Copper Conductive Ink Composition for Low-Temperature Processing
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Solution Overview
Problem
Current conductive ink technologies face challenges in producing high-quality copper-based inks that are compatible with low-temperature processing and flexible substrates, as they often require high temperatures and strong reducing agents, making it difficult to achieve stable and conductive copper coatings.
Innovation Solution
A copper-based ink composition comprising a copper metal precursor compound, a chelating agent, and a reducing agent with adjusted redox potential, which allows for the controlled reduction of copper ions to metallic copper at temperatures of 140° C. or lower, using a blocking agent or modifying the reducing agent, and includes solvents and catalysts to ensure stability and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high temperature processing is used to reduce copper ions to metallic copper, then conductivity is improved, but substrate integrity is compromised
Solution Approach 1:
The patent changes the chemical parameters of the reducing agent to achieve copper reduction at lower temperatures. Specifically, it uses a reducing agent with controlled redox potential and molecular weight that enables copper ion reduction without requiring high temperature processing, thus maintaining substrate integrity while achieving desired conductivity
Solution Approach 2:
The patent introduces a chelating agent as an intermediary that forms a complex with copper ions, facilitating controlled reduction at lower temperatures. The chelating agent mediates between the copper precursor and the reducing agent, enabling temperature-controlled reduction that preserves substrate integrity
2Productivity
If strong reducing agents are used to reduce copper ions, then reduction efficiency is improved, but control over reduction speed is worsened
Solution Approach 1:
The patent carefully selects and adjusts the redox potential and molecular weight parameters of the reducing agent to achieve optimal balance between reduction efficiency and speed control. This parameter optimization ensures that copper ions reduce at an controlled rate while maintaining high efficiency
Solution Approach 2:
The patent employs a reducing agent system that provides feedback control over the reduction process. The chelating agent-copper complex system allows monitoring and control of reduction progress, enabling precise control over reduction speed while maintaining efficiency
3Reliability
If particle-based inks are used, then conductivity is improved, but processing complexity is worsened
Solution Approach 1:
The patent extracts the copper ions from the bulk material and incorporates them into a molecular-level complex with the chelating agent and reducing agent. This extraction approach allows copper to be delivered in a controlled, molecular-scale format that simplifies processing while maintaining conductivity
Solution Approach 2:
The patent changes the physical state and size parameters of copper from bulk particles to molecular-scale complexes. This parameter transformation enables the copper to be processed through standard inkjet printing without requiring specialized particle handling, thus reducing processing 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 ink composition achieves high conductivity (resistivity of 2×10−5 Ω-cm or less) and stability at room temperature, enabling the formation of conductive copper structures suitable for various patterning techniques and flexible substrates, with the ability to maintain conductivity upon annealing at mild temperatures.
Implementation Method 1
a reducing agent; wherein the redox potential of the reducing agent is adjusted for controlled reduction of copper ion in the copper metal precursor to metal copper metal
Implementation Method 2
a chelating agent
Implementation Method 3
enabling the formation of conductive copper structures suitable for various patterning techniques
Data Source
AI summary
Disclosed herein are ink compositions for making a conductive copper structure. The ink composition comprise a copper metal precursor compound, a chelating agent, and a reducing agent. In some embodiments, the redox potential of the reducing agent is adjusted for controlled reduction of copper ion in the copper metal precursor to metal copper metal. Also disclosed herein are methods for making the ink compositions and methods for using the same.