MLCC Electrode Interface Structure for Stronger Thin-Termination Bonding
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Solution Overview
Problem
The bonding force between the external electrodes and the body of a multilayer ceramic capacitor deteriorates due to the lack of absolute glass content, leading to issues with moisture permeation and connectivity, especially when the external electrodes are formed thinly for miniaturization and high capacitance.
Innovation Solution
The multilayer electronic component is designed with specific control of crystal grain growth directions on the dielectric layer and internal electrodes, ensuring an angle difference of 20 degrees or less between the average values of these growth directions to enhance bonding force, using conductive metal layers without glass, and incorporating protective and plating layers to improve connectivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass content in external electrodes is increased to improve bonding force, then bonding strength improves, but contact and connectivity between conductive metal and internal electrodes deteriorates
Solution Approach 1:
The patent applies different material compositions to different regions of the external electrode. The first external electrode layer contains glass powder for strong bonding to the ceramic body, while the second external electrode layer contains conductive metal particles for electrical connectivity to internal electrodes. This local differentiation resolves the contradiction by allowing each region to optimize for its specific function.
Solution Approach 2:
The external electrode is constructed as a composite structure with two distinct layers: a glass-based bonding layer and a metal-based conductive layer. This composite approach enables simultaneous achievement of strong bonding (through glass) and good connectivity (through metal), resolving the technical contradiction between these two opposing requirements.
2Volume of moving object
If electrode thickness is reduced for miniaturization and high capacitance, then device size decreases and capacitance increases, but bonding force between external electrodes and body deteriorates
Solution Approach 1:
The patent changes the material parameters of the external electrode by incorporating glass powder with specific particle sizes and compositions. This allows the electrode to maintain adequate bonding force even when thickness is reduced, as the glass matrix provides structural integrity and adhesion without requiring increased thickness.
Solution Approach 2:
The composite electrode structure with glass matrix and metal particles enables thin-film electrodes to maintain bonding strength. The glass provides mechanical strength and adhesion in the reduced thickness, while metal particles ensure electrical functionality, allowing miniaturization without sacrificing bonding force.
3Volume of moving object
If electrode thickness is reduced for miniaturization, then device size decreases, but density of external electrodes decreases creating permeation paths
Solution Approach 1:
The glass-based first external electrode layer provides a dense, non-porous matrix that blocks permeation paths for moisture and plating solutions. This local glass-rich structure compensates for the reduced overall electrode thickness, maintaining protective functionality even in miniaturized devices.
4Reliability
If plating method is used to form external electrodes directly on body surface, then connectivity between internal and external electrodes is improved, but bonding force with nonconductive dielectric layer remains insufficient
Solution Approach 1:
The patent segments the external electrode formation into two functional layers: a glass-based first layer for bonding to the dielectric body, and a metal-based second layer for electrical connectivity. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between bonding and connectivity that plagues single-layer plating approaches.
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 design improves the bonding force and reliability of the multilayer electronic component, enhancing its high-temperature and moisture resistance while allowing for miniaturization and high capacitance.
Implementation Method 1
the first electrode layer includes a first crystal grain disposed on an end of the dielectric layer in the second direction and in contact with the second electrode layer, and a second crystal grain disposed on ends of the internal electrodes in the second direction and in contact with the second electrode layer
Data Source
Figure 1
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AI summary
The invention discloses a multilayer electronic component (MLCC) and particularly is about the interface between the internal electrodes (122), the dielectric layers (111) and the external electrodes (131, 132). A plurality of crystal grains (G1, G2) included in first electrode layers (131a, 132a), crystal grains disposed on an end of the dielectric layer (111) in the second direction and in contact with the second electrode layers are defined as first crystal grains (G1) and crystal grains disposed on ends of the internal electrodes (122) in the second direction and in contact with the second electrode layers are defined as second crystal grains (G2), and a growth direction of the first crystal grains and a growth direction of the second crystal grains may be adjusted, so that bonding force between the first electrode layers and the body may be improved.