Wafer Welding via Pulsed-Jet Microdrop Deposition

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Solution Overview

Problem

Existing methods for welding wafers using a moistening liquid result in defects such as structural deformation and microbiological deterioration due to general wetting, leading to an unappealing appearance and compromised adhesion properties.

Innovation Solution

Applying demineralized water or aqueous solutions in discrete microdrops to the wafer contact surfaces using a jet deposition method, which minimizes water contact and prevents penetration into the wafer structure, allowing for a heat-resistant weld without added cementing substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a moistening liquid is applied by spraying onto the wafer surfaces, then adhesion between wafers is improved, but the wafer structure deforms and appearance deteriorates due to collapsed porous cells

Engineering Contradiction:
ImproveadhesionVSAvoidwafer structure
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent applies moistening liquid only to specific local areas of the wafer surface (adhesion zones) rather than general spraying. This is achieved through applicators that target only the regions where wafers contact each other, preserving the porous structure in non-contact areas while providing sufficient moisture for adhesion in contact zones.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses minimal amounts of moistening liquid applied only where necessary for adhesion, rather than excessive general wetting. This partial action approach applies moisture selectively to contact surfaces without over-saturating the entire wafer, preventing structural deformation while achieving adequate bonding.

Inventive Principle:
Principle #16Partial or excessive action

2Ease of manufacture

If a moistening liquid is applied by spraying onto the wafer surfaces, then wafers can be joined by contact, but microbiological deterioration occurs due to increased water contact

Engineering Contradiction:
Improvejoining processVSAvoidmicrobiological deterioration
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent limits moistening liquid application to only the specific contact zones where wafers join, rather than general surface wetting. This localized approach minimizes the total water contact area, reducing the risk of microbiological deterioration while maintaining ease of manufacture through simple contact joining.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent converts the potential harm of water application into a benefit by using minimal, targeted moisture application. The small amount of water applied only to contact zones is sufficient for adhesion but too limited to promote microbiological growth, thus transforming the potential harm into a controlled beneficial effect.

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

3Strength

If general wetting of wafer surfaces is applied, then adhesion surfaces are activated, but a dense layer forms that alters appearance and reduces adhesion properties

Engineering Contradiction:
Improveadhesion propertiesVSAvoidadhesion quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies moistening liquid only to specific local contact zones rather than general surface wetting. This prevents the formation of dense layers in non-contact areas while activating adhesion surfaces locally where wafers join, maintaining both appearance quality and adhesion properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses minimal partial wetting of only the contact surfaces rather than excessive general wetting. This controlled partial action activates adhesion properties where needed without creating dense layers that would deteriorate appearance and adhesion quality in other regions.

Inventive Principle:
Principle #16Partial or excessive action

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 method achieves improved adhesion and appearance by reducing water exposure, preventing structural deformation and microbiological deterioration, while maintaining a hollow body without visible welding regions.

Implementation Method 1

Applying demineralized water or aqueous solutions in discrete microdrops to the wafer contact surfaces using a jet deposition method

Methodology Applied
Scientific EffectJet deposition: Jet

Implementation Method 2

the aqueous moistening liquid is applied to at least one of the contact surfaces, and optionally to both of these surfaces, in the form of droplets (or preferably microdrops) which are discrete

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2804483B1Method for welding wafers and equipment therefor
Publication Date: 2016.05.25 FERRERO SPA
  • EP2804483B1 patent drawingFigure 1~2
  • EP2804483B1 patent drawingFigure 3~5
  • EP2804483B1 patent drawingFigure 6

AI summary

Method for producing a hollow body formed by a pair of wafers (2, 2a), welded together along respective mating annular surfaces (4), by applying an aqueous moistening liquid to at least one of the mating surfaces of the wafers, previously subjected to baking, and by adhesion by mutual contact of said surfaces, characterized in that the moistening liquid is applied to said at least one surface in the form of separate and distinct droplets (G) by pulsed-jet deposition means, creating a relative motion between said jet deposition means and said wafers along the annular profile of said surfaces.