HBA-Activated Flux Composition for Low-Void Solder Joints

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Solution Overview

Problem

The generation of voids in solder joint portions during soldering using fluxes containing surfactants is a significant issue, as surfactants can contribute to the formation of voids despite their intended purpose of improving wettability.

Innovation Solution

A flux composition is developed that includes 2-hydroxyisobutyric acid (HBA) as an activator, cationic and nonionic surfactants within specific weight percentage ranges, and optional co-activators to suppress void generation, with HBA levels between 0.1 to 20 wt% and surfactant levels between 10 to 60 wt%, optimizing wettability and oxide reduction while minimizing void formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a surfactant is added to flux to improve wettability, then wettability is improved, but void generation increases

Engineering Contradiction:
ImprovewettabilityVSAvoidvoid generation
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by introducing 2-hydroxyisobutyric acid (HBA) as an activator and specifying precise content ranges for cationic (10-60 wt%) and nonionic (5-60 wt%) surfactants. This parameter optimization resolves the contradiction by achieving improved wettability while suppressing void generation through controlled composition rather than simply increasing surfactant content

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite flux system combining multiple components: HBA as activator, cationic surfactant, nonionic surfactant, and optionally co-activators. This composite approach allows the synergistic interaction between components to achieve both good wettability and reduced void generation, resolving the contradiction that cannot be solved by single-component adjustments

Inventive Principle:
Principle #40Composite materials

2Object-generated harmful factors

If flux composition is optimized to suppress void generation, then void generation is suppressed, but wettability may deteriorate

Engineering Contradiction:
Improvevoid generationVSAvoidwettability
Core Design Contradiction:
Object-generated harmful factorsVSEase of operation

Solution Approach 1:

The patent establishes specific content ranges for each component: HBA (0.1-20 wt%), cationic surfactant (10-60 wt%), and nonionic surfactant (5-60 wt%). These parameter specifications ensure that void generation is suppressed while wettability is maintained at appropriate levels, resolving the contradiction between reducing harmful effects and preserving operational performance

Inventive Principle:
Principle #35Parameter changes

3Reliability

If activator content is increased to improve oxide removal, then oxide removal is improved, but metallic surface corrosion increases

Engineering Contradiction:
Improveoxide removalVSAvoidmetallic surface corrosion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent specifies HBA content within 0.1-20 wt% range, optimizing the balance between oxide removal capability and corrosion suppression. This parameter control ensures reliable oxide removal while preventing excessive corrosion that would occur with higher activator concentrations

Inventive Principle:
Principle #35Parameter changes

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 flux effectively suppresses void generation in solder joints, maintaining wettability and preventing metallic surface corrosion, as demonstrated by examples showing void generation percentages of 15% or less in solder joint portions.

Implementation Method 1

the acid anhydride absorbs water and thereby functions as an activator

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

The flux chemically removes metal oxides that are present on the surface of solder and metal oxides present on the metallic surface of a subject of soldering

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

the objective of adding a surfactant to fluxes is typically to improve the wettability of solder during soldering

Methodology Applied
Scientific EffectSurface tension reduction: Surface Tension

Data Source

PatentUS11931829B2Flux and solder paste
Publication Date: 2024.03.19 SENJU METAL IND CO LTD

AI summary

A flux containing 0.1 to 20 wt % of 2-hydroxyisobutyric acid as an activator, 10 to 60 wt % of a cationic surfactant and 5 to 60 wt % of a nonionic surfactant. A solder paste contains a flux containing 0.1 to 20 wt % of 2-hydroxyisobutyric acid as an activator, 10 to 60 wt % of a cationic surfactant, and 5 to 60 wt % of a nonionic surfactant and a metal powder.