Multilayer Capacitor Electrode Structure for Moisture Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors face issues with reduced high-temperature insulation resistance and moisture resistance reliability due to alloy formation between internal and external electrodes, blister defects from residual carbon, and glass elution, which affect bonding strength and capacitance per unit volume.
Innovation Solution
The multilayer electronic component design includes specific area and thickness ratios for glass in external electrodes, ensuring S1-2>S1-1, S2-2>S2-1, T1-2≤8 μm, and T2-2≤8 μm, to prevent alloy formation, glass elution, and facilitate residual carbon discharge, thereby enhancing moisture resistance and bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass is added to the external electrode to improve bonding strength, then bonding strength between body and external electrode is improved, but glass may be eluted to the outer surface causing reliability issues
Solution Approach 1:
The patent applies different glass content levels to different regions of the external electrode. The side surface electrode layer has a first glass content (higher) for bonding strength, while the upper surface electrode layer has a second glass content (lower) to prevent elution. This local differentiation resolves the contradiction between bonding strength and moisture resistance.
2Strength
If external electrode thickness is increased to improve bonding strength, then bonding strength is improved, but capacitance per unit volume decreases and blisters form due to residual carbon
Solution Approach 1:
The patent differentiates the thickness and glass content of electrode layers based on their location. The side surface electrode layer has greater thickness and higher glass content for bonding, while the upper surface electrode layer has reduced thickness and lower glass content to prevent blisters and maintain capacitance density. This resolves the contradiction between bonding strength and capacitance per unit volume.
3Strength
If glass content in external electrode is increased to improve bonding strength, then bonding strength is improved, but residual carbon cannot be discharged causing blisters
Solution Approach 1:
The patent controls glass content locally in different electrode layers. The side surface electrode layer contains sufficient glass for bonding strength, while the upper surface electrode layer has reduced glass content (second glass content < first glass content) to enable proper carbon discharge during firing and prevent blister formation.
4Reliability
If dielectric layer thickness is reduced to increase capacitance per unit volume, then capacitance per unit volume is improved, but bonding strength and reliability may be compromised
Solution Approach 1:
The patent compensates for reduced dielectric layer thickness by optimizing the external electrode structure. Different electrode layers have differentiated glass content and thickness, with the side surface electrode providing enhanced bonding through higher glass content, thereby maintaining bonding strength even when dielectric layer thickness is reduced to increase capacitance density.
Data Source
AI summary
A multilayer electronic component includes a body including a dielectric layer and first and second internal electrodes and including first and second surfaces, third and fourth surfaces, and fifth and sixth surfaces, a first external electrode including a 1-1-th electrode layer disposed on the third surface, and a 1-2-th electrode layer disposed on the first and second surfaces, a second external electrode including a 2-1-th electrode layer disposed on the fourth surface, and a 2-2-th electrode layer disposed on the first and second surfaces, wherein S1-2>S1-1, T1-2≤8 μm, S2-2>S2-1, and T2-2≤8 μm where based on a cross section of the first and second external electrodes, S1-1, S1-2, S2-1, S2-2 are fractions of an area occupied by glass in the 1-1-th, 1-2-th, 2-1-th, and 2-2-th electrode layers, respectively, T1-2 and T2-2 are thicknesses of the 1-2-th and 2-2-th electrode layers, respectively.