Variable-Depth Nanoimprint Master Template for Precise Height Grading
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Solution Overview
Problem
Current nanoimprint lithography methods require multiple and complex photolithography steps to replicate features with varying depths, which are time-consuming and expensive, and substrates may not be compatible with CMOS processing, complicating the manufacturing process.
Innovation Solution
A method for producing a master template with variable height features using a layer stack comprising a substrate, etch stop layer, and pattern layer, with height gradation created through lithography and etching processes, allowing precise patterning and integration of continuous height variation and multiple features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple photolithography steps are used to replicate features with varying depths, then manufacturing precision is improved, but device complexity and production time increase
Solution Approach 1:
The patent segments the master template fabrication into distinct functional layers: a substrate layer, a pattern layer with variable depth features, and an imprint layer. This segmentation allows each layer to be optimized independently, enabling complex variable depth features to be created through simpler, separate processing steps rather than requiring multiple photolithography cycles on a single layer.
Solution Approach 2:
The patent introduces vertical dimensionality by creating a multi-layer structure where the pattern layer is deposited on top of the substrate at varying heights. This dimensional approach allows variable depth features to be formed by controlling the thickness and positioning of the pattern layer, rather than relying on complex lateral patterning processes.
2Manufacturing precision
If multiple photolithography steps are used to replicate features with varying depths, then manufacturing precision is improved, but production time increases
Solution Approach 1:
The patent performs preliminary actions by pre-forming the variable depth structure in the pattern layer before the actual imprint process. The pattern layer is prepared with the desired height variations through deposition and planarization steps, so that during imprinting, the variable depth features are transferred directly without requiring additional photolithography steps, thereby accelerating production.
Solution Approach 2:
The patent merges the master template fabrication and the feature replication into a single integrated process. By incorporating the variable depth features directly into the master template structure, the patent combines what would traditionally be separate fabrication and imprinting steps into one unified process, significantly reducing production time.
3Manufacturing precision
If conventional photolithography tools are used for substrates incompatible with CMOS processing, then manufacturing precision is maintained, but ease of manufacture decreases
Solution Approach 1:
The patent creates a universal master template structure that can be used with various substrate types, including both CMOS-compatible and non-CMOS substrates. The pattern layer and imprint layer are designed to be substrate-agnostic, allowing the same fabrication approach to work across different material systems, thereby improving ease of manufacture without sacrificing patterning accuracy.
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 efficient and precise fabrication of complex nano-structured devices with improved uniformity and efficiency in diffraction-based waveguide displays, compatible with CMOS materials and standard manufacturing technologies.
Implementation Method 1
the pattern may be provided by applying a lithographic process to the height graded pattern layer
Implementation Method 2
forming the master template by providing a pattern comprising a plurality of features into the height graded pattern layer
Data Source
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Figure 3~5
AI summary
A method for producing a master template with variable height features for imprint lithography on a device substrate includes providing a layer stack comprising a substrate, an etch stop layer on the substrate, and a pattern layer on the etch stop layer. The method involves creating height gradation in the pattern layer to obtain a height graded pattern layer, forming the master template by providing a pattern comprising a plurality of features into the height graded pattern layer. This method enables the production of features with varying heights, which can be particularly useful in applications such as optical devices where such features may influence the functionality and efficiency of the device.