MLCC Terminal Electrode Coating With Low-Stress Electrochemical Deposition

Solution Overview

Problem

Traditional multilayer ceramic capacitors (MLCCs) face issues with high internal stress and defects due to high-temperature sintering, leading to cracks and defects, and the breading effect caused by density differences between inner electrodes and dielectric ceramic layers, which affects their yield and reliability.

Innovation Solution

The method employs ultra-low-temperature electrochemical deposition to fabricate terminal electrodes and insulating protective layers, using a sintered MLCC with thinned dielectric ceramic layers and high-density inner electrodes, where metal coatings are grown through immersion in a metal solution below 80°C, eliminating the need for high-temperature sintering and ensuring uniform electrode density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high-temperature sintering is used to form terminal electrodes, then good ohmic contact and low thermal resistance are achieved, but high internal stress causes cracks and defects

Engineering Contradiction:

Improvethermal resistanceVSAvoidinternal stress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from high-temperature sintering (800-900°C) to low-temperature electrochemical deposition (below 80°C), fundamentally altering the process conditions to achieve terminal electrode formation without inducing high internal stress that causes cracks and defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal-mechanical sintering process with an electrochemical deposition process, substituting thermal energy with electrical energy to form terminal electrodes, thereby avoiding the high internal stress and cracking associated with high-temperature mechanical sintering

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If high-temperature sintering is used to form terminal electrodes, then good connection is achieved, but device cracks and defects occur

Engineering Contradiction:

Improveconnection qualityVSAvoiddefects

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent changes the temperature parameter from high-temperature sintering (800-900°C) to low-temperature electrochemical deposition (below 80°C), fundamentally altering the process conditions to achieve terminal electrode formation without inducing high internal stress that causes cracks and defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal-mechanical sintering process with an electrochemical deposition process, substituting thermal energy with electrical energy to form terminal electrodes, thereby avoiding the high internal stress and cracking associated with high-temperature mechanical sintering

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If additional high-temperature protective insulating ceramic layers are added, then the breading effect is reduced, but internal stress increases causing cracks

Engineering Contradiction:

Improvebreading effectVSAvoidinternal stress

Core Design Contradiction:

ShapeVSObject-affected harmful factors

Solution Approach 1:

The patent changes the temperature parameter from high-temperature sintering (800-900°C) to low-temperature electrochemical deposition (below 80°C), fundamentally altering the process conditions to achieve terminal electrode formation without inducing high internal stress that causes cracks and defects

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal-mechanical sintering process with an electrochemical deposition process, substituting thermal energy with electrical energy to form terminal electrodes, thereby avoiding the high internal stress and cracking associated with high-temperature mechanical sintering

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach reduces internal stress, improves yield, and enhances the reliability of MLCCs by maintaining high capacitance without the breading effect, while also reducing production costs and thermal resistance.

Implementation Method 1

processing plating of wet chemical immersion by immersing the MLCC in a metal solution at a temperature below 80° C., to, through electrochemical deposition, start slowly growing a metal coating on surfaces of the inner electrodes

Methodology Applied

Scientific EffectElectrochemical deposition: Electrodeposition

Data Source

PatentUS11810720B2Method for fabricating terminal electrode of multilayer ceramic capacitor having inner electrodes printed on full area together with protective layers

Publication Date: 2023.11.07 BEST METAL MATERIAL CORP

AI summary

A method is provided for fabricating a terminal electrode. The terminal electrode is applied on a multilayer ceramic capacitor (MLCC). The method prints inner electrodes on full area together with protective layers. The MLCC uses the thickness of thinned dielectric ceramic layers and the stacking of nickel inner-electrode layers. High capacitance is achieved at ends and sides with high electrode-to-ceramic ratios. Thus, the present invention uses a coating technology of ultra-low-temperature electrochemical deposition to fabricate low internal-stress MLCC terminal electrodes together with insulating protective layers for improving MLCC yield while cost reduced.