Multilayer ceramic capacitor
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Solution Overview
Problem
Multilayer ceramic capacitors with thinner dielectric layers face reliability issues due to increased electric field intensity, particularly with inner electrodes containing Ni as a main component, which do not meet the demands for miniaturization and higher capacitance.
Innovation Solution
The multilayer ceramic capacitor employs inner electrodes with distinct metal compositions: Cu and Sn for positive electrodes and Cu with noble metals for negative electrodes, based on standard electrode potentials, to reduce oxygen ion segregation and enhance insulation, thereby improving reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dielectric layers are made thinner to achieve miniaturization and higher capacitance, then capacitance and size requirements are met, but electric field intensity increases and reliability during voltage application deteriorates
Solution Approach 1:
The patent applies different metal compositions to different inner electrodes based on their polarity. First inner electrodes (positive polarity) use a first metal composition while second inner electrodes (negative polarity) use a second metal composition. This local differentiation addresses the reliability issue by optimizing each electrode's material properties for its specific electrical role, preventing insulation degradation caused by uniform material limitations under high electric field conditions.
Solution Approach 2:
The patent employs composite metal compositions for the inner electrodes, where the first metal composition and second metal composition are distinct in terms of element types and contents. This composite approach allows combining materials with complementary properties that resist oxygen ion segregation and maintain insulation performance under high electric field intensity, thereby resolving the contradiction between miniaturization and reliability.
2Ease of manufacture
If inner electrodes include Ni as a main component, then manufacturing is simplified, but insulation degradation occurs during voltage application and reliability deteriorates
Solution Approach 1:
The patent fundamentally changes the material composition parameter of the inner electrodes by replacing Ni-based compositions with Cu-based compositions containing specific metal elements. The first metal composition includes Cu and at least one of Ag, Au, Pt, or Pd, while the second metal composition includes Cu and at least one of Al, Ga, In, or Tb. This parameter change eliminates the insulation degradation issue associated with Ni while maintaining manufacturability through established Cu-based paste technologies.
3Volume of moving object
If dielectric layers are made thinner to reduce capacitor size, then miniaturization is achieved, but the intensity of electric field applied to each layer increases
Solution Approach 1:
The patent addresses the increased electric field intensity by applying different metal compositions to different inner electrodes. The first metal composition and second metal composition are designed with specific metal elements that provide enhanced electrical stability and resistance to field-induced degradation. This local optimization allows the capacitor to withstand higher electric field intensities in thinner dielectric layers, enabling miniaturization without sacrificing reliability.
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 insulation degradation and enhances reliability under high electric field conditions, ensuring excellent performance in miniaturized capacitors with higher capacitance.
Implementation Method 1
the first inner electrodes have a first metal composition including Cu and Sn, and the second inner electrodes have a second metal composition including Cu... based on standard electrode potentials
Data Source
AI summary
In a multilayer ceramic capacitor including first and second inner electrodes alternately arranged with respect to a stacking direction of a multilayer body, a polarity based on a direction of voltage applied between a first outer electrode and a second outer electrode is determined such that the first inner electrodes function as positive electrodes and the second inner electrodes function as negative electrodes. The first inner electrodes have a first metal composition including Cu and Sn, and the second inner electrodes have a second metal composition including Cu. The second metal composition of the second inner electrodes includes Cu as a main component, and at least one metal element selected from Au, Pt, Ir, Pd, Os, Ag, Rh, and Ru, which have standard electrode potentials higher than that of Cu, as an additive component.