Multilayer Ceramic Capacitor Electrode Glass Ratio
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Solution Overview
Problem
The challenge in developing small multilayer ceramic electronic components with high capacitance is the difficulty in achieving reliable chip sealing and preventing plating solution permeation due to insufficient or excessive glass content in external electrode pastes, especially with thin external electrodes, which affects reliability and compactness.
Innovation Solution
A multilayer ceramic electronic component design that includes a ceramic body with a dielectric layer and internal electrodes, where the external electrodes consist of a conductive metal and glass, with a specific ratio of glass to metal area (0.05≦A/B≦0.6) and thickness ratios (T1/Tc≧0.8 and T2/Tc≧0.5) to prevent plating solution permeation, ensuring improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the external electrode is thinned to achieve miniaturization, then the size of the electronic component is reduced, but the reliability deteriorates due to increased risk of plating solution permeation
Solution Approach 1:
The patent applies different glass contents to different regions of the external electrode. The end portion (edge region) has a higher glass content (30-200 volume%) compared to the central portion, creating local quality variation. This resolves the contradiction by providing enhanced sealing at the vulnerable edge regions where plating solution permeation is most likely to occur, while maintaining the overall thin profile for miniaturization.
Solution Approach 2:
The external electrode is formulated as a composite material containing both conductive metal particles and glass particles. This composite structure allows the electrode to simultaneously provide electrical conductivity (from metal) and sealing properties (from glass), resolving the contradiction between thinning for size reduction and maintaining reliability through adequate sealing.
2Reliability
If the glass content in external electrode paste is increased to enhance chip sealing properties, then sealing properties are improved, but plating defects occur due to glass elution to surface after sintering
Solution Approach 1:
The patent specifies different glass content ranges for different regions: the central portion has 10-50 volume% glass while the end portion has 30-200 volume% glass. This local differentiation allows sufficient glass content at edges for sealing without excessive glass throughout the entire electrode that would cause elution and plating defects.
Solution Approach 2:
The patent changes the glass content parameter spatially across the external electrode. By controlling the glass content to be higher at the ends and lower at the center, it optimizes the balance between sealing performance (requiring high glass) and preventing elution (requiring controlled glass distribution).
3Ease of manufacture
If the glass content in external electrode paste is insufficient to ensure compactness, then manufacturing is easier, but chip sealing properties become defective
Solution Approach 1:
The patent applies higher glass content (30-200 volume%) specifically to the end portion of the external electrode where sealing is most critical, while the central portion uses moderate glass content (10-50 volume%). This localized approach ensures adequate sealing properties without requiring excessive glass throughout the entire electrode, maintaining manufacturing feasibility.
4Volume of moving object
If the external electrode thickness is reduced for miniaturization, then the component size is decreased, but the possibility of plating solution permeation through thin portions increases
Solution Approach 1:
The patent enhances the end portion of the external electrode with higher glass content (30-200 volume%) to provide localized sealing reinforcement at the thinnest and most vulnerable regions. This allows the overall electrode to remain thin for miniaturization while preventing plating solution permeation at critical edge locations through concentrated glass sealing material.
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 plating solution permeation and enhances the reliability of multilayer ceramic electronic components by maintaining optimal glass content and thickness ratios, thereby improving sealing properties and humidity resistance, even with reduced external electrode thickness.
Implementation Method 1
preventing the permeation of a plating solution thereinto
Implementation Method 2
contains glass as an auxiliary material to provide adhesion between the external electrode and the chip
Data Source
AI summary
There is provided a multilayer ceramic electronic component, including: a ceramic body including a dielectric layer; a plurality of internal electrodes disposed to face each other within the ceramic body, having the dielectric layer interposed therebetween; and external electrodes electrically connected to the internal electrodes, wherein the ceramic body includes an active layer corresponding to a capacitance forming part and a cover layer formed on at least one of an upper surface and a lower surface of the active layer and corresponding to a non-capacitance forming part, an average thickness of the cover layer is 15 μm or less, the external electrodes include a conductive metal and a glass, and when an area of the external electrodes occupied by the glass is A and an area thereof occupied by the conductive metal is B, 0.05≦A/B≦0.6 is satisfied.