Imprint Lithography Template Fabrication via Master Copying
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Solution Overview
Problem
Current imprint lithography techniques face limitations in achieving high resolution and overlay accuracy due to the deformation of soft imprint templates and the need for expensive optics and materials in optical lithography, as well as the complexity and cost of electron beam lithography for template fabrication.
Innovation Solution
A method involving the use of a planarization layer and an imprintable medium on a substrate, where a master imprint template is used to imprint a pattern, followed by polymerization and etching to transfer the pattern to the substrate, creating an imprint template that can be used for either inverse or corresponding patterns, thereby reducing the reliance on expensive equipment and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electron beam lithography is used to fabricate imprint templates, then high resolution patterns can be achieved, but the process becomes time consuming and expensive
Solution Approach 1:
The patent uses a master imprint template to create multiple imprinted templates through a copying process. The master template is imprinted into an imprintable medium multiple times, creating replicas that can be used for production. This copying approach allows one high-precision master (fabricated by e-beam) to generate many production templates, improving overall productivity while maintaining the resolution benefits of the master template.
Solution Approach 2:
The template fabrication process is segmented into two distinct stages: (1) creating a single master template using electron beam lithography for high precision, and (2) using the master template to imprint multiple production templates. This segmentation allows the expensive, slow e-beam process to be used only once for the master, while the faster imprinting process handles mass production of templates.
2Manufacturing precision
If optical lithography is used to achieve higher resolution, then sub-100 nm features can be printed, but expensive optics, advanced illumination sources and specialised resist materials are required
Solution Approach 1:
The patent replaces the complex optical lithography system with a mechanical imprinting system. Instead of using light, lenses, and specialized resists, the invention uses a physical master template that is mechanically pressed into an imprintable medium. This mechanical approach achieves the same sub-100 nm resolution without requiring expensive optics or specialized materials, as the pattern is transferred through direct physical contact rather than optical projection.
3Ease of manufacture
If soft imprint templates are used, then the fabrication process is simpler, but overlay accuracy deteriorates due to template deformation
Solution Approach 1:
The patent performs preliminary hardening of the imprintable medium through UV curing before the imprinting process. By pre-polymerizing the imprintable medium, the template gains rigidity and resistance to deformation during subsequent imprinting operations. This preliminary action ensures that the template maintains its dimensional stability and overlay accuracy while still allowing for relatively simple fabrication processes.
Solution Approach 2:
The patent changes the physical state of the imprintable medium from soft and deformable to rigid and stable through UV polymerization. This parameter change occurs in stages: initial curing provides enough rigidity for accurate imprinting, while the process remains simpler than traditional hard template fabrication. The chemical transformation of the material properties resolves the contradiction between ease of manufacture and manufacturing precision.
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
This approach allows for the creation of imprint templates with improved resolution and accuracy, reducing the need for complex optics and specialized materials, and lowering the cost of template fabrication while maintaining high overlay precision.
Implementation Method 1
polymerizing the imprintable medium by exposing it to actinic radiation
Data Source
AI summary
A method of making an imprint template includes providing a transfer layer on a substrate and providing a layer of imprintable medium on the transfer layer, using a master imprint template to imprint a pattern into the imprintable medium, polymerizing the imprintable medium by exposing it to actinic radiation, then etching the resulting polymer layer, the transfer layer and the substrate such that the imprinted pattern is transferred to the substrate, the substrate thereby becoming an imprint template bearing a pattern which is the inverse of a pattern provided on the master imprint template.