Oxide-Containing Copper Fine Particles for One-Step Low-Temperature Sintering
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Solution Overview
Problem
Copper fine particles are difficult to sinter at low temperatures without requiring two-steps heating or additional copper materials, leading to low productivity and high costs.
Innovation Solution
Oxide-containing copper fine particles with a specific mass ratio of Cu64O and optionally Cu2O, coated with a carboxylic acid, are heated under normal pressure to facilitate sintering at 200°C or lower through a one-step process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper fine particles are used as a substitute for silver fine particles, then cost is reduced and resistance to ion migration is improved, but sintering temperature cannot be lowered to 250°C or lower
Solution Approach 1:
The invention changes the chemical composition parameters of copper fine particles by incorporating specific oxide components (CuO and/or Cu2O) at controlled ratios (0.1-10 wt% CuO and/or 1-20 wt% Cu2O based on copper fine particle mass). This compositional parameter change enables copper fine particles to be sintered at low temperatures (250°C or lower) while maintaining reliability and resistance to ion migration.
Solution Approach 2:
The invention creates a composite structure within copper fine particles by combining metallic copper with copper oxide components (CuO and/or Cu2O). This composite material approach allows the particles to exhibit both the low-cost, high ion migration resistance of copper and the low-temperature sinterability provided by the oxide components, resolving the contradiction between reliability and sintering temperature.
2Temperature
If two-steps heating (oxidation treatment and reduction treatment) is used to sinter copper fine particles, then low-temperature sintering is achieved, but the number of process steps increases
Solution Approach 1:
The invention applies preliminary action by pre-incorporating copper oxide components (CuO and/or Cu2O) into the copper fine particles before the sintering process. This preliminary preparation eliminates the need for separate oxidation and reduction treatment steps during sintering, as the oxide components are already present in the desired form and distribution, enabling direct one-step low-temperature sintering.
Solution Approach 2:
The invention merges the oxidation treatment and reduction treatment into a single sintering step. By pre-incorporating oxide components into the copper fine particles, the separate oxidation and reduction processes are combined into one simultaneous sintering operation, reducing the number of process steps from two to one while achieving low-temperature sintering.
3Temperature
If additional copper material (copper complex) is used to sinter copper fine particles at low temperature, then low-temperature sintering is achieved, but the number of materials and process steps increases
Solution Approach 1:
The invention makes the copper fine particles themselves multi-functional by incorporating oxide components that serve dual purposes: they act as both the base material and the sintering aid. This eliminates the need for separate copper complex materials, as the oxide-containing copper particles perform both structural and sintering functions, reducing the number of materials required.
Solution Approach 2:
The invention extracts the sintering aid function from separate copper complex materials and integrates it directly into the copper fine particles through oxide component incorporation. This extraction and integration eliminates the need for additional copper complex materials, simplifying the manufacturing process while achieving low-temperature sintering.
4Reliability
If sintering under high vacuum is used to obtain conductive sintered compact, then sufficient conductivity is achieved, but batch processing is required and productivity is lowered
Solution Approach 1:
The invention changes the sintering atmosphere parameter from high vacuum to atmospheric pressure conditions. By incorporating oxide components (CuO and/or Cu2O) into the copper fine particles, the sintering process can be conducted at atmospheric pressure while still achieving sufficient conductivity, thereby enabling continuous processing and improving productivity without batch vacuum operations.
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
Achieves sufficient conductivity in a sintered compact without additional materials or complex heating processes, enhancing productivity and reducing costs.
Implementation Method 1
The fine wiring is mainly obtained by heating and sintering metal fine particles
Implementation Method 2
heating the oxide-containing copper fine particles to 100° C. to 200° C.
Implementation Method 3
coated with a carboxylic acid
Implementation Method 4
incorporation of cuprous oxide (Cu2O) into copper fine particles
Data Source
AI summary
Disclosed is oxide-containing copper fine particles including Cu64O and optionally Cu2O and coated with a carboxylic acid, wherein a mass ratio of Cu64O to a total mass of Cu, Cu64O and Cu2O is 0.5 to 2.0% by mass.