Anisotropic Conductive Film Oblique UV Curing

Solution Overview

Problem

The conventional anisotropic conductive films with a two-layer structure experience resin flow and conductive particle displacement during heating, leading to decreased mounting conductive particle capture ratio, short circuits, and compromised insulating properties due to the absence of a polymerization initiator in the insulating resin layer.

Innovation Solution

An anisotropic conductive film is created by arranging conductive particles in a single layer on a photopolymerizable resin layer, which is then irradiated with inclined ultraviolet light to fix the particles, followed by the addition of a thermo- or photo-cationically, anionically, or radically polymerizable resin layer, ensuring stable particle fixation and improved resin flow control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the insulating resin layer contains no polymerization initiator, then the production cost decreases, but resin flow occurs during heating causing conductive particle displacement and short circuits

Engineering Contradiction:

Improveproduction costVSAvoidconduction reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent divides the resin layer into two distinct layers: a first connection layer containing a polymerization initiator that is cured before mounting, and a second connection layer containing no polymerization initiator that remains uncured during mounting to enable resin flow and particle redistribution. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between cost and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first connection layer is cured in advance before the mounting process by irradiating with ultraviolet light. This preliminary curing creates a stable base layer that prevents excessive resin flow while allowing the second layer to remain flexible and enable particle redistribution during subsequent heating and pressing operations.

Inventive Principle:

Principle #10Preliminary action

2Ease of manufacture

If the insulating resin layer contains no polymerization initiator, then the production cost decreases, but mounting conductive particle capture ratio decreases due to particle displacement

Engineering Contradiction:

Improveproduction costVSAvoidmounting conductive particle capture ratio

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent divides the resin layer into two distinct layers: a first connection layer containing a polymerization initiator that is cured before mounting, and a second connection layer containing no polymerization initiator that remains uncured during mounting to enable resin flow and particle redistribution. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between cost and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first connection layer is cured in advance before the mounting process by irradiating with ultraviolet light. This preliminary curing creates a stable base layer that prevents excessive resin flow while allowing the second layer to remain flexible and enable particle redistribution during subsequent heating and pressing operations.

Inventive Principle:

Principle #10Preliminary action

3Ease of manufacture

If the insulating resin layer contains no polymerization initiator, then the production cost decreases, but insulating properties decrease due to resin flow and short circuits

Engineering Contradiction:

Improveproduction costVSAvoidinsulating properties

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent divides the resin layer into two distinct layers: a first connection layer containing a polymerization initiator that is cured before mounting, and a second connection layer containing no polymerization initiator that remains uncured during mounting to enable resin flow and particle redistribution. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between cost and reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first connection layer is cured in advance before the mounting process by irradiating with ultraviolet light. This preliminary curing creates a stable base layer that prevents excessive resin flow while allowing the second layer to remain flexible and enable particle redistribution during subsequent heating and pressing operations.

Inventive Principle:

Principle #10Preliminary 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

This configuration enhances conduction reliability, insulating properties, and mounting conductive particle capture ratio by aligning the conductive particle flow directions and preventing short circuits, while maintaining initial conduction properties.

Implementation Method 1

irradiating the photopolymerizable resin layer with inclined ultraviolet light or with ultraviolet light inclined in at least two directions to fix or temporarily fix the conductive particles

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

the second connection layer is a thermo- or photo-cationically, anionically, or radically polymerizable resin layer

Methodology Applied

Scientific EffectThermal polymerization:

Data Source

PatentUS9997486B2Anisotropic conductive film including oblique region having lower curing ratio

Publication Date: 2018.06.12 DEXERIALS CORP

AI summary

An anisotropic conductive film has a first connection layer and a second connection layer formed on surface of the first connection layer. The first connection layer is a photopolymerized resin layer, and the second connection layer is a thermo- or photo-cationically, anionically, or radically polymerizable resin layer. On the surface of first connection layer on the side of second connection layer, conductive particles for anisotropic conductive connection are arranged in a single layer. A region in which the curing ratio is lower than that of the surface of the first connection layer exists in a direction oblique to the thickness direction of the first connection layer. Alternatively, the curing ratio of a region relatively near another surface of the first connection layer among regions of the first connection layer in the vicinity of the conductive particles is lower than that of the surface of the first connection layer.