Amino Alcohol-Coated Copper Paste for Oxidation-Free Low-Temperature Sintering
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Solution Overview
Problem
Current materials used for thermal management in semiconductor devices and LEDs require high thermal conductivity and long-term high-temperature heat resistance, while also needing to withstand reflow processes and minimize stress due to thermal expansion differences, which is challenging for traditional die attach pastes.
Innovation Solution
A paste composition containing copper fine particles with a thickness or minor axis of 10 to 500 nm, coated with amino alcohol, and an organic solvent, which are produced through a pyrolysis method using a copper-containing compound, amino alcohol, and a reducing compound, providing enhanced thermal conductivity and adhesion without requiring a reducing atmosphere during firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high content ratio of metal filler or ceramic-based filler is used to obtain high thermal conductivity, then thermal conductivity is improved, but viscosity increases and processability deteriorates
Solution Approach 1:
The patent changes the particle size parameter of the filler from conventional sizes to ultrafine sizes (1-10 μm for metal particles, 0.1-1 μm for ceramic particles). This parameter change allows achieving high thermal conductivity with lower filler content ratios, thereby maintaining lower viscosity and improving processability while still achieving the desired thermal management performance
Solution Approach 2:
The patent uses a composite filler system combining ultrafine metal particles (Al, Cu, Ag, Au) with ultrafine ceramic particles (AlN, SiN, SiO2, TiO2). This composite approach synergistically enhances thermal conductivity while the fine particle sizes prevent excessive viscosity increase, resolving the contradiction between thermal performance and processability
2Ease of manufacture
If copper particles are used instead of silver particles, then cost is reduced and migration resistance is improved, but oxidation resistance deteriorates
Solution Approach 1:
The patent introduces an organic solvent as an intermediary medium that creates a controlled atmosphere during the sintering process. This solvent prevents direct contact between copper particles and oxidizing environments, thereby protecting the copper from oxidation while maintaining the cost and migration resistance advantages of copper over silver
Solution Approach 2:
The patent creates an inert protective environment using organic solvents (such as toluene, xylene, or alcohol-based solvents) that vaporize during sintering to form a protective atmosphere around the copper particles. This inert environment prevents copper oxidation while allowing the use of cheaper and more migration-resistant copper particles instead of silver
3Ease of manufacture
If nano-sized copper fine particles are used, then sinterability is improved and reducing atmosphere requirement is eliminated, but particle production complexity increases
Solution Approach 1:
The patent performs preliminary surface treatment of copper particles with organic solvents and controlling their size distribution before the sintering process. This preliminary preparation enhances sinterability and eliminates the need for reducing atmospheres during sintering, while the pre-established particle characteristics simplify the overall manufacturing process despite the initial particle production complexity
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 paste composition achieves high thermal conductivity, low electrical resistance, and excellent adhesion, enabling efficient heat dissipation and long-term reliability in semiconductor devices and LEDs, with improved sinterability and reduced oxidation of copper fine particles.
Implementation Method 1
copper fine particles having a thickness or minor axis of 10 to 500 nm and coated with amino alcohol
Implementation Method 2
an organic solvent, wherein a compounding amount of (B) the organic solvent is 2 to 20 parts by mass relative to 100 parts by mass of (A) the copper fine particles
Implementation Method 3
high thermal conductivity is required of a material itself for bonding the heat dissipating member
Implementation Method 4
providing enhanced thermal conductivity and adhesion without requiring a reducing atmosphere during firing
Data Source
AI summary
There is provided a paste composition using copper fine particles that are capable of exhibiting conductivity after low-temperature sintering, which themselves are less oxidized, and that can be produced with a high yield ratio. A paste composition contains: (A) copper fine particles having a thickness or minor axis of 10 to 500 nm and coated with amino alcohol represented by the chemical formula (1) and (B) an organic solvent.