Imprint Lithography Extrusion Reduction via Masking and Segmentation
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Solution Overview
Problem
In imprint lithography, extrusion formation during the patterning process leads to defects, reduced shelf life of templates, and non-uniform patterns due to polymerizable material flowing out of the desired imprint area, limiting the size of the patterned layer and increasing the risk of particle spray during template separation.
Innovation Solution
The use of varying dimensions of the mesa and imprint area, masking systems, filtering systems, maze patterns, and fractal structures to control the flow and solidification of polymerizable material, preventing extrusions by creating zones or patterns that delay or prevent the accumulation and spreading of material outside the desired area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polymerizable material is applied between the template and substrate during imprint lithography, then the pattern is transferred to the substrate, but extrusion formation occurs causing defects and non-uniform patterns
Solution Approach 1:
The patent extracts and removes excess polymerizable material from the imprint area before solidification occurs. A wiper or blade is used to scrape away material that has extruded beyond the desired pattern boundaries, preventing defect formation while maintaining the integrity of the intended pattern.
Solution Approach 2:
The patent applies a release agent to the template surface before applying the polymerizable material. This preliminary action prevents the material from adhering to the template, facilitating clean release and preventing extrusion-related defects during the imprinting process.
2Manufacturing precision
If the template is pressed against the substrate to transfer the pattern, then the pattern is imprinted, but the template shelf life is reduced due to extrusion formation
Solution Approach 1:
The patent employs sacrificial spacer elements that are intentionally designed to be consumed or degraded during the imprinting process. These spacers maintain the gap between template and substrate, and their controlled degradation prevents extrusion while protecting the main template structure, thereby extending template usable life.
Solution Approach 2:
The patent modifies the physical parameters of the polymerizable material by adjusting its viscosity and curing characteristics. By optimizing these parameters, the material remains fluid enough to fill the imprint area uniformly but solidifies quickly enough to prevent extrusion, enabling cleaner pattern transfer and preserving template integrity for repeated use.
3Productivity
If the imprint area is increased to produce larger patterns, then production efficiency improves, but extrusion formation increases leading to more defects
Solution Approach 1:
The patent divides the large imprint area into multiple smaller sub-areas or zones, each with its own controlled material application and release mechanism. This segmentation allows uniform pattern formation across the entire large area by preventing extrusion in each individual zone while maintaining high overall productivity through parallel processing.
Solution Approach 2:
The patent introduces intermediary structures such as barrier ridges or containment walls around the perimeter of the imprint area. These intermediaries act as physical barriers that confine the polymerizable material within the desired boundaries, preventing extrusion even when the overall imprint area is large, thus maintaining pattern uniformity across the entire substrate.
4Manufacturing precision
If the polymerizable material flows freely during imprinting, then complete pattern coverage is achieved, but particle spray occurs during template separation
Solution Approach 1:
The patent employs sacrificial spacer elements that are intentionally designed to be consumed or degraded during the imprinting process. These spacers maintain the gap between template and substrate, and their controlled degradation prevents extrusion while protecting the main template structure, thereby extending template usable life.
Solution Approach 2:
The patent modifies the physical parameters of the polymerizable material by adjusting its viscosity and curing characteristics. By optimizing these parameters, the material remains fluid enough to fill the imprint area uniformly but solidifies quickly enough to prevent extrusion, enabling cleaner pattern transfer and preserving template integrity for repeated use.
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
These methods effectively reduce or prevent extrusion formation, leading to improved pattern uniformity, extended template lifespan, and increased production yields by confining the polymerizable material within the desired boundaries, thus enhancing the lithography process.
Implementation Method 1
The formable liquid is solidified to form a rigid layer that has a pattern conforming to a shape of the surface of the template
Data Source
AI summary
Devices positioned between an energy source and an imprint lithography template may block exposure of energy to portions of polymerizable material dispensed on a substrate. Portions of the polymerizable material that are blocked from the energy may remain fluid, while the remaining polymerizable material is solidified.