Multi-Layer Ceramic Capacitor Side Margins for Voltage and Capacitance

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Solution Overview

Problem

Multi-layer ceramic capacitors face challenges in achieving high withstand voltage characteristics while maintaining electrostatic capacity due to electrolytic strain causing structural defects and dielectric constant reduction when thin side margins are used, and the addition of elements like Mg and Mn can lead to decreased electrostatic capacity.

Innovation Solution

The use of side margins with specific compositions, where manganese and magnesium concentrations are higher in the outer region for mechanical strength and lower in the inner region to suppress diffusion into the ceramic layer, and silicon is concentrated in the inner region to promote glass phase precipitation and flexibility, effectively managing electrolytic strain and maintaining electrostatic capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a thin side margin is used to extend the crossing area of internal electrodes, then the miniaturization and capacity increase are achieved, but structural defects such as cracks occur due to electrolytic strain and withstand voltage characteristics deteriorate

Engineering Contradiction:

Improvecrossing area of internal electrodesVSAvoidwithstand voltage characteristics

Core Design Contradiction:

Area of moving objectVSReliability

Solution Approach 1:

The side margin is divided into first and second regions with different compositions. The first region (adjacent to ceramic layer) has lower Mn/Mg concentration to suppress diffusion and maintain dielectric constant, while the second region (outer region) has higher Mn/Mg concentration to provide mechanical strength and suppress cracks from electrolytic strain. This local differentiation resolves the contradiction between thin side margin and withstand voltage characteristics.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The side margin uses a composite structure with two regions having different elemental compositions. The inner region prioritizes dielectric properties by suppressing Mn/Mg diffusion into the ceramic layer, while the outer region prioritizes mechanical strength to resist cracks. This composite approach allows the thin side margin to simultaneously achieve both electrical and mechanical requirements.

Inventive Principle:

Principle #40Composite materials

2Strength

If elements such as Mg and Mn are added to the side margin to promote densification and suppress cracks, then mechanical strength is improved, but the added elements diffuse into the ceramic layer to reduce the dielectric constant and electrostatic capacity decreases

Engineering Contradiction:

Improvemechanical strength of side marginVSAvoidelectrostatic capacity

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The side margin is segmented into two regions with different Mn/Mg concentrations. The first region has lower concentration to prevent diffusion into the ceramic layer and preserve dielectric constant, while the second region has higher concentration to provide mechanical strength. This segmentation allows both requirements to be satisfied simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the side margin are given different local compositions: the inner region prioritizes low Mn/Mg content to protect dielectric properties, while the outer region prioritizes high Mn/Mg content for mechanical strength. This local quality differentiation resolves the contradiction between strength and electrostatic capacity.

Inventive Principle:

Principle #3Local quality

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

This configuration enhances the withstand voltage characteristics, suppresses structural defects, and maintains electrostatic capacity by managing stress and preventing dielectric constant reduction, while also improving wear resistance and reducing appearance defects.

Implementation Method 1

the added element diffuses into the ceramic layer of the multi-layer unit to reduce the dielectric constant of the ceramic layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

since the first inner region contains silicon having a concentration higher than that of the ceramic layer, the glass phase is likely to precipitate in the first inner region

Methodology Applied

Scientific EffectGlass phase precipitation: Precipitation

Implementation Method 3

in the case where a high voltage is applied to the internal electrodes, the ferroelectricity of the ceramic layer can cause electrolytic strain

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS12170175B2Multi-layer ceramic capacitor

Publication Date: 2024.12.17 TAIYO YUDEN KK

AI summary

A multi-layer ceramic capacitor includes: a multi-layer unit including ceramic layers laminated in a first direction and electrodes disposed between the ceramic layers, positions of end portions of the electrodes falling within a range of 0.5 μm in a second direction; and side margins each containing manganese or magnesium and silicon and facing each other in the second direction. When each margin is equally divided into an inner region and an outer region, a total concentration of manganese and magnesium in the outer region is higher than a total concentration of manganese and magnesium in the inner region and higher than a total concentration of manganese and magnesium in the ceramic layers, and a concentration of silicon in the inner region is not less than a concentration of silicon in the outer region and higher than a concentration of silicon in the ceramic layers.