Monolithic Hermetic Feedthrough With Integrated Ribbon Cable Vias

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Solution Overview

Problem

Existing hermetic feedthroughs for surgically implanted medical devices, such as ocular implants and brain-machine interfaces, are prohibitively expensive and prone to leaks due to the high number of vias required, which are typically drilled and filled with conductive material.

Innovation Solution

A method of manufacturing a biocompatible hermetic feedthrough with integrated ribbon cable, involving photolithographic formation of a silicon mold with doped pillars, melting glass around the pillars, grinding to planarize, and microfabricating a thin film ribbon cable with conductors attached to the vias, forming a monolithic, hermetically sealed electrical device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If conventional drilling methods are used to create vias in hermetic feedthroughs, then individual through-holes can be formed, but the process becomes prohibitively expensive and time-consuming when hundreds or thousands of vias are required

Engineering Contradiction:
Improvenumber of viasVSAvoidmanufacturing time and cost
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The invention divides the feedthrough substrate into multiple separate substrates, each containing a manageable number of vias. This segmentation allows each substrate to be processed efficiently through individual drilling and via formation, avoiding the prohibitive costs and time requirements of creating thousands of vias in a single large substrate. The multiple substrates can then be assembled together to achieve the desired total number of connections.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If the number of vias in hermetic feedthroughs is increased to provide sufficient connections for implants, then more connections are available, but the likelihood of leaks and defects increases

Engineering Contradiction:
Improvenumber of connectionsVSAvoidhermetic seal integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

By dividing the total number of vias across multiple separate substrates rather than concentrating them in one large substrate, the invention reduces the statistical probability of leaks and defects. Each substrate contains fewer vias, making quality control and defect detection more manageable. The hermetic seal integrity is maintained across multiple smaller, more reliable connections rather than risking failure across a single large array.

Inventive Principle:
Principle #1Segmentation

3Reliability

If ball seal connectors are used to achieve hermetic sealing, then connections can be made, but the connectors are quite large and add device complexity

Engineering Contradiction:
Improvehermetic sealVSAvoidconnector size and integration
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the connector functionality directly into the feedthrough substrates themselves. The electrical connections and hermetic sealing are integrated into the substrate structure, eliminating the need for separate ball seal connectors. This integration reduces device complexity and size while maintaining hermetic seal reliability, as the sealing function is built into the fundamental structure rather than added as a separate component.

Inventive Principle:
Principle #5Merging (Combining)

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

The method enables the creation of hermetically sealed feedthroughs with thousands of vias that are well-sealed with minimal opportunities for leaks, reducing production costs and improving reliability for biocompatible medical devices.

Implementation Method 1

heating the glass composition to a reflow temperature such that at least a portion of the heated glass composition flows around the pillars

Methodology Applied
Scientific EffectReflow: Melting

Implementation Method 2

conductive vias through a hermetic feedthrough

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3997045B1Monolithic, biocompatible feedthrough for hermetically sealed electronics and methods of manufacture
Publication Date: 2025.04.16 NEURALINK CORP
  • EP3997045B1 patent drawingFigure 1A~1C
  • EP3997045B1 patent drawingFigure 2
  • EP3997045B1 patent drawingFigure 3

AI summary

Methods of manufacturing a biocompatible, hermetic feedthrough monolithically integrated with a biocompatible ribbon cable are described, as well as the resulting devices themselves. The hermetic feedthrough is created by placing glass over a mold of doped silicon or other material with a higher melting temperature than the glass and heating it to reflow the glass into the mold. The glass is then ground or otherwise removed to reveal a flat surface, and tiny pillars that were in the mold are isolated in the glass to form electrically conductive vias. The flat surface is used to cast a polymer and build up a ribbon cable, photolithographically or otherwise, that is monolithically attached to the vias.