Particle Beam Microscopy Self-Cleaning via UV Ozone Generation
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Solution Overview
Problem
Conventional particle beam microscopy systems face inefficiencies in removing contaminants from vacuum chamber components, leading to compromised inspection processes due to the short half-life and mean free path of ozone, which limits its cleaning effectiveness.
Innovation Solution
Supplying a precursor gas, such as oxygen, to the vacuum chamber and activating it with ultraviolet radiation to generate ozone in close proximity to contaminants, thereby increasing its concentration and effectiveness in decomposing and removing contaminants from surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ozone is supplied to the vacuum chamber for contaminant decomposition, then cleaning effectiveness is improved, but the short half-life and mean free path of ozone limit its effectiveness
Solution Approach 1:
The patent applies preliminary action by generating ozone in advance within the vacuum chamber before the actual cleaning process begins. The ozone is produced and accumulated in the chamber environment beforehand, ensuring that when cleaning is needed, sufficient reactive oxygen is already present to effectively decompose contaminants on surfaces, overcoming the limitation of ozone's short half-life during transport from external sources.
2Reliability
If a plasma generator is used to generate oxygen radicals for contaminant decomposition, then cleaning capability is improved, but the system complexity increases
Solution Approach 1:
The patent applies self-service by utilizing the existing vacuum chamber environment and readily available oxygen to generate ozone in situ. Instead of introducing complex external plasma generators or specialized equipment, the system uses simple electrical discharge or UV irradiation within the chamber to convert ambient oxygen into reactive ozone, allowing the vacuum chamber itself to serve the cleaning function without additional complex devices.
3Productivity
If contaminants are allowed to accumulate in the vacuum chamber during operation, then inspection process continues, but cleaning efficiency deteriorates
Solution Approach 1:
The patent applies continuity of useful action by implementing ongoing ozone generation within the vacuum chamber that can operate continuously or periodically during inspection processes. The ozone is continuously produced in the chamber environment, maintaining a persistent cleaning action that prevents contaminant accumulation while allowing inspection to proceed, thus sustaining both productivity and cleaning efficiency simultaneously.
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 method enhances contaminant removal efficiency by maintaining a higher partial pressure of the precursor gas and continuous activation with electromagnetic radiation, ensuring effective decomposition and continuous purging of reaction products, thereby improving the cleanliness of the vacuum chamber components.
Implementation Method 1
The conversion of the precursor gas into the reaction gas may be activated by irradiation with electromagnetic radiation
Implementation Method 2
a reaction gas as such having a decomposing effect on contaminants is not supplied to the vacuum chamber, but rather a precursor gas of the reaction gas is supplied to the vacuum chamber. The precursor gas is converted into the reaction gas within the vacuum chamber
Data Source
AI summary
A particle beam system 1 for cleaning itself comprises an irradiation system to direct electromagnetic radiation onto the surfaces to be cleaned and a supply system 61 to supply a precursor gas to the interior of the vacuum chamber 11 of the particle beam system 1. The precursor gas is activated in a vicinity of the surfaces to be cleaned and is converted into a reaction gas which reacts with the contaminants present on the irradiated surfaces such that said contaminants may be pumped out then.