Positive Photosensitive Siloxane Composition for High-Temperature Planarization
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Solution Overview
Problem
Current photosensitive siloxane compositions for planarization films in TFT substrates face issues with high temperature resistance, pattern sagging, and low sensitivity, particularly when used in heat curing processes, leading to deterioration in film thickness and transmittance, and increased parasitic capacitance in liquid crystal displays.
Innovation Solution
A positive photosensitive siloxane composition comprising two kinds of polysiloxanes with different dissolution rates in tetramethylammonium hydroxide aqueous solution, combined with a diazonaphthoquinone derivative, which prevents pattern sagging and enhances sensitivity and resolution without the need for cross-linkers or high molecular weight siloxanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If acrylic resin materials are used for planarization films, then ease of manufacture is improved, but heat resistance deteriorates at temperatures of 230°C or more causing decomposition, film thickness reduction, and transmittance deterioration
Solution Approach 1:
The patent changes the chemical composition parameters by using siloxane resin instead of acrylic resin, and by controlling the molecular weight and hydroxyl group content of the siloxane resin. This transformation allows the material to maintain stability at high temperatures (230°C or more) while remaining manufacturable through conventional coating and curing processes.
Solution Approach 2:
The patent creates a composite photosensitive composition by combining siloxane resin with specific photosensitive components (naphthoquinone diazide compounds and sulfonic acid esters). This composite approach achieves both heat resistance and photosensitivity, resolving the contradiction between ease of manufacture and heat resistance.
2Temperature
If polysiloxane is used as a photosensitive composition component, then heat resistance is improved, but dissolution rate in developer becomes insufficient requiring higher molecular weight or cross-linkers which causes pattern sagging
Solution Approach 1:
The patent optimizes the molecular weight parameter of the siloxane resin to be 10,000 or less, and controls the hydroxyl group content within specific ranges. These parameter changes enable the polysiloxane to dissolve at appropriate rates in TMAH developer without requiring cross-linkers or high molecular weight variants, thus preventing pattern sagging while maintaining heat resistance.
Solution Approach 2:
The patent introduces local quality by specifying particular functional groups (hydroxyl groups) and their controlled concentrations within the siloxane resin structure. This localized functional modification enables selective dissolution control in the developer while preserving the overall heat-resistant properties of the siloxane backbone.
3Temperature
If heat resistant acrylic materials are used, then temperature resistance is improved, but dielectric constant increases causing larger parasitic capacitance and higher electricity consumption
Solution Approach 1:
The patent changes the base material from acrylic resin to siloxane resin, fundamentally altering the dielectric properties. The siloxane resin structure inherently provides lower dielectric constant while maintaining heat resistance, thus reducing parasitic capacitance and electricity consumption in display devices.
4Measurement precision
If complicated photosensitive composition systems are used, then sensitivity is improved, but organic compound content increases causing coloration and gas generation at high temperatures
Solution Approach 1:
The patent extracts and eliminates unnecessary organic compounds from the photosensitive composition system. By using a simplified system with siloxane resin combined with specific photosensitive components (naphthoquinone diazide and sulfonic acid esters), it achieves adequate sensitivity without the coloration and gas generation problems caused by excessive organic content at high temperatures.
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 high sensitivity, resolution, and residual film thickness with excellent heat resistance and transparency, suitable for various applications including TFT substrates, interlayer dielectric films, and optical devices.
Implementation Method 1
a positive photosensitive siloxane composition comprising (I) two kinds or more of polysiloxanes which have different dissolution rates in a tetramethylammonium hydroxide aqueous solution each other, (II) a diazonaphthoquinone derivative, and (III) solvent
Implementation Method 2
two kinds or more of polysiloxanes which have different dissolution rates in a tetramethylammonium hydroxide aqueous solution each other
Data Source
AI summary
A positive photosensitive siloxane composition containing: a polysiloxane (Ia), which is obtained by hydrolyzing and condensing the silane compound represented by RSi(OR1)3 in general formula (1) and the silane compound represented by Si(OR1)4 in general formula (2) in the presence of a basic catalyst, and a pre-baked film of which has a dissolution rate of 1,000 Å/second or less in a 5 wt % TMAH aqueous solution; a polysiloxane (Ib), which is obtained by hydrolyzing and condensing at least the silane compound represented by general formula (1) in the presence of an acid or basic catalyst, and a pre-baked film of which has a dissolution rate of 100 Å/second or more in a 2.38 wt % TMAH aqueous solution; and a diazonaphthoquinone derivative and solvent. (In the formula: R represents a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, in which any methylene may be replaced by oxygen, or represents an aryl group having 6 to 20 carbon atoms, in which any hydrogen may be replaced by fluorine; and R1 is an alkyl group having 1 to 5 carbon atoms.)