Sealing Bead Openwork Patterns for Cavity Control

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Solution Overview

Problem

Existing methods for encapsulating micro-systems, such as MEMS, fail to effectively control the deformation of sealing beads during bonding, leading to potential overflow onto active zones and compromised device functionality due to unoptimized surface design and mechanical strength.

Innovation Solution

Incorporating openwork patterns with perpendicular empty zones into the sealing bead before crushing, allowing for controlled deformation and improved adhesion between substrates, thereby ensuring precise cavity dimensions and enhanced mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a continuous sealing bead is used, then the sealing is complete and continuous, but the deformation during crushing is difficult to control and may overflow onto active zones

Engineering Contradiction:
Improvesealing completenessVSAvoiddeformation control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The sealing bead is segmented into an openwork pattern with empty zones distributed throughout its structure. This segmentation allows the bead to deform in a controlled manner during crushing while maintaining sealing integrity, preventing overflow onto active zones by providing designated compression zones that absorb deformation.

Inventive Principle:
Principle #1Segmentation

2Strength

If the sealing bead height is increased to ensure complete sealing, then the sealing strength is improved, but the cavity height control becomes less precise

Engineering Contradiction:
Improvesealing strengthVSAvoidcavity height control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The openwork pattern creates local variations in the sealing bead structure, with empty zones strategically positioned to control deformation behavior. This allows different regions of the bead to have different mechanical properties, enabling complete sealing through increased effective height while maintaining precise cavity height control through localized compression zones.

Inventive Principle:
Principle #3Local quality

3Strength

If a solid sealing bead is used, then the mechanical strength is high, but the active surface area is reduced due to larger bead dimensions

Engineering Contradiction:
Improvemechanical strengthVSAvoidactive surface area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The sealing bead employs an openwork porous structure with empty zones distributed throughout. This porous design maintains mechanical strength through the distributed framework while significantly reducing the material volume and footprint of the bead, thereby preserving more active surface area on the chip for device functionality.

Inventive Principle:
Principle #31Porous materials

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 approach enables better control over the sealing bead's deformation and final dimensions, ensuring the integrity of the cavity and the active surface, thus protecting the micro-systems from external attacks while maintaining proper device functionality.

Implementation Method 1

bonded to each other by crushing a closed peripheral sealing bead

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

bonding a cover to a substrate with a bead of resin

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2050713B1Method of manufacturing a cavity having a seal bead
Publication Date: 2012.05.23 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP2050713B1 patent drawingFigure 1~3
  • EP2050713B1 patent drawingFigure 4~7

AI summary

The structure comprises facing substrates bonded to each other by crushing a closed peripheral sealing bead (3), delimiting, between the substrates, a closed cavity in which a microsystem is disposed. The sealing bead (3) has, before crushing, openwork patterns (5) delimiting, within the bead (3), a plurality of void zones (6).