Multilayer Ceramic Component Outer Electrode Shrinkage Stress
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Solution Overview
Problem
Multilayer ceramic electronic components face separation issues of outer electrodes from the electronic component element due to significant shrinkage differences during co-firing, leading to shearing stress and potential detachment.
Innovation Solution
The structure of the outer electrode is improved by incorporating a first layer with an oxide of the ceramic layer elements and a second layer without oxides, reducing shrinkage differences and shearing stress, and ensuring strong anchoring through sintering of the oxide layer with the electronic component element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer outer electrode structure is used, then the device complexity is low, but the outer electrode separates from the electronic component element due to shrinkage difference during co-firing
Solution Approach 1:
The outer electrode is divided into two distinct layers: a first outer electrode layer containing an oxide of at least one element of the ceramic layer, and a second outer electrode layer not containing such oxides. This segmentation allows each layer to serve different functions - the first layer bonds to the ceramic element while the second layer provides additional conductivity, thereby preventing separation while maintaining structural organization.
Solution Approach 2:
The outer electrode employs a composite structure combining two different material compositions. The first layer uses conductive paste containing ceramic oxides (e.g., BaO, Al2O3, SiO2) that bond with the electronic component element, while the second layer uses paste without these oxides for enhanced conductivity. This composite approach resolves the contradiction between attachment reliability and electrical performance.
2Reliability
If the outer electrode contains oxides of ceramic layer elements, then the shrinkage difference during co-firing is reduced, but the electrical conductivity decreases
Solution Approach 1:
The outer electrode is segmented into two functional layers: the first layer contains ceramic oxides that match the electronic component element's composition, ensuring minimal shrinkage difference and strong bonding during co-firing; the second layer excludes these oxides, providing superior electrical conductivity. This segmentation allows each layer to optimize for its specific function without compromise.
Solution Approach 2:
The outer electrode uses a composite structure where the first layer's conductive paste includes ceramic oxides (BaO, Al2O3, SiO2) for bonding compatibility, while the second layer's paste lacks these oxides for enhanced conductivity. The composite design balances bonding strength and electrical performance across different layers.
3Reliability
If the outer electrode is applied extensively over multiple surfaces, then the electrical connection coverage is improved, but the shearing stress during co-firing increases
Solution Approach 1:
The extensive outer electrode structure is segmented into two layers, with the first layer providing broad coverage for stress distribution and bonding, while the second layer enhances conductivity. This segmentation allows the electrode to extend over multiple surfaces (first, second, third, and fourth surfaces) without concentrating excessive shearing stress at the interface, as the first layer's oxide-containing composition ensures gradual bonding.
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
This configuration effectively prevents or reduces outer electrode separation from the fired electronic component element, maintaining electrical conductivity and ensuring reliable attachment even in small-sized components.
Implementation Method 1
During the co-firing, the dielectric ceramic layer and the conductor paste are each sintered and shrink. At least a portion of the oxide included in the first layer is sintered to be joined to the electronic component element.
Implementation Method 2
During the co-firing, the dielectric ceramic layer and the conductor paste are each sintered and shrink. When the shrinkage difference between the two is large, at least one of the outer electrodes may not withstand the shearing stress generated at the interface between the two.
Data Source
AI summary
A multilayer ceramic electronic component includes an electronic component element including a ceramic layer and an inner conductor, and outer electrodes disposed on the surface of the electronic component element. The outer electrodes include a first layer disposed on the surface of the electronic component element, and a second layer disposed on the first layer. The first layer includes an oxide of at least one of elements of the ceramic layer. The second layer does not include oxides of elements of the ceramic layer.