Copper Particle Composition for Thick Aerosol Jet Conductors

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Solution Overview

Problem

Conventional conductive materials face difficulties in atomization and forming sufficient thickness when applied to aerosol jet printing, particularly for thin wires with line widths of 200 µm or less, which limits their application in molded interconnect devices (MID) requiring thick wiring.

Innovation Solution

A composition containing copper particles and organic solvents with specific vapor pressure ratios and viscosity ranges, allowing for effective atomization and printing of thick wires, comprising copper particles with varying shapes and organic solvents with different volatilities to enhance dischargeability and fusion properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional conductive materials are used for aerosol jet printing, then the printing process can be performed, but the conductive material cannot be properly atomized and the formed wiring does not have sufficient thickness

Engineering Contradiction:
Improvewiring thicknessVSAvoidatomization performance
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent modifies the physical and chemical parameters of the conductive material composition, specifically controlling particle size distribution (0.1-2.0 μm median diameter with 70-90% of particles between 0.03-1.0 μm), shape ratio (spherical 40-80%, flake 20-60%), and organic solvent content (30-70 parts by mass per 100 parts copper particles). These parameter changes enable proper atomization while forming wirings with sufficient thickness for thin wire applications.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If copper particles are used for cost-effectiveness, then manufacturing cost is reduced, but oxidation resistance and dispersion stability become problematic

Engineering Contradiction:
Improvemanufacturing costVSAvoidoxidation resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent creates a composite conductive material system combining copper particles with specific organic solvents and dispersants. The flake-shaped copper particles act as a barrier layer protecting spherical copper particles from oxidation, while the organic solvent system maintains dispersion stability. This composite approach preserves the cost advantages of copper while improving oxidation resistance and handling stability.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If thick wiring is formed for sufficient current capacity, then current amount is secured, but the line width must be increased which is not suitable for thin wire applications

Engineering Contradiction:
Improvecurrent capacityVSAvoidline width
Core Design Contradiction:
Quantity of substanceVSLength of moving object

Solution Approach 1:

The patent applies local quality by using a bimodal particle size distribution and mixed particle shapes to achieve non-uniform packing density within the wiring cross-section. The fine particles (0.03-0.1 μm) fill gaps between larger particles, creating a densely packed structure with high copper content per unit area. This enables thick wirings with sufficient current capacity while maintaining small line widths for thin wire applications.

Inventive Principle:
Principle #3Local quality

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 composition enables the formation of conductors with sufficient thickness for aerosol jet printing, ensuring excellent atomization and printing performance, even on complex surfaces, while maintaining low temperature conductorization and oxidation resistance.

Implementation Method 1

the organic solvents include one or more first organic solvent(s) having a vapor pressure at 20°C of 200 Pa or more and 20 kPa or less, and one or more second organic solvent(s) having a vapor pressure at 20°C of 0.5 Pa or more and less than 200 Pa

Methodology Applied
Scientific EffectVapor pressure: Vapour Pressure

Implementation Method 2

a conductor, a method for manufacturing same, and a structure... a conductorizing step of sintering the metal particles by heating the conductive material

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3712906B1Composition, conductor, method for manufacturing same, and structure
Publication Date: 2024.07.17 RESONAC CORP

AI summary

Disclosed is a composition containing copper particles and organic solvents, in which the organic solvents include a first organic solvent having a vapor pressure at 20°C of 200 Pa or more and 20 kPa or less, and a second organic solvent having a vapor pressure at 20°C of 0.5 Pa or more and less than 200 Pa.