Thiol-ene Resist Composition for High Refractive Index Nanoimprint Lithography
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Solution Overview
Problem
Current nanoimprint lithography (NIL) inks have limitations in achieving high refractive indices (n>1.65) and are not suitable for roll-to-roll processes, with existing materials requiring postannealing steps and being unsuitable for high-resolution patterning of optical devices.
Innovation Solution
A composition comprising a thiol, -ene monomers, a polymerization initiator, and optionally metal oxides, such as TiO2, is used to create a high-refractive-index polymer matrix that can be cured at room temperature without postannealing, achieving refractive indices up to 1.8 and high transparency for nanoimprint processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional NIL inks are used, then the patterning process can be performed, but the refractive index remains limited (n<1.65) and postannealing is required
Solution Approach 1:
The patent changes the chemical parameters of the resist material by using thiol-ene monomers with specific refractive indices (1.6-1.8) in stoichiometric ratios, combined with metal oxide nanoparticles (0.1-50 wt%), to achieve room temperature curing while maintaining high refractive index (n>1.65) without requiring postannealing treatment
Solution Approach 2:
The patent creates a composite resist material combining organic thiol-ene monomers with inorganic metal oxide nanoparticles (TiO2, ZnO, etc.), where the inorganic component provides high refractive index and the organic component enables room temperature photopolymerization, achieving both high optical performance and simplified processing
2Manufacturing precision
If high refractive index materials are used, then optical performance improves, but the materials require postannealing steps that complicate the process
Solution Approach 1:
The patent extracts the postannealing step from the conventional NIL process by designing a resist composition that achieves complete curing through room temperature photopolymerization alone, eliminating the need for subsequent thermal annealing treatment while maintaining high refractive index (n>1.65)
Solution Approach 2:
The patent changes the chemical composition parameters to include thiol-ene monomers with specific refractive indices (1.6-1.8) and metal oxide content (0.1-50 wt%), enabling the material to achieve high optical performance and complete crosslinking at room temperature without requiring postannealing
3Manufacturing precision
If traditional resist materials are used, then patterning can be achieved, but high-resolution patterning for optical devices is not suitable
Solution Approach 1:
The patent optimizes the resist composition parameters including thiol-ene monomer selection (with refractive index 1.6-1.8), stoichiometric ratio (1:1 to 1:4), and metal oxide nanoparticle content (0.1-50 wt%), achieving both high pattern resolution for optical devices and ease of manufacture through room temperature processing
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 the fabrication of nanostructured films with refractive indices greater than 1.65 and high transparency (>90%) without the need for postannealing, suitable for roll-to-roll processes and high-resolution patterning of optical devices.
Implementation Method 1
cured by thermal or radiation energy, e.g., by UV radiation at room temperature with light having a wavelength ranging from 244 nm to 400 nm
Implementation Method 2
at least one metal oxide used in an amount ranging from 0.1 to 50 wt. % per weight of the composition; the thiol and the -ene monomer with a refractive index in the range of 1.6 to 1.8
Data Source
AI summary
Provided is a composition for resist patterning comprising a thiol; at least one -ene monomer; at least one polymerization initiator; and, optionally, a metal oxide used in an amount of 0.1 to 50 wt. % per weight of the composition; the thiol and -ene monomer are used in a stoichiometric ratio with a refractive index between 1.6 and 1.8. The composition is used in a patterning process wherein the composition is dispensed to the substrate, is covered with a mask, and is cured, e.g., by UV radiation, at room temperature with light having a wavelength in the range of 200 nm to 450 nm. The process may be carried out with thermal annealing.