Multi-level optical structures via imprinting and etching
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Solution Overview
Problem
Existing methods for manufacturing multi-level optical structures are limited in their ability to efficiently transfer complex patterns from a tool to a substrate, particularly in high-volume production processes.
Innovation Solution
A method involving a multi-level structured tool that imprints a pixel layout design onto an imprint material on a substrate, followed by selective etching operations to transfer the pattern into an optical sublayer, allowing for the creation of complex optical elements like meta optical elements and diffractive optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-level imprinting methods are used, then the manufacturing process is simple, but the ability to efficiently transfer complex multi-level patterns is limited
Solution Approach 1:
The substrate is divided into multiple sublayers (optical sublayer, first hard mask sublayer, spacer sublayer, second hard mask sublayer) with distinct functions. Each sublayer is selectively etched at different stages to transfer the multi-level pattern precisely, allowing complex patterns to be formed through segmented processing rather than attempting to transfer everything at once.
Solution Approach 2:
The tool is pre-structured with the multi-level pixel layout design before imprinting. The imprint material is prepared with the multi-level structure in advance, and the etching operations are planned in a predetermined sequence. This preliminary preparation enables the complex pattern transfer to proceed efficiently without requiring complex real-time adjustments during the imprinting process.
2Manufacturing precision
If multiple imprinting operations are performed to transfer complex patterns, then the pattern transfer accuracy improves, but the manufacturing time and productivity decrease
Solution Approach 1:
Multiple pattern transfer operations are merged into a single imprinting operation. The multi-level structured tool transfers all required pattern levels simultaneously into the imprint material in one action, rather than requiring multiple separate imprinting steps. This is followed by sequential etching operations that selectively remove materials to reveal the final multi-level structure, achieving both accuracy and efficiency.
3Manufacturing precision
If selective etching operations are used to transfer patterns, then the dimensional accuracy of the optical sublayer is improved, but the number of process steps increases
Solution Approach 1:
Different materials are assigned to different sublayers based on their specific local functions and etching characteristics. The optical sublayer, hard mask sublayers, and spacer sublayer are composed of materials with different etch rates and properties, allowing selective removal of each layer in a controlled sequence. This local differentiation of material properties enables precise dimensional control while maintaining a relatively simple overall process.
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 enables the efficient transfer of multi-level structures with minimal dimensional change, facilitating high-volume production of optical elements with specified optical characteristics and functionality.
Implementation Method 1
the multi-level structured surface of the tool is imprinted into the imprint material by nanoimprint lithography
Implementation Method 2
at least one of the etch operations is an inductively coupled plasma (ICP) etch
Data Source
AI summary
The present disclosure describes optical structures and methods for manufacturing the optical structures. In some implementations, a method includes imprinting a multi-level structured surface of a tool into an imprint material that is disposed on a substrate so that the imprint material is imprinted with a multi-level structure corresponding to the multi-level structured surface of the tool. The substrate includes sublayers disposed on a support, and the sublayers are disposed one atop another and include an optical sublayer on the support, a first hard mask sublayer on the optical sublayer, a spacer sublayer on the first hard mask sublayer, and a second hard mask sublayer on the spacer sublayer. Etching operations subsequently are performed to cause the imprinted multi-level structure to be transferred into the optical sublayer of the substrate.