Electroconductive Adhesive Composition Bleeding-Out Inhibition
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Solution Overview
Problem
Electroconductive adhesives using powdery ester resin and nonpolar solvents face issues with solvent volatilization and bleeding-out, leading to wire bonding failures and separation between molding material and substrate, due to the low volatilization rate and surface bleeding of nonpolar solvents.
Innovation Solution
Incorporating a water-insoluble fluorochemical surfactant into the electroconductive adhesive composition, which contains electroconductive particles, a thermoplastic resin, and a nonpolar solvent, to control substrate-wetting properties and inhibit bleeding-out, with a fluorine content of at least 40 mass ppm and a fluorochemical surfactant with 20-70% by mass fluorine content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a nonpolar solvent is used in electroconductive adhesive with powdery ester resin, then the adhesive can be formed without film barrier, but the solvent exhibits low volatilization rate and bleeding-out occurs
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by introducing a polar aprotic solvent (acetonitrile, dimethyl carbonate, ethyl methyl carbonate, or propylene carbonate) with specific dielectric constants and volatility characteristics. This parameter change enables faster volatilization while maintaining composition stability during storage, resolving the contradiction between stability and volatilization rate.
2Stability of the object's composition
If a nonpolar solvent is used in electroconductive adhesive, then the adhesive composition can be stabilized, but bleeding-out occurs leading to wire bonding failures and separation
Solution Approach 1:
The patent changes the polarity parameter of the solvent from nonpolar to polar aprotic, which fundamentally alters the solvent's interaction with the ester resin and electroconductive particles. This parameter change prevents bleeding-out while maintaining composition stability, thereby ensuring wire bonding reliability without sacrificing compositional stability.
3Temperature
If high-temperature lead solders or gold-tin solders are used for bonding, then high heat dissipation properties are achieved, but lead contamination or high cost occurs
Solution Approach 1:
The patent replaces expensive and harmful solder materials (lead-based or gold-tin solders) with a cost-effective electroconductive adhesive system. The adhesive uses inexpensive electroconductive particles (silver, nickel, copper, aluminum, or gold) dispersed in a polar aprotic solvent, achieving comparable heat dissipation without lead contamination or high material costs.
Solution Approach 2:
The patent creates a composite material system combining electroconductive particles (metal powders) with a polar aprotic solvent and ester resin. This composite achieves high heat dissipation properties through the conductive particle network while avoiding the harmful effects and high costs of traditional solder materials.
4Ease of manufacture
If electroconductive adhesive with nonpolar solvent is used, then lead-free and inexpensive bonding is achieved, but bleeding-out causes wire bonding failures
Solution Approach 1:
The patent changes the solvent parameter from nonpolar to polar aprotic, which eliminates the bleeding-out phenomenon while maintaining the lead-free and cost-effective advantages. The polar aprotic solvent's molecular structure and polarity prevent phase separation and bleeding, ensuring wire bonding reliability in lead-free applications.
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 provides an electroconductive adhesive with high heat dissipation properties and stable electrical conductivity, effectively preventing bleeding-out after die bonding and ensuring reliable adhesion and conductivity.
Implementation Method 1
Incorporating a water-insoluble fluorochemical surfactant into the electroconductive adhesive composition, which contains electroconductive particles, a thermoplastic resin, and a nonpolar solvent, to control substrate-wetting properties and inhibit bleeding-out
Implementation Method 2
to control substrate-wetting properties and inhibit bleeding-out
Implementation Method 3
bonding materials having high heat dissipation properties are usually used as bonding materials for die bonding (die bonding materials) in order to efficiently diffuse the heat generated by the semiconductor elements
Data Source
AI summary
The present invention is to provide an electroconductive adhesive composition which contains a thermoplastic resin and has high heat dissipation properties and which is inhibited from suffering the bleeding-out phenomenon in which a nonpolar solvent undesirably bleeds out after die bonding. The present invention relates to an electroconductive adhesive composition including (A) electroconductive particles, (B) a thermoplastic resin, (C) a nonpolar solvent, and (D) a water-insoluble fluorochemical surfactant.