Electron Gun Tip Sublimation Control via Segmented Emission Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electron beam exposure apparatuses face issues with the sublimation of the electron gun tip, leading to unstable electron beam emission and reduced throughput due to changes in the electron emission surface shape, which affects line width precision and exposure reliability.
Innovation Solution
An electron gun design incorporating an electron source with a suppressor electrode and an electron beam converging unit using a magnetic or electrostatic lens to minimize sublimation by maintaining the electron source at a low temperature and controlling the electron beam convergence, thereby reducing the emission angle and preventing micro-discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electron source is heated to a high temperature to emit electrons, then electron emission is achieved, but the tip material sublimates and the emission surface shape changes
Solution Approach 1:
The tip is divided into two functional layers: an electron emission layer (LaB6 or CeB6) that emits electrons when heated, and a base layer (W or Re) that provides structural stability and resists sublimation. This segmentation allows the emission layer to perform its function while the base layer maintains tip shape stability.
Solution Approach 2:
The tip uses a composite structure combining LaB6/CeB6 emission material with W/Re base material. The composite material properties enable both effective electron emission and resistance to sublimation-induced shape change, resolving the contradiction between emission performance and structural stability.
2Manufacturing precision
If the electron beam emission angle is reduced to improve line width precision, then manufacturing precision improves, but electron beam convergence becomes more difficult
Solution Approach 1:
The patent introduces a magnetic field dimension to control electron beam convergence. By applying a magnetic field in the vertical direction (perpendicular to the beam propagation), the electrons are forced to follow curved trajectories, achieving beam convergence and small emission angles without complicating the horizontal beam path geometry.
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 solution extends the operational period of the electron gun, maintains stable electron beam emission, and enhances throughput by preventing sublimation and maintaining uniform beam irradiation, ensuring high reliability and precision in pattern writing.
Implementation Method 1
an electron source for emitting electrons; an electron beam converging unit for converging an electron beam of thermal field emission electrons
Implementation Method 2
an electron beam converging unit using a magnetic or electrostatic lens to minimize sublimation
Implementation Method 3
an electron beam converging unit using a magnetic or electrostatic lens to minimize sublimation
Data Source
AI summary
An electron gun includes: an electron source; an accelerating electrode; an extraction electrode for extracting electrons from an electron emission surface of the electron source; a suppressor electrode for suppressing emission of electrons from a side surface of the electron source; and an electron beam converging unit for converging an electron beam of thermal field emission electrons emitted from the electron emission surface by applying an electric field to the electron emission surface. The electron beam converging unit is an electrostatic lens electrode which is placed between the extraction electrode and the accelerating electrode and having an opening portion in its center. A voltage is applied to the electrostatic lens electrode to converge the electron beam.