Lead-Free Solder Filtration and Fatty Acid Coating for Fine PCB Joining
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Solution Overview
Problem
Conventional soldering techniques result in poor appearance with protrusions and bumps, solder bridges, difficulty in soldering micro components, increased CO2 emissions, and issues with mixing of solids like oxides leading to bending difficulties and cracks.
Innovation Solution
A method involving heating, filtration with a filter of 10 μm aperture size, and cooling to produce a solder product with improved flowability, reduced solid content, and a surface layer of carboxylic acid to enhance soldering quality and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional soldering is used, then soldering process is simple, but solder has poor appearance with protrusions and bumps and forms solder bridges
Solution Approach 1:
The patent applies preliminary action by filtering the molten solder through a filter with 10 μm aperture size before the soldering process. This preliminary filtration removes solid impurities and prevents the formation of protrusions, bumps, and solder bridges, thereby improving solder appearance quality without significantly complicating the overall soldering process
Solution Approach 2:
The patent introduces a filter as an intermediary component between the solder supply and the soldering location. This filter with 10 μm aperture size acts as a mediator that separates solid impurities from the molten solder, allowing only clean liquid solder to reach the joint, thus improving appearance quality while maintaining process simplicity
2Manufacturing precision
If molten solder contains solids, then solder flow is sufficient, but solids project from solder pocket causing micro LED to mount in inclined fashion
Solution Approach 1:
The patent applies the taking out principle by extracting solid impurities from the molten solder through filtration with a 10 μm aperture filter. This removal of solids prevents them from projecting out of the solder pocket during cooling, ensuring that micro LEDs mount in the correct position without inclination, while maintaining adequate solder flow for proper filling
3Quantity of substance
If conventional solder product is used, then soldering process is straightforward, but solder lacks flow and increases amount of solder used
Solution Approach 1:
The patent applies parameter changes by controlling the aperture size of the filter to 10 μm, which optimizes the removal of solid impurities while maintaining solder flowability. This specific parameter setting ensures that the molten solder flows smoothly during soldering, reducing the amount of solder needed to achieve proper joint formation, thereby decreasing both material usage and environmental impact
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 enables finer, high-quality soldering with reduced failures, increased joining strength, and reduced environmental impact by minimizing solid mixing and plating needs, while enhancing solder flowability and aesthetics.
Implementation Method 1
a filtration step of filtering the molten metal with a filter having an aperture size of not more than 10 μm
Implementation Method 2
a surface layer of carboxylic acid to enhance soldering quality and adhesion
Implementation Method 3
a heating step of heating and melting a raw material to obtain a molten metal
Implementation Method 4
a cooling step of cooling and solidifying the filtered molten metal
Data Source
AI summary
A solder product 20 includes: a lead-free solder part 21 containing tin as a main component and a metal element other than lead as a secondary component; and a carboxylic acid having 10 to 20 carbons, the carboxylic acid being mainly distributed over the surface of the solder product 20 to form a surface layer 22. The carboxylic acid is preferably a fatty acid having 12 to 16 carbons, and more preferably a palmitic acid.