Multilayer Ceramic Capacitor Si Segregation Side Margin

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Solution Overview

Problem

Existing methods for producing large-capacitance and small-size multilayer ceramic capacitors face challenges due to low strength of side margins and potential moisture penetration, which can reduce insulation resistance.

Innovation Solution

A multilayer ceramic capacitor design featuring a side margin with a Si segregation structure, where the inner layer has a larger Si segregation area than the outer layer, providing enhanced strength and preventing moisture penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the side margin is made thin to reduce size, then the capacitor achieves small-size and large-capacitance, but the side margin has low strength and moisture may penetrate through

Engineering Contradiction:

Improvecapacitor sizeVSAvoidside margin strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by creating a dual-layer side margin structure where the inner layer and outer layer have different thicknesses. The inner layer is thinner to minimize overall size, while the outer layer is thicker to provide sufficient mechanical strength and moisture barrier protection. This differential thickness design allows the side margin to simultaneously achieve small size and high strength.

Inventive Principle:

Principle #3Local quality

2Volume of moving object

If the side margin is made thin to reduce size, then the capacitor achieves small-size, but insulation resistance may reduce due to moisture penetration

Engineering Contradiction:

Improvecapacitor sizeVSAvoidinsulation resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If cutting margin is increased to improve lamination accuracy, then lamination accuracy improves, but the capacitor size increases

Engineering Contradiction:

Improvelamination accuracyVSAvoidcapacitor size

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The patent applies preliminary action by forming the side margin on the green chip before sintering. This allows the internal electrode layers to extend to the end surfaces of the green chip without requiring large cutting margins, as the side margin is added subsequently to provide the necessary mechanical support and coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies segmentation by dividing the side margin into two separate layers (inner layer and outer layer) with different functions. The inner layer provides basic coverage while the outer layer provides enhanced protection, allowing each layer to be optimized for its specific purpose rather than requiring a single thick margin.

Inventive Principle:

Principle #1Segmentation

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 design achieves a side margin with high strength and improved insulation resistance, even when thin, by effectively segregating Si to prevent moisture ingress and maintain capacitance.

Implementation Method 1

Si is segregated in an inner region including the inner layer and a boundary between the inner layer and the central layer portion

Methodology Applied

Scientific EffectSi segregation: Diffusion

Data Source

PatentUS11289274B2Multilayer ceramic capacitor

Publication Date: 2022.03.29 MURATA MFG CO LTD

AI summary

A multilayer ceramic capacitor includes a laminate including a dielectric ceramic layer and first and second internal electrode layers laminated in a lamination direction, and first and second external electrode connected to the internal electrode layers. The laminate includes a central layer portion, a peripheral layer portion sandwiching the central layer portion, and a side margin sandwiching the central layer portion and the peripheral layer portion. The side margin including an inner layer and an outer layer. In a cross section including a lamination direction and a width direction obtained by cutting the laminate at a central portion in a length direction, Si is segregated in an inner region including the inner layer and a boundary between the inner layer and the central layer portion, and a Si segregation spot in the inner region has a larger area than a Si segregation spot in the outer layer.