Electron Gun Shield Structure for High-Voltage Insulation Reliability
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Solution Overview
Problem
The existing charged particle beam apparatuses face challenges with dielectric breakdown due to high-potential wiring discharges between wirings or insulating gas containers at ground potential.
Innovation Solution
A charged particle beam apparatus with a metal housing filled with insulating gas, featuring a charged particle source and shield, and an acceleration electrode powered via a shield to prevent high-potential wiring discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-potential wiring is used to supply power to acceleration electrodes, then the charged particle beam apparatus can operate with required acceleration voltage, but dielectric breakdown may occur due to discharge between wirings or between wirings and insulating gas containers at ground potential
Solution Approach 1:
The shield is connected to the acceleration electrode at high potential, creating an equipotential region. Power is supplied to the acceleration electrode through the shield rather than through wiring in the insulating gas, eliminating the risk of dielectric breakdown. This resolves the contradiction by maintaining the required high voltage while removing the harmful high-potential wiring from the insulating gas environment.
Solution Approach 2:
The shield acts as an intermediary structure that bridges the high-potential acceleration electrode and the ground-potential housing. By routing power supply through the shield instead of direct wiring through the insulating gas, the shield mediates the power transmission while preventing discharge, thus resolving the reliability issue.
2Reliability
If a shield is introduced to relax electric field at protrusion tips and suppress discharge, then dielectric breakdown is prevented, but the device complexity increases due to additional shielding structures
Solution Approach 1:
The shield serves multiple functions simultaneously: it acts as an electric field shielding structure to relax high electric fields at protrusion tips, serves as a power supply conduit to deliver voltage to the acceleration electrode, and functions as a structural support element. By combining multiple functions into a single component, the device complexity increase is minimized while achieving reliable discharge suppression.
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 enhances the reliability of the insulating structure, preventing dielectric breakdown and ensuring stable operation of the charged particle beam apparatus.
Implementation Method 1
a metal housing 101 that is filled with an insulating gas 102
Implementation Method 2
an electric field is high at tips of the protrusions, and thus the dielectric breakdown due to discharge may occur. However, since the electron gun is surrounded with a high-potential shield as described above, the electric field at the tips of the protrusions can be relaxed, and the dielectric breakdown due to discharge can be suppressed
Data Source
AI summary
Provided is a charged particle beam apparatus capable of realizing a highly reliable insulating structure. This charged particle beam apparatus emits a charged particle beam from a charged particle beam emission device onto a sample, detects charged particles generated from the sample, and creates a sample image or processes the sample. The charged particle beam emission device is provided with a charged particle source and a shield arranged in an interior of a metal housing that is filled with an insulating gas, and an acceleration electrode arranged below the charged particle source, power being supplied to the acceleration electrode via the shield.