Multilayer Ceramic Capacitor Internal Electrode Material and Thickness
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Solution Overview
Problem
Multilayer ceramic capacitors face challenges in size reduction and maintaining high Q values in high frequency regions due to thick internal electrodes, which also lead to peeling issues during firing and moisture resistance concerns.
Innovation Solution
A multilayer ceramic capacitor design with internal electrodes made of Cu or Ag, optimized thickness, and connectivity configuration to ensure high Q values and prevent peeling, along with a mounting structure that allows perpendicular orientation for uniform current flow and improved connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the internal electrode is increased to lower electric resistance and raise Q value, then the Q value in high frequency region is improved, but the size of the multilayer ceramic capacitor increases
Solution Approach 1:
The patent changes the material parameter of the internal electrode from traditional Pd to Cu or Ag, which have lower electrical resistance. This material substitution allows achieving the same Q value with a thinner electrode thickness, thus reducing the overall capacitor size while maintaining high frequency performance
Solution Approach 2:
The patent uses composite material structures by combining Cu or Ag internal electrodes with specific dielectric ceramic layers. This composite approach optimizes the balance between electrical conductivity and dielectric properties, enabling size reduction while maintaining high Q values in the high frequency region
2Reliability
If the thickness of the internal electrode is increased to lower electric resistance, then the Q value is improved, but peeling occurs in the interface between the internal electrode and the dielectric ceramic layer during firing
Solution Approach 1:
The patent changes the material composition parameter from Pd-based to Cu or Ag-based internal electrodes. These materials have better thermal expansion compatibility with the dielectric ceramic layer, reducing shrinkage differences during firing and preventing interface peeling while maintaining low electrical resistance
Solution Approach 2:
The patent addresses thermal expansion mismatch by selecting Cu or Ag as internal electrode materials, which have thermal expansion coefficients more compatible with the dielectric ceramic. This reduces the shrinkage difference during the firing process, preventing peeling at the electrode-dielectric interface
3Reliability
If the thickness of the internal electrode is increased to lower electric resistance, then the Q value is improved, but moisture resistance deteriorates
Solution Approach 1:
The patent changes the internal electrode material to Cu or Ag with optimized thickness parameters. This allows achieving adequate electrical conductivity with thinner electrodes, reducing the moisture penetration pathway through the electrode and improving overall moisture resistance while maintaining acceptable Q values
Data Source
AI summary
A multilayer ceramic capacitor includes a stacked body including a stack of a plurality of dielectric layers and a plurality of internal electrodes, and a pair of external electrodes. In the stacked body, a width dimension is greater than a thickness dimension, a length dimension preferably is about 0.4 mm or less, a width dimension preferably is about 0.15 mm or more and about 0.35 mm or less, a thickness dimension preferably is about 0.2 mm or less, and each of the internal electrodes is made of Cu or Ag as a main component and has a width dimension that is about 60% or more of the width dimension of the stacked body.