Imprint Lithography Void Detection via Optical Feedback
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Solution Overview
Problem
Imprint lithography methods face challenges in reducing the time required to fill voids between the imprintable liquid medium and the patterned surface, leading to low throughput rates and potential defects in the resulting patterned layer, especially in UV-imprint lithography techniques like SFIL.
Innovation Solution
The method involves measuring light emergent from the interface between the imprintable liquid medium and the patterned surface during the filling period to obtain data on voids, deriving an estimated end time for filling based on this data, and adjusting the processing steps accordingly, allowing for earlier commencement of curing or further processing without increasing defect levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the filling period is extended to ensure complete filling of voids, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
The system uses an optical sensor to detect the presence of voids at the interface between the imprintable liquid medium and the patterned surface during the filling period. This real-time feedback allows the system to monitor filling progress and determine when filling is complete, enabling precise control of the filling period duration to avoid both incomplete filling and excessive waiting time.
Solution Approach 2:
The optical detection system is positioned to monitor the filling process in advance, allowing the system to detect voids before they become defects in the cured layer. By detecting voids during the filling period and adjusting the process accordingly, the system ensures complete filling without requiring excessive filling time.
2Productivity
If the filling period is shortened to increase throughput, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
The optical sensor provides real-time feedback on void presence during the filling period, allowing the system to determine the exact moment when filling is complete. This enables the system to use the minimum necessary filling time to achieve complete filling, maximizing throughput without sacrificing filling completeness.
3Manufacturing precision
If the holding period is extended to ensure proper curing, then manufacturing precision is improved, but productivity deteriorates
Solution Approach 1:
By using optical detection to confirm complete filling before initiating the holding period for curing, the system ensures that the holding period only needs to accommodate the curing process itself, not also compensate for incomplete filling. This reduces the required holding period duration while maintaining curing quality.
4Manufacturing precision
If real-time monitoring is implemented to detect voids, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical or computational void detection methods with a simple optical sensor that detects voids based on light transmission or reflection differences. This optical approach provides accurate void detection during the filling period with minimal added system complexity.
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 reduces the filling and holding periods, enhancing the throughput of the imprint lithography process while minimizing defects by ensuring voids are filled efficiently, allowing for more rapid separation of the imprint template and substrate without increasing defect rates.
Implementation Method 1
measuring light emergent from an interface between the imprintable liquid medium and the patterned surface during the filling period to obtain data concerning one or more voids at the interface
Implementation Method 2
illuminating the UV-curable imprintable liquid medium with UV-radiation for an illumination period
Data Source
AI summary
An imprint lithography method is disclosed for forming a patterned layer from an imprintable liquid medium on a substrate by means of an imprint template having a patterned surface. The method involves contacting the patterned surface and imprintable liquid medium together for a filling period. Light emergent (e.g., scattered or reflected) from an interface between the medium and the patterned surface is collected and measured during the filling period to obtain data concerning one or more voids at the interface, and an estimated end time for the filling period is derived from a relationship between the data and time. The method may allow subsequent process steps to be undertaken more rapidly, with reduced risk of defects arising from remnants of unfilled voids. An imprint lithography apparatus and component for putting the method into effect are also disclosed.