Multilayer Ceramic Capacitor Outer Electrode Porosity Design

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Solution Overview

Problem

Multilayer ceramic capacitors face reliability issues due to penetration of plating solutions and moisture during the plating process, which degrades their electrical characteristics and can lead to blister failures.

Innovation Solution

The capacitors incorporate outer electrodes with specific porosity regions, ranging from 1% to 10% at the interfaces with inner electrodes, and a secondary region with lower porosity, using conductive metals like Ag and Pd, along with a glass frit content of 25-45 vol%, to control gas and binder discharge during firing and prevent plating solution penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the outer electrode is made dense to prevent plating solution penetration, then reliability improves, but gas and binder discharge during firing becomes difficult

Engineering Contradiction:

Improveresistance to plating solution penetrationVSAvoidgas and binder discharge during firing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The outer electrode is designed with non-uniform porosity distribution: a first region with higher porosity (5-15%) at the interface with the inner electrode to facilitate gas and binder discharge, and a second region with lower porosity (0.1-5%) at the outer surface to prevent plating solution penetration. This local differentiation resolves the contradiction by providing different porosity characteristics in different spatial locations of the same component.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the outer electrode porosity is increased to facilitate gas and binder discharge, then manufacturing ease improves, but plating solution penetration increases

Engineering Contradiction:

Improvegas and binder discharge during firingVSAvoidresistance to plating solution penetration

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the capacitor size is reduced to meet compactness requirements, then adaptability improves, but the risk of plating solution penetration increases

Engineering Contradiction:

Improvecompactness for mobile devicesVSAvoidresistance to plating solution penetration

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The outer electrode is designed with non-uniform porosity distribution, with the low-porosity second region (0.1-5%) positioned at the outer surface to provide enhanced protection against plating solution penetration. This allows compact capacitors to maintain high reliability despite reduced size, as the critical protection function is localized to where it is most needed.

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 design effectively reduces blister occurrence and suppresses plating solution penetration, enhancing the reliability and electrical characteristics of the multilayer ceramic capacitors by managing porosity and plating layers.

Implementation Method 1

The first and second outer electrodes may include a glass frit whose content is in the range of 25 vol % to 45 vol % with respect to total composition

Methodology Applied

Scientific EffectGlass frit:

Data Source

PatentUS8248752B2Multilayer ceramic capacitor

Publication Date: 2012.08.21 SAMSUNG ELECTRO MECHANICS CO LTD

AI summary

A multilayer ceramic capacitor is provided. In the multilayer ceramic capacitor, a plurality of first and second inner electrodes are formed inside a ceramic sintered body. Ends of the first and second inner electrodes are alternately exposed to both ends of the ceramic sintered body. First and second outer electrodes are formed on both ends of the ceramic sintered body and connected to the first and second inner electrodes. The first and second outer electrodes include a first region having a porosity in the range of 1% to 10%, and a second region having a porosity less than that of the first region.