Hollow Nanostructures via Sacrificial Layer Erosion
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Solution Overview
Problem
Current methods for manufacturing nanometer-sized devices, such as AFM cantilevers and SNOM probes, cannot produce hollow nanostructures or alter their geometry effectively, limiting control over dimensions and shape.
Innovation Solution
A method involving a suspended film substrate with a sacrificial resist layer, where focused ionic beam etching or dry etching processes are used to create hollow nanostructures with precise control over dimensions, allowing for various shapes and dimensions by changing the writing technique and materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional lithography and etching processes are used, then nanometer-sized devices can be manufactured, but hollow nanostructures cannot be obtained and geometry control is limited
Solution Approach 1:
A sacrificial layer is deposited on the substrate before forming the nanostructure. This preliminary action creates a template that defines the future hollow geometry, allowing precise dimensional control while enabling various shapes (circular, rectangular, elliptical) by changing the sacrificial layer pattern rather than the etching process itself
Solution Approach 2:
The sacrificial layer acts as an intermediary element between the substrate and the final hollow nanostructure. It is first deposited, then patterned to define the desired geometry, and finally removed to create the hollow structure. This intermediary enables both precise dimension control and geometric versatility
2Ease of manufacture
If through-hole etching is used as disclosed in US 6,215,114, then optical probes can be manufactured, but hollow nanostructures with controlled dimensions cannot be obtained
Solution Approach 1:
Instead of directly etching through-holes, a sacrificial layer is first deposited and patterned to define the precise geometry. This preliminary patterning step enables accurate dimensional control before the actual etching process begins, overcoming the limitation of direct through-hole etching
Solution Approach 2:
The method changes the approach from direct etching to a multi-step process involving sacrificial layer deposition, patterning, and removal. By changing the process parameters and steps, precise dimensional control is achieved while maintaining ease of manufacture through standard lithography and etching techniques
3Productivity
If rapid manufacturing is pursued, then productivity increases, but control over nanostructure dimensions and geometry deteriorates
Solution Approach 1:
The sacrificial layer is deposited and patterned in advance using standard lithography techniques, which are already optimized for speed and precision. This preliminary action allows rapid manufacturing while maintaining dimensional control, as the geometry is defined by the well-established lithography process rather than complex etching parameters
Solution Approach 2:
The manufacturing process is segmented into distinct steps: sacrificial layer deposition, lithography patterning, etching, and sacrificial layer removal. This segmentation allows each step to be optimized independently, maintaining both speed and precision through specialized processes for each function
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 the rapid and precise production of hollow nanostructures with high aspect ratios and optoelectronic characteristics superior to existing devices, offering flexibility in writing techniques and materials, and the ability to create coaxial structures with different materials.
Implementation Method 1
a complete erosion of the substrate (1) and of the starting layer (2), and a partial erosion of the sacrificial layer (4) deposited on the starting layer (2), are carried out in a progressive sequence by the use of a focused ionic beam (8)
Implementation Method 2
Alternatively, it is possible to use a dry etching process, such as RIE (Reactive Ion Etching)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Method for obtaining hollow nano-structures comprising the steps of: providing a suspended film starting layer (2) on a support, substrate (1); depositing on the starting layer (2) a sacrificial layer (4); performing, in progressive sequence, a complete erosion phase of said support substrate (1) and starting layer (2) and performing an at least partial erosion phase of the sacrificial layer (4) previously deposited on the starting layer (2) so as to obtain holes passing through the starting layer (2) and passing or non passing through the sacrificial layer (4); depositing, on the side of the support substrate (1) opposite to that where the starting layer (2) is put (2), at least one covering layer (6') arranged to internally cover the holes created by the progressive erosion.