Selective Nanostructure Etching With Low-Energy Particle Beams
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Solution Overview
Problem
Current methods struggle to fabricate semiconductor devices with lateral sizes below 20 nm due to limitations in spatial resolution of ultraviolet lithography and the need for alternative approaches to achieve precise and damage-free nanostructure fabrication.
Innovation Solution
A method involving selective dry etching using a low energy particle beam perpendicular to the main surface of nanostructures, which etches at a higher rate on the main surface than on inclined surfaces, allowing for maskless fabrication of nanostructures with dimensions below 20 nm without the need for additional lithography steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ultraviolet lithography is used for manufacturing semiconductor devices, then the process is commonly used in industry, 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 nanostructure with perpendicular incidence, achieving lateral resolutions below 20 nm that are inaccessible to conventional optical lithography.
Solution Approach 2:
The patent changes the etching parameters by using low energy particles (specific energy range not disclosed) with perpendicular incidence angle. This parameter change enables selective etching of the main surface while preserving inclined surfaces, allowing precise control of lateral dimensions below 20 nm that overcomes the resolution limit of ultraviolet lithography.
2Productivity
If conventional etching methods are used, then the process is simple, but additional equipment and lithography steps are required, increasing production costs and reducing throughput
Solution Approach 1:
The patent merges the patterning and etching functions into a single dry etching process. The particle beam etching simultaneously defines the pattern and removes material, eliminating the need for separate lithography and etching steps. This integration increases productivity by reducing the number of process steps and equipment requirements.
Solution Approach 2:
The patent employs selective etching where the low energy particle beam automatically etches the main surface while being repelled by or not etching the inclined surfaces. This self-selective behavior eliminates the need for complex masking processes, as the geometry of the nanostructure itself guides the etching process, reducing both process complexity and equipment requirements.
3Productivity
If high energy particle beams are used for etching, then material removal is efficient, but defects such as broken atomic bonds and knocked-out atoms are generated in the nanostructure
Solution Approach 1:
The patent uses low energy particles with a specific energy range (not disclosed) that is below the threshold for generating sputtering and atomic displacement defects. This energy parameter is carefully selected to enable chemical etching reactions while avoiding the harmful effects of high energy particle bombardment, thus maintaining high etching efficiency without compromising nanostructure integrity.
Solution Approach 2:
The patent converts the typically harmful high energy particle bombardment into a beneficial low energy process. By using particles with energy below the sputtering and displacement thresholds, the process achieves efficient material removal through selective chemical reactions while avoiding the generation of defects such as broken atomic bonds and knocked-out atoms that would occur with high energy beams.
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 reduced costs and equipment investment, overcoming resolution limits of optical lithography, and facilitating further device downscaling with fewer processing steps and reduced alignment issues.
Implementation Method 1
subjecting the nanostructure for a dry etching, wherein etching comprises: subjecting the nanostructure for a low energy particle beam
Implementation Method 2
the particle energy may be less than an energy needed for sputtering, and the energy spread of the particles of the particle beam sufficiently narrow relative to the window of the etching process
Data Source
Figure 1A~1B
Figure 2A
Figure 2B~2C
AI summary
The present invention relates to a method for forming a nanostructure (10). The method comprising: providing a substrate (51) having a first layer (53) and a photoresist layer (54), wherein the first layer (53) is between the photoresist layer (54) and the substrate (51); lithography patterning the photoresist layer (54), thereby exposing areas (55) of the first layer (53); etching the exposed areas (55) of the first layer (53), thereby forming first recesses (56) in the first layer (55); removing the remaining photoresist layer (54), thereby forming ridges of the first layer between the first recesses (56) of the first layer (53); subjecting the first layer (53) for a first dry etching process. The first dry etching process comprises: subjecting the first layer to a particle beam; whereby selective etching of the ridges of the first layer (53) relative to walls (57) of the first recesses in the first layer (53) is achieved such that second recesses (59) in the first layer (53) are formed, the second recesses (59) in the first layer (53) having their openings at the ridges of the first layer (53); thereby a nanostructure consisting of a plurality of first fins (60) delimited by the first and second recesses (56, 59) in the first layer (53) are formed, the first fins (60) having a first pitch..