Sealed Inert Micro-Fuse Assembly to Prevent Arcing During Programming

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Solution Overview

Problem

Thin-film micro-fuses in micro-electrical devices and MEMS face issues with arcing, plasma discharge, and molten metal splattering due to being surrounded by air containing oxygen and other contaminants during programming, leading to undesirable effects such as metallic spray patterns.

Innovation Solution

Creating an inert environment around the micro-fuses using a substrate and a topping wafer to form a sealed cavity, which can be evacuated and filled with inert gases like nitrogen or argon, preventing ionizing gases and contaminants from interfering with the fuse operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thin-film micro-fuses are operated in air environment, then the programming process can be performed, but arcing, plasma discharge, and molten metal splattering occur causing metallic spray patterns and undesirable effects

Engineering Contradiction:
Improvemicro-fuse operation reliabilityVSAvoidarcing and plasma discharge
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies the inert atmosphere principle by evacuating air from the cavity and filling it with inert gas (nitrogen or argon) to prevent ionizing gases and contaminants from interfering with fuse operation. This eliminates oxygen and water vapor that cause arcing, plasma discharge, and molten metal splattering during programming, thereby resolving the technical contradiction between maintaining reliable micro-fuse operation and preventing harmful electrical effects.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If a sealed cavity structure is created with topping wafer and substrate, then the inert environment is maintained, but the device structure becomes more complex

Engineering Contradiction:
Improveinert environment maintenanceVSAvoidsealed cavity structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the micro-fuse assembly into separate components: a substrate containing the micro-fuses, a topping wafer that seals the cavity, and an intermediate inert environment. This segmentation allows the inert environment to be maintained while keeping each component relatively simple in structure, resolving the contradiction between reliability through environmental control and device complexity.

Inventive Principle:
Principle #1Segmentation

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 inert environment significantly reduces the risk of arcing and plasma discharge, maintaining the integrity of the micro-fuses and preventing undesirable electrical effects during programming, allowing for precise control and reliable operation.

Implementation Method 1

a topping wafer configured to sealingly engage to at least one of the substrate or the thin-film micro-fuses to define a cavity therebetween

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

The cavity is configured to encapsulate the thin-film micro-fuses within an inert environment sealed within the cavity

Methodology Applied
Scientific EffectInert atmosphere protection:

Data Source

PatentEP3800661B1Inert environment fusible links
Publication Date: 2023.08.23 ROSEMOUNT AEROSPACE INC
  • EP3800661B1 patent drawingFigure 1A~2
  • EP3800661B1 patent drawingFigure 3
  • EP3800661B1 patent drawingFigure 4

AI summary

A micro-fuse assembly includes a substrate (42), a number of thin-film micro-fuses on the substrate (42), and a topping wafer (70) configured to sealingly engage to at least one of the substrate or the thin-film micro-fuses to define a cavity therebetween. The cavity is configured to encapsulate the thin-film micro-fuses within an inert environment sealed within the cavity. A method of encapsulating a micro-fuse assembly within an inert environment using a topping wafer is also disclosed.