Hermetic Electrical Feedthrough via Laser Welding

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Solution Overview

Problem

Existing methods for creating hermetic electrical feedthroughs in substrate pieces, such as those with optoelectronic or mobile device sensors, face challenges like warping and non-planar surfaces due to heating during cementing or soldering, leading to unreliable seals and high manufacturing costs, while laser welding methods are complex and costly with potential gas leakage issues.

Innovation Solution

A method using a thin conductor layer, specifically ITO film, between substrate layers, where a focused laser beam forms a hermetic weld between the layers, creating a reliable and economical feedthrough by melting and mixing the materials at the interface, ensuring a gas-tight seal without warping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cementing or soldering is used to join substrate layers, then the layers can be connected together, but warping occurs and surfaces become non-planar leading to unreliable hermetic seals

Engineering Contradiction:
Improvehermetic seal reliabilityVSAvoidsurface planarity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical joining methods (cementing, soldering) with laser welding to join substrate layers. This substitution eliminates the warping and non-planar surface issues associated with thermal heating methods while achieving reliable hermetic seals through precise laser-induced melting and bonding at the layer interfaces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the joining parameters by using focused laser energy with controlled power and duration to melt and bond substrate layers. This parameter change allows precise control of the welding process to achieve hermetic sealing without the excessive heating that causes warping in traditional methods.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high material layer thicknesses are used to prevent warping, then warping is reduced, but material costs increase considerably

Engineering Contradiction:
Improvehermetic seal reliabilityVSAvoidmaterial thickness
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent replaces thermal joining methods with laser welding, which provides precise localized heating. This allows the use of thinner material layers because the laser energy is concentrated at the bonding interface, preventing the warping issues that would otherwise require thick layers to compensate for, thereby reducing material costs while maintaining seal reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional welding methods are used to form hermetic peripheral welds, then connections are formed, but manufacturing costs increase and gas leakage issues persist

Engineering Contradiction:
Improvehermetic sealingVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses focused laser welding to replace traditional peripheral welding methods. The laser beam is directed through the transparent substrate to melt and bond layers at specific feedthrough locations, creating hermetic seals without the complexity of peripheral welding operations and eliminating gas leakage paths while reducing manufacturing costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent applies laser welding locally at specific feedthrough locations rather than performing peripheral welding around the entire component. This localized approach creates hermetic seals exactly where needed (at the conductor layer interfaces) without the complexity and cost of complete peripheral welding, while preventing gas leakage through targeted sealing.

Inventive Principle:
Principle #3Local quality

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 produces completely hermetic feedthroughs with reliable and cost-effective results, preventing gas leakage and maintaining optimal material thickness, ensuring efficient power and data transfer while avoiding the drawbacks of prior art techniques.

Implementation Method 1

a focused laser beam forms a hermetic weld between the layers, creating a reliable and economical feedthrough by melting and mixing the materials at the interface

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

by melting and mixing the materials at the interface

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP3187297B1Hermetic electrical feedthrough with substrate piece and a method for implementing it
Publication Date: 2019.12.04 SCHOTT PRIMOCELER OY
  • EP3187297B1 patent drawingFigure 1~3
  • EP3187297B1 patent drawingFigure 4~6

AI summary

The present invention relates to at least one hermetic electrical feedthrough in a substrate piece and a method for implementing it, said piece (P) comprising at least two substrate layers (10, 11) and a conductor layer (12), a component (13) fitted inside said piece and a conductor (1), the conductor (1) extending from the outer surface of said piece to the component for providing an electrical connection, and wherein the feedthrough is fitted between said substrate layers. The invention also relates to a method for implementing the hermetic electrical feedthrough in the substrate piece. The substrate layers (10, 11) and the conductor layer (12) are pressed together and joined with each other by means of at least one weld (3) formed between the component (13) and the periphery (21) of the substrate piece, wherein the at least one weld (3) is made with a focused laser beam, and wherein the at least one weld (3) encircles the component (13) at the height level of a common interface area (25) of said substrate layers and the conductor layer, each weld extends substantially from a first edge (1.1) of a conductor (1) to its second edge or to a second edge (1.2) of another conductor adjacent to it, wherein the opposite surfaces of the substrate layers (10, 11) facing the conductor (1) constrict against the conductor (1) due to thermal tensions caused by welding heat, wherein joints between the conductor (1) and said surfaces become hermetic.