MEMS Membrane Bridge Insulation Layout to Prevent Point Discharge

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Solution Overview

Problem

The existing MEMS devices face a risk of device damage due to point discharge caused by a too close distance between the membrane bridge and the driving electrode, leading to breakdown of the dielectric layer on the side surface of the driving electrode when the membrane bridge is pulled down.

Innovation Solution

The MEMS device design includes a dielectric substrate with a driving electrode and reference electrodes, where the first dielectric layer covers the driving electrode and fills the gaps between the electrodes, and a second dielectric layer is arranged on the bridge deck close to the substrate, ensuring the thickness of the dielectric layer at the gaps is greater than the driving electrode, and the second dielectric layer covers at least the orthographic projection of the driving electrode, preventing breakdown.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the membrane bridge is pulled down closer to the driving electrode to improve device performance, then the device can achieve better actuation efficiency, but the dielectric layer on the side surface of the driving electrode breaks down due to point discharge

Engineering Contradiction:

Improveactuation efficiencyVSAvoiddevice reliability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A sacrificial layer is introduced as an intermediary element during the manufacturing process. This sacrificial layer is positioned between the membrane bridge and the driving electrode during fabrication, allowing the dielectric layer thickness to be precisely controlled. After manufacturing, the sacrificial layer is removed, leaving the membrane bridge at the optimal position without causing point discharge, thus resolving the contradiction between actuation efficiency and reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the dielectric layer thickness is increased to prevent breakdown, then the reliability improves, but the distance between the membrane bridge and driving electrode increases reducing actuation efficiency

Engineering Contradiction:

Improvedevice reliabilityVSAvoidactuation efficiency

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The dielectric layer is formed with appropriate thickness before the membrane bridge is positioned. By performing the dielectric layer formation as a preliminary action with precise thickness control, the subsequent positioning of the membrane bridge can achieve optimal actuation efficiency without risking dielectric breakdown, thus resolving the contradiction between reliability and actuation efficiency

Inventive Principle:

Principle #10Preliminary action

3Speed

If the membrane bridge is positioned closer to the driving electrode to reduce gap distance, then the actuation speed improves, but point discharge occurs causing dielectric layer breakdown

Engineering Contradiction:

Improveactuation speedVSAvoidpoint discharge

Core Design Contradiction:

SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent employs a sacrificial layer that can be selectively removed through etching processes, analogous to pneumatic and hydraulic control mechanisms. This allows precise control over the final gap distance between the membrane bridge and driving electrode, achieving fast actuation speed while preventing point discharge by maintaining an optimal, controlled gap rather than an excessively small one

Inventive Principle:

Principle #29Pneumatics and hydraulics

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 design effectively prevents the breakdown of the dielectric layer on the side surface of the driving electrode, enhancing the reliability and reusability of the MEMS device by maintaining a stable structure and performance.

Implementation Method 1

a first dielectric layer covering the driving electrode on a side of the driving electrode away from the dielectric substrate... a thickness of a part of the first dielectric layer at each of the first gap and the second gap is greater than a thickness of the driving electrode

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Implementation Method 2

a second dielectric layer is on a side of a bridge deck of the membrane bridge close to the dielectric substrate, and an orthographic projection of the second dielectric layer on the dielectric substrate covers at least an orthographic projection of the driving electrode on the dielectric substrate

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS20250019224A1MEMS device, manufacturing method thereof, and electronic apparatus

Publication Date: 2025.01.16 BOE TECHNOLOGY GROUP CO LTD

AI summary

A MEMS device includes: a dielectric substrate; a driving electrode, first and second reference electrodes on the dielectric substrate; a first dielectric layer covering the driving electrode; and a membrane bridge on a side of the first dielectric layer away from the dielectric substrate, where a first gap is between the first reference electrode and the driving electrode; a second gap is between the second reference electrode and the driving electrode; and a thickness of a part of the first dielectric layer at each of the first and second gaps is greater than a thickness of the driving electrode; and/or, a second dielectric layer is on a side of a bridge deck of the membrane bridge close to the dielectric substrate, and an orthographic projection of the second dielectric layer on the dielectric substrate covers at least an orthographic projection of the driving electrode on the dielectric substrate.