Multilayer Ceramic External Electrode Coating Against Moisture Migration
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Solution Overview
Problem
Multilayer ceramic electronic components face degradation due to moisture penetration and ion migration, leading to reliability issues and short circuits when exposed to high temperature and humidity environments, causing mechanical stress and hydrophilic oxide layer formation.
Innovation Solution
A multilayer ceramic electronic component design featuring a ceramic body with alternately stacked internal electrodes and external electrodes, including a conductive layer with glass and a coating layer with inorganic film and vinyl group-based layers to prevent moisture penetration and ion migration, enhancing bonding strength and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plating layer is formed on the external electrode after sintering, then the electrical conductivity is improved, but the reliability deteriorates due to moisture penetration and ion migration
Solution Approach 1:
A coating layer is introduced as an intermediary between the external electrode and the environment. This coating layer acts as a barrier that prevents moisture from penetrating into the electrode structure, thereby eliminating the harmful effects of moisture-induced ion migration while preserving the electrical conductivity provided by the plating layer.
Solution Approach 2:
The external electrode structure is transformed into a composite system consisting of multiple layers: the plating layer for electrical conductivity and the coating layer for moisture protection. This composite structure combines the beneficial properties of different materials to simultaneously achieve high conductivity and high reliability in humid environments.
2Temperature
If the ceramic body is exposed to high temperature and humidity, then the manufacturing process is simplified, but the reliability deteriorates due to ion migration
Solution Approach 1:
The coating layer serves as a protective intermediary that blocks the pathway for ion migration. Even when the ceramic body is exposed to high temperature and humidity conditions that would normally accelerate ion migration, the coating layer prevents ions from moving through the external electrode, thereby maintaining reliability under thermal stress.
3Strength
If the oxide layer with high surface energy is formed on the ceramic body surface, then the bonding strength is improved, but the reliability deteriorates due to moisture adhesion
Solution Approach 1:
The coating layer is positioned as an intermediary between the hydrophilic oxide layer and the external environment. It allows the oxide layer to maintain its high bonding strength to the ceramic body while simultaneously preventing moisture from adhering to the surface, thus eliminating the harmful effect of moisture attraction.
Solution Approach 2:
Different regions of the external electrode structure are assigned different functions: the oxide layer provides local bonding strength at the ceramic body interface, while the coating layer provides local moisture resistance at the external surface. This spatial differentiation of properties allows both bonding strength and moisture resistance to coexist.
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 solution effectively prevents moisture penetration, suppresses ion migration, and reduces short circuit defects, thereby improving the reliability and longevity of the multilayer ceramic electronic components.
Implementation Method 1
the first coating layer includes a plurality of openings disposed on the first electrode layer and the second electrode layer... the first conductive layer and the second conductive layer are sintered electrodes including a conductive metal and glass
Implementation Method 2
when the multilayer ceramic electronic component is continuously exposed to a high temperature and/or high humidity environment, the possibility of ion migration is increased in the external electrode... The oxide layer formed on the surface of the ceramic body has high surface energy causes moisture to easily adhere to the surface
Implementation Method 3
the first conductive layer and the second conductive layer are sintered electrodes including a conductive metal and glass
Data Source
AI summary
A multilayer ceramic electronic component includes a ceramic body including a first internal electrode and a second internal electrode disposed to be alternately stacked with a dielectric layer interposed therebetween; a first external electrode connected to the first internal electrode and including a first electrode layer, a first conductive layer, and a first metal layer; a second external electrode connected to the second internal electrode and including a second electrode layer, a second conductive layer, and a second metal layer; and a first coating layer disposed on the ceramic body, the first electrode layer and the second electrode layer. The first conductive layer and the second conductive layer are sintered electrodes including a conductive metal and glass, and the first coating layer includes a plurality of openings disposed on the first electrode layer and the second electrode layer.