Polyimide Precursor Thiol Ester UV Patterning
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Solution Overview
Problem
Existing methods for patterning functional thin films in electronic devices, such as organic electroluminescence (EL) and organic field-effect transistor (FET) elements, face challenges including complex processes and the need for durability of patterning layers, particularly in maintaining electrical insulation properties.
Innovation Solution
A polyimide precursor with a thiol ester structure is used, which alters hydrophilicity/hydrophobicity of the surface upon low-level ultraviolet ray irradiation, enabling efficient formation of under layer films for image formation and electrode pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a patterning layer is formed using conventional materials (tetracarboxylic acid anhydride with aliphatic ring structure), then the layer provides durability and electrical insulation properties, but extremely large amounts of ultraviolet ray irradiation are required resulting in long exposure treatment time
Solution Approach 1:
The invention changes the chemical structure parameter of the polyimide precursor by introducing a thiol ester group into the main chain. This structural modification enables the material to undergo significant hydrophilicity/hydrophobicity changes with minimal UV irradiation, reducing exposure time from hours to minutes while maintaining the durability and insulation properties of the patterning layer
Solution Approach 2:
The thiol ester group is specifically positioned in the main chain of the polyimide precursor structure to create localized reactive sites. These localized groups enable selective surface modification upon UV irradiation, allowing the patterning process to occur rapidly at the surface level without requiring extensive energy input throughout the entire material structure
2Reliability
If a patterning layer is formed using materials requiring large amounts of ultraviolet ray irradiation, then the patterning layer can be formed, but the process complexity increases and productivity decreases
Solution Approach 1:
By modifying the polyimide precursor structure to include thiol ester groups, the UV sensitivity parameter is dramatically improved. This allows the patterning process to be completed in minutes rather than hours, directly increasing manufacturing throughput and productivity while maintaining reliable patterning layer formation
Solution Approach 2:
The polyimide precursor is pre-synthesized with thiol ester groups incorporated into the main chain during the polymerization stage. This preliminary structural preparation ensures that subsequent UV irradiation can rapidly induce the desired hydrophilicity changes without requiring complex in-process modifications or extended exposure times
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 significantly reduces process time in manufacturing electronic devices by altering the surface properties of the films, enhancing productivity and maintaining essential insulation properties.
Implementation Method 1
a layer using a tetracarboxylic acid anhydride having an aliphatic ring structure (for example, Patent Document 4) has been disclosed. However, long time exposure treatment is necessary for these examples because these materials require extremely large amounts of ultraviolet ray irradiation
Data Source
AI summary
There is provided a polyimide precursor which can alter the hydrophilicity/hydrophobicity of the surface of a cured film formed readily even by a low level of ultraviolet ray irradiation; and a polyimide produced from the polyimide precursor. The polyimide precursor having a structure represented by the following formula (1):where A represents a tetravalent organic group; B represents a bivalent organic group having a thiol ester bond in its main chain; R1 and R2 independently represent a hydrogen atom or a univalent organic group; and n represents a natural number.