MEMS Stress Decoupling via Spring Displacement

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

MEMS devices with membrane structures face challenges in managing thermal-induced compressive stress, which can lead to buckling, damage, and uneven heat distribution, limiting their lifespan and operational efficiency.

Innovation Solution

A MEMS device design featuring a suspended membrane structure with an elastically deformable spring structure in the outer membrane region that converts thermal-induced compressive stress into local spring displacement, reducing stress on the inner membrane and enabling controlled heat dissipation through a heat sink.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the stiffness of the membrane structure is increased to mitigate thermomechanical buckling, then the structural stability is improved, but the manufacturing complexity and device complexity increase due to corrugations and additive structures

Engineering Contradiction:

Improvestructural stabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The membrane structure is divided into an inner membrane section and an outer membrane section, with the outer section serving as a sacrificial element that absorbs thermal stress through controlled buckling, protecting the inner section while avoiding complex additive structures

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The outer membrane section is designed to intentionally buckle and contact the backplate under thermal stress, converting the harmful buckling effect into a beneficial protective mechanism that shields the inner membrane section from damage

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Temperature

If perforations are formed in the membrane structure for ventilation or thermal isolation, then heat management is improved, but the reliability decreases due to fracture initiation sites in highly tensile membrane structures

Engineering Contradiction:

Improveheat managementVSAvoidlifespan

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The membrane is segmented into inner and outer sections with different functional roles, allowing the outer section to handle thermal stress while the inner section maintains structural integrity without perforations

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The outer membrane section acts as an intermediary sacrificial element that absorbs thermal stress and protects the inner membrane section, eliminating the need for perforations in the load-bearing inner section

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If the membrane structure contacts other components such as electrodes or housing, then heat dissipation increases, but the operational reliability decreases due to uncontrolled heat flow and potential damage

Engineering Contradiction:

Improveheat dissipationVSAvoidoperational reliability

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The outer membrane section is pre-designed to buckle and contact the backplate in a controlled manner, preventing uncontrolled contact with other components and ensuring predictable heat dissipation paths before thermal stress becomes harmful

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The controlled contact between the outer membrane section and backplate converts potentially harmful uncontrolled buckling into a beneficial mechanism for managing thermal stress and directing heat flow away from the inner membrane section

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 reduces the risk of buckling, maintains a homogeneous temperature profile, and enhances the device's mechanical robustness and lifespan by effectively managing thermal stress and heat dissipation.

Implementation Method 1

thermal-induced compressive stress

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

elastically deformable spring structure

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 3

heat dissipation is more predictable and controllable, as heat dissipation is rather expected to occur via the spring structure

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20240166495A1Device with a stress decoupling structure

Publication Date: 2024.05.23 INFINEON TECHNOLOGIES AG

AI summary

A MEMS device comprises a suspended membrane structure having an inner membrane section and an outer membrane section. The outer membrane section surrounds the inner membrane section. The membrane structure comprises an elastically deformable spring structure in the outer membrane section, such that the spring structure is arranged to convert a thermal-induced compressive stress in the suspended membrane structure into a spring displacement.