Laminated Ceramic Component Compressive Stress

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Solution Overview

Problem

Multilayer ceramic electronic components face challenges in achieving sufficient mechanical strength due to the brittleness of ferrite materials and issues like delamination, cracking, and warpage caused by differences in shrinkage behavior between magnetic and insulating layers.

Innovation Solution

A multilayer ceramic electronic component with a ceramic laminate structure comprising a ceramic base layer and auxiliary layers, both formed entirely of polycrystalline phases with matching crystal structures and linear expansion coefficients, where the auxiliary layers have a lower expansion coefficient than the base layer, providing compressive stress and strong bonding to enhance mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If insulating layers are stacked on magnetic layers to increase flexibility in arrangement, then flexibility is improved, but delamination and cracking occur due to shrinkage difference

Engineering Contradiction:

Improveflexibility in arrangementVSAvoidstructural integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses ferrite auxiliary layers with the same crystal structure as the ferrite base layer, creating homogeneous material composition. This homogeneity ensures consistent shrinkage behavior during firing, preventing delamination and cracking while maintaining the flexibility to arrange surface-mounted circuit parts.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent carefully controls the linear expansion coefficient of the ferrite auxiliary layer to be within a specific range (0.5-5.0 ppm/°C) relative to the base layer. This parameter control ensures minimal shrinkage difference during firing, preventing structural defects while allowing design flexibility.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If ferrite materials are used for magnetic layers, then magnetic properties are achieved, but mechanical strength is insufficient due to brittleness

Engineering Contradiction:

Improvemagnetic functionalityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent creates a composite structure where ferrite auxiliary layers with optimized linear expansion coefficients are combined with the ferrite base layer. This composite approach maintains the magnetic properties of ferrite while the controlled expansion characteristics improve overall mechanical strength and reduce brittleness-related failures.

Inventive Principle:

Principle #40Composite materials

3Strength

If ceramic auxiliary layers with lower linear expansion coefficient are added to provide compressive stress, then mechanical strength is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidlayer structure complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent uses ferrite materials for both the base layer and auxiliary layers, maintaining homogeneous material composition throughout. This approach generates the necessary compressive stress to improve mechanical strength while avoiding the manufacturing complexity that would arise from using dissimilar materials with different processing requirements.

Inventive Principle:

Principle #33Homogeneity

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 significantly improves mechanical strength by preventing delamination and cracking, reducing internal stress, and maintaining reliable electrical properties, especially when the ferrite materials have the same compositional system and low permeability, allowing for higher current usage and reduced magnetic interference.

Implementation Method 1

the one or more ceramic auxiliary layers have a linear expansion coefficient α2 lower than the linear expansion coefficient α1 of the ceramic base layer

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2028664B1Laminated ceramic electronic component

Publication Date: 2015.12.30 MURATA MFG CO LTD

Figure 1~2
Figure 3~4

AI summary

A multilayer ceramic electronic component including a ferrite ceramic laminate having a multilayer structure is disadvantageously brittle because of a fundamental feature of ferrite. A ceramic laminate (5) is constituted by a ceramic base layer (2) and ceramic auxiliary layers (3 and 4) arranged on both main surfaces of the ceramic base layer (2), the ceramic base layer (2) and the ceramic auxiliary layers (3 and 4) being formed by co-firing. The ceramic base layer (2) and the ceramic auxiliary layers (3 and 4) are composed of ferrite materials having the same compositional system and have substantially the same crystal structure. The linear expansion coefficient of the ceramic auxiliary layers (3 and 4) is smaller than the linear expansion coefficient of the ceramic base layer (2).