Photoresist Composition for Black Matrix Rectangular Patterns
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Solution Overview
Problem
Current methods for forming a black matrix in displays result in a trapezoidal pattern due to insufficient light exposure, leading to reduced image quality and increased line width, as the lower part of the photoresist film is not adequately cured, causing underdevelopment and undercut issues.
Innovation Solution
A photoresist composition comprising 5-10 wt% binder resin, 5-10 wt% photopolymerization monomer, 1-5 wt% photopolymerization initiator (including an oxime ester-based compound) activated in the 400-410 nm wavelength range, 5-10 wt% black coloring agent, and a solvent, applied to a substrate, exposed, and developed to form a fine pattern black matrix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the line width of a mask is decreased to improve resolution, then the image quality requires higher resolution, but the light intensity irradiated in the exposure process is decreased, resulting in insufficient curing of the photoresist
Solution Approach 1:
The patent changes the chemical composition parameters of the photoresist by incorporating specific photopolymerization monomers (acrylate and/or methacrylate groups) and photopolymerization initiators that are highly sensitive to the exposure light wavelength range (380-420 nm). This enables the photoresist to achieve sufficient curing even when the irradiated light intensity is reduced due to narrower mask line widths, thereby resolving the contradiction between improved resolution and reduced illumination intensity.
Solution Approach 2:
The patent uses a composite photoresist system combining binder resin, photopolymerization monomers with specific functional groups (acrylate/methacrylate), and photopolymerization initiators. This composite material formulation enhances the overall photosensitivity and curing efficiency of the photoresist, allowing it to maintain adequate adhesion and pattern formation even under reduced light intensity conditions when using masks with decreased line widths for higher resolution displays.
2Manufacturing precision
If the mask line width is decreased, then higher resolution is achieved, but the lower part of the photoresist film is not adequately cured, causing undercut and trapezoidal shape formation
Solution Approach 1:
The patent modifies the photoresist composition parameters by selecting photopolymerization initiators with high quantum efficiency and appropriate absorption coefficients for the exposure wavelength range (380-420 nm). This ensures that even the lower portions of the photoresist film receive sufficient energy for complete polymerization, preventing undercuring and the resulting undercut defects while maintaining the high resolution enabled by narrower mask line widths.
Solution Approach 2:
The photopolymerization monomers with acrylate and/or methacrylate groups act as intermediaries that facilitate efficient light energy transfer and polymerization reaction. These monomers enhance the propagation rate of the polymerization reaction, ensuring complete curing throughout the photoresist film thickness even when light intensity is reduced due to smaller mask features, thereby preventing undercut formation while achieving high resolution patterns.
3Reliability
If conventional photoresist composition is used, then the photoresist may not be sufficiently cured, but changing the composition to achieve sufficient curing may affect other properties
Solution Approach 1:
The patent optimizes the concentration ratios of key components in the photoresist composition: binder resin (5-20 wt%), photopolymerization monomers (10-40 wt%), and photopolymerization initiator (1-10 wt%). By carefully controlling these parameters, the patent achieves sufficient curing reliability while avoiding excessive complexity in the composition formulation. The specific functional group requirements (acrylate and/or methacrylate) provide a clear guideline for material selection without requiring overly complex multi-component systems.
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 solution enables the formation of a black matrix with a rectangular shape and improved adhesion, reducing taper angles and enhancing image resolution by ensuring uniform curing and pattern precision.
Implementation Method 1
1 wt % to 5 wt % of a photopolymerization initiator activated by light in a wavelength range of 400 nm to 410 nm
Implementation Method 2
photopolymerization initiator activated by light in a wavelength range of 400 nm to 410 nm
Data Source
AI summary
A photoresist composition including 5 wt % to 10 wt % of a binder resin, 5 wt % to 10 wt % of a photopolymerization monomer, 1 wt % to 5 wt % of a photopolymerization initiator comprising an oxime ester-based compound and activated by light in a wavelength range of 400 nm to 410 nm, 5 wt % to 10 wt % of a black coloring agent, and a residual amount of a solvent.