Multilayer Ceramic Component Buffer Layer Crack Prevention
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Solution Overview
Problem
The miniaturization and high capacitance requirements in multilayer ceramic electronic components lead to increased diffusion of glass components from external electrodes into the ceramic body, causing stress and internal defects like radial cracking due to the difference in diffusion rates of conductive metals between internal and external electrodes.
Innovation Solution
Incorporating buffer layers with a boron content of 50% or more between internal and external electrodes, and controlling the thickness of these buffer layers by regulating the temperature increase rate and glass composition, particularly with alkali metal and vanadium oxide, to manage the diffusion of conductive metals and reduce stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of laminated internal electrodes is increased and their thickness is reduced to achieve miniaturization and high capacitance, then the capacitance and miniaturization requirements are met, but the diffusion of glass component from external electrodes into the ceramic body is increased, causing stress and internal defects
Solution Approach 1:
A buffer layer is introduced as an intermediary between the external electrode and the internal electrodes. This buffer layer selectively blocks the diffusion of glass component from the external electrode into the ceramic body and internal electrodes, while allowing controlled diffusion of conductive metal. The buffer layer thus mediates the harmful interaction between external and internal electrodes, preventing stress concentration and radial cracking that would otherwise occur due to excessive glass diffusion.
Solution Approach 2:
The buffer layer is applied locally only at specific positions where external electrodes contact the ceramic body, rather than uniformly across the entire component. This localized application targets the specific areas where glass diffusion and stress concentration occur, effectively blocking harmful diffusion at the interface between external and internal electrodes while maintaining the overall miniaturized structure and high capacitance characteristics.
2Volume of moving object
If the thickness of internal electrodes is reduced to enable miniaturization, then smaller component size is achieved, but stress concentration increases leading to radial cracking and reduced reliability
Solution Approach 1:
The buffer layer serves as a stress-distributing intermediary between the thin internal electrodes and the external electrodes. By controlling the diffusion of conductive metal into the buffer layer and preventing glass diffusion, the buffer layer reduces stress concentration at the interface. This allows the internal electrodes to maintain reduced thickness for miniaturization while the buffer layer provides mechanical support and stress distribution to prevent radial cracking.
3Reliability
If the diffusion of conductive metal from external electrodes into internal electrodes is increased, then electrical connection is improved, but stress occurs due to volume expansion causing radial cracking
Solution Approach 1:
The buffer layer acts as a controlled diffusion intermediary that regulates the interaction between external and internal electrodes. It allows limited diffusion of conductive metal to ensure adequate electrical connection while simultaneously blocking excessive diffusion that would cause volume expansion and stress. The buffer layer thus mediates the balance between electrical connectivity and stress prevention, eliminating radial cracking while maintaining reliable electrical connection.
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 buffer layers effectively reduce stress and prevent radial cracks, maintaining the reliability and insulation resistance of the ceramic components by controlling the diffusion of metal elements and glass penetration, thus ensuring the components' durability and performance.
Implementation Method 1
the diffusion of glass component into the ceramic body may be increased in the case that an increased amount of internal electrodes is present in multilayer ceramic electronic components
Implementation Method 2
the glass component may be diffused and penetrate into a ceramic body during a sintering procedure
Data Source
AI summary
There is provided a multilayer ceramic electronic component, including: a ceramic body having internal electrodes formed therein; external electrodes formed on external surfaces of the ceramic body and connected to the internal electrodes; and buffer layers formed on contact surfaces between the internal electrodes and the external electrodes, among external surfaces of the ceramic body, in an interior direction of the ceramic body, wherein when a thickness of the internal electrode is denoted by Te, a number of laminated internal electrodes is denoted by N, a thickness of the buffer layer is denoted by t, and a width of a margin of the ceramic body in a length direction of the ceramic body is denoted by L, Te≦0.6 μm, N>200, and 3 μm≦t<L, so that the occurrence of radial cracks can be prevented and thus reliability can be improved.