Multilayer Ceramic Capacitor Side Margin Oxygen Diffusion
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Solution Overview
Problem
The manufacturing process of multilayer ceramic capacitors often results in reduced capacity due to contraction and oxidation of internal electrodes during the re-oxidation process, which affects insulation resistance.
Innovation Solution
A multilayer ceramic capacitor design with a side margin region structure where SiO2 or a combination of SiO2 and B2O3 is used, allowing for controlled oxygen diffusion during re-oxidation, suppressing oxygen defects and maintaining capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a re-oxidation process is performed in a weakly oxidizing atmosphere after baking to increase insulation resistance, then insulation resistance is improved, but capacity is reduced due to contraction or oxidation of the internal electrode
Solution Approach 1:
The patent applies local quality by creating a side margin region with different composition (higher SiO2 or B2O3 content) compared to the main body of the dielectric layer. This localized compositional difference allows the side margin region to serve as a dedicated oxygen supply zone during re-oxidation, enabling oxygen to diffuse preferentially to the internal electrode edges without causing excessive oxidation in the capacity-determining regions, thus resolving the contradiction between improving insulation resistance and maintaining capacity.
2Object-generated harmful factors
If the internal electrode is baked in a strongly reducing atmosphere to suppress oxidation, then oxidation is suppressed, but oxygen defects in the dielectric layer increase reducing insulation resistance
Solution Approach 1:
The patent applies preliminary action by pre-configuring the side margin region with higher SiO2 or B2O3 content before the re-oxidation process. This preliminary structural preparation ensures that when re-oxidation is performed, oxygen can quickly and efficiently diffuse from the side margin region to the internal electrode, preventing oxygen defects from forming in the first place rather than having to correct them later, thus maintaining both low oxidation and high insulation 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
The solution effectively suppresses capacity reduction and maintains high insulation resistance by ensuring sufficient oxygen diffusion and preventing excessive oxidation and contraction of internal electrodes.
Implementation Method 1
a main component of the second-phase being SiO2 or a combination of SiO2 and B2O3, wherein a content ratio of the second-phase of the first ceramic layer is 15% or more and 45% or less
Implementation Method 2
a fourth step of re-oxidizing the ceramic multilayer structure after the third step at 600 degrees C. or more and 1000 degrees C. or less
Implementation Method 3
a third step of baking a ceramic multilayer structure in which a plurality of stack units obtained by the second step
Data Source
AI summary
A multilayer ceramic capacitor includes: a multilayer structure in which dielectric layers and internal electrode layers are alternately stacked, the plurality of internal electrode layers being alternately exposed to a first edge face and a second edge face; and side margin regions that cover edge portions to which the plurality of internal electrode layers extend toward two side faces and have a structure in which a first ceramic layer and a second ceramic layer are alternately stacked in a stacking direction of the internal electrode layer and the dielectric layer, an amount of a second-phase of the first ceramic layer being larger than that of the second ceramic layer, a main component of the second-phase being SiO2 or a combination of SiO2 and B2O3, wherein a content ratio of the second-phase of the first ceramic layer is 15% or more and 45% or less.