Leadframe Wetability via Barrel Plating
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Solution Overview
Problem
Semiconductor components with exposed leadframe portions face issues of non-wetability during surface mount processes, leading to corrosion and unreliable solder joints, especially in extreme atmospheric conditions, and current manufacturing methods are not cost-efficient.
Innovation Solution
The implementation of a semiconductor component manufacturing process where leadframe leads are partially embedded in a mold compound, with exposed regions coated using a barrel plating process to form a wetable electrically conductive layer, such as tin, to enhance wetability and prevent corrosion, while maintaining cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leadframe leads are left exposed after cutting, then manufacturing process is simple, but wetability is poor leading to corrosion and unreliable solder joints
Solution Approach 1:
The patent applies preliminary action by embedding the leadframe leads in the mold compound before the final cutting step. This pre-embedding protects the leads and prepares them for subsequent plating operations, ensuring they will have proper wetability and corrosion resistance before they are exposed in the final singulation step.
Solution Approach 2:
The mold compound serves as an intermediary material that protects the leadframe leads during manufacturing. By embedding the leads in the mold compound, the patent creates a protective environment that allows for controlled plating operations and prevents damage to the leads, while the mold compound itself can be removed or designed to expose the plated leads in the final product.
2Reliability
If leadframe leads are coated with tin plating, then wetability and corrosion resistance improve, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by selectively plating only the portions of the leadframe leads that will be exposed and require wetability for soldering. The plating process is targeted to specific regions rather than coating the entire leadframe structure, which reduces material consumption and manufacturing cost while still providing the necessary corrosion resistance and solderability where needed.
Solution Approach 2:
The patent uses partial action by applying tin plating only to the extent necessary for achieving reliable solder joints and corrosion resistance. Rather than over-plating the entire leadframe, the process applies coating just to the exposed lead portions that contact the PCB, optimizing material usage and reducing manufacturing costs while maintaining adequate protective and functional 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 process ensures improved wetability of leadframe leads, reducing corrosion and forming reliable solder joints, thereby enhancing the reliability and cost-efficiency of semiconductor component manufacturing.
Implementation Method 1
The exposed regions are then coated to form a wetable electrically conductive layer, such as tin
Data Source
AI summary
A semiconductor component having wetable leadframe lead surfaces and a method of manufacture. A leadframe having leadframe leads is embedded in a mold compound. A portion of at least one leadframe lead is exposed and an electrically conductive material is formed on the exposed portion. The mold compound is separated to form singulated semiconductor components.