Insulated Conductive Particles for Anisotropic Conductive Film

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Solution Overview

Problem

Anisotropic conductive films face challenges in preventing aggregation of conductive particles, leading to electrical shorts and reduced reliability in connections between fine-pitched wired circuit patterns and bumped electrodes, which limits the increase in conductive particle content.

Innovation Solution

The development of an anisotropic conductive film composition with insulated conductive particles, where nonconductive particles with a core and coating layer are attached to the surface of conductive particles, preventing aggregation and ensuring reliable electrical connections by allowing the conductive particles to deviate and form connections between electrodes while maintaining insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the content of conductive particles is increased to improve electrical connection reliability, then the electrical connection reliability is improved, but the conductive particles aggregate leading to electrical shorts between neighboring bump electrodes or wired circuit patterns

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidparticle aggregation causing electrical shorts

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A nonconductive particle is introduced as an intermediary between adjacent conductive particles. This nonconductive particle acts as a physical barrier that prevents direct contact between conductive particles, thereby preventing aggregation and electrical shorts while allowing sufficient conductive particles to be present for reliable electrical connections

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adhesive composition uses a composite structure consisting of conductive particles, nonconductive particles, and adhesive resin. This composite material design allows the conductive particles to provide electrical connection while the nonconductive particles embedded within the adhesive matrix prevent harmful aggregation, achieving both conductivity and insulation simultaneously

Inventive Principle:

Principle #40Composite materials

2Quantity of substance

If the pitch of wired circuit patterns is reduced to increase connection density, then the connection density is improved, but the risk of electrical shorts between neighboring patterns increases

Engineering Contradiction:

Improveconnection densityVSAvoidelectrical shorts between fine-pitched patterns

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The nonconductive particles serve as intermediary elements that physically separate conductive particles, preventing them from bridging across fine-pitched wired circuit patterns. This allows higher connection density to be achieved without increasing the risk of electrical shorts between neighboring patterns

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-generated harmful factors

If nonconductive particles are completely coated on conductive particles to prevent aggregation, then aggregation prevention is improved, but electrical connection reliability deteriorates due to insulation barrier

Engineering Contradiction:

Improveaggregation preventionVSAvoidelectrical connection reliability

Core Design Contradiction:

Object-generated harmful factorsVSReliability

Solution Approach 1:

The nonconductive particles are positioned locally between adjacent conductive particles rather than completely coating each conductive particle. This local placement provides aggregation prevention at the interfaces between particles while leaving the surfaces of individual conductive particles exposed to establish electrical connections with electrodes

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of completely coating conductive particles with nonconductive material, the invention uses partial action by placing nonconductive particles only where needed between conductive particles to prevent aggregation, while deliberately leaving portions of conductive particle surfaces exposed to maintain electrical conductivity

Inventive Principle:

Principle #16Partial or excessive action

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 prevents electrical shorts and enhances reliability in both electrical connection and insulation, allowing for higher particle content without compromising performance, even at finer pitches.

Implementation Method 1

a polymerizable compound configured to cross-link the body-forming resin upon polymerization

Methodology Applied

Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentUS7815999B2Insulated conductive particles and anisotropic conductive adhesive film containing the particles

Publication Date: 2010.10.19 KUKDO CHEM CO LTD

AI summary

An insulated conductive particle for an anisotropic conductive film is disclosed. One embodiment of the particle includes a conductive particle and insulating fixative particles discontinuously fixed on the surface of the conductive particle. The insulating particles provides insulation with other adjacent insulated conductive particles, while the insulated conductive particle is electrically connected between electrodes with the insulating fixative particles being deviated from its position. The instant disclosure also provides a method for manufacturing the insulated conductive particle, an anisotropic conductive adhesive film containing the insulated conductive particles, and an electrically connected structure using the film.