MLCC Side Margin Vanadium Diffusion for Sintering Reliability
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Solution Overview
Problem
The sinterability of the protective side margin in multi-layer ceramic capacitors is prone to be lowered by the presence of rare-earth elements, leading to potential malfunction such as peel-off, and existing techniques fail to maintain high reliability without compromising sinterability.
Innovation Solution
A multi-layer ceramic capacitor design with a side margin having a higher concentration of rare-earth elements and vanadium than the ceramic layers, where these elements diffuse during sintering to enhance reliability while vanadium improves sinterability, ensuring sufficient protection and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a larger amount of rare-earth element is provided to the protective section (side margin) to suppress crystal growth and prevent short circuit, then reliability is improved, but sinterability of the protective section is lowered
Solution Approach 1:
The patent changes the chemical composition parameters of the protective section by adding vanadium element in addition to rare-earth elements. Specifically, the protective section contains 0.01-5 mass% vanadium and 0.01-5 mass% rare-earth elements, creating a new compositional parameter space that simultaneously achieves high reliability and good sinterability.
Solution Approach 2:
The patent creates a composite material system in the protective section combining rare-earth elements and vanadium element. This composite approach allows the rare-earth elements to suppress crystal growth and prevent short circuits while vanadium maintains sinterability, resolving the contradiction between reliability improvement and manufacturing ease.
2Reliability
If rare-earth element concentration is increased in the protective section to prevent short circuit between internal electrodes, then occurrence of short circuit is suppressed, but sinterability of the protective section is further lowered
Solution Approach 1:
The vanadium element acts as an intermediary substance that mediates between the rare-earth elements and the ceramic matrix. It allows the rare-earth elements to perform their crystal growth suppression function while the vanadium itself maintains the sinterability of the protective section, preventing the worsening effect.
3Reliability
If protective section is provided to cover the periphery of internal electrodes, then protection against short circuit is improved, but sinterability of the protective section is lowered due to rare-earth elements
Solution Approach 1:
The patent applies local quality by creating a protective section with specific local composition (rare-earth elements 0.01-5 mass% and vanadium 0.01-5 mass%) only where needed at the periphery of internal electrodes. This localized compositional modification provides protection against short circuits while maintaining overall sinterability of the ceramic body.
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 configuration achieves high reliability by reducing oxygen defects and maintaining adequate sinterability of the side margin, preventing failures and ensuring long-term performance without impairing DC bias characteristics.
Implementation Method 1
the rare-earth element and the vanadium diffuse from the side margin to the multi-layer unit at the time of sintering
Implementation Method 2
the rare-earth element contained in large amounts in the protective section further lowers the sinterability of the protective section
Implementation Method 3
the rare-earth element diffused to the ceramic body suppresses the crystal growth at the time of sintering
Implementation Method 4
the vanadium improves the sinterability of the side margin. In other words, in this configuration, using the vanadium in addition to the rare-earth element allows sufficient sinterability to be ensured in the side margin
Data Source
AI summary
A multi-layer ceramic capacitor includes a multi-layer unit and a side margin. The multi-layer unit includes ceramic layers laminated in a first direction, and internal electrodes disposed between the ceramic layers. The side margin covers the multi-layer unit from a second direction orthogonal to the first direction, the side margin having a higher concentration of a rare-earth element and a higher concentration of vanadium than center portions of the ceramic layers in the second direction.