Sacrificial Bilayer Coating for Electron Beam Charging Reduction
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Solution Overview
Problem
Insulating substrates and resins experience charging effects when exposed to electron beams, leading to positioning errors in lithography and image distortion in electron microscopy, due to electron trapping and electric field creation, which limits resolution and precision.
Innovation Solution
A non-destructive method involving the deposition of a non-conductive sacrificial layer followed by a conductive layer on insulating substrates or resins, allowing for electron irradiation and subsequent removal of both layers without altering the sample, using methods like PVD and solubilization in water or hydrogen peroxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin conductive layer is deposited on the insulating substrate to reduce charge effects, then the charging effects are reduced, but the sample is altered or destroyed requiring corrosive removal solutions
Solution Approach 1:
The conductive layer is segmented into two distinct layers: a sacrificial non-conductive layer (e.g., silicon oxide, silicon nitride) and a conductive layer (e.g., gold, platinum). The sacrificial layer can be selectively removed by chemical etching or plasma treatment, taking the conductive layer with it, thereby restoring the original sample without requiring corrosive removal solutions.
Solution Approach 2:
The sacrificial layer acts as an intermediary between the insulating substrate and the conductive layer. It provides a removable interface that allows the conductive layer to be deposited and subsequently removed without directly interacting with or damaging the insulating substrate.
2Reliability
If a metallic layer is deposited on the insulating material for electron microscopy observation, then charge effects are reduced, but the sample nature is changed making the technique destructive
Solution Approach 1:
The metallic conductive layer is segmented from the substrate through the introduction of a sacrificial layer. This allows the metallic layer to be removed along with the sacrificial layer after observation, restoring the sample to its original state and enabling reuse for other experiments.
Solution Approach 2:
The sacrificial layer is designed to be discarded (removed) after serving its purpose of enabling conductive layer deposition and subsequent sample observation. The removal process recovers the original sample structure, making it available for reuse.
3Reliability
If conductive resins are used to increase substrate conductivity, then charge effects are reduced, but corrosive and toxic chemical solutions are required with restrictive storage and use conditions
Solution Approach 1:
The sacrificial layer is designed as a disposable, short-living component that is deposited, serves its function during electron beam irradiation, and then removed. This eliminates the need for long-term storage and handling of corrosive conductive resins, as the conductive layer is only present temporarily during the observation or lithography process.
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 effectively reduces charge effects during electron beam exposure, enabling precise pattern positioning and high-resolution imaging without sample alteration, and allows for the reuse of insulating materials, with flexibility across various substrates.
Implementation Method 1
elimination of the sacrificial layer and of the conductive layer... using methods like PVD and solubilization in water or hydrogen peroxide
Implementation Method 2
The deposition of the bilayer can be carried out by known methods, for example a method of the PVD ('Physical Vapor Deposition') type
Implementation Method 3
part of the electrons of the beam is trapped by the insulating substrate or the resin and thereby creates an electric field which deflects the incident electrons
Data Source
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AI summary
A treatment method (100) for avoiding or limiting the charge effects on a supporting member formed by an insulating substrate or a resin and intended to be subjected to electron radiation, characterised in that it comprises the following steps: depositing (101) a non-conductive sacrificial layer (203, 203') on the substrate or the resin, depositing (102) a conductive layer (204, 204') on the sacrificial layer (203, 203'), carrying out electron radiation (103) for lithography or observation, eliminating (104) the sacrificial layer (203, 203') and the conductive layer (204, 204').