Multilayer Ceramic Electrode Plating for Hydrogen-Resistant Adhesion
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Solution Overview
Problem
Existing methods for manufacturing multilayer ceramic capacitors face issues with hydrogen occlusion in external electrodes, leading to decreased insulation resistance due to hydrogen diffusion into the ceramic body, and adhesion problems between Ni plating layers, which affect the mechanical strength and solder wettability.
Innovation Solution
A multilayer ceramic electronic component design with a five-layer external electrode structure, including a base film, first Ni film, metal film with lower ionization tendency, second Ni film with higher hydrogen concentration, and a surface layer film, where heat treatment is performed in a weakly oxidizing or reducing atmosphere to enhance adhesion and prevent hydrogen diffusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat treatment is performed after forming the Ni plating layer, then the surface of the Ni plating layer becomes oxidized and unstable
Solution Approach 1:
The Pd or Pt film serves as a protective intermediary layer during heat treatment. Since these metals have lower oxidation tendencies than Ni, they protect the Ni plating layer surface from oxidizing during the heat treatment process. This allows heat treatment to be performed for hydrogen removal while maintaining the stability and solderability of the external electrode surface.
2Ease of manufacture
If Sn plating layer is formed directly on the Ni plating layer surface, then adhesion of the Sn plating layer may be lowered and wettability of solder may decrease
Solution Approach 1:
A Pd or Pt intermediary film is introduced between the Ni plating layer and the Sn plating layer. This intermediary layer ensures stable adhesion of the Sn plating layer and maintains good solder wettability, while also protecting the Ni layer from oxidation. The presence of this intermediate layer does not significantly complicate the manufacturing process while providing substantial reliability improvements.
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 solution ensures high adhesion between electrode layers, reduces hydrogen diffusion, and maintains solder wettability, thereby improving the reliability and mechanical strength of the multilayer ceramic capacitors.
Implementation Method 1
a metal film that is formed on the first Ni film and contains a metal having a lower ionization tendency than Ni, as a main component
Implementation Method 2
heat treatment is performed under a temperature condition of 150° C. or higher after the formation of the Ni layer
Implementation Method 3
Hydrogen generated in this plating process tends to be occluded and remain in the external electrodes. In a multilayer ceramic capacitor, hydrogen in the external electrodes diffuses into the ceramic body
Data Source
AI summary
A method of manufacturing a multilayer ceramic electronic component includes: forming a base film on each of the end surfaces of a ceramic body; forming a first Ni film on the base film by electrolytic plating; forming a metal film on the first Ni film, the metal film containing a metal having a lower ionization tendency than Ni as a main component; forming a second Ni film on the metal film by electrolytic plating; and forming a surface layer film on the second Ni film, wherein before the forming of the second Ni film, the ceramic body on which the metal film is formed is subjected to heat treatment, in a weakly oxidizing atmosphere or a reducing atmosphere, at a temperature equal to or higher than a temperature at which the first Ni film is recrystallized.