Water-Soluble Flux Composition to Prevent Solder Ball Missing
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Solution Overview
Problem
Water-soluble fluxes used in soldering often result in solder ball deviation or 'ball missing' during reflow and flux residue washing, compromising the reliability of the solder joint.
Innovation Solution
A flux composition containing 1,2,3-propanetricarboxylic acid, nonionic surfactants, and weak cationic surfactants, without water, which enhances solder wettability and suppresses ball missing by optimizing the mass ratios of these components within specific ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a water-soluble flux is used to enable easy washing of flux residue, then ease of operation is improved, but reliability deteriorates due to ball missing after reflow and washing
Solution Approach 1:
The invention changes the chemical parameters of the flux by specifying 1,2,3-propanetricarboxylic acid content at 1-15% by mass and total surfactant content at 30-65% by mass. This optimization balance enables the flux to maintain strong solder wettability and adhesion during reflow while remaining water-soluble for easy residue removal, thus resolving the contradiction between ease of washing and solder joint reliability
Solution Approach 2:
The invention creates a composite flux formulation combining 1,2,3-propanetricarboxylic acid with specific nonionic surfactants and weak cationic surfactants. This composite composition synergistically provides both the water solubility needed for easy washing and the enhanced adhesion properties that prevent ball missing, thereby resolving the reliability-ease of operation contradiction
2Manufacturing precision
If flux composition is optimized for solder wettability, then manufacturing precision is improved, but reliability may worsen due to potential ball missing during washing
Solution Approach 1:
The invention optimizes the concentration parameter of 1,2,3-propanetricarboxylic acid to 1-15% by mass and surfactant content to 30-65% by mass. This precise parameter control achieves excellent solder wettability for accurate joint formation while simultaneously providing sufficient adhesion strength to prevent ball missing during subsequent washing operations, thus resolving the contradiction between manufacturing precision and reliability
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 ensures improved solder wettability and effectively prevents ball missing after reflow and flux residue washing, maintaining the integrity of the solder joint.
Implementation Method 1
fluxes used for soldering have efficacy of chemically removing a metal oxide present between a solder and the metallic surface of an object to be joined
Implementation Method 2
a flux with which the wettability of solder can be enhanced
Data Source
AI summary
A flux containing an organic acid, a water-soluble base agent, and a solvent, but not containing water is adopted. In this flux, the organic acid includes 1,2,3-propanetricarboxylic acid. The water-soluble base agent is one or more selected from the group consisting of a nonionic surfactant and a weak cationic surfactant. The content of the 1,2,3-propanetricarboxylic acid is 1 % by mass or more and 15% by mass or less with respect to the total amount of the entire flux, the total content of the water-soluble base agent is 30% by mass or more and 65% by mass or less with respect to the total amount of the entire flux, and the total content of the solvent is 30% by mass or more and 65% by mass or less with respect to the total amount of the entire flux. According to this flux, the wettability of solder can be enhanced and ball missing after reflow and flux residue washing is suppressed.