Sintered Copper Electrode with Variable Resin Thickness

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Solution Overview

Problem

Electronic components face issues with high electrical resistance and the occurrence of flex cracks and migration due to stress from external devices, particularly when solder-mounted on circuit boards or other electronic components.

Innovation Solution

The electronic component design includes a sintered copper metal layer, a conductive resin layer with copper particles, and a plating layer, where the thickness of the conductive resin layer is smaller than the plating layer, and the copper particles have an average aspect ratio of 1.1 or more, reducing electrical resistance and preventing flex cracks and migration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conductive resin layer is disposed on the metal layer, then stress from the electronic device is absorbed and flex crack occurrence is controlled, but electrical resistance increases due to the resin material

Engineering Contradiction:

Improveflex crack controlVSAvoidelectrical resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The conductive resin layer is designed with non-uniform thickness, being thinner at the edge portion and thicker at the center portion. This local quality variation allows the edge portion to provide better electrical conductivity while the center portion provides stress absorption, thus resolving the contradiction between low electrical resistance and flex crack control.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thickness parameter of the conductive resin layer is changed across different regions. By making the thickness smaller at the edge and larger at the center, the patent optimizes both electrical resistance and mechanical stress distribution, allowing the layer to simultaneously provide good conductivity and effective stress absorption.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the conductive resin layer thickness is reduced to lower electrical resistance, then electrical resistance decreases, but the layer becomes more susceptible to peeling under stress

Engineering Contradiction:

Improveelectrical resistanceVSAvoidlayer adhesion

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

Different thicknesses are applied to different regions of the conductive resin layer. The edge portion has smaller thickness for low electrical resistance, while the center portion has larger thickness to maintain adhesion and resist peeling under stress, thus resolving the contradiction between electrical resistance and layer adhesion.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The solution moves from a uniform thickness approach to a spatially varying thickness approach. By introducing thickness variation across the surface of the conductive resin layer, the patent simultaneously achieves low electrical resistance at edges and high adhesion at the center, resolving the contradiction through dimensional variation.

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

This configuration effectively reduces electrical resistance and minimizes the occurrence of flex cracks and migration, while maintaining a firm connection between the element body and external electrodes, even under stress conditions.

Implementation Method 1

The metal layer is disposed on the side surface and the end surface and made of sintered copper

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

The conductive resin layer is disposed on the metal layer in such a manner that a partial region of the metal layer is exposed and contains a plurality of copper particles and a resin

Methodology Applied

Scientific EffectElectrical conduction through particulate material: Conduction (electrical)

Implementation Method 3

The plating layer is disposed on the partial region of the metal layer and the conductive resin layer

Methodology Applied

Scientific EffectOxidation prevention: Oxidation

Data Source

PatentUS11646160B2Electronic component

Publication Date: 2023.05.09 TDK CORP

AI summary

An electronic component includes an element body including a side surface and an end surface adjacent to each other, and an external electrode disposed on the side surface and the end surface. The external electrode includes a metal layer disposed on the side surface and the end surface and made of sintered copper, a conductive resin layer that is disposed on the metal layer in such a manner that a partial region of the metal layer is exposed and contains a plurality of copper particles and a resin, and a plating layer disposed on the partial region of the metal layer and the conductive resin layer. The conductive resin includes a first portion located on the side surface. The plating layer includes a second portion located on the side surface. A thickness of the first portion is smaller than a thickness of the second portion.