Solder Paste Flux Composition to Prevent Reflow Solder Spatter
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Solution Overview
Problem
Solder spatters during reflow soldering in vacuum ovens can cause short circuits and reduce the quality of wire bonding due to the boiling delays in the flux portion of solder pastes, leading to undesirable solder metal deposition on substrates.
Innovation Solution
Incorporating a benzene derivative, such as 3-hydroxyphenyl acetate or 3-hydroxyphenyl benzoate, as a solder spatter-preventing additive in the flux of solder pastes, which reduces or prevents the formation of solder spatters by adjusting the flux composition to include 0.5 to 5% by weight of the derivative.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flux is used in solder paste, then the soldering process can proceed, but solder spatter forms during reflow soldering causing short circuits and quality issues
Solution Approach 1:
The patent introduces a benzene derivative as an intermediary substance added to the flux composition. This derivative acts as a mediator that modifies the flux-solder interaction during reflow soldering, preventing the harmful spatter effect while maintaining the necessary flux functionality for oxide removal and wetting enhancement.
Solution Approach 2:
The patent modifies the chemical composition parameters of the flux by incorporating a benzene derivative at specific concentrations (0.5-5 wt%). This parameter change alters the physical-chemical behavior of the flux during heating, suppressing the boiling disturbances that cause solder spatter while preserving the flux's core functions.
2Object-generated harmful factors
If flux composition is adjusted to prevent solder spatter, then solder spatter is reduced, but the flux must be precisely formulated to maintain other soldering functions
Solution Approach 1:
The patent specifies precise compositional parameters for the flux, including the benzene derivative content (0.5-5 wt%) and the viscosity range (50-200 Pa·s at 23°C). These parameter definitions provide clear formulation guidelines that balance spatter prevention with maintenance of other critical flux functions such as wetting and oxide removal.
Solution Approach 2:
The patent creates a composite flux composition that combines traditional flux components (rosin, organic acids, amines) with the benzene derivative additive. This composite formulation integrates multiple functional ingredients in specific proportions to achieve both spatter suppression and preservation of essential soldering properties.
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 use of benzene derivatives in the flux significantly reduces or eliminates unwanted solder spatters, enhancing the quality of connections between electronic components and substrates by minimizing solder deposition issues during reflow soldering.
Implementation Method 1
solder metal can spatter due to boiling disturbances within the flux component of the hot, molten solder paste
Implementation Method 2
fluxes that, among other things, serve to dissolve the oxide layer on the surfaces of the solder powder, the component and the substrate, thus ensuring better wettability during the soldering process
Implementation Method 3
The solder paste is heated to melt the solder within it through a reflow process, thus creating contact between the electronic component and the substrate
Data Source
AI summary
Solder paste consisting of 82 to 92 wt% of a tin-based solder and 8 to 18 wt% of a flux, wherein the flux, based on its total weight in the solder paste, comprises 0.5 to 5 wt% of at least one benzene derivative of the formula C6H6-(x+y)(OH)x[O(CO)R]y with x = 0, 1 or 2; y = 0, 1 or 2; (x+y) = 2; and R = phenyl or C1-C12-alkyl.