Metasurface Lens Fabrication via Segmented Image Transfer
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Solution Overview
Problem
The existing methods for fabricating large-scale metasurface lenses face inefficiencies and high costs due to limitations in exposure field size of lithography machines, leading to splicing errors that reduce optical performance.
Innovation Solution
A method involving dividing the metasurface lens image into sub-images and using corresponding masks for image transfer on a wafer, followed by lens fabrication, which includes active alignment to optimize modulation transfer function and splicing, thereby improving efficiency and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If step-scanning lithography is used to fabricate large-scale metasurface lens, then the exposure field size can be extended, but splicing errors increase and optical performance deteriorates
Solution Approach 1:
The patent divides the large-scale metasurface lens pattern into multiple sub-patterns that can be fabricated separately within the limited exposure field, then spliced together. This segmentation approach allows the use of standard lithography equipment while still achieving large-scale fabrication, though it introduces splicing errors at the boundaries between sub-patterns.
Solution Approach 2:
The patent introduces an optical compensation lens as an intermediary element to correct the splicing errors introduced by dividing the pattern into sub-patterns. This compensation lens acts as a mediator that optically compensates for the discontinuities and alignment errors at the splicing boundaries, thereby restoring the overall optical performance.
2Manufacturing precision
If Electron Beam Lithography is used for large-scale pattern, then fabrication precision is maintained, but productivity decreases and cost increases
Solution Approach 1:
The patent segments the large-scale pattern into multiple smaller sub-patterns that can be fabricated using standard step-scanning lithography. This segmentation enables the use of higher-productivity, lower-cost lithography equipment while maintaining acceptable precision through subsequent optical compensation.
Solution Approach 2:
The patent uses optical copying and imaging techniques to transfer the segmented patterns onto the substrate and to create the compensation lens patterns. This optical copying approach is much faster and more cost-effective than electron beam lithography, while the compensation lens ensures the copied patterns achieve the required optical performance.
Data Source
AI summary
A metasurface lens fabrication method includes obtaining a metasurface lens image, dividing the metasurface lens image to obtain at least two sub-images and one or more masks each corresponding to one or more of the at least two sub-images, performing image transfer on a first wafer through the at least two sub-images and the one or more masks to obtain a second wafer with the metasurface lens image, and performing lens fabrication processing on the second wafer to obtain the metasurface lens.