MEMS Decoupling Structure for Thermal Stress Compensation

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Solution Overview

Problem

The assembly of MEMS and NEMS components with their packaging is prone to mechanical and thermal stresses due to differences in thermal expansion coefficients between the component materials and the packaging materials, leading to increased size requirements and potential operational issues.

Innovation Solution

A suspended and mobile decoupling structure is integrated within the component itself, allowing for mechanical and thermal decoupling between the component and the packaging, which absorbs or compensates for stresses without requiring additional space or intermediate elements, thus maintaining the component's operational integrity and reducing size constraints.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an intermediate frame is added between the component and the box to provide mechanical and thermal decoupling, then the stress compensation is improved, but the space requirement in the z-direction increases

Engineering Contradiction:
Improvestress compensationVSAvoidspace requirement in z-direction
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The decoupling structure is merged with the component substrate itself rather than being a separate intermediate frame. The substrate is structured to include suspended beams that directly provide mechanical and thermal decoupling functionality, eliminating the need for additional space-consuming intermediate structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The decoupling structure is arranged in the thickness direction (z-direction) of the component substrate itself, utilizing the existing vertical dimension of the component rather than adding another layer of intermediate structures. This integrates the decoupling function within the component's own dimensional envelope.

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

2Reliability

If additional intermediate elements are introduced to provide mechanical and thermal decoupling, then the stress absorption is improved, but the device complexity increases

Engineering Contradiction:
Improvestress absorptionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The decoupling structure is merged with the component substrate itself rather than being a separate intermediate frame. The substrate is structured to include suspended beams that directly provide mechanical and thermal decoupling functionality, eliminating the need for additional space-consuming intermediate structures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The component substrate itself provides the decoupling functionality through its own structural design, without requiring external intermediate elements. The suspended beams are formed as part of the substrate, allowing the component to self-decouple from the packaging structure.

Inventive Principle:
Principle #25Self-service

3Reliability

If the assembly is made more robust to handle thermal and mechanical stresses, then the reliability is improved, but the size of the assembly increases

Engineering Contradiction:
Improveassembly robustnessVSAvoidoverall assembly size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The decoupling structure is merged with the component substrate itself rather than being a separate intermediate frame. The substrate is structured to include suspended beams that directly provide mechanical and thermal decoupling functionality, eliminating the need for additional space-consuming intermediate structures.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively mitigates thermal and mechanical stresses, maintaining the component's functionality while minimizing the overall size of the assembly, and simplifies electrical connections by separating them from the decoupling structure, reducing costs and ensuring reliable operation.

Implementation Method 1

the material of the case, for example a plastic material, a resin, or even a PCB (polychlorobiphenyl), generally has a coefficient of thermal expansion very different from that of the material of the component

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

The assembly between the MEMS component and the package is often sensitive to mechanical and/or thermal stresses

Methodology Applied
Scientific EffectMechanical stress: Mechanical Force

Data Source

PatentEP3728108B1Use of an uncoupling structure for assembling a component having a casing
Publication Date: 2023.04.12 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP3728108B1 patent drawingFigure 1~3
  • EP3728108B1 patent drawingFigure 4~6
  • EP3728108B1 patent drawingFigure 7A~7F

AI summary

Assembly between a MEMS and/or NEMS electromechanical component (20) and a casing (1), the electromechanical component (20) comprising at least one suspended and movable structure (26) which is provided with at least one fixing zone (26a), on which a region (3) for receiving the casing is fixed, the suspended structure being at least partially formed in a cover (29) for protecting the component or in a layer (25) which is different from the one in which the sensitive element of the component is formed.