Anisotropic Conductive Film SAN Copolymer Adhesion

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Solution Overview

Problem

Conventional anisotropic conductive films (ACFs) exhibit insufficient adhesive properties, low glass transition temperature, and poor mechanical connection reliability due to epoxy-based and (meth)acrylate-based binders, which also face issues with heat and moisture resistance, and curing agent rheology leading to foam generation or low conductivity.

Innovation Solution

An anisotropic conductive film composition incorporating a styrene-acrylonitrile (SAN) copolymer resin with a thermoplastic resin, (meth)acrylate oligomer, (meth)acrylate monomer, and radical or epoxy curing agents, along with conductive particles, to enhance adhesion, reduce contact resistance, and improve mechanical and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If epoxy-based binder is used in conventional ACF, then adhesion properties are improved, but glass transition temperature is low and mechanical connection reliability is poor

Engineering Contradiction:

Improveadhesion propertiesVSAvoidmechanical connection reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent changes the chemical composition parameters of the binder by incorporating SAN copolymer resin with specific glass transition temperature (100-200°C) and molecular weight (5,000-200,000) ranges, replacing conventional epoxy-based binders to achieve both improved adhesion and mechanical reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite binder system combining thermoplastic resin (5-50 wt%) with SAN copolymer resin (5-50 wt%), where the thermoplastic resin provides adhesion and the SAN copolymer provides mechanical strength and heat resistance, achieving synergistic effects

Inventive Principle:

Principle #40Composite materials

2Strength

If epoxy-based binder is used in conventional ACF, then adhesion properties are improved, but curing temperature and curing time increase

Engineering Contradiction:

Improveadhesion propertiesVSAvoidcuring time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The patent changes the curing parameters by using radical initiators that enable curing at lower temperatures and shorter times compared to epoxy-based systems, while maintaining adhesion properties through the thermoplastic resin component

Inventive Principle:

Principle #35Parameter changes

3Strength

If (meth)acrylate-based binder is used in conventional ACF, then adhesion properties are improved, but heat and moisture resistance is low

Engineering Contradiction:

Improveadhesion propertiesVSAvoidheat and moisture resistance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent creates a composite binder system where thermoplastic resin provides adhesion and SAN copolymer resin provides heat and moisture resistance, achieving synergistic effects that overcome the limitations of single-component (meth)acrylate-based binders

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition by incorporating SAN copolymer with specific glass transition temperature (100-200°C) and molecular weight (5,000-200,000) ranges, replacing conventional (meth)acrylate-based binders to achieve both adhesion and environmental resistance

Inventive Principle:

Principle #35Parameter changes

4Strength

If (meth)acrylate-based binder is used in conventional ACF, then adhesion properties are improved, but foam generation occurs at low curing rate or conductivity decreases at high curing rate

Engineering Contradiction:

Improveadhesion propertiesVSAvoidfoam generation

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the rheological parameters by using radical initiators and controlling the composition of (meth)acrylate oligomer and monomer to achieve optimal curing rate that prevents foam generation while maintaining conductivity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates different functional zones within the binder: thermoplastic resin provides adhesion at the interface, while SAN copolymer and curing composition control the bulk properties and curing behavior to prevent foam generation

Inventive Principle:

Principle #3Local quality

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 SAN copolymer-based composition provides improved adhesion, low contact resistance, and enhanced reliability under high temperature and humidity conditions, maintaining superior characteristics and ensuring good adhesion to metals like zinc and copper, thus improving semiconductor productivity.

Implementation Method 1

The curing composition may include at least one (meth)acrylate oligomer, at least one (meth)acrylate monomer, and at least one radical initiator

Methodology Applied

Scientific EffectRadical polymerization: Photopolymerisation

Implementation Method 2

the conductive particles may establish an electrical connection therebetween

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS7879259B2Anisotropic conductive film composition

Publication Date: 2011.02.01 KUKDO CHEM CO LTD

AI summary

An anisotropic conductive film (ACF) composition includes a binder having a thermoplastic resin and a styrene-acrylonitrile (SAN) copolymer resin, a curing composition, and conductive particles.