Nanoimprint Lithography Mask Optical Film Coatings
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Solution Overview
Problem
Current nanoimprint lithography (NIL) technologies face challenges in achieving smaller feature sizes and reducing defect levels while maintaining productivity, as existing mask materials and coatings do not effectively optimize exposure radiation intensity and release characteristics.
Innovation Solution
The use of conformal film coatings with higher indices of refraction than the host material, combined with fractional fluorinated hydrocarbon layers, to enhance optical intensity and reduce feature sizes, achieved through processes like Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD), allowing for improved fill and release properties and higher productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask materials and coatings are used, then manufacturing simplicity is maintained, but exposure radiation intensity is insufficient and feature sizes cannot be reduced further
Solution Approach 1:
The patent applies composite materials by combining multiple coating layers with different optical properties on the mask surface. Specifically, it uses a high-index-of-refraction coating layer (e.g., TiO2, SiO2, or Nb2O5) combined with a low-index fluorinated hydrocarbon layer. This composite structure optimizes both the intensity of exposure radiation and the ability to achieve smaller feature sizes by controlling light interference and reflection patterns.
Solution Approach 2:
The patent changes optical parameters by selecting coating materials with specific indices of refraction and controlling layer thicknesses. The high-index layer (n>1.4) is designed with thicknesses between 1-10 nm, while the fluorinated layer thickness is controlled at 0.5-5 nm. These parameter optimizations enable enhanced radiation intensity and reduced feature sizes by manipulating optical interference effects.
2Ease of operation
If fractional fluorine terminated surfaces are used, then release properties are improved, but fill properties and optical intensity optimization are compromised
Solution Approach 1:
The patent segments the coating into functionally distinct layers: a high-index-of-refraction layer optimized for optical intensity enhancement and a separate fluorinated hydrocarbon layer optimized for release properties. This segmentation allows each layer to independently optimize its specific function without compromising the other, enabling simultaneous improvement of fill properties and release characteristics.
Solution Approach 2:
The patent applies local quality by giving different regions of the mask surface different coating compositions. The high-index layer provides localized optical enhancement where needed, while the fluorinated layer provides localized release properties. This spatial differentiation of material properties enables optimization of both fill and release functions in their respective zones.
3Manufacturing precision
If mask feature sizes are reduced, then device density is increased, but defect levels increase and manufacturing difficulty increases
Solution Approach 1:
The patent applies preliminary action by pre-coating the mask surface with optimized optical coatings before the imprinting process. The high-index and fluorinated layers are deposited in advance to create optimal optical and release conditions, which prevents defects during the actual imprinting of small features. This preparatory optimization enables reliable manufacturing of sub-10 nm features.
Solution Approach 2:
The patent changes material parameters by selecting specific coating compositions and thicknesses that optimize performance at reduced feature sizes. The high-index layer thickness (1-10 nm) and fluorinated layer thickness (0.5-5 nm) are precisely controlled to maintain appropriate optical interference effects and release properties even when feature sizes are reduced to 10 nm or below, thereby maintaining low defect levels.
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
Conformal coatings with higher indices of refraction increase exposure radiation intensity within NIL mask features, enabling smaller feature sizes and reduced defect levels, thereby enhancing productivity and process efficiency in NIL.
Implementation Method 1
Optical intensity simulations indicate the possibility that higher index coating materials affect an increase in the intensity of exposure radiation in the region of the NIL mask feature
Implementation Method 2
The mask is then closely coupled to the wafer, touching the photosensitive material and drawing it into the features of the mask by capillary action
Implementation Method 3
In order to promote the separation or release, fluorine terminated surfaces have been proposed
Implementation Method 4
achieved through processes like Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD)
Data Source
AI summary
Structures and associated methods for making smaller physical feature sizes for masks used in imprint lithography for application to patterning for advanced semiconductor and data storage devices.