Multilayer Ceramic Component Moisture Resistance via End-Thickness Variation
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Solution Overview
Problem
Conventional multilayer ceramic electronic components face issues with moisture resistance due to thin external electrodes on ridge lines, which allow water to easily enter the interfaces between internal and dielectric layers, leading to reliability concerns.
Innovation Solution
The design includes external electrodes that cover the end surfaces and extend to main and lateral surfaces, with thicker outer layers at the ends and a specific curvature of ridge lines to prevent water ingress, along with a manufacturing process that forms a mother stacked body, compresses, grinds, and polishes to achieve these dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stacked body uses rounded ridge lines in conventional design, then the manufacturing process is simpler, but the external electrodes on ridge lines become thin and allow water ingress
Solution Approach 1:
The patent applies local quality by creating a thickness variation in the outer layer of the stacked body. Specifically, the outer layer is designed to be thicker at the end surfaces than at the center in the length direction, forming a localized thickened portion at the ridges. This local structural modification prevents water ingress at critical areas without changing the overall rounded ridge line design, thus maintaining manufacturing simplicity while improving moisture resistance.
2Reliability
If the outer layer thickness is increased at end surfaces, then water ingress is prevented, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies preliminary action by incorporating the thickness variation directly into the stacked body structure before external electrode formation. The outer layer is designed with greater thickness at end surfaces during the stacking process itself, creating a pre-formed barrier structure. This approach establishes the moisture protection feature in advance, avoiding the need for complex post-processing or precision control during electrode deposition.
3Reliability
If external electrodes are made thinner on ridge lines, then the manufacturing process remains conventional, but insulation resistance decreases due to water entry
Solution Approach 1:
The patent applies the intermediary principle by using the thickened outer layer portion as a protective barrier between the external electrodes and the internal electrode layers. This intermediate thickened structure prevents water from reaching the electrode interfaces, thereby protecting insulation resistance without requiring changes to the external electrode formation process itself. The thickened outer layer acts as a mediator that blocks harmful moisture while allowing the conventional electrode manufacturing to proceed.
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 enhances the moisture resistance of multilayer ceramic electronic components by ensuring thicker electrode coverage and reduced water entry, as demonstrated by improved insulation resistance in pressure cooker bias tests.
Implementation Method 1
The gravity causes the conductive paste on ridge lines of the stacked body to flow toward the center of an end surface of the stacked body
Implementation Method 2
Also, the surface tension causes the conductive paste to gather on the main surfaces and the lateral surfaces of the stacked body
Data Source
AI summary
In a multilayer ceramic electronic component, a stacked body includes a first outer layer and a first outermost internal electrode layer. The first outer layer defines a first main surface. The first outermost internal electrode layer is adjacent to the first outer layer. The first outermost internal electrode layer is in contact with a first external electrode at a first end surface. The thickness of the first outer layer at the first end surface is greater than the thickness of the first outer layer at the center or approximate center in a length direction.