Multi-Layer Ceramic Electrode Plating for Hydrogen Release
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Solution Overview
Problem
The formation of external electrodes in multi-layer ceramic capacitors through plating processes leads to hydrogen occlusion, which diffuses into the ceramic body, causing a decrease in insulation resistance and reducing the adhesion and wettability of solder during mounting.
Innovation Solution
A method involving the formation of a base film on a ceramic body, followed by a first nickel film through electrolytic plating, heat treatment in a weakly reducing atmosphere to release hydrogen, and subsequent formation of a second nickel film to stabilize the surface, ensuring adequate solder bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an Ni plating layer is formed after oxidation treatment of the external electrode main body, then the protective layer is formed, but the adhesion between the protective layer and the Ni plating layer is reduced
Solution Approach 1:
The patent applies preliminary action by performing heat treatment in a weakly reducing atmosphere before forming the Ni plating layer. This preliminary heat treatment removes hydrogen from the oxide film and creates a surface state that improves subsequent plating adhesion, preventing the adhesion problem that would occur if plating were done directly after oxidation.
Solution Approach 2:
The patent changes the atmospheric parameters and temperature conditions through heat treatment in a weakly reducing atmosphere. By controlling the atmosphere composition and temperature, the surface properties of the oxide film are modified to enable better adhesion of the subsequent Ni plating layer while maintaining the protective function.
2Reliability
If heat treatment is performed on the Ni plating layer surface, then hydrogen is released, but the surface of the Ni plating layer is oxidized and becomes unstable
Solution Approach 1:
The patent applies preliminary action by performing heat treatment in a weakly reducing atmosphere before forming the final Ni plating layer. This timing allows hydrogen release while avoiding excessive oxidation, and the subsequent Ni plating restores surface stability and solder wettability.
Solution Approach 2:
The patent uses a weakly reducing atmosphere during heat treatment to create a protective environment that prevents excessive oxidation of the Ni plating layer surface. This controlled atmosphere allows hydrogen release while maintaining surface stability and preventing the formation of unstable oxides.
3Ease of manufacture
If Sn plating layer is formed directly on oxidized Ni plating layer surface, then the plating process is simplified, but the adhesion of the Sn plating layer is reduced and solder wettability is reduced
Solution Approach 1:
The patent applies preliminary action by performing heat treatment in a weakly reducing atmosphere before forming the Sn plating layer. This preliminary treatment prepares the surface by removing hydrogen and creating optimal conditions for Sn plating adhesion and solder wettability, ensuring reliable electrical connections.
Solution Approach 2:
The patent changes the surface parameters through heat treatment in a controlled atmosphere, modifying the surface energy and chemical composition to enhance Sn plating adhesion and solder wettability. This parameter optimization ensures reliable electrical connections while maintaining manufacturing efficiency.
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
This approach suppresses hydrogen diffusion into the ceramic body, maintains solder wettability, and enhances the adhesion of plating films, thereby improving the reliability of the multi-layer ceramic electronic component and circuit board.
Implementation Method 1
the hydrogen in the external electrodes is diffused into a ceramic body
Implementation Method 2
heat treatment is performed at a temperature equal to or higher than a temperature at which the first nickel film is recrystallized
Implementation Method 3
forming a first nickel film on the base film by an electrolytic plating method
Implementation Method 4
the surface of the Ni plating layer subjected to the heat treatment is oxidized
Data Source
AI summary
A multi-layer ceramic electronic component includes: a ceramic body including internal electrodes laminated and drawn to an end face of the ceramic body; and an external electrode including: a base film disposed on the end face of the ceramic body and formed from an electrically conductive material, a first nickel film disposed on and in contact with the base film in a thickness direction of the base film, and a second nickel film disposed on the first nickel film in a thickness direction of the first nickel film, wherein the base film is in contact with the internal electrodes, or the first nickel film is thicker than the second nickel film.