Soldering Device with Organic Fatty Acid Film for Copper Corrosion Prevention
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Solution Overview
Problem
Existing soldering methods face challenges in productivity and reliability due to copper corrosion and inconsistent solder bump formation, particularly when dealing with varying sizes of electronic components and compact CSPs, leading to reduced yield and increased costs.
Innovation Solution
A soldering device and method utilizing a first and second organic fatty acid-containing solution bath, combined with a steam atmosphere and ejection units to spray and remove molten solder, forming a copper corrosion prevention layer and organic fatty acid coating, ensuring uniformity and preventing corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dipping method is used to form solder bumps, then productivity is improved, but copper corrosion occurs on copper electrodes leading to reduced reliability
Solution Approach 1:
An organic fatty acid-containing solution is introduced as an intermediary substance between the copper electrode and the molten solder. This solution forms a protective film on the copper electrode surface, preventing direct contact between copper and solder, thereby eliminating copper corrosion while maintaining the efficiency of the dipping method
Solution Approach 2:
The patent converts the harmful effect of copper corrosion into a beneficial protective mechanism. By using the organic fatty acid solution to intentionally form a controlled protective film, the potential harm of chemical reaction is transformed into a beneficial corrosion prevention mechanism that protects the copper electrode
2Manufacturing precision
If the screen plate method is used to form solder bumps, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The patent replaces the mechanical screen plate system with a chemical film formation system. Instead of using a physical screen plate to control solder flow, the organic fatty acid solution chemically forms a protective film that controls solder deposition, eliminating the need for complex mechanical positioning while maintaining precision
Solution Approach 2:
The patent changes the fundamental parameter of solder bump formation from mechanical constraint (screen plate openings) to chemical control (organic fatty acid film properties). By adjusting parameters such as solution concentration, temperature, and immersion time, precise control over solder bump formation is achieved without mechanical limitations
3Productivity
If the copper electrode is directly dipped in molten solder, then productivity is improved, but copper corrosion reduces electrical joint reliability
Solution Approach 1:
The organic fatty acid-containing solution serves as a mediator layer between the copper electrode and molten solder. This intermediary film prevents direct harmful interaction while allowing the dipping process to proceed rapidly, thus maintaining productivity while eliminating copper corrosion
Solution Approach 2:
The copper electrode is pre-treated with the organic fatty acid solution before contact with molten solder. This preliminary action creates a protective barrier in advance, preventing the harmful copper corrosion reaction from occurring during the subsequent soldering process
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 achieves high yield and reliability by preventing copper corrosion and maintaining solder wettability, allowing for cost-effective production of substrates and electronic components with consistent electrical joints.
Implementation Method 1
immersing a workpiece member having a copper electrode in an organic fatty acid-containing solution
Implementation Method 2
the copper combines with tin contained in the solder in order to produce a Cu—Sn intermetallic compound. The Cu—Sn intermetallic compound is formed in a manner that the copper electrodes are corroded by the tin in the solder
Implementation Method 3
an ejection unit to spray a jet stream of a molten solder to the copper electrode provided on the workpiece member
Implementation Method 4
ejection unit to spray a jet stream of a molten solder to the copper electrode provided on the workpiece member
Implementation Method 5
an ejection unit to spray a liquid to an excess of the molten solder for removal
Implementation Method 6
a second organic fatty acid-containing solution bath in which the workpiece member from which the excess of the molten solder is removed in the space section is immersed again in the organic fatty acid-containing solution
Data Source
AI summary
Provided are a soldering device and a soldering method which allow for soldering at low cost with high yield and high reliability. The soldering device has: first organic fatty acid-containing solution bath 21 in which workpiece member 10 having a copper electrode is immersed in organic fatty acid-containing solution 31a; space section 24 having a steam atmosphere of organic fatty acid-containing solution 31b, the space section horizontally having ejection unit 33 to spray a jet stream of a molten solder to the copper electrode provided on workpiece member 10 and ejection unit 34 to spray a liquid to an excess of the molten solder for removal; and second organic fatty acid-containing solution bath 23 in which workpiece member 10 from which the excess of the molten solder is removed in space section 24 is immersed again in organic fatty acid-containing solution 31c.