Cross-Tied MEMS Switch Arrays for Higher Current and Dielectric Strength

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Solution Overview

Problem

Existing MEMS switches face challenges with low current-carrying capacity and dielectric strength, particularly when individual switches do not meet specifications, and manufacturing a large number of identical switches is rarely feasible.

Innovation Solution

The arrangement of MEMS switches is configured in a Total Cross-Tied (TCT) circuit with conductor connections along spaced-apart planes, using silicon-on-insulator substrates and glass wafers, allowing parallel connection and redundant paths to enhance reliability and avoid conductor crossings, thereby increasing current-carrying capacity and dielectric strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple MEMS switches are interconnected to form an array to increase current-carrying capacity, then the current-carrying capacity increases, but the reliability decreases due to the large number of identically manufactured switches required

Engineering Contradiction:
Improvecurrent-carrying capacityVSAvoidreliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent applies three-dimensional integration by stacking conductor connections along spaced-apart planes (first plane on silicon substrate, second plane on glass wafer). This vertical dimensionality allows TCT configuration with series and parallel connections, increasing both current-carrying capacity and reliability without requiring a large number of identical switches on a single plane.

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

Solution Approach 2:

The patent uses composite material structure combining silicon substrate and glass wafer bonded together. The silicon substrate carries the first conductor plane and MEMS switches, while the glass wafer carries the second conductor plane. This composite structure enables complex interconnections and improves overall device reliability through material diversity.

Inventive Principle:
Principle #40Composite materials

2Power

If a large number of MEMS switches are manufactured to form an array, then the current-carrying capacity increases, but the manufacturing complexity increases

Engineering Contradiction:
Improvecurrent-carrying capacityVSAvoidmanufacturing complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent segments the conductor connections into two separate planes distributed on different substrates (silicon and glass). This segmentation simplifies manufacturing by avoiding complex three-dimensional routing on a single substrate and reducing conductor crossing requirements, while still achieving the desired array functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By utilizing the vertical dimension with spaced-apart planes on stacked substrates, the patent eliminates the need for complex planar conductor crossings. Conductors on different planes can connect without intersecting, significantly reducing manufacturing complexity compared to single-plane configurations.

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

3Device complexity

If conductor connections are arranged in a single plane, then the device complexity is reduced, but conductor crossings must be specifically considered during manufacturing

Engineering Contradiction:
Improvedevice complexityVSAvoidease of manufacture
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The patent resolves conductor crossing issues by distributing conductor connections along spaced-apart planes in the vertical dimension. Conductors that would cross in a single plane are separated into different planes, eliminating the need for complex crossing management during manufacturing while maintaining low device complexity.

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

4Reliability

If individual MEMS switches do not meet specifications, then the reliability decreases, but the arrangement allows easy bypass of faulty switches

Engineering Contradiction:
ImprovereliabilityVSAvoidease of repair
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The TCT configuration with redundant circuit paths provides beforehand cushioning against switch failures. The series and parallel interconnections create alternative current paths, so if individual switches do not meet specifications or fail, the system maintains functionality through redundant paths, and faulty switches can be bypassed without system failure.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 TCT configuration significantly enhances the reliability and manufacturability of MEMS switch arrays by increasing current-carrying capacity and dielectric strength while enabling easy bypass of faulty switches and reducing manufacturing complexity.

Implementation Method 1

MEMS switches are based on the mostly electrostatically actuated movement of a moving element

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 2

conductor connections advantageously extend along at least two spaced-apart planes

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3977497B1Arrangement of MEMS switches
Publication Date: 2026.03.18 ROBERT BOSCH GMBH
  • EP3977497B1 patent drawingFigure 1
  • EP3977497B1 patent drawingFigure 2
  • EP3977497B1 patent drawingFigure 3

AI summary

In an arrangement of MEMS switches (20) with mobile elements (90), said MEMS switches (20) are interconnected in a total -cross-tied configuration (10).