Multi-Layer Ceramic Capacitor Bonding Layer for Crack-Free Side Margins

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Solution Overview

Problem

Multi-layer ceramic capacitors face environmental resistance issues due to stress generated during sintering between internal electrodes and ceramic side margins, leading to cracks and peeling, which reduces moisture resistance.

Innovation Solution

Incorporating a bonding portion formed from an oxide of the base metal material on the bonding surface between the ceramic multi-layer chip and the side margin, which provides higher strength and enhances bonding strength, preventing cracks and peeling by dispersing particles uniformly across the bonding surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If side margins (ceramic side surface layers) are provided to the side surfaces of the laminate portion, then the periphery of internal electrodes is protected, but stress is generated between the laminate portion and side margins during sintering, leading to cracks and peeling

Engineering Contradiction:

Improveprotection of internal electrodesVSAvoidbonding strength at interface

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

A bonding portion comprising an oxide of the base metal material is introduced as an intermediary layer between the laminate portion (containing internal electrodes) and the ceramic side margin. This bonding portion is formed on the bonding surface where the cover of the laminate portion contacts the side margin, serving as a mediator that prevents direct contact between mismatched materials and eliminates stress concentration, thereby preventing cracks and peeling while maintaining protective function.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If side margins are provided to protect internal electrodes, then electrode protection is improved, but environmental resistance (moisture resistance) is reduced due to cracks and peeling

Engineering Contradiction:

Improveprotection of internal electrodesVSAvoidmoisture resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The bonding portion acts as a sealing intermediary that prevents moisture ingress by eliminating cracks and peeling at the interface between the laminate portion and side margin. By preventing direct contact between mismatched materials and eliminating stress concentration, the bonding portion creates a hermetic seal that protects the internal electrodes from environmental factors such as moisture, thereby improving environmental resistance while maintaining electrode protection.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If internal electrodes and side margin are sintered at different temperatures, then sintering flexibility is improved, but stress is generated during sintering due to different sintering behaviors

Engineering Contradiction:

Improvesintering temperature flexibilityVSAvoidstress at bonding surface

Core Design Contradiction:

Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The bonding portion comprising an oxide of the base metal material serves as a stress-absorbing intermediary layer between the laminate portion and ceramic side margin. This bonding portion has different thermal expansion and sintering characteristics that bridge the gap between the two materials, allowing them to be sintered at different temperatures without generating excessive stress. The bonding portion accommodates the differential sintering behavior, enabling sintering temperature flexibility while preventing stress concentration and interface failure.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 effectively increases the environmental resistance of the multi-layer ceramic capacitor by preventing moisture ingress and ensuring reliable insulation properties, with the bonding portion's area occupancy ratio optimized to maintain high bonding strength and insulation.

Implementation Method 1

During the sintering of the multi-layer ceramic capacitor, the internal electrodes formed of the base metal material start to be sintered at a temperature of several hundreds of degrees Celsius. Along with the sintering, the internal electrodes shrink toward the center of the ceramic multi-layer chip.

Methodology Applied

Scientific EffectSintering: Sintering

Implementation Method 2

the bonding portion starts to be generated, as the oxide including the base metal material, at a temperature of several hundreds of degrees Celsius at which the internal electrodes start to be sintered

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS11742143B2Multi-layer ceramic capacitor and method of producing the same

Publication Date: 2023.08.29 TAIYO YUDEN KK

AI summary

A multi-layer ceramic capacitor includes a ceramic multi-layer chip, a side margin, and a bonding portion. The ceramic multi-layer chip includes a capacitance forming unit including internal electrodes, the internal electrodes being laminated in a first direction and including a base metal material as a main component, positions of end portions of the internal electrodes in a second direction orthogonal to the first direction being aligned with one another within a range of 0.5 μm in the second direction, and a cover that is disposed outside the capacitance forming unit in the first direction and includes ceramics as a main component. The side margin includes ceramics as a main component and covers the ceramic multi-layer chip in the second direction. The bonding portion is disposed on a bonding surface and includes an oxide including the base metal material, the bonding surface being bonded to the side margin on the cover.