Embedded Metallic Structures in Glass Wafer Hermetic Sealing

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Solution Overview

Problem

Implantable medical devices face challenges in achieving a small size, hermetic sealing, and bio-stability when exposed to bodily fluids, as current materials and designs fail to provide an effective barrier against fluid exposure and conductive trace protection.

Innovation Solution

The integration of embedded metallic structures within a glass wafer structure, including a conductive trace on a first wafer filled with conductive material, a planarized insulation layer, and a bonded second wafer, which forms a hermetically sealed and bio-stable package, allowing for thicker walls and reduced device size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the housing wall thickness is increased to provide better hermetic sealing and protection, then the reliability and bio-stability improve, but the overall device size increases

Engineering Contradiction:
Improvehermetic sealing effectivenessVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent embeds metallic structures (conductive traces and via fills) directly within the glass housing walls themselves, nesting the electrical interconnect features inside the protective barrier. This eliminates the need for separate internal cavities or thicker walls to accommodate traces, allowing thin-walled hermetic packaging while maintaining electrical connectivity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from planar conductive traces on surfaces to three-dimensional embedded structures within the glass matrix. By moving conductive elements into the third dimension (within the wall thickness), the design achieves both protection and connectivity without increasing external device dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional hermetic sealing methods are used, then the protection against bodily fluids is provided, but the device size and complexity increase

Engineering Contradiction:
Improveprotection against bodily fluidsVSAvoidhousing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the housing structure with the electrical interconnect structure by embedding conductive traces and via fills directly within the glass housing material. This combination eliminates separate components for sealing and electrical connection, reducing overall device complexity while maintaining hermetic protection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses glass as a composite material that simultaneously provides hermetic sealing, structural integrity, and embedded electrical connectivity. The glass housing integrates multiple functions (protection, structural support, and electrical interconnection) into a single material system, simplifying the overall device architecture.

Inventive Principle:
Principle #40Composite materials

3Reliability

If metallic structures are embedded in glass, then the hermetic seal and bio-stability are improved, but the manufacturing process complexity increases

Engineering Contradiction:
Improvebio-stabilityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent forms conductive via fills and traces within the glass housing during the housing fabrication process itself, before final assembly. By performing electrical interconnect formation as a preliminary step during glass processing, the manufacturing sequence is optimized to reduce overall process complexity despite the advanced embedding technique.

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 enhances the life expectancy of implantable medical devices by providing a robust, hermetically sealed, and bio-stable environment that protects conductive traces from bodily fluids, extending the device's operational life while minimizing size.

Implementation Method 1

the housing (packaging) of the medical devices needs to provide a hermetic seal to separate the internal circuits of the device from the bodily fluids of the patient

Methodology Applied
Scientific EffectHermetic sealing: Physical Containment

Implementation Method 2

The first wafer has at least one first wafer via filled with conductive material. The at least one conductive trace is formed on a surface of the first wafer. The at least one conductive trace is in contact with the at least one first wafer via that is filled with the conductive material

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The planarized insulation layer is formed over the first wafer and at least one conductive trace. The planarized insulation layer further has at least one insulation layer via that provides a path to a portion of the at least one conductive trace

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

The second wafer is bonded to the planarized insulation layer

Methodology Applied
Scientific EffectWafer bonding: Welding

Data Source

PatentEP3381050B1Embedded metallic structures in glass
Publication Date: 2022.08.24 MEDTRONIC INC
  • EP3381050B1 patent drawingFigure 1
  • EP3381050B1 patent drawingFigure 2A~2C
  • EP3381050B1 patent drawingFigure 3

AI summary

A device having embedded metallic structures in a glass is provided. The device includes a first wafer, at least one conductive trace, a planarized insulation layer and a second wafer. The first wafer has at least one first wafer via that is filled with conductive material. The at least one conductive trace is formed on the first wafer. The at least one conductive trace is in contact with the at least one first wafer via that is filled with the conductive material. The planarized insulation layer is formed over the first wafer and at least one conductive trace. The planarized insulation layer further has at least one insulation layer via that provides a path to a portion of the at least one conductive trace. The second wafer is bonded to the planarized insulation layer.