Thiol-ene Prepolymer Composition for Nanoimprint Lithography
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Solution Overview
Problem
Current roll-to-roll nanoimprint lithography processes face challenges in producing sub-nanometer structures reliably and efficiently due to issues with polymer embossing stamps, such as high adhesion with the embossing varnish, limited durability, and slow curing times, which hinder the production of defect-free, high-resolution patterns.
Innovation Solution
A prepolymer composition is developed containing a multifunctional monomer with thiol groups, polymerizable monomers, and a surface-active non-stick additive, which enables rapid UV crosslinking, reduced shrinkage, and improved molding accuracy, allowing for the creation of embossing varnishes that can produce sub-nanometer structures without the need for separate release materials and with enhanced stability and adhesion control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer embossing stamps are used in roll-to-roll nanoimprint lithography, then production costs are reduced and ease of manufacture is improved, but the stamps deform easily and can only be used to a very limited extent, resulting in poor manufacturing precision and limited durability
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and physical properties of the embossing stamp material. It uses a prepolymer composition containing thiol-functionalized oligomers and multifunctional monomers that undergo rapid UV-induced crosslinking, transforming the material from a soft, deformable state to a rigid, dimensionally stable state that maintains submicrometer pattern fidelity
Solution Approach 2:
The patent employs composite materials by combining multiple components in the prepolymer formulation: thiol-functionalized oligomers, multifunctional monomers, photoinitiators, and reactive diluents. This composite system enables simultaneous achievement of low initial viscosity for good mold filling, rapid crosslinking speed, and final dimensional stability for high-precision embossing
2Ease of manufacture
If polymer embossing stamps are used instead of nickel shims, then production costs are reduced, but the stamps are relatively easy to deform and have limited durability
Solution Approach 1:
The patent transforms the mechanical properties of the polymer stamp through controlled chemical reactions. The material starts with appropriate viscosity for manufacturing, then undergoes UV-induced crosslinking that fundamentally changes its mechanical parameters, achieving both the cost advantage of polymer materials and the durability required for multiple embossing cycles
Solution Approach 2:
The patent utilizes a chemical phase transition through UV-induced crosslinking of the prepolymer composition. The material transitions from a mobile, processable liquid state to a rigid, crosslinked solid state, enabling the stamp to be manufactured easily in the liquid form while achieving the durability and dimensional stability of a solid structure for reliable repeated use
3Productivity
If conventional mass printing processes are used, then throughput is extremely high at several 100 m per minute, but the structural resolution range is insufficient for nanometer-scale structures
Solution Approach 1:
The patent replaces conventional mechanical printing processes with a photochemical system. Instead of using mechanical pressure and contact to transfer patterns, it uses UV light-induced crosslinking of a photopolymerizable embossing varnish, enabling nanometer-scale resolution while maintaining continuous roll-to-roll production capability
Solution Approach 2:
The patent utilizes the phase transition of the embossing varnish from liquid to crosslinked solid state upon UV irradiation. This photochemical phase transition allows the formation of high-resolution nanometer-scale structures that would be impossible to achieve with conventional mechanical printing processes, while maintaining high throughput through continuous processing
4Quantity of substance
If polyurethane acrylate oligomers are used in high weight proportion for embossing, then the curing process is slow and the embossing accuracy is relatively low, but they provide the base material for the embossing varnish
Solution Approach 1:
The patent changes the chemical parameters of the oligomer system by introducing thiol functional groups that participate in rapid thiol-ene click chemistry. This modification transforms the curing kinetics from slow radical polymerization to fast click chemistry, achieving complete conversion in seconds even with high oligomer content, thereby maintaining both material performance and high production speed
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 prepolymer composition enables the production of embossing varnishes that can be repeatedly used to create high-resolution patterns with improved molding accuracy and reduced adhesion, facilitating the creation of nanostructured films with low surface energy, thus enabling multiple impressions without defects and maintaining pattern integrity.
Implementation Method 1
at least one photoinitiator is contained
Implementation Method 2
the multifunctional monomer building block contains a multifunctional monomer building block with at least two thiol groups
Data Source
Figure 1~2
Figure 3~4
Figure 5~6b
AI summary
The invention relates to a prepolymer composition containing at least one mono- or oligomer unit with at least one polymerizable C-C double bond and at least one multifunctional monomer unit, said multifunctional monomer unit being a multifunctional monomer unit with at least two thiol groups selected from the group consisting of: 3-mercaptopropionates, 3-mercaptoacetates, thioglycolates and alkyl thiols, that the mono- or oligomer unit with at least one polymerizable double bond is selected from the group consisting of acrylates, methyl acrylates, vinyl ethers, allyl ethers, propenyl ether, alkenes, dienes, unsaturated esters, allyl triazines, allyl isocyanates and N-vinyl amides and that at least one surface-active anti-adhesive additive selected from the group consisting of alkyl(meth)acrylates, polysiloxane (meth)acrylates, perfluoroalkyl(meth)acrylates, perfluoropolyether(meth)acrylates, alkylvinyl ethers, polysiloxane vinyl ethers, perfluoroalkyl vinyl ethers and perfluoropolyether vinyl ethers, as well as a photo-initiator are contained, and use thereof.