Anisotropic Conductive Nickel Particle with Layered Plating

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Solution Overview

Problem

Existing conductive particles for anisotropic conductive materials face issues with adhesion between the base particle and the conductive layer, as well as impact resistance, due to the limitations of nickel plating coatings with low phosphorus concentration and inadequate crystal structure.

Innovation Solution

A conductive particle with a non-crystal nickel plating layer and a crystal nickel plating layer, where the nickel crystal grain aggregate orientation in the (111) plane is 80% or more, formed by strictly controlling the pH during the nickel plating reaction, enhancing adhesion and impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a nickel plating coating with low phosphorus concentration is formed, then the nickel plating coating is hard, but the nickel plating coating breaks easily and adhesion between base particle and nickel plating coating is poor

Engineering Contradiction:
Improvehardness of nickel plating coatingVSAvoidadhesion between base particle and nickel plating coating
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The nickel plating coating is divided into multiple layers with different phosphorus concentrations: a first nickel plating layer with low phosphorus concentration (0-5 wt%) providing hardness, a second nickel plating layer with medium phosphorus concentration (5-10 wt%) providing intermediate properties, and a third nickel plating layer with high phosphorus concentration (10-15 wt%) providing flexibility and adhesion. This segmentation allows each layer to perform its specific function while working together to resolve the contradiction between hardness and adhesion.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the nickel plating coating have different phosphorus concentrations tailored to local requirements: the inner layer (first layer) has low phosphorus for hardness and wear resistance, the middle layer (second layer) has medium phosphorus for balanced properties, and the outer layer (third layer) has high phosphorus for flexibility and adhesion to the base particle. This local quality variation resolves the contradiction by optimizing properties at different locations.

Inventive Principle:
Principle #3Local quality

2Strength

If a nickel plating coating with low phosphorus concentration is formed, then the nickel plating coating is hard, but the nickel plating coating cannot follow impact and breaks

Engineering Contradiction:
Improvehardness of nickel plating coatingVSAvoidimpact resistance of nickel plating coating
Core Design Contradiction:
StrengthVSForce

Solution Approach 1:

The nickel plating coating is segmented into three layers with progressively increasing phosphorus concentrations from the inner layer (low phosphorus) to the outer layer (high phosphorus). The low-phosphorus inner layer provides hardness, while the high-phosphorus outer layer provides impact resistance and flexibility, resolving the contradiction between hardness and impact resistance through structural segmentation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The phosphorus concentration parameter is varied across different layers of the nickel plating coating: 0-5 wt% in the first layer, 5-10 wt% in the second layer, and 10-15 wt% in the third layer. This parameter change creates a gradient structure where hardness decreases and flexibility increases from the inner to outer layers, resolving the contradiction between hardness and impact resistance.

Inventive Principle:
Principle #35Parameter changes

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 conductive particle achieves excellent adhesion between the base particle and the conductive layer, improved conductivity, and enhanced impact resistance, suitable for high-performance applications in electronic devices.

Implementation Method 1

a nickel plating coating is formed as a conductive film

Methodology Applied
Scientific EffectElectroplating: Electroplating

Implementation Method 2

a proportion of a nickel crystal grain aggregate oriented in a nickel (111) plane derived from an integrated intensity ratio in X-ray diffraction measurement

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS7491445B2Electroconductive fine particle and anisotropically electroconductive material comprising non-crystal and crystal nickel plating layers and method of making thereof
Publication Date: 2009.02.17 SEKISUI CHEMICAL CO LTD

AI summary

It is the object of the present invention to provide a conductive particle which has excellent adhesion between a base particle and a conductive layer, a conductive layer being resistant to breaking, impact resistance being improved, and an anisotropic conductive material using the conductive particle. The prevent invention is a conductive particle, which comprises a base particle and a conductive layer formed on a surface of said base particle, said conductive layer having a non-crystal nickel plating layer in contact with the surface of said base particle and a crystal nickel plating layer, and a proportion of a nickel crystal grain aggregate oriented in a nickel (111) plane derived from an integrated intensity ratio in X-ray diffraction measurement being 80% or more.