Electron Gun Acceleration Electrode Heating for Vacuum Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electron guns face instability in electron beam intensity due to gas, ions, and electrons emitted from the acceleration electrode, which reduces the vacuum degree and hinders stable electron beam supply.
Innovation Solution
Incorporating a second heating unit for the acceleration electrode in addition to the existing heating unit for the extraction electrode to thermally desorb gases and ions, maintaining a high vacuum and preventing electron beam intensity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a heater is used to heat the extraction electrode and a chamber having a cathode and a chamber having a heater are independently evacuated, then the periphery of the cathode can be maintained at an extremely high vacuum, but gas, ions, and electrons are emitted from the acceleration electrode which reduces the degree of vacuum and causes unstable electron beam supply
Solution Approach 1:
The vacuum system is divided into two independent chambers: a first vacuum chamber housing the electron source and extraction electrode, and a second vacuum chamber housing the acceleration electrode. This segmentation allows independent vacuum control for each component, enabling the acceleration electrode chamber to be separately evacuated and heated without affecting the electron source vacuum environment.
Solution Approach 2:
The acceleration electrode is heated in advance through a heater before electron beam irradiation to prevent gas emission during operation. This preliminary heating action removes adsorbed gases from the acceleration electrode surface before they can be released into the vacuum chamber during high-voltage operation.
2Reliability
If the acceleration electrode is not heated, then the device structure remains simple, but gas emission from the acceleration electrode reduces vacuum degree and causes electron beam intensity variation
Solution Approach 1:
The acceleration electrode is equipped with its own heater that enables it to self-regulate its temperature and prevent gas emission. This self-service capability allows the acceleration electrode to maintain a state that prevents vacuum degradation without requiring external intervention or complex control systems.
Solution Approach 2:
The temperature of the acceleration electrode is changed from room temperature to an elevated temperature through heater application. This parameter change prevents gas adsorption and emission from the acceleration electrode surface, thereby maintaining stable vacuum conditions and consistent electron beam intensity.
3Reliability
If the acceleration electrode is heated to prevent gas emission, then electron beam supply becomes stable, but energy consumption increases
Solution Approach 1:
Instead of heating the entire vacuum system or all components excessively, only the acceleration electrode is heated to the minimum necessary temperature to prevent gas emission. This partial action approach applies heating energy selectively and minimally, reducing overall energy consumption while achieving the desired stability.
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 configuration ensures a stable electron beam supply by preventing the emission of ESD gas and ions from the acceleration electrode, maintaining an extremely high vacuum and reducing the risk of discharge, thereby enhancing the reproducibility and clarity of images in scanning electron microscopes.
Implementation Method 1
a first heating unit that heats the extraction electrode, and a second heating unit that heats the acceleration electrode
Implementation Method 2
a first heating unit that heats the extraction electrode, and a second heating unit that heats the acceleration electrode
Implementation Method 3
An image quality of the generated image depends on the electron beam applied to the sample, and an electron gun capable of stably supplying a high luminance electron beam is required
Implementation Method 4
As such an electron gun, there are a Cold Field Emission Electron Gun (hereinafter referred to as CFE electron gun) and a Schottky Emission Electron Gun (hereinafter referred to as SE electron gun)
Data Source
AI summary
An object of the invention is to stably supply an electron beam from an electron gun, that is, to prevent variation in intensity of the electron beam. The invention provides a charged particle beam device that includes an electron gun having an electron source, an extraction electrode to which a voltage used for extracting electrons from the electron source is applied, and an acceleration electrode to which a voltage used for accelerating the electrons extracted from the electron source is applied, a first heating unit that heats the extraction electrode, and a second heating unit that heats the acceleration electrode.