Filter Member for Atmospheric SEM Contamination Prevention
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Solution Overview
Problem
In scanning electron microscopes (SEMs) operating under atmospheric pressure, the risk of contamination of the charged particle optical barrel occurs when the diaphragm fractures, allowing air to flow in and potentially sucking in samples like liquids or gels, leading to performance degradation or failure, and existing solutions complicate the device structure and introduce time lags.
Innovation Solution
A filter member is placed on the path of the primary charged particle beam to intercept scattering substances and prevent contamination, allowing the beam to pass through while blocking foreign particles, thus maintaining a clean optical barrel without structural complexity or time lag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a partition member with monitoring mechanism is added to prevent contamination, then reliability is improved, but device complexity increases
Solution Approach 1:
The filter member is pre-installed in the charged particle optical barrel before observation begins, positioned to intercept any potential scattering substances. This preliminary placement ensures immediate protection upon diaphragm fracture without requiring activation sequences or complex monitoring systems.
Solution Approach 2:
The filtering function is extracted from the complex partition member system and implemented as a simple, dedicated filter member within the optical barrel. This separate, focused component performs the protection function without requiring integration with vacuum monitoring or driving mechanisms.
2Reliability
If a monitoring and partition mechanism is implemented, then reliability is improved, but time lag is introduced
Solution Approach 1:
The filter member is pre-positioned within the optical barrel during system setup, ready to immediately intercept scattering substances. This eliminates the time lag inherent in monitoring-based systems by having the protection mechanism already in place before any fracture event occurs.
Solution Approach 2:
The filter member acts as a passive intermediary barrier between the diaphragm and the charged particle optical components. It provides continuous protection without requiring active monitoring or control systems, thereby eliminating response time delays.
3Device complexity
If the optical barrel is kept simple without filter, then device complexity is reduced, but contamination risk increases
Solution Approach 1:
The filter member is designed as a simple, replaceable component that can be easily removed and replaced if contaminated. This allows the optical barrel to maintain simplicity while incorporating protection, as the filter acts as a sacrificial element that safeguards the more critical optical components.
Solution Approach 2:
The filter member is placed specifically at the location where scattering substances would enter the optical barrel, providing localized protection exactly where needed. This targeted approach adds minimal complexity to the overall system while effectively addressing the contamination risk.
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
The filter effectively reduces the risk of contamination in the charged particle optical barrel, maintaining system performance without adding complexity or introducing time delays, even when the diaphragm is damaged.
Implementation Method 1
a filter member which is placed on a path of the primary charged particle beam at least in a state where the primary charged particle beam is directed to the sample and, further, is adapted to transmit or pass, therethrough, the primary charged particle beam and a secondary charged particle derived from the sample, while intercepting at least a portion of a scattering substance
Data Source
AI summary
In a SEM device which enables observations under an atmospheric pressure, in the event that a diaphragm is damaged during an observation of a sample, air flows into a charged particle optical barrel from the vicinity of the sample, due to the differential pressure between the inside of the charged particle optical barrel under vacuum and the vicinity of the sample under the atmospheric pressure. At this time, the sample may be sucked into the charged particle optical barrel. In this case, a charged particle optical system and a detector are contaminated thereby, which causes performance degradation or failures of the charged particle microscope. For coping therewith, it is necessary to prevent the charged particle optical barrel from being contaminated, without inducing a time lag, with a simple structure. In a charged particle beam device adapted to place a sample in a non-vacuum environment, there is provided a filter member which is placed on the path of a primary charged particle beam at least in a state where the primary charged particle beam is directed to the sample and, further, is adapted to transmit or pass, therethrough, the primary charged particle beam and secondary charged particles derived from the sample, while intercepting at least a portion of a scattering substance which is scattered in the event of a fracture of the diaphragm.