Multilayer Ceramic Capacitor Side Margin Design for Crack Reduction
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Solution Overview
Problem
Large, high-capacitance multilayer ceramic capacitors are prone to cracks due to their high specific gravity, which can occur during manufacturing or mounting, and are exacerbated by differences in shrinkage between capacitance and side margin sections during firing, as well as metal diffusion during external electrode baking, leading to reliability issues.
Innovation Solution
A ceramic electronic component with a multilayer structure featuring alternately stacked dielectric and internal electrode layers, where the internal electrode layers have different widths and are exposed on opposite edges, and external electrodes are formed from a different metal, with a specific ratio of internal electrode layer widths and a margin section to reduce stress and crack occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of internal electrode layers is increased to achieve high capacitance, then the capacitance increases, but the weight increases and the component becomes prone to cracks during dropping
Solution Approach 1:
The patent applies local quality by creating a side margin section with a different structure from the capacitance section. The side margin section has no internal electrode layers or has reduced number of layers, providing localized protection against cracks while maintaining high capacitance in the capacitance section through dense stacking of internal electrode layers.
2Quantity of substance
If the internal electrode layers are made thinner and stacked more densely to achieve high capacitance, then the capacitance increases, but the shrinkage difference between capacitance section and side margin section increases, leading to more cracks
Solution Approach 1:
The patent creates a local quality difference by forming a side margin section with distinct structural characteristics. This section has different shrinkage properties that compensate for the shrinkage of the capacitance section, thereby reducing overall shrinkage non-uniformity and preventing cracks during the firing process.
3Reliability
If the baking temperature of external electrodes is increased to ensure reliability, then the reliability improves, but the diffusion length of main component metal increases, resulting in more cracks
Solution Approach 1:
The patent extracts or removes the internal electrode layers from the side margin section, creating a metal-free zone. This prevents metal diffusion from external electrodes into the ceramic body during high-temperature baking, eliminating the harmful effect of metal diffusion while maintaining reliable electrode bonding in the capacitance section.
4Strength
If thicker cover layers are used to protect the capacitance section, then the protection capability improves, but the ability to follow shrinkage decreases, increasing crack risk in cover layers
Solution Approach 1:
The patent applies local quality by creating a side margin section with a structure that has different mechanical properties. This section can accommodate shrinkage differently than the capacitance section, reducing stress concentration and preventing cracks in the cover layers while maintaining protection capability.
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 design effectively reduces crack occurrence and enhances moisture resistance and reliability by mitigating stress from differential shrinkage and metal diffusion, while maintaining high capacitance.
Implementation Method 1
during baking of the external electrodes, the main component metal of the external electrode and the main component metal of the internal electrode layer interdiffuse, causing the internal electrode layer to expand
Implementation Method 2
the difference between the shrinkage of the capacitance section and the shrinkage of the side margin section during firing becomes larger
Data Source
AI summary
A ceramic electronic component includes a multilayer chip having a substantially rectangular parallelepiped shape and including a first multilayer structure and a second multilayer structure disposed on each of top and bottom faces of the first multilayer structure, the first multilayer structure including first ceramic dielectric layers having a first width in a first direction in which side faces of the multilayer chip are opposite to each other, the second multilayer structure including second internal electrode layers having a second width less than the first width in the first direction, and a pair of external electrodes formed from the respective two edge faces to at least one of side faces of the multilayer chip, wherein main components of the first and second internal electrode layers differ from a main component of the external electrodes.