Conductive Adhesive with Sub-Micron Particles for Low Viscosity
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Solution Overview
Problem
Existing electrically conductive adhesives face challenges in providing improved electrical interconnection between small contact areas, thermomechanical or mechanical fatigue resistance, low processing viscosity, and processing temperature, while maintaining a balance of filler loading, adhesive strength, curing speed, and stable electrical conductivity.
Innovation Solution
A novel adhesive composition comprising a thermosetting or thermoplastic resin component, micron-sized electrically conductive particles (2 μm to 50 μm), and sub-micron-sized electrically conductive particles (300 nm to 900 nm), which can be cured within 0.1 seconds to 180 minutes at 50° C to 220° C, forming a stable and conductive bond with low processing viscosity and high electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high filler loading is used to improve electrical conductivity, then electrical conductivity is improved, but processing viscosity increases
Solution Approach 1:
The patent changes the particle size parameter of the conductive filler, using sub-micron-sized particles (300 nm to 900 nm) instead of conventional larger particles. This parameter change allows achieving high electrical conductivity with lower filler loading, thereby maintaining low processing viscosity while improving electrical conductivity.
Solution Approach 2:
The patent creates a composite adhesive formulation combining resin with specific ratios of micron-sized and sub-micron-sized conductive particles. This composite approach optimizes the balance between electrical conductivity and rheological properties, allowing the adhesive to flow properly during application while maintaining high conductivity after curing.
2Reliability
If high filler loading is used to improve electrical conductivity, then electrical conductivity is improved, but adhesive strength decreases
Solution Approach 1:
The patent optimizes the filler loading parameter to a specific range (5-50 wt%) rather than using maximum possible loading. This parameter optimization ensures sufficient electrical conductivity while maintaining adequate resin content to provide strong adhesive bonding between substrates.
Solution Approach 2:
The composite formulation balances conductive filler content with resin content, creating a material that achieves both electrical conductivity and adhesive strength through synergistic combination of components rather than relying on high filler loading alone.
3Productivity
If fast curing is used to improve productivity, then curing speed is improved, but processing temperature increases
Solution Approach 1:
The patent changes the curing parameter by selecting resins with appropriate glass transition temperatures (Tg) and curing characteristics that enable fast curing at moderate temperatures. The resin selection and formulation allow achieving high productivity without requiring excessive processing temperatures that could damage sensitive electronic components.
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 adhesive achieves a stable electrically conductive interconnection with increased resistance to thermomechanical fatigue, low and long-term stable electrical contact resistance, and suitable for use in electronic devices, integrated circuits, and solar modules, with a balanced filler loading and curing speed.
Implementation Method 1
c) from 0.01 to 15 wt. % of sub-micron-sized electrically conductive particles having an average particle size of 300 nm to 900 nm
Implementation Method 2
The adhesive of the present can be cured in about 0.1 s to 180 minutes at a temperature within the range of about 50° C. to about 220° C.
Data Source
AI summary
The present invention relates to adhesives that are suitable for use as electrically conductive materials in the fabrication of electronic devices, integrated circuits, semiconductor devices, passive components, solar cells, solar modules, and/or light emitting diodes. The adhesives comprise at least one resin component, micron-sized electrically conductive particles having an average particle size of 2 μm to 50 μm, and from 0.01 to 15 wt. % of sub-micron-sized electrically conductive particles having a average particle size of 300 nm to 900 nm.