Copper Nanoparticle Paste with Phosphine Protection for 3D Printing
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Solution Overview
Problem
Current technologies fail to prevent oxidation of copper nanoparticles during preparation and storage, limiting their application in high-precision direct-writing 3D printing, especially for line widths smaller than 10 µm, due to the high reactivity and susceptibility of small copper particles to oxidation.
Innovation Solution
A copper nanoparticle paste is prepared using a triaryl phosphine or trialkyl phosphine compound as a reducing agent, combined with epoxy resin to form a stable oil-soluble paste, which isolates copper nanoparticles from water and oxygen, forming a phosphine oxide compound that protects the copper surface during sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If copper nanoparticles are used to reduce cost, then material cost is reduced, but electrical conductivity deteriorates due to oxidation
Solution Approach 1:
A phosphine compound is introduced as an intermediary substance that mediates between copper nanoparticles and oxygen/water. The phosphine compound adsorbs onto the copper nanoparticle surface, forming a protective layer that prevents direct contact between copper and oxidizing agents, thereby maintaining electrical conductivity while enabling the use of cost-effective copper materials
Solution Approach 2:
The phosphine compound creates a chemically inert protective environment around copper nanoparticles. This protective layer acts as a barrier that isolates the reactive copper surface from oxidative environments, effectively creating a localized inert atmosphere that preserves electrical conductivity during storage and processing
2Manufacturing precision
If copper nanoparticle size is reduced to achieve high-precision printing, then manufacturing precision is improved, but stability deteriorates due to increased oxidation susceptibility
Solution Approach 1:
A molecular-level thin film of phosphine compound is formed on the surface of copper nanoparticles. This flexible molecular shell conformally coats the nanoparticle surface, providing oxidation protection while maintaining the small particle size necessary for high-precision direct-writing 3D printing with line widths below 10 µm
Solution Approach 2:
The solution changes the chemical environment around copper nanoparticles by introducing phosphine compounds. This parameter change transforms the surface chemistry from highly reactive to protected, enabling stable storage and handling of ultrfine copper particles while maintaining their small size for precision printing applications
3Ease of manufacture
If conventional reducing agents are used in copper paste preparation, then copper nanoparticle formation is achieved, but harmful factors increase due to surface breakdown and gas generation
Solution Approach 1:
The phosphine compound acts as a sacrificial protective layer that can be easily decomposed during sintering. This disposable protective mechanism provides oxidation protection during storage and processing, then willingly decomposes at sintering temperatures to leave no harmful residues, avoiding the problems of surface breakdown and gas generation associated with conventional reducing agents
Solution Approach 2:
The solution converts the typically harmful role of reducing agents into a beneficial protective function. Instead of using reducing agents that cause surface breakdown and gas generation, a phosphine compound is used that provides oxidation protection and decomposes cleanly, transforming the reduction step from a source of harmful effects to a beneficial protective measure
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 copper nanoparticle paste maintains high electrical conductivity and stability, suitable for high-precision direct-writing 3D printing with line widths of at least 1 µm, and retains electrical resistivity below 10 µΩ·cm after 10 days of storage.
Implementation Method 1
A triaryl phosphine or trialkyl phosphine compound is used as a reducing agent, and copper nanoparticles are prepared
Implementation Method 2
forming a phosphine oxide compound that protects the copper surface during sintering
Implementation Method 3
combined with epoxy resin to form a stable oil-soluble paste, which isolates copper nanoparticles from water and oxygen
Implementation Method 4
the electrical resistivity of the sintered copper wire is below 10 µΩ·cm after 10 days of storage
Data Source
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AI summary
The present disclosure provides a copper nanoparticle paste suitable for high-precision direct-writing 3D printing, and preparation and application thereof. A triaryl phosphine compound or trialkyl phosphine compound is adopted as a copper powder protective agent, and copper nanoparticles are prepared into oil-soluble paste containing epoxy resin; and thus, the problem that the copper nanoparticle paste is prone to be oxidized in preparation and storage processes is solved, and the electrical conductivity of the copper nanoparticle paste is improved, to ensure that the copper nanoparticle paste is suitable for the high-precision direct-writing 3D printing.