Photosensitive Siloxane Composition for Low-Permittivity Planarization
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Solution Overview
Problem
Current materials for planarization films in optical devices, such as LCD and organic EL devices, face challenges with high permittivity leading to signal delay and image quality issues, and existing heat-resistant materials decompose at high temperatures, affecting transparency and luminance efficiency.
Innovation Solution
A photosensitive siloxane composition comprising an alkali-soluble resin with carboxyl and alkoxysilyl polymerization units, a polysiloxane, a diazonaphthoquinone derivative, and a compound generating acid or base upon heat or light exposure, which forms a low-permittivity, chemically resistant, and heat-resistant cured film through a coating, exposure, and development process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If acrylic resin and quinone diazide compound are used for planarization film, then the film can be formed at room temperature, but the materials decompose at high temperature (230°C or above) causing film thickness decrease and coloration
Solution Approach 1:
The patent uses a composite material system combining polysiloxane (heat-resistant inorganic-organic hybrid) with acrylic resin and quinone diazide compound. The polysiloxane component provides high-temperature stability and prevents decomposition, while the acrylic resin and quinone diazide enable low-temperature film formation and photosensitivity. This composite approach resolves the contradiction between ease of manufacture and heat resistance.
2Reliability
If acrylic resin is modified to be heat-resistant, then heat resistance improves, but permittivity increases causing large parasitic capacitance and signal delay
Solution Approach 1:
The patent changes the fundamental material parameter from organic acrylic resin to inorganic-organic hybrid polysiloxane. This parameter change achieves heat resistance through the inorganic Si-O-Si backbone structure while maintaining low permittivity due to the low-polarity siloxane bonds, thereby avoiding the signal delay problem associated with high-permittivity materials.
3Reliability
If wiring thickness is increased to reduce wiring resistance, then signal delay is reduced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the signal delay problem from the wiring structure and relocates it to the insulating film material properties. By using low-permittivity polysiloxane-based insulating film, the parasitic capacitance is reduced, allowing thin wiring to maintain low signal delay without increasing wiring thickness or complexity.
4Reliability
If polysiloxane is used for planarization film, then heat resistance and transparency improve, but the material lacks sufficient solubility and processability
Solution Approach 1:
The patent creates a composite material where polysiloxane is combined with acrylic resin and quinone diazide compound in specific proportions. The acrylic resin component provides solubility in organic solvents and ease of coating, while the polysiloxane maintains heat resistance and transparency. The quinone diazide adds photosensitivity for pattern formation. This composite approach balances processability with performance.
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 composition achieves a cured film with excellent planarization, electrical insulation, and chemical resistance, suitable for various optical elements, including LCD and organic EL devices, with improved heat resistance and transparency, reducing signal delay and enhancing image quality.
Implementation Method 1
a compound generating acid or base when exposed to heat or light
Implementation Method 2
a diazonaphthoquinone derivative
Data Source
AI summary
[Object] To provide a composition capable of forming a cured film having low permittivity and excellence in chemical resistance, in heat resistance and in resolution; and further to provide a production process employing the composition. [Means] The present invention provides a composition comprising: an alkali-soluble resin, namely, a polymer comprising a carboxyl-containing polymerization unit and an alkoxysilyl-containing polymerization unit; a polysiloxane; a diazonaphthoquinone derivative; a compound generating acid or base when exposed to heat or light; and a solvent.