Multilayer Ceramic Component Nickel Plating for Hydrogen Control
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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 followed by a first nickel film, subjected to heat treatment in a weakly reducing atmosphere to release and recrystallize hydrogen, and then forming a second nickel film on the first nickel film to stabilize the surface, ensuring adequate solder bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plating process is used to form external electrodes, then external electrodes are formed, but hydrogen is occluded and diffuses into ceramic body causing insulation resistance decrease
Solution Approach 1:
The patent extracts and removes hydrogen from the plating layer through heat treatment before hydrogen can diffuse into the ceramic body. The heat treatment process specifically targets and eliminates the harmful hydrogen occluded during plating, preventing insulation resistance degradation while maintaining the electrode structure.
Solution Approach 2:
The patent performs heat treatment as a preliminary action before final electrode formation or mounting. This preliminary hydrogen removal prevents subsequent insulation problems, addressing the issue before it can manifest during operation or soldering processes.
2Reliability
If Ni plating layer is formed after oxidation treatment, then protective layer is formed, but adhesion between protective layer and Ni plating layer is reduced
Solution Approach 1:
The patent changes the atmospheric parameters (introducing carbon-containing atmosphere) and temperature parameters (heating to 400-800°C) to transform the oxide layer into a carbon-containing layer. This parameter change fundamentally alters the surface chemistry to improve adhesion with subsequent Ni plating layers.
Solution Approach 2:
The patent uses carbon-containing atmosphere to chemically transform the oxide layer through controlled carbonization reactions. This chemical transformation creates a surface layer with enhanced bonding characteristics that strongly adheres to Ni plating.
3Ease of manufacture
If Sn plating layer is formed directly on oxidized surface, then external electrode is completed, but adhesion of Sn plating layer is reduced
Solution Approach 1:
The patent performs preliminary carbon-containing atmosphere heat treatment to create an adherent surface before forming the Sn plating layer. This preliminary surface preparation ensures strong adhesion of subsequent plating layers by eliminating oxide barriers and creating a chemically active surface.
Solution Approach 2:
The patent changes the surface chemical composition through controlled carbonization in carbon-containing atmosphere, transforming the oxide surface into a carbon-enriched surface that strongly bonds with Sn plating materials.
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 preventing insulation resistance degradation and ensuring reliable mounting.
Implementation Method 1
performing, after forming the first nickel film, heat treatment in a weakly reducing atmosphere at a temperature equal to or higher than a temperature at which the first nickel film is recrystallized
Implementation Method 2
the first nickel film subjected to the heat treatment is recrystallized and provided with a configuration to suppress the hydrogen from diffusing
Implementation Method 3
the first nickel film subjected to the heat treatment is recrystallized and provided with a configuration to suppress the hydrogen from diffusing
Implementation Method 4
forming a first nickel film on the base film by an electrolytic plating method
Data Source
AI summary
A method for producing a multilayer ceramic electronic component is disclosed. The method includes: forming a laminate comprising a plurality of ceramic sheets and a plurality of internal electrodes, wherein one end of at least one of the internal electrodes is exposed on a surface of the laminate; forming a base film of an electrically conductive material on the surface such that the base film is electrically connected to the exposed end of the internal electrode; forming a first nickel film on the base film by electrolytic plating; performing a heat treatment on the first nickel film at a temperature at or above its recrystallization temperature; and subsequently forming a second nickel film on the first nickel film by electrolytic plating.