Multilayer Ceramic Capacitor Margin Composition for Moisture Resistance

Solution Overview

Problem

Reducing the thickness of the side margin portion in multilayer ceramic capacitors to increase capacitance and area of internal electrode layers compromises moisture resistance, leading to reliability issues.

Innovation Solution

Incorporating side margin portions made of a ceramic material with specific compositions of Ba, Ti, and Mg, and internal electrode layers with controlled Mg content, to enhance moisture resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the thickness of the side margin portion is reduced to increase the area of the internal electrode layer, then the capacitance increases, but the moisture resistance decreases

Engineering Contradiction:

ImprovecapacitanceVSAvoidmoisture resistance

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies local quality by creating a Mg-enriched end portion in the internal electrode layer at the width direction end, while the extension electrode portion has a different composition. This localized compositional variation provides enhanced moisture resistance at the critical end portion where moisture penetration occurs, while maintaining the overall capacitance through the extended electrode structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining Ni with Mg in specific proportions in the internal electrode layer. The Ni provides electrical conductivity while Mg enhances moisture resistance. The specific composition range (Ni: 99.6-99.2 wt%, Mg: 0.4-0.8 wt%) creates a composite structure that simultaneously achieves both high capacitance and improved moisture resistance

Inventive Principle:

Principle #40Composite materials

2Area of stationary object

If the thickness of the side margin portion is reduced to increase the area of the internal electrode layer, then the area of the internal electrode layer increases, but the resistance to moisture penetration decreases

Engineering Contradiction:

Improvearea of internal electrode layerVSAvoidmoisture resistance

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a Mg-enriched end portion in the internal electrode layer at the width direction end, while the extension electrode portion has a different composition. This localized compositional variation provides enhanced moisture resistance at the critical end portion where moisture penetration occurs, while maintaining the overall capacitance through the extended electrode structure

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining Ni with Mg in specific proportions in the internal electrode layer. The Ni provides electrical conductivity while Mg enhances moisture resistance. The specific composition range (Ni: 99.6-99.2 wt%, Mg: 0.4-0.8 wt%) creates a composite structure that simultaneously achieves both high capacitance and improved moisture resistance

Inventive Principle:

Principle #40Composite materials

3Reliability

If Mg content in the side margin portion is increased to improve moisture resistance, then the moisture resistance improves, but the device complexity increases

Engineering Contradiction:

Improvemoisture resistanceVSAvoidcomposition control complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the Mg content within specific ranges (0.2-2.0 mol% relative to Ti in side margin portions, and 0.13-0.39 mol% relative to Ni in internal electrode layers). This quantitative parameter control achieves optimal moisture resistance while maintaining manufacturing feasibility through clearly defined compositional specifications

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12406807B2Multilayer ceramic capacitor

Publication Date: 2025.09.02 MURATA MFG CO LTD

AI summary

A multilayer ceramic capacitor includes a multilayer body including dielectric layers and internal electrode layers, and external electrodes. The multilayer body includes side margin portions made of a dielectric. In the internal electrode layers, a width of an extension electrode portion is smaller than a width of a counter electrode portion. The side margin portions each include Ba and Ti as a main component and Mg as a sub component. The Mg content is about 0.2 mol % or more and about 2.0 mol % or less with respect to 100 mol of Ti. The internal electrode layers each include Ni as a main component, and an end portion of the counter electrode portion includes Mg as a sub component. The Mg content is about 0.13 mol % or more and about 0.39 mol % or less with respect to 100 mol of Ni.