Elastomeric Tip Array for Sub-Diffraction Lithography
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Solution Overview
Problem
Conventional lithography techniques face limitations in achieving sub-diffraction limit feature sizes and arbitrary nanoscale pattern formation due to diffraction limits and the need for specialized equipment, while existing near-field scanning optical microscopy methods are low throughput and challenging to align over large areas.
Innovation Solution
A method involving a tip array with translucent, elastomeric tips and a blocking layer, where apertures are defined to channel radiation for patterning, allowing for sub-micron scale patterning over large areas with flexible pattern design and low fabrication costs, enabling arbitrary feature creation without the need for photomasks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional far-field optical lithography is used, then standard optical instrumentation and light sources are available, but lateral feature resolution is diffraction-limited to approximately half the incident wavelength
Solution Approach 1:
The patent transitions from far-field optical lithography to near-field scanning optical microscopy (NSOM), utilizing evanescent electromagnetic fields that decay exponentially with distance. This dimensional shift from propagation-based optics to near-field coupling enables sub-diffraction limit resolution by confining light to the nanoscale interaction region between the aperture and substrate.
Solution Approach 2:
The patent introduces a sub-diffraction aperture as an intermediary element that couples evanescent fields to the substrate. This aperture acts as a light pipe, confining and directing electromagnetic energy to achieve sub-wavelength feature sizes while maintaining compatibility with standard optical instrumentation.
2Manufacturing precision
If NSOM-based techniques are used to achieve sub-diffraction limit patterning, then feature size is reduced below diffraction limit, but throughput is low and scan area is restricted to several hundred microns
Solution Approach 1:
The patent divides the scanning probe into an array of multiple probes arranged in a grid pattern. Each probe can independently scan and pattern a portion of the substrate, allowing parallel processing of multiple regions simultaneously. This segmentation of the single-probe system into a multi-probe array directly increases throughput while maintaining sub-diffraction limit resolution at each probe tip.
3Manufacturing precision
If hard non-deformable aperture arrays are used for NSOM, then sub-diffraction patterning is enabled, but aligning large area substrate surface with near-field proximity remains challenging
Solution Approach 1:
The patent replaces rigid hard aperture arrays with soft, deformable polymer probes that can be brought into close proximity with the substrate surface. The flexible nature of the polymer tips allows them to conform to surface variations and maintain consistent near-field coupling over large areas, eliminating the alignment challenges associated with rigid aperture arrays.
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
Enables high-throughput, flexible, and cost-effective sub-micron patterning with precise control over feature size and geometry, surpassing the diffraction limit and allowing for complex patterns on large areas, including arbitrary geometries.
Implementation Method 1
The tip substrate layer and the plurality of tips are at least translucent, e.g. permitting transmission of light of a desired wavelength for patterning
Implementation Method 2
SNP optics rely on the evanescent field of incident light passing through an aperture, the intensity of which is strongly dependent on the distance between this aperture and the surface
Implementation Method 3
a blocking layer coated on the first surface of the substrate layer including the plurality of tips, and a plurality of apertures defined in the blocking layer exposing the tip ends of the plurality of tips
Data Source
AI summary
The disclosure relates to methods of beam pen lithography using a tip array having a plurality of transparent, elastomeric, reversibly-deformable tips coated with a blocking layer and apertures defined in the blocking layer to expose tip ends of the tips in the array. The tip array can be used to perform a photolithography process in which the tips are illuminated with a radiation that is channeled through the tips and out the apertures to expose a photosensitive substrate. Also disclosed are tip arrays formed of polymers and gels, apparatus including the tip arrays and radiation sources, and related apparatus for selectively masking tips in the tip array from radiation emitted from the radiation source.