Spatial Light Modulator for Nanoimprint Lithography Defect Control
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Solution Overview
Problem
Nanoimprint lithography techniques face challenges in minimizing extrusion and non-fill defects near mesa sidewalls due to stochastic nature and limited adjustability of actinic radiation distribution, which affects the yield and precision of the manufacturing process.
Innovation Solution
A method using a spatial light modulator to control actinic radiation dosage patterns by adjusting duty cycles, transmissivity, or reflectivity of pixels based on defect maps, allowing for precise curing and minimizing defects by generating optimized modulation values for each pixel, thereby improving the dimensional control and reducing extrusion and non-fill defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If actinic radiation is applied uniformly to cure the formable material, then the curing process is simple and fast, but extrusion and non-fill defects occur near mesa sidewalls
Solution Approach 1:
The patent applies local quality by spatially modulating the actinic radiation dosage across different regions of the template. The spatial light modulator creates position-dependent duty cycles, allowing areas near mesa sidewalls to receive reduced radiation dosage while maintaining adequate curing in other regions. This localized control prevents extrusion and non-fill defects specifically where they occur without compromising overall curing efficiency.
Solution Approach 2:
The patent implements dynamics by making the radiation dosage adjustable and time-dependent through duty cycle modulation. Rather than static uniform exposure, the system dynamically controls which pixels are active and for how long, allowing adaptive compensation for defect-prone regions. This dynamic control enables real-time optimization of curing patterns to minimize defects.
2Manufacturing precision
If the duty cycle of spatial light modulator pixels is adjusted to reduce defects, then manufacturing precision improves, but the curing process time increases
Solution Approach 1:
The patent applies partial action by selectively applying reduced radiation dosage only to specific pixels corresponding to defect-prone regions near mesa sidewalls, while maintaining full or higher dosage in other areas. This selective approach achieves dimensional control where needed without unnecessarily extending the curing time for the entire template, thus minimizing overall process time while improving precision.
Solution Approach 2:
The patent implements periodic action through duty cycle modulation, where pixels are activated in periodic on-off sequences rather than continuous exposure. By adjusting the duty cycle (ratio of on-time to total period), the system delivers the required cumulative radiation dosage while allowing temporal spacing that prevents defect formation, achieving both precision and time efficiency.
3Reliability
If actinic radiation dosage is increased to ensure complete curing, then curing reliability improves, but extrusion defects increase near mesa sidewalls
Solution Approach 1:
The patent applies local quality by implementing spatially varying duty cycles that reduce radiation dosage specifically at pixels corresponding to mesa sidewall regions where extrusion defects occur, while maintaining higher or normal dosage in other areas to ensure complete curing. This localized dosage adjustment prevents extrusion without compromising overall curing reliability.
Solution Approach 2:
The patent implements feedback by using a measured map of actual cured regions to generate updated duty cycle adjustments. The system measures the actual curing outcome, compares it to the desired result, and uses this information to refine subsequent radiation patterns, thereby reducing extrusion defects while maintaining curing completeness through iterative optimization.
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
The method effectively reduces the occurrence of extrusion and non-fill defects, enhancing the yield and precision of the nanoimprint lithography process by carefully controlling the actinic radiation dosage, leading to improved manufacturing outcomes.
Implementation Method 1
The spatial light modulator may illuminate a first portion of the formable material under the template to a first actinic radiant dosage pattern in accordance with the map of modulation values producing a first cured film
Data Source
AI summary
Methods and systems that include the generation of a map of modulation values for a spatial light modulator. In which a map representative of a desired curing region is received. Receiving, for each pixel of a spatial light modulator, spatial information representative of an intensity distribution of actinic radiation at a plane of formable material under a template that is guided from the spatial light modulator to the plane of the formable material for curing the formable material under the template. Receiving a dose threshold for the formable material. Generating a map of modulation values for each pixel in the spatial light modulator based on: the dose threshold; the spatial information for all of the pixels; and the map representative of the desired curing region.