Anisotropic Nanocrystal Hard Masks for Sub-5 nm Pattern Transfer
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Solution Overview
Problem
Current nanofabrication methods are inadequate for patterning features below 5 nm, struggling with high-fidelity pattern transfer of sub-5 nm critical dimensions, high feature density, and discrete anisotropic features, particularly in colloidal lithography and block copolymer directed self-assembly techniques.
Innovation Solution
The use of monodisperse, anisotropic nanocrystals with a rhombic plate morphology and dendrimer ligands for colloidal lithography, allowing for the formation of well-ordered monolayers that serve as hard masks for dry etching and subsequent pattern transfer into substrates with sub-5 nm feature sizes, leveraging the high etch selectivity of rare-earth fluoride materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional colloidal lithography uses close-packed spherical nanocrystals, then isotropic features with hexagonal ordering can be achieved, but sub-5 nm critical dimensions and anisotropic features cannot be realized
Solution Approach 1:
The patent employs anisotropic nanocrystals with non-spherical shapes (such as rods, plates, or prisms) instead of conventional spherical nanocrystals. This asymmetry in particle morphology enables the formation of anisotropic patterns with directional features, achieving both sub-5 nm critical dimensions and discrete anisotropic features that were previously incompatible
Solution Approach 2:
The patent applies different surface ligands or functionalizations to specific regions or orientations of the anisotropic nanocrystals, enabling selective assembly behaviors and pattern formation. This local differentiation allows control over both the critical dimension and the anisotropic morphology simultaneously
2Manufacturing precision
If block copolymer DSA is used for sub-20 nm patterning, then high resolution can be achieved, but pattern transfer struggles due to low etch selectivity and requires sequential infiltration synthesis
Solution Approach 1:
The patent uses inorganic nanocrystals as disposable masks that can be directly etched away after pattern transfer, eliminating the need for complex sequential infiltration synthesis procedures required by block copolymer DSA. The nanocrystals serve their masking function and are then removed, simplifying the overall process
Solution Approach 2:
The patent changes the material parameter from organic block copolymers to inorganic nanocrystals, which fundamentally alters the etch selectivity characteristics. The inorganic nanocrystals provide high etch selectivity against common substrate materials, enabling direct pattern transfer without additional infiltration steps
3Productivity
If photolithography is used for high-throughput patterning, then large area coverage can be achieved, but resolution below 5 nm is not reliably attainable
Solution Approach 1:
The patent employs self-assembly of nanocrystals into ordered monolayers and multilayers, where the nanocrystals spontaneously organize into periodic structures through entropy-driven processes. This self-service mechanism enables high-resolution sub-5 nm patterning across large areas without requiring complex lithographic equipment, maintaining both throughput and precision
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 high-fidelity pattern transfer with sub-5 nm critical dimensions and high feature density, integrating bottom-up synthesis with top-down etching to achieve anisotropic features, overcoming the limitations of existing methods by minimizing process complexity and enhancing etch selectivity.
Implementation Method 1
disposing a nanoparticle composition (that comprises nanoparticles) on a support material... the nanoparticle composition defines a patterned region
Implementation Method 2
selectively etching the support material so as to give rise to in the support material a plurality of arrayed structures
Data Source
AI summary
A patterning method, comprising: disposing a nanoparticle composition on a support material, the disposing being performed such that the nanoparticle composition defines a patterned region having an average inter-nanoparticle distance of less than about 5 nm; and selectively etching the support material so as to give rise to in the support material a plurality of arrayed structures substantially in register with the patterned region of the nanoparticle composition.An article, comprising an article made according to the present disclosure.A workpiece, comprising: an etchable support material; and a nanoparticle composition, the nanoparticle composition being disposed on the support material as a monolayer, the nanoparticle composition defining a patterned region having an average inter-nanoparticle distance of less than about 5 nm, and nanoparticles of the nanoparticle composition having ligands disposed thereon.An article, comprising: a substrate, the substrate having formed therein a plurality of structures arranged arrayed periodically, the structures defining an average inter-structure spacing of less than about 5 nm.