Solder Particle Classification for Short-Circuit-Free Wiring Connections

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Solution Overview

Problem

Existing solder particles with adhered minute particles cause electrical short circuits and poor conduction due to broad particle size distributions, leading to issues in wiring pattern connections.

Innovation Solution

A method involving an impact force application step to reduce the percentage of composite solder particles with adhered particles to 5% or less, using air flow or centrifugal force for classification, and ensuring a limited percentage of small-particle-diameter solder particles to prevent short circuits and improve conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If commercially available solder particles produced by atomization method are used, then production efficiency is maintained, but composite particles with adhered minute particles are formed causing short circuits between wiring patterns

Engineering Contradiction:

Improveproduction efficiencyVSAvoidelectrical insulation between wiring patterns

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention extracts and removes the harmful composite particles (solder particles with adhered minute particles) from the particle mixture through classification processes. This is achieved by separating particles based on size and morphology, eliminating the composite particles that cause short circuits while retaining the functional solder particles for conduction.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the particle size distribution parameters by implementing classification steps that remove small-particle-diameter particles (≤0.5X μm) and composite particles. By controlling the particle size parameters and removing outlying particles, the invention achieves both good conduction (enough particles reach electrodes) and insulation (no composite particles block wiring patterns).

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If solder particles with broad particle size distribution are used, then manufacturing simplicity is maintained, but small-particle-diameter particles fail to reach electrodes or cause short circuits when quantity is increased

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidconduction reliability and insulation

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention optimizes the particle size distribution parameters by removing particles with diameters ≤0.5X μm (where X is the number average particle diameter). This parameter control ensures that remaining particles are large enough to reach electrodes effectively for conduction, while preventing the formation of harmful composite particles. The classification process maintains manufacturing feasibility while achieving reliable electrical performance.

Inventive Principle:

Principle #35Parameter changes

3Quantity of substance

If normal solder particles are used without classification, then production cost is reduced, but composite particles block normal particles causing short circuits between wiring patterns

Engineering Contradiction:

Improvesolder particle quantityVSAvoidelectrical insulation between wiring patterns

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention extracts harmful composite particles from the bulk solder particle population through classification. By removing particles with specific size characteristics (small-particle-diameter particles and composite particles), the invention prevents these particles from blocking the movement of normal solder particles to wiring patterns, thereby maintaining electrical insulation while preserving adequate solder particle quantity for conduction.

Inventive Principle:

Principle #2Taking out (Extraction)

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 effectively prevents electrical short circuits and enhances insulation performance by ensuring the majority of solder particles contribute to conduction, maintaining reliable connections between wiring patterns.

Implementation Method 1

an impact force application step of applying an impact force to solder particles so that a percentage of composite solder particles becomes 5% by number or less

Methodology Applied

Scientific EffectImpact force: Impact Force

Implementation Method 2

using air flow or centrifugal force for classification

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS20250001528A1Solder particles, solder particle production method, and conductive composition

Publication Date: 2025.01.02 DEXERIALS CORP

AI summary

Solder particles include composite solder particles at a percentage of 5% by number or less in a total of the solder particles, the composite solder particles including multiple adhered solder particles. A solder particle production method includes an impact force application step of applying an impact force to solder particles so that a percentage of composite solder particles becomes 5% 10 by number or less in a total of the solder particles, the composite solder particles including multiple adhered solder particles.