Photocurable Polyimide Dielectric for Low-Temperature Transistors
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Solution Overview
Problem
The existing processes for preparing organic field-effect transistors with polyimide dielectric layers require high temperatures, which are not compatible with all plastic substrates, such as polycarbonate, limiting their use in flexible and thin organic field-effect transistors.
Innovation Solution
A process involving photocurable polyimides that are cured using light of specific wavelengths, eliminating the need for high-temperature heat treatment, allowing the formation of polyimide layers at temperatures below 160°C, preferably below 150°C, and enabling the use of plastic substrates like polycarbonate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heat treatment is used to cure polyimide dielectric layers, then the polyimide layer achieves high chemical and thermal stability, but the process becomes incompatible with plastic substrates like polycarbonate that cannot withstand high temperatures
Solution Approach 1:
The patent changes the curing parameter from thermal energy to optical energy. By using photocurable polyimide precursors that cure upon exposure to light of specific wavelengths, the process eliminates the need for high-temperature heat treatment, enabling compatibility with temperature-sensitive plastic substrates while still achieving the desired cross-linked polyimide structure and stability
Solution Approach 2:
The patent replaces the thermal curing mechanism with a photochemical curing mechanism. Instead of using heat (thermal field) to initiate the cross-linking reaction of polyimide precursors, the invention uses light irradiation (optical field) to trigger the same chemical transformation, thereby avoiding thermal damage to plastic substrates
2Reliability
If conventional high-temperature processing is used, then complete curing of polyimide is achieved, but the process complexity increases due to requirements for high-temperature equipment and controlled environments
Solution Approach 1:
The patent replaces complex high-temperature processing equipment and controlled thermal environments with simpler light irradiation systems. The photochemical curing process can be performed at ambient or near-ambient temperatures using standard UV or visible light sources, significantly reducing the complexity of processing equipment and environmental controls required
3Reliability
If high-temperature curing is applied, then the dielectric layer achieves optimal electrical properties, but the substrate material options are limited to high-temperature resistant materials only
Solution Approach 1:
The patent changes the energy delivery parameter from thermal to optical, enabling the curing of polyimide dielectric layers on a wide range of substrate materials including temperature-sensitive plastics like polycarbonate. This parameter change expands substrate material selection while maintaining the electrical properties achieved through complete curing
Solution Approach 2:
The photocurable polyimide precursor system provides universal applicability across multiple substrate types. The same photochemical curing process can be used on glass, plastic, metal, or other substrates without requiring substrate-specific temperature adjustments, making the process universally applicable to diverse substrate materials
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
This approach allows for the production of organic field-effect transistors with polyimide dielectric layers on various substrates, including polycarbonate, while maintaining high chemical and thermal stability, and enabling pattern formation and solution processing techniques.
Implementation Method 1
irradiating the layer comprising photocurable polyimide A with light of a wavelength of ≥360 nm in order to form the layer comprising polyimide B
Data Source
AI summary
The present invention provides a process for the preparation of a transistor on a substrate, which transistor comprises a layer, which layer comprises polyimide B, which process comprises the steps ofi) forming a layer comprising photocurable polyimide A by applying photocurable polyimide A on a layer of the transistor or on the substrateii) irradiating the layer comprising photocurable polyimide A with light of a wavelength of >=360 nm in order to form the layer comprising polyimide B,and a transistor obtainable by that process.