Low-Residue Flux Composition for Void-Reduced Solder Paste
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solder pastes often contain defects such as gas or air inclusions in solder connections, which can lead to poor solderability, especially in the presence of atmospheric oxygen, requiring specialized conditions like vacuum soldering or inert gas environments.
Innovation Solution
A flux composition consisting of 30-80% acidic resins, 10-60% organic solvent, and 0-15% amines, characterized by a weight loss of ≥50% during thermogravimetric analysis in synthetic air, which improves solderability and reduces defects in solder connections without the need for special atmospheric conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flux compositions are used, then solder pastes can be manufactured with standard components, but gas or air inclusions form in solder joints leading to poor solderability
Solution Approach 1:
The patent modifies the chemical composition parameters of the flux by specifying precise weight percentage ranges of acidic resins (30-80%), organic solvents (10-60%), and amines (0-15%). This parameter optimization ensures complete evaporation of volatile components during soldering, eliminating gas inclusions while maintaining effective oxide removal capability for reliable solderability
Solution Approach 2:
The patent transforms the potentially harmful effect of organic solvents (which can cause gas inclusions) into a beneficial property by carefully selecting solvent types and concentrations (10-60% range) that ensure complete evaporation before solder solidification. The amine components (0-15%) are similarly optimized to provide flux activation while eliminating residual gases, converting what could be defect sources into reliable soldering performance
2Reliability
If special atmospheric conditions (vacuum or inert gas) are used, then solderability improves, but process complexity and cost increase
Solution Approach 1:
The patent creates a flux composition that is self-sufficient for atmospheric soldering by incorporating balanced proportions of acidic resins, organic solvents, and amines. This formulation enables the flux to effectively protect the solder joint and eliminate oxides in normal air conditions without requiring external vacuum or inert gas systems, allowing the process to serve itself using standard atmospheric conditions
Solution Approach 2:
The patent changes the chemical parameters of the flux to enable atmospheric compatibility by optimizing the ratio of volatile organic solvents (10-60%) that evaporate cleanly, and amine content (0-15%) that provides sufficient activation. This parameter optimization allows the soldering process to proceed reliably in air, eliminating the need for complex atmospheric control equipment
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 composition significantly reduces the formation of cavities in solder connections and enhances solderability in air environments, ensuring reliable connections without the need for vacuum or inert gas soldering.
Implementation Method 1
during a thermogravimetric analysis (TGA) carried out in the range of 25 to 350°C with a heating rate of 10 K/min and with the introduction of synthetic air, it suffers a weight loss of ≥50 wt.％ when a temperature of 280°C is reached
Implementation Method 2
The flux according to the invention comprises 10 to 60 wt.％, preferably 20 to 50 wt.％ of at least one organic solvent
Implementation Method 3
Fluxes serve, among other things, to dissolve the oxide layer on the surfaces of the solder powder, the electronic component, and the substrate
Implementation Method 4
Fluxes serve, among other things, to dissolve the oxide layer on the surfaces of the solder powder, the electronic component, and the substrate, thus ensuring better wettability during the soldering process
Implementation Method 5
The solder paste is heated to melt the solder (solder metal, solder alloy) within the paste, for example, through a reflow process
Data Source
AI summary
Flux comprising (i) 30 to 80 wt.% of one or more acidic resins, (ii) 10 to 60 wt.% of at least one organic solvent, (iii) 0 to 15 wt.% of one or more amines, and (iv) 0 to 20 wt.% of one or more components different from those in (i) to (iii), wherein the flux is characterized in that, during thermogravimetric analysis carried out in the range of 25 to 350°C with a heating rate of 10 K/min and with the introduction of synthetic air, it suffers a weight loss of ≥50 wt.% upon reaching a temperature of 280°C; and solder paste comprising 80 to 92 wt.% of one or more different solders and 8 to 20 wt.% of the flux.