Ionic Liquid Crystal Layering for Sub-5 Nm Pattern Transfer
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Solution Overview
Problem
Current semiconductor patterning methods face challenges in achieving sub-10 nm feature sizes due to limitations in direct self-assembly of block copolymers and ionic liquid crystals (ILCs), particularly in forming and transferring vertically layered patterns on semiconductor substrates.
Innovation Solution
The method involves depositing an ILC solution on a substrate surface and exposing it to a gas phase, non-polar solvent at a predetermined pressure to promote self-assembly into vertically layered structures, followed by oxidation to convert the tail group layers into a metal oxide pattern, which can be used as a hard mask for pattern transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If direct self-assembly of block copolymers or ionic liquid crystals is used to form patterns, then sub-10 nm feature sizes can be achieved, but the ability to form vertically layered structures for robust pattern transfer is limited
Solution Approach 1:
The patent segments the self-assembly process into two distinct stages: first forming horizontally layered structures during deposition, then transforming them into vertically layered structures through controlled oxidation. This segmentation allows each stage to optimize for its specific function, achieving both sub-10 nm precision and robust pattern transfer capability
Solution Approach 2:
The patent performs preliminary horizontal layer formation during the deposition stage, then uses oxidation as a triggering action to transform these pre-formed structures into the desired vertical configuration. This preliminary action ensures that the material is already organized into layers before the transformation, improving the reliability of the final pattern transfer
2Manufacturing precision
If conventional photolithography is used to reduce feature size, then shorter wavelengths of light must be used, but the minimum feature size is still limited by the wavelength according to the Rayleigh criterion
Solution Approach 1:
The patent replaces the optical imaging system with a self-assembly system that uses molecular interactions and oxidation chemistry to define patterns. This substitution eliminates the diffraction limit inherent in optical systems, enabling sub-10 nm feature sizes without requiring increasingly complex short-wavelength lithography equipment
Solution Approach 2:
The patent changes the fundamental parameter from optical wavelength to molecular scale dimensions. By using the size of individual ionic liquid crystal molecules and their self-assembly behavior, the system achieves resolution determined by molecular dimensions rather than optical diffraction limits, dramatically improving manufacturing precision
3Manufacturing precision
If multi-patterning techniques are used to achieve smaller pitches, then additional process steps are required, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs self-service through direct self-assembly of ionic liquid crystals, where the material automatically organizes into the desired pattern without requiring external guidance or multiple patterning steps. The oxidation process then self-propagates through the material to complete the transformation, eliminating the need for complex multi-patterning workflows
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 the formation of vertically layered ILC structures with alternating layers, allowing for pitch multiplication and robust pattern transfer, overcoming the limitations of existing technologies in achieving sub-5 nm feature sizes.
Implementation Method 1
The gas phase, non-polar solvent promotes self-assembly of the ILCs into a vertically layered structure on the surface of the semiconductor substrate
Implementation Method 2
The vertically layered structure has alternating layers of head group layers and tail group layers, with the anions segregated to the head group layers
Implementation Method 3
followed by oxidation to convert the tail group layers into a metal oxide pattern
Data Source
AI summary
Embodiments of improved methods and processes are provided for patterning a semiconductor substrate using direct self-assembly (DSA) of ionic liquid crystals (ILCs). In the disclosed embodiments, an ILC solution comprising ILCs is deposited on a variety of substrate surfaces. An upper surface of the ILC solution is exposed to a gas phase, non-polar solvent (such as, e.g., hexane gas). The gas phase, non-polar solvent provides an ambient environment that promotes self-assembly of the ILCs into vertically layered ILC structures.