Multilayer Ceramic Capacitor Diffusion Region for Moisture Resistance

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Solution Overview

Problem

Existing multilayer ceramic capacitors face challenges in achieving both thinning of external electrodes and maintaining moisture resistance, as thinning the electrodes increases the likelihood of pinhole formation and moisture infiltration.

Innovation Solution

Incorporating a diffusion region at the boundary between the counter and lead-out portions of internal electrode layers, where metals from these regions diffuse, forming a thicker barrier to prevent moisture ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the thickness of external electrodes is reduced to increase the volume of the multilayer body, then the area ratio of internal electrodes is improved, but the moisture resistance deteriorates due to increased pinhole formation and shortened infiltration path

Engineering Contradiction:

Improvevolume of multilayer bodyVSAvoidmoisture resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent applies local quality by creating a diffusion region with a specific metal composition at the boundary portion between the counter portion and lead-out portion of the internal electrode layer. This localized region has different properties (containing both first and second metals) compared to other areas, providing enhanced moisture barrier functionality specifically where needed without affecting the overall electrode thickness reduction

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by forming a diffusion region that contains a mixture of first metal (from the counter portion) and second metal (from the lead-out portion). This composite metal structure at the boundary portion provides superior moisture resistance compared to single-metal configurations, allowing the external electrodes to be thinner while maintaining reliability

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If the thickness of external electrodes is reduced to increase the area ratio of internal electrodes, then the capacitor performance is improved, but the likelihood of pinhole formation increases

Engineering Contradiction:

Improvearea ratio of internal electrodesVSAvoidpinhole formation

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent addresses pinhole formation by introducing a diffusion region with unique metal composition at the boundary portion. This localized structural enhancement provides additional protection against pinhole formation without requiring increased external electrode thickness, thus preserving the high area ratio of internal electrodes

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The diffusion region acts as a preventive measure against pinhole formation and moisture infiltration. By creating this protective layer in advance during the manufacturing process, the patent cushions against potential defects before they can compromise the capacitor's performance

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Length of moving object

If the thickness of external electrodes is reduced, then the infiltration path for external moisture is shortened, but the moisture resistance deteriorates

Engineering Contradiction:

Improvethickness of external electrodesVSAvoidmoisture resistance

Core Design Contradiction:

Length of moving objectVSReliability

Solution Approach 1:

The patent compensates for the shortened infiltration path by creating a diffusion region with enhanced metal composition at the boundary portion. This localized enhancement provides an additional moisture barrier that offsets the reduced thickness, maintaining moisture resistance despite the shorter overall infiltration path

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent addresses the thickness reduction issue by introducing a compositional dimension rather than a dimensional solution. Instead of increasing thickness, the diffusion region provides enhanced protection through its unique metal composition (mixture of first and second metals) at the boundary portion, solving the problem in a different dimension

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 diffusion region effectively prevents moisture infiltration, enhancing moisture resistance while allowing for thinner external electrodes, thereby improving capacitor performance.

Implementation Method 1

providing a diffusion region in which a metal included in the counter portion and a metal included in the lead-out portion are both present in a boundary portion between the counter portion and the lead-out portion

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS20250336603A1Multilayer ceramic capacitor

Publication Date: 2025.10.30 MURATA MFG CO LTD

AI summary

A multilayer ceramic capacitor includes a multilayer body includes internal electrode layers and dielectric layers stacked in a stacking direction, external electrodes connected to the internal electrode layers and extending in a length direction intersecting the stacking direction of the multilayer body. An internal electrode layer includes two regions including metals at least partially different from each other. A diffusion region between the two regions in which each of the metals is present.