Copper Alkoxide Inks for Low-Temperature Printed Electronics
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Solution Overview
Problem
Current methods for manufacturing electronic devices, such as RFID tags and circuit boards, result in significant waste and environmental concerns due to the subtractive processes used for metal deposition, particularly with copper, which is difficult to process at low temperatures without oxidation, limiting the use of copper inks for printed electronics.
Innovation Solution
Development of copper alkoxide-based inks that can be printed and cured at temperatures below 150°C without copper powders, allowing for the formation of oxide-free copper metal lines through thermal decomposition, enabling direct writing of copper lines on thermally sensitive substrates and subsequent electroplating for thickness buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If copper powder is used in conventional inks, then high copper loading is achieved, but the ink cannot be processed at low temperatures without oxidation
Solution Approach 1:
The patent changes the chemical form of copper from metallic copper powder to copper alkoxide complex, fundamentally altering the thermal processing characteristics. This parameter change enables the ink to be cured at low temperatures (below 150°C) without oxidation, as the copper alkoxide decomposes to form copper metal in situ under inert conditions, eliminating the oxidation problem associated with conventional copper powder inks
Solution Approach 2:
The invention creates a composite copper alkoxide complex that combines copper metal with organic alkoxide ligands. This composite material exhibits unique properties: it maintains copper's high conductivity potential while gaining the ability to be processed at low temperatures through thermal decomposition, thus resolving the contradiction between low processing temperature and oxidation resistance
2Manufacturing precision
If subtractive processes are used for metal deposition, then pattern accuracy is improved, but material waste increases significantly
Solution Approach 1:
The patent inverts the conventional subtractive approach by using a direct-write additive process. Instead of depositing copper powder and then removing excess material through etching, the copper alkoxide ink is printed directly in the desired pattern and cured to form the final copper structure. This inversion eliminates the need for etching and material removal, achieving both pattern accuracy and minimal waste
Solution Approach 2:
The invention extracts the harmful etching step from the manufacturing process by using a direct-printing approach. The copper alkoxide ink contains the exact pattern needed, and upon curing, forms the final copper structure without requiring subsequent material removal, thus extracting the waste-generating step from the process
3Reliability
If copper powder is used in inks, then high conductivity is achieved, but adhesion to flexible substrates deteriorates
Solution Approach 1:
The copper alkoxide complex acts as a composite material that provides both the desired electrical conductivity and improved adhesion. The organic alkoxide ligands in the complex enhance interaction with the substrate surface, while the copper metal formed upon curing ensures high conductivity, thus resolving the contradiction between conductivity and adhesion
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 alkoxide inks provide a robust, conducting copper matrix with excellent adhesion to flexible substrates, achieving high copper loading and enabling efficient production of copper lines with improved mechanical properties and conductivity, comparable to silver inks, while minimizing waste and environmental impact.
Implementation Method 1
heating the precursor on the substrate to decompose the precursor to copper metal and volatile by-products
Implementation Method 2
removing the volatile by-products
Data Source
AI summary
Novel copper alkoxide compound based ink formulations and their chemical syntheses are disclosed. The method of using the ink formulations to print conducting copper metal lines with standard ink jet printing and curing at <150° C. is also disclosed.