Stripping Composition for Color Resist Removal
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Solution Overview
Problem
Current methods for removing color resist and organic insulating films from substrates are inefficient, leading to discarded substrates and safety concerns due to the use of hazardous chemicals and complex, expensive equipment, especially for negative type resist films.
Innovation Solution
A stripping composition comprising 0.5 to 45 wt % hydroxide compound, 10 to 89 wt % alkyleneglycolalkylether compound, 5 to 45 wt % alkanolamine compound, and 0.01 to 5 wt % inorganic salt compound is used to effectively remove color resist or organic insulating films without damaging the substrate, allowing for substrate reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional inorganic stripping solutions (sulfuric acid, nitric acid, fuming sulfuric acid, mixed solution of nitric acid and hydrogen peroxide) are used to remove color resist, then stripping capability is achieved, but safety risks increase due to heating to 120°C or more and hazardous chemical handling
Solution Approach 1:
The patent changes the chemical parameters of the stripping solution by using an organic solvent system (acetonitrile, dimethylformamide, or a mixture thereof) with specific concentration ranges (5-50 vol%) combined with amine compounds and hydroxide compounds. This parameter change allows effective stripping at lower temperatures (room temperature to 100°C) without the extreme heating and hazardous chemicals of conventional methods, thus reducing safety risks while maintaining stripping capability.
Solution Approach 2:
The patent employs readily available, less hazardous organic solvents and common chemical compounds (acetonitrile, dimethylformamide, amine compounds, hydroxide compounds) that can be easily handled and disposed of, replacing expensive and hazardous inorganic stripping solutions. These materials are safer for user handling, require less specialized equipment, and can be disposed of more environmentally friendly, thereby reducing safety risks and operational complexity.
2Reliability
If RIE method using plasma is used to remove cured color resist, then removal capability is achieved, but device complexity and cost increase due to high vacuum, high energy requirements, difficult process control, expensive equipment, and limited applicability to wide areas
Solution Approach 1:
The patent replaces the complex mechanical and physical plasma RIE system with a simpler chemical solution-based stripping method. Instead of using high-energy plasma, vacuum systems, and complex reaction chambers, the invention uses a chemically active organic solvent solution that can be applied directly to the substrate. This substitution eliminates the need for high vacuum equipment, plasma generation systems, and complex process control mechanisms, thereby reducing device complexity and cost while maintaining effective removal capability.
Solution Approach 2:
The patent introduces organic solvent compounds (acetonitrile, dimethylformamide) as intermediary substances that facilitate the stripping process. These intermediaries dissolve or swell the cured color resist material, enabling its removal through chemical action rather than physical plasma etching. This intermediary approach simplifies the overall process by using readily available chemicals that can be applied in simple liquid form, avoiding the need for complex plasma generation and vacuum systems.
3Device complexity
If conventional wet etching methods are used to remove color resist, then stripping process is simplified, but stripping performance is insufficient for negative type resist films
Solution Approach 1:
The patent creates a composite stripping solution system combining multiple components: organic solvents (acetonitrile, dimethylformamide), amine compounds, and hydroxide compounds in specific proportions. This composite formulation synergistically enhances the stripping performance on negative type resist films by combining the solventing action of organic compounds with the swelling and dissolving effects of amine and hydroxide compounds. The composite approach maintains process simplicity while achieving superior stripping performance compared to single-component conventional wet etching solutions.
Solution Approach 2:
The patent modifies the chemical parameters of the stripping solution by adjusting the concentration ranges of organic solvents (5-50 vol%), amine compounds (5-45 wt%), and hydroxide compounds (0.5-45 wt%). These parameter optimizations enhance the solution's ability to penetrate, swell, and dissolve the crosslinked polymer structure of cured negative type resist films. By tuning these chemical parameters, the solution achieves effective stripping performance while maintaining the simplicity of a liquid-based wet etching process.
4Productivity
If color resist is removed to enable substrate reuse, then productivity improves, but substrate damage occurs especially to metal electrodes containing Al
Solution Approach 1:
The patent uses organic solvent compounds (acetonitrile, dimethylformamide) as intermediary substances that selectively interact with the color resist material. These intermediaries provide a controlled chemical environment that swells and dissolves the resist without directly attacking or corroding the metal electrode layers underneath. The amine and hydroxide compounds act as additional intermediaries that facilitate selective removal of the resist while protecting sensitive substrate materials, thereby enabling substrate reuse without damage to aluminum electrodes or other metal layers.
Solution Approach 2:
The patent optimizes the chemical parameters of the stripping solution, including the concentration ranges of organic solvents (5-50 vol%), amine compounds (5-45 wt%), and hydroxide compounds (0.5-45 wt%), to achieve selective stripping. These parameter adjustments create a chemical environment that is aggressive enough to remove cured negative type resist but controlled enough to protect underlying metal electrodes. The specific combination and concentration of these compounds ensure that the stripping action is confined to the resist layer, preventing penetration and damage to sensitive substrate materials, thus enabling safe substrate reuse.
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 enables easy and safe removal of color resist and organic insulating films, preventing damage to the substrate and reducing waste, while improving productivity and safety by using a more efficient and environmentally friendly process.
Implementation Method 1
10 to 89 wt % of an alkyleneglycolalkylether compound, 5 to 45 wt % of an alkanolamine compound
Implementation Method 2
The composition enables easy and safe removal of color resist and organic insulating films
Implementation Method 3
0.5 to 45 wt % of a hydroxide compound, 0.01 to 5 wt % of an inorganic salt compound
Data Source
AI summary
The present invention provides a stripping composition and a stripping method capable of easily stripping a color resist or an organic insulating film formed on a substrate to reuse the substrate when defects are found during a process of forming the color filter or organic insulating film on the substrate. In one embodiment, the stripping composition includes about 0.5 to about 45 wt % of hydroxide compound, about 10 to about 89 wt % of alkyleneglycolalkylether compound, about 5 to about 45 wt % of alkanolamine compound, and about 0.01 to about 5 wt % of inorganic salt compound. Advantageously, the stripping process can be performed without damaging a thin film transistor of a bottom substrate while removing the color resist or organic insulating film.