Anisotropic Conductive Film Viscosity and Bubble Control
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Solution Overview
Problem
Existing anisotropic conductive films face challenges in securing both electrical conductivity and insulation properties, particularly in maintaining low connection resistance and reliability under high temperature/high-humidity conditions, while avoiding excessive hardness and bubbling issues.
Innovation Solution
An anisotropic conductive film with a minimum melt viscosity of 900 Pa·s to 90,000 Pa·s at 80° C. to 140° C., composed of a polymer resin, a radical polymerizable material with a molecular weight of 500 g/mol or less, and conductive particles, which includes 4-hydroxybutyl (meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, and pentaerythritol tri(meth)acrylate, and has a conductive particle compression rate of 20% to 70% and a bubble area of 20% or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the anisotropic conductive film uses conventional resin compositions, then it provides basic adhesion, but it exhibits excessive hardness and poor flowability leading to bubbling and high connection resistance
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by incorporating radical polymerizable materials with specific molecular weights (500 g/mol or less) at controlled concentrations (1-25 wt%). This parameter modification transforms the resin's flow characteristics and curing behavior, enabling it to achieve both low connection resistance and adequate adhesion without excessive hardness.
Solution Approach 2:
The patent creates a composite resin system combining conventional adhesive resins with radical polymerizable materials. This composite approach integrates the adhesion properties of traditional resins with the flow-enhancing and low-viscosity characteristics of the radical polymerizable components, resolving the contradiction between strength and reliability.
2Stability of the object's composition
If the anisotropic conductive film uses high viscosity resin, then it maintains structural stability, but it shows poor flowability and inadequate particle collection leading to high connection resistance
Solution Approach 1:
The patent modifies the viscosity parameter of the resin by adding radical polymerizable materials with molecular weights of 500 g/mol or less. These materials significantly reduce the resin's viscosity during the curing process, improving flowability and particle collection while maintaining structural stability through controlled polymerization.
Solution Approach 2:
The patent introduces dynamic viscosity control through radical polymerizable materials that remain fluid during application and heating, then progressively固化 (cure) to provide structural stability. This dynamic transition from liquid to solid state enables the resin to adapt to different processing stages while maintaining both flowability and stability.
3Reliability
If the anisotropic conductive film is compressed at high temperature, then it achieves good particle collection and low initial connection resistance, but it forms bubbles and shows poor reliability under high temperature/high humidity conditions
Solution Approach 1:
The patent changes the curing temperature parameter by utilizing radical polymerization that proceeds at lower temperatures compared to conventional thermal curing. This temperature reduction prevents excessive bubble formation during compression while still achieving adequate particle collection and low connection resistance. The radical polymerizable materials enable curing at temperatures that avoid the bubbling problem.
Solution Approach 2:
The patent replaces conventional thermal curing mechanisms with radical polymerization chemistry. This substitution allows the resin to cure through chemical reaction rather than purely thermal processes, reducing the temperature-induced bubble formation while maintaining effective compression and particle alignment for low connection resistance.
4Object-affected harmful factors
If the anisotropic conductive film uses radical polymerizable material with molecular weight over 500 g/mol, then it provides adequate viscosity control, but it fails to achieve sufficient flowability and particle collection resulting in high connection resistance
Solution Approach 1:
The patent critically changes the molecular weight parameter of the radical polymerizable material to 500 g/mol or less. This specific parameter threshold enables the material to provide sufficient flowability and particle collection capability while maintaining adequate viscosity control. Lower molecular weight materials have smaller molecular dimensions that facilitate better particle wetting and collection, directly reducing connection resistance.
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 film achieves stable electrical conductivity, improved indentation characteristics, and reliable connection resistance, even under high temperature/high-humidity conditions, ensuring long-term use and reliability of connected devices.
Implementation Method 1
the anisotropic conductive film is prepared from a composition that includes a polymer resin; a radical polymerizable material having a molecular weight of 500 g/mol or less; a radical polymerization initiator; and conductive particles
Implementation Method 2
An anisotropic conductive film may be composed of polymer layers having electric anisotropy and adhesion, and may exhibit conductive properties in the thickness direction of the film and insulating properties in the surface direction thereof
Implementation Method 3
When an anisotropic conductive film disposed between circuit boards to be connected is subjected to heating and compression under certain conditions, circuit terminals of the circuit boards are electrically connected through conductive particles
Data Source
AI summary
A display device connected by an anisotropic conductive film, wherein the anisotropic conductive film includes conductive particles and has a minimum melt viscosity of 900 Pa·s to 90,000 Pa·s at 80° C. to 140° C.