Selective Nanostructure Etching Using Inclined Surface Masking
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Solution Overview
Problem
Existing methods struggle to fabricate semiconductor devices with lateral sizes below 20 nm due to limitations in spatial resolution of ultraviolet lithography, necessitating alternative approaches for precise nanostructure fabrication.
Innovation Solution
A method involving selective dry etching using a low energy particle beam perpendicular to the main surface of nanostructures with inclined surfaces, allowing for maskless fabrication by utilizing inclined surfaces as a natural mask, reducing the need for lithography and multiple patterning steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultraviolet lithography is used for manufacturing semiconductor devices, then the manufacturing process is established and reliable, but the spatial resolution is limited and cannot achieve lateral sizes below 20 nm
Solution Approach 1:
The patent replaces the optical lithography system with a particle beam-based dry etching system. Instead of using ultraviolet light to define patterns, the invention uses a particle beam to directly etch the desired nanostructure patterns into the semiconductor material, substituting an optical-mechanical system with a particle-matter interaction system that achieves higher spatial resolution
Solution Approach 2:
The invention changes the fundamental parameter of the fabrication process from optical wavelength (limiting resolution) to particle beam energy and angular distribution. By controlling particle beam parameters such as energy (50-500 eV), angular distribution (narrow cone), and incidence angle, the process achieves lateral resolutions below 20 nm that are impossible with ultraviolet lithography
2Manufacturing precision
If multiple patterning steps are used to achieve sub 20 nm features, then the manufacturing precision is improved, but the productivity decreases and production costs increase
Solution Approach 1:
The invention segments the fabrication process into a single direct patterning step using particle beam etching, eliminating the need for multiple sequential patterning steps. Each particle beam exposure directly creates the final sub-20 nm pattern, rather than requiring multiple lithography and etching cycles to achieve the same resolution
Solution Approach 2:
The particle beam etching process performs the patterning action directly and completely in one step, preparing the final structure without requiring subsequent refinement steps. The inclined surfaces are formed with precise angles during the initial etching process itself, eliminating the need for additional alignment and patterning operations
3Productivity
If high energy particle beams are used for etching, then the etching rate increases, but the damage to the nanostructure increases
Solution Approach 1:
The invention optimizes the particle beam energy parameter to a specific range (50-500 eV, preferably 100-300 eV) that balances etching efficiency with structure preservation. This energy range provides sufficient momentum for material removal while avoiding the high-energy damage mechanisms that occur at higher energies, such as atomic displacement and defect generation
Solution Approach 2:
The etching process uses periodic pulsed particle beam exposure rather than continuous high-energy bombardment. This allows the material to be removed in controlled increments, with brief intervals that prevent excessive heat accumulation and structural damage, maintaining both etching rate and structure integrity
4Ease of operation
If conventional lithography is used, then the process is simple and easy to operate, but the manufacturing precision for sub 20 nm structures cannot be achieved
Solution Approach 1:
The invention replaces the complex multi-step optical lithography system with a simpler direct particle beam writing system. Instead of requiring photoresist coating, optical exposure, development, and multiple etching steps, the particle beam directly writes the pattern into the material in one operation, simplifying the overall process while achieving superior resolution
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
Enables precise and efficient fabrication of nanostructures with lateral sizes below 20 nm, reducing production costs and device complexity while maintaining minimal damage to the semiconductor devices.
Implementation Method 1
subjecting the nanostructure for a low energy particle beam having a direction perpendicular to the main surface; whereby a recess in the nanostructure is formed
Data Source
AI summary
The present invention relates to a method for selective etching of a nanostructure (10). The method comprising: providing the nanostructure (10) having a main surface (12) delimited by, in relation to the main surface (12), inclined surfaces (14); and subjecting the nanostructure (10) for a dry etching, wherein the dry etching comprises: subjecting the nanostructure (10) for a low energy particle beam (20) having a direction perpendicular to the main surface (12); whereby a recess (16) in the nanostructure (10) is formed, the recess (16) having its opening at the main surface (12) of the nanostructure (10).