Multilayer Ceramic Capacitor Stepped Electrode Adhesion
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Solution Overview
Problem
In the manufacturing of miniaturized and high-capacity multilayer ceramic capacitors, the adhesive force between the ceramic body and the side margin portion is often inadequate, leading to delamination, degraded insulation resistance, and reduced waterproof reliability, especially when excessive thermocompression bonding is used to enhance this force, which can damage the thin dielectric layer and internal electrode.
Innovation Solution
The solution involves adjusting the shape of the internal electrodes to include body portions and lead portions with a smaller width, exposing these through the ceramic body's surfaces, and forming side margin portions on the lateral surfaces, thereby increasing the dielectric area ratio and enhancing the adhesive force between the ceramic body and the side margin portions without the need for high heat and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermocompression bonding is excessively performed to enhance adhesive force between ceramic body and side margin portion, then adhesive force is improved, but thin dielectric layer and internal electrode are damaged
Solution Approach 1:
The patent changes the geometric parameters of the internal electrode, specifically creating a stepped structure where the electrode width varies along its length. This parameter change allows the electrode to expose a smaller width through the lateral surface, reducing the bonding area required and thus reducing the excessive thermocompression bonding that causes damage to the thin dielectric layer and electrode.
Solution Approach 2:
The internal electrode is segmented into different width portions: a first width portion and a second width portion that is smaller. This segmentation allows different functional zones - the larger width provides sufficient bonding area for adhesive force, while the smaller width reduces the bonding area to prevent damage from excessive compression, resolving the contradiction between needing strong adhesion and avoiding damage.
2Reliability
If side margin portion is attached to lateral surface of ceramic body, then adhesive force is enhanced, but side margin portion may be partially delaminated from ceramic body
Solution Approach 1:
By changing the width parameter of the internal electrode to create a stepped structure, the patent optimizes the bonding interface geometry. The smaller width portion through which the electrode exits the lateral surface creates a more favorable bonding configuration that enhances adhesion while preventing delamination, addressing both the need for strong bonding and structural stability.
Solution Approach 2:
The patent creates a stepped configuration where the internal electrode has different width portions, effectively copying a structural solution that provides both sufficient bonding area and reduced compression stress. This geometric copying approach ensures that the bonding interface has optimal characteristics for both adhesion strength and delamination resistance.
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 approach improves the reliability and electrical characteristics of the multilayer ceramic capacitors by maintaining the adhesive force and preventing delamination, while minimizing damage to the dielectric layer and internal electrode, thus ensuring excellent insulation resistance and waterproof reliability.
Implementation Method 1
preparing a ceramic body including an active portion that includes a dielectric layer and a plurality of internal electrodes overlapping each other across the dielectric layer
Data Source
AI summary
A multilayer ceramic capacitor includes a ceramic body including an active portion that includes a dielectric layer and a plurality of internal electrodes overlapping each other across the dielectric layer, and cover portions formed above and below the active portion, and including first and second surfaces opposing each other, third and fourth surfaces connecting the first and second surfaces, and fifth and sixth surfaces connected to the first to fourth surfaces and opposing each other, and first and second side margin portions disposed on the first and second surfaces. In a cross-section of the ceramic body in a length-thickness (L-T) direction, a ratio Sd/Sc of an area Sd of a region except for the active portion to an overall area Sc of the cross-section is greater than 27%.