Imprint Lithography Composition for Low Viscosity and High Strength
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Solution Overview
Problem
Current imprint lithography materials face challenges in achieving optimal release characteristics, low viscosity, low vapor pressure, and sufficient mechanical strength for forming fine-feature relief patterns without distortion, especially in micro-fabrication processes.
Innovation Solution
A composition incorporating a surfactant, polymerizable component, and initiator, with a viscosity below 100 centipoises in a liquid state, vapor pressure less than 20 Torr, and a solid cured state with a tensile modulus of over 100 MPa, break stress greater than 3 MPa, and elongation at break of more than 2%, facilitating efficient filling and pattern transfer with minimal distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the viscosity of the polymerizable fluid composition is reduced to enable fast spreading and filling of relief patterns, then the material can rapidly fill fine features with minimal pressure, but the cohesive strength of the cured material may be compromised
Solution Approach 1:
The patent changes the chemical composition parameters of the polymerizable fluid to achieve low viscosity while maintaining strength. Specifically, it uses monomers with low glass transition temperatures and specific functional groups that provide both fluidity and strong crosslinking capability upon curing, resolving the contradiction between fast spreading and cohesive strength
Solution Approach 2:
The patent creates a composite material system combining multiple monomers, oligomers, and crosslinking agents in specific ratios. This composite formulation allows the material to exhibit low viscosity in liquid state for rapid filling while forming a robust crosslinked network in cured state, simultaneously satisfying both requirements
2Loss of substance
If the vapor pressure of the imprinting material is reduced to minimize evaporation, then material loss is reduced, but the viscosity may increase slowing down the filling process
Solution Approach 1:
The patent carefully selects monomers and additives with appropriate vapor pressure parameters. By choosing compounds with moderate molecular weights and specific functional groups, the formulation achieves low vapor pressure to minimize evaporation while maintaining sufficiently low viscosity for rapid filling through optimized chemical structure
3Manufacturing precision
If the composition is designed to adhere well to the transfer layer, then pattern fidelity is improved, but release from the imprint template becomes more difficult
Solution Approach 1:
The patent applies local quality by designing the polymerizable fluid composition to have different adhesion characteristics for different surfaces. The composition contains surfactants and adhesion promoters that selectively enhance bonding to the transfer layer while maintaining compatibility with release coatings on the template, achieving both pattern fidelity and easy release
Solution Approach 2:
The patent introduces surfactants and coupling agents as intermediary substances in the composition. These intermediaries facilitate strong adhesion to the transfer layer through chemical bonding while simultaneously providing good interfacial compatibility with the release coating, resolving the adhesion-release contradiction
4Device complexity
If minimal pressure is applied to move the material into the relief pattern, then device complexity is reduced, but the material may not fill fine features adequately
Solution Approach 1:
The patent changes the rheological parameters of the material by formulating it with low viscosity monomers and oligomers. This enables the material to flow into fine relief features under minimal pressure (2-4 psi) without requiring complex pressure control systems, simultaneously simplifying the device and ensuring complete feature filling
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 material ensures high fidelity in imprint lithography by providing excellent release characteristics, rapid spreading, and robust mechanical properties, enabling the formation of precise patterns with minimal distortion and operational simplicity, even for small features.
Implementation Method 1
an initiator responsive to a stimuli to vary the viscosity in response thereto
Implementation Method 2
subjecting the polymerizable fluid composition to conditions to solidify and to polymerize the same (typically, exposing the polymerizable fluid composition to UV to crosslink it)
Data Source
AI summary
The present invention is directed to a material for use in imprint lithography that features a composition having a viscosity associated therewith and including a surfactant, a polymerizable component, and an initiator responsive to a stimuli to vary the viscosity in response thereto, with the composition, in a liquid state, having the viscosity being lower than about 100 centipoises, a vapor pressure of less than about 20 Torr, and in a solid cured state a tensile modulus of greater than about 100 MPa, a break stress of greater than about 3 MPa and an elongation at break of greater than about 2%.