Multilayer Ceramic Capacitor Ni-Mg-O Electrodes Crack Resistance
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Solution Overview
Problem
Multilayer ceramic capacitors face reliability issues due to high crack and blister occurrence rates as they become smaller and more compact, leading to degradation in performance.
Innovation Solution
A multilayer ceramic capacitor design featuring alternately laminated dielectric layers and inner electrodes with oxide represented by Ni—Mg—O at the ends, a passivation layer containing Mg and Si, and a firing process under controlled oxygen partial pressure to reduce crack and blister occurrence, while improving adhesiveness and humidity resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the ceramic body is made smaller and thinner to meet compact electronic product requirements, then the capacitance density increases, but the crack and blister occurrence rates increase, degrading reliability
Solution Approach 1:
The patent applies local quality by forming an oxidized inner electrode layer specifically at both ends of the inner electrode in the lamination direction, rather than uniformly throughout. This localized oxidation creates a protective zone at the critical end regions where cracks and blisters are most likely to occur, while maintaining the overall compact structure. The oxidized layer has different properties (higher adhesion, lower stress) than the unoxidized portions, providing targeted protection where needed.
Solution Approach 2:
The patent employs composite materials by creating an inner electrode with a dual-nature structure: an oxidized outer layer and a non-oxidized inner core. This composite structure combines the benefits of both oxidized and non-oxidized states - the oxidized layer provides stress relief and adhesion enhancement at the surfaces, while the non-oxidized core maintains electrical conductivity and mechanical strength. This composite approach allows the capacitor to be compact while resisting crack and blister formation.
2Productivity
If conventional manufacturing processes are used for compact capacitors, then production efficiency is maintained, but defect rates increase due to stress concentration in slim multilayer structures
Solution Approach 1:
The patent applies preliminary action by oxidizing the inner electrode surfaces before the final capacitor assembly is completed. The oxidized inner electrode is formed during the green sheet preparation or lamination stage, before sintering and final assembly. This preliminary oxidation prepares the electrode surfaces in advance to have lower stress and better adhesion properties, preventing crack and blister formation during subsequent manufacturing steps like high-pressure pressing and sintering, thereby maintaining high manufacturing precision without sacrificing productivity.
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 significantly reduces crack and blister occurrence rates, enhancing the reliability and humidity resistance of the capacitors, thereby maintaining high performance even in compact sizes.
Implementation Method 1
performing a firing process under an oxygen partial pressure at which one or more inner electrodes disposed at both ends in a direction of lamination among the plurality of inner electrodes are oxidized
Data Source
AI summary
A multilayer ceramic capacitor and a method of manufacturing the same are provided. The multilayer ceramic capacitor includes a capacitive part, a passivation layer, and first and second outer electrodes. In the capacitive part, a plurality of dielectric layers and a plurality of first and second inner electrodes are alternately laminated, and ends of the first and second inner electrodes are alternately and respectively exposed in a direction of lamination of the dielectric layers. The passivation layer is provided at either or both of the top and bottom surfaces of the capacitive part. The first and second outer electrodes are electrically connected to the first and second inner electrodes exposed in a direction of lamination of the dielectric layers. One or more inner electrodes disposed at both ends in a direction of lamination among the plurality of inner electrodes include oxide represented by Ni—Mg—O.