Multilayer Ceramic Capacitor External Electrode Cracking Prevention

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Solution Overview

Problem

Existing multilayer ceramic capacitors are prone to cracking due to stress caused by substrate deflection, as the amount of glass component in external electrodes is not adequately specified, leading to insufficient crack suppression.

Innovation Solution

A multilayer ceramic capacitor design with a first metal layer containing 5 wt% or more ceramic, contacting the edge faces, and a second metal layer with less than 5 wt% ceramic, contacting the side faces, is implemented to enhance adhesiveness and prevent cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single metal layer with glass component is used for external electrodes, then the electrode structure is simple, but crack suppression is insufficient due to stress from substrate deflection

Engineering Contradiction:

Improvecrack suppressionVSAvoidelectrode structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The external electrode is divided into two distinct metal layers: a first metal layer with 5-20 wt% glass component for adhesion to the multilayer chip, and a second metal layer with 0-5 wt% glass component for low-temperature sintering and crack suppression. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between reliability and structural simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different glass component amounts are applied to different locations/functions within the external electrode structure. The first metal layer contains higher glass content (5-20 wt%) for strong bonding to the ceramic chip, while the second metal layer contains lower glass content (0-5 wt%) for flexibility and crack prevention. This local differentiation of material properties resolves the contradiction by optimizing each region for its specific purpose.

Inventive Principle:

Principle #3Local quality

2Reliability

If the glass component amount in external electrodes is not specified, then the manufacturing process is flexible, but crack suppression is insufficient

Engineering Contradiction:

Improvecrack suppressionVSAvoidmanufacturing specification

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention specifies precise parameter ranges for glass component content in each metal layer: 5-20 wt% in the first metal layer and 0-5 wt% in the second metal layer. These parameter specifications transform the manufacturing process from flexible but unreliable to controlled and reliable, resolving the contradiction between ease of manufacture and crack suppression effectiveness.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If external electrodes extend to side faces of the multilayer chip, then electrical connection is improved, but stress concentration increases leading to cracking

Engineering Contradiction:

Improveelectrical connectionVSAvoidstress concentration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The external electrode uses a composite structure of two metal layers with different glass component ratios. The second metal layer with low glass content (0-5 wt%) provides a more compliant, less brittle interface with the side faces, reducing stress concentration while maintaining electrical connection. This composite material approach resolves the contradiction between electrical connectivity and stress-induced cracking.

Inventive Principle:

Principle #40Composite materials

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 effectively suppresses cracking by maintaining connection between external and internal electrodes, reducing peeling and stress conduction, thereby ensuring the reliability of the multilayer ceramic capacitors.

Implementation Method 1

a first metal layer whose ceramic amount is 5 wt % or more contacts with the two edge faces

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

a second metal layer whose ceramic amount is less than 5 wt % contacts with the at least one of the side faces

Methodology Applied

Scientific EffectStress absorption: Absorption (physical)

Data Source

PatentUS10453614B2Multilayer ceramic capacitor and manufacturing method of multilayer ceramic capacitor

Publication Date: 2019.10.22 TAIYO YUDEN KK

AI summary

A multilayer ceramic capacitor includes: a multilayer chip having a parallelepiped shape in which each of a plurality of ceramic dielectric layers and each of a plurality of internal electrode layers are alternately stacked and are alternately exposed to two edge faces of the multilayer chip; and a pair of external electrodes that are formed from the two edge faces to at least one of side faces of the multilayer chip; wherein in the external electrodes, a first metal layer whose ceramic amount is 5 wt % or more contacts with the two edge faces, and a second metal layer whose ceramic amount is less than 5 wt % contacts with the at least one of the side faces.