Diaroyl Carbazole Sensitizers for Photoresist Curing
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Solution Overview
Problem
Current photoinitiators and sensitizing agents, such as benzophenone and thioxanthone derivatives, do not demonstrate satisfactory sensitizing effects when combined with carbazolyl oxime ester, and some compounds like eosin and anthocyanin can reduce photocuring efficiency due to phenolic hydroxyl or anilino groups, leading to a lack of ideal sensitizing agents for improving exposure sensitivity and resolution in photocurable compositions.
Innovation Solution
The development of novel diaroyl carbazole compounds, which, when used in specific ratios with carbazolyl oxime ester, form a photoinitiator composition that significantly enhances sensitizing effects, particularly in photoresists, by employing a Friedel-Crafts acylation reaction to synthesize these compounds and mixing them with carbazolyl oxime ester photoinitiators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensitizing agents (benzophenone, thioxanthone derivatives) are used with carbazolyl oxime ester, then the photoinitiator system can be formed, but the sensitizing effect is not satisfactory and photocuring efficiency is reduced
Solution Approach 1:
The patent modifies the molecular structure of carbazole by introducing specific substituents (fluorine atoms, alkyl groups, alkoxy groups) at defined positions to create diaroyl carbazole compounds with optimized photophysical properties. This structural parameter change enables the sensitizing agent to effectively transfer energy to the carbazolyl oxime ester photoinitiator, resolving the insufficient sensitizing effect while maintaining high photocuring efficiency
Solution Approach 2:
The invention creates a composite photoinitiator system consisting of carbazolyl oxime ester (primary photoinitiator) combined with diaroyl carbazole compounds (sensitizing agents). This composite approach leverages the complementary photophysical properties of both components, where the diaroyl carbazole absorbs light and transfers energy to the oxime ester, achieving synergistic sensitizing effect that conventional single agents cannot provide
2Illumination intensity
If pigment content is increased to improve color saturation and hiding power, then the visual performance is improved, but light energy utilization rate is reduced due to absorption by pigment
Solution Approach 1:
The patent develops diaroyl carbazole sensitizing agents with optimized absorption spectra and energy transfer efficiency. These compounds are designed to absorb light in regions that complement the pigment absorption, and efficiently transfer energy to the photoinitiator. This parameter optimization allows the system to maintain high light energy utilization rate even when pigment content is increased for better color saturation and hiding power
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 diaroyl carbazole compounds show a substantial sensitizing effect when combined with carbazolyl oxime ester, achieving higher sensitivity and improved photocuring efficiency, especially in photoresists, with optimal results at specific molar ratios, surpassing the performance of previous sensitizing agents.
Implementation Method 1
UV photocuring technique is widely used in the fields of coatings, printing inks and electronic device manufacturing. Photoinitiators and co-initiators such as sensitizing agents are key factors affecting curing efficiency.
Implementation Method 2
the light energy utilization rate in the curing process is reduced due to the absorption by pigment
Data Source
AI summary
Provided in the present invention is a novel diaroyl carbazole compound, used together with a carbazolyl oxime ester photoinitiator to show a significant synergistic initiation effect in a photoresist composition; the best sensitising effect is shown when the molar ratio of the diaroyl carbazole compound and the carbazolyl oxime ester photoinitiator is 0.1-1.4.