, and preventing electromagnetic interference (EMI) ingress, while also addressing issues of high cost and reliability, particularly in MRI environments and with the use of expensive platinum materials.

Innovation Solution

A novel hermetic ceramic feedthrough structure using a double drilling process with Ceramic Reinforced Metal Composite (CRMC) materials, where alumina ceramic insulators are pre-sintered and ball milled to create a thermally stable phase, allowing for the direct injection of platinum and forming a robust, compact, and cost-effective conductive pathway system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional hermetic terminal designs use platinum materials and conventional manufacturing processes, then biocompatibility and resistance to degradation are achieved, but cost increases and device complexity increases

Engineering Contradiction:

Improvebiocompatibility and resistance to degradationVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses composite co-fired filled via structures combining ceramic materials (alumina, zirconia) with metallic materials (platinum, palladium, nickel) to create hermetic feedthroughs that maintain biocompatibility and degradation resistance while enabling more efficient manufacturing processes compared to traditional single-material approaches

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent combines multiple manufacturing steps into a single co-firing process where ceramic bodies and metallic fills are sintered simultaneously, reducing the number of separate manufacturing operations and lowering overall process complexity while maintaining product reliability

Inventive Principle:

Principle #5Merging (Combining)

2Manufacturing precision

If hermetic terminals use conventional single drilling process, then manufacturing is simpler, but manufacturing precision and hermeticity are compromised

Engineering Contradiction:

Improvevia hole alignment and hermeticityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent divides the drilling process into two sequential steps: first drilling through the green ceramic body, then drilling through the fired ceramic. This segmentation allows each drilling operation to be optimized independently, achieving precise via hole alignment and hermeticity that would be difficult to achieve with a single drilling process

Inventive Principle:

Principle #1Segmentation

3Productivity

If hermetic feedthroughs use traditional manufacturing processes, then process simplicity is maintained, but productivity and cost-effectiveness decrease

Engineering Contradiction:

Improvemanufacturing efficiency and cost-effectivenessVSAvoidmanufacturing process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent performs preliminary drilling of via holes in the green ceramic body before firing, and then performs a second drilling after firing to complete the through-holes. This preliminary action approach allows for better control of drilling operations and enables more efficient manufacturing with higher productivity compared to traditional single-step processes

Inventive Principle:

Principle #10Preliminary action

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 results in smaller, more reliable, and cost-effective hermetic feedthroughs with increased conductive pathway counts, improved thermal stability, and reduced risk of EMI ingress, enhancing the longevity and performance of implantable medical devices.

Implementation Method 1

alumina ceramic insulators are pre-sintered and ball milled to create a thermally stable phase

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

alumina ceramic insulators are pre-sintered and ball milled to create a thermally stable phase

Methodology Applied

Scientific EffectBall milling:

Implementation Method 3

platinum and alumina co-fire materials as the active conductive pathways

Methodology Applied

Scientific EffectCo-firing: Sintering

Data Source

PatentUS10559409B2Process for manufacturing a leadless feedthrough for an active implantable medical device

Publication Date: 2020.02.11 GREATBATCH LTD

AI summary

A method for manufacturing a feedthrough dielectric body for an active implantable medical device includes the steps of first forming a ceramic reinforced metal composite (CRMC) paste by mixing platinum with a ceramic material to form a CRMC material, subjecting the CRMC material to a first sintering step to thereby form a sintered CRMC material, ball-milling or grinding the sintered CRMC material to form a powdered CRMC material; and then mixing the powdered CRMC material with a solvent to form the CRMC paste. The method further includes forming an alumina ceramic body in a green state, forming at least one via hole through the alumina ceramic body, filling the via hole with the CRMC paste, drying the ceramic body including the CRMC paste to form a first CRMC material filling the via hole, forming a second via hole through the first CRMC material, providing a metal core in the second via hole, and subjecting the ceramic body including the first CRMC material and the metal core to a second sintering step to thereby form the dielectric body. The dielectric body is then sealed in a ferrule opening to form a feedthrough.