Vacuum Pump Control for Electron Beam Imaging
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Solution Overview
Problem
Existing electron beam devices face image quality issues due to vibrations caused by the opening and closing of valves in the vacuum system, leading to insufficient image quality and potential damage during the imaging of large objects or automated processes.
Innovation Solution
A method for operating a pressure system that involves disconnecting the pump from the pressure reservoir, measuring reservoir pressure, determining a functional relationship between pressure values, and extrapolating this relationship to predict when a threshold pressure will be reached, allowing for informed decision-making to stop imaging during disturbances and maintain image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is connected to the pressure reservoir and operated continuously, then the vacuum level is maintained, but vibrations occur during valve operations causing image quality degradation
Solution Approach 1:
The system performs preliminary actions by disconnecting the pump from the pressure reservoir before imaging operations and reconnecting it before vacuum maintenance operations. This anticipatory switching prevents vibrations during imaging by ensuring the pump is disconnected beforehand, while maintaining vacuum quality by reconnecting before necessary maintenance
Solution Approach 2:
The system dynamically switches the connection state between the pump and pressure reservoir based on operational requirements. The connection is dynamically changed from connected (for vacuum maintenance) to disconnected (for imaging operations), allowing the system to adapt its configuration to optimize for either vacuum maintenance or vibration-free imaging at different times
2Productivity
If imaging is performed continuously without interruption, then productivity is high, but low-quality images are generated during pump operations
Solution Approach 1:
The system implements periodic action by alternating between imaging operations and pump operations in distinct cycles. Imaging is performed during periods when the pump is disconnected, and vacuum maintenance is performed during separate periods when the pump is connected. This periodic separation ensures high-quality images are captured during imaging cycles while vacuum is maintained during pump cycles
Solution Approach 2:
The system performs preliminary switching of the pump connection state before initiating imaging sequences. By disconnecting the pump beforehand, the system prepares the vibration-free environment needed for high-quality imaging, ensuring productivity is not significantly reduced while maintaining image quality standards
3Object-affected harmful factors
If the pump is disconnected from the pressure reservoir, then vibrations are eliminated during imaging, but the vacuum level deteriorates over time
Solution Approach 1:
The system uses periodic action by alternating between disconnected (for imaging) and connected (for vacuum maintenance) states. During disconnected periods, vibrations are eliminated for high-quality imaging. During connected periods, the vacuum level is restored and maintained. This periodic cycling balances the competing requirements of vibration elimination and vacuum maintenance
Solution Approach 2:
The system performs preliminary reconnection of the pump before the vacuum level deteriorates to unacceptable levels. By monitoring vacuum quality and reconnecting in advance, the system prevents excessive vacuum degradation during imaging periods while minimizing the duration of pump disconnection to maintain vibration-free imaging conditions
Data Source
AI summary
Operating a pressure system of a device for imaging, analyzing and/or processing an object, and a particle beam device for carrying out this method. In particular, the particle beam device is an electron beam device and/or an ion beam device. The method may include disconnecting a pump from a pressure reservoir, connecting the pressure reservoir to a vacuum chamber, measuring a reservoir pressure existing in the pressure reservoir, determining a first pressure value of the reservoir pressure at a first time and a second pressure value of the reservoir pressure at a second time, determining a functional relationship between the first pressure value of the reservoir pressure and the second pressure value of the reservoir pressure, extrapolating the functional relationship for times later than the second time, determining a threshold time using the extrapolated functional relationship, and determining a remaining time period until the reservoir pressure reaches the pressure threshold.