Deflection Plate Beam Position Sensing for Electron Beam Alignment
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Solution Overview
Problem
Current electron beam inspection systems face challenges in accurately detecting and compensating for the absolute position of the electron beam within the electron beam column housing, leading to registration measurement inaccuracies and increased complexity in alignment processes.
Innovation Solution
A system utilizing a multichannel electrode tube with deflection plates and a processor to determine the electron beam's position based on voltage differences across the plates, allowing for precise alignment and compensation of the electron beam's position, enabling sub-nanometer level registration measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual alignment by technician is used, then alignment can be performed, but the process becomes complex, lengthy, and expensive with subjective results that vary by technician
Solution Approach 1:
The system performs self-alignment through automated detection of the electron beam's actual position using deflection plates and voltage measurement, eliminating the need for manual technician alignment. The system automatically compensates for position deviations by adjusting voltages based on detected beam position, making the alignment process independent of human operators.
Solution Approach 2:
The patent replaces manual mechanical alignment procedures with an automated electrical detection and control system. Instead of technicians physically adjusting components, the system uses voltage measurements across deflection plates to detect beam position and automatically compensates through electrical signals, substituting mechanical adjustment with electrical control.
2Measurement precision
If drift compensation using interferometers is used, then relative distance between electron beam column housing and stage can be measured, but absolute electron beam position drift cannot be detected
Solution Approach 1:
The patent introduces deflection plates as an intermediary element between the electron beam and the detection system. These plates serve as a mediator that interacts with the electron beam through voltage-induced electric fields, allowing the system to detect absolute beam position by measuring voltage differences required to maintain beam deflection, thereby recovering the absolute position information that was previously undetectable.
Solution Approach 2:
The system detects absolute electron beam position by measuring changes in voltage parameters across the deflection plates. By monitoring the voltage required to maintain specific beam deflection patterns, the system translates electrical parameter changes into positional information, enabling detection of absolute beam drift that was previously impossible with interferometric methods alone.
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 solution provides more accurate registration measurements and reduces the complexity of electron beam alignment, enhancing the precision and efficiency of electron beam inspection systems.
Implementation Method 1
Each of the deflection plates is disposed opposite another of the deflection plates across the path of the electron beam in the multichannel electrode tube
Implementation Method 2
a multichannel electrode tube with deflection plates and a processor to determine the electron beam's position based on voltage differences across the plates
Data Source
AI summary
A multichannel electrode tube includes at least four deflection plates. Each of the deflection plates is disposed opposite another of the deflection plates across the path of an electron beam that passes through the multichannel electrode tube. A voltage difference between of a pair of the deflection plates that are arranged opposite each other across the path of the electron beam is determined. A position of the electron beam in the multichannel electrode tube is then determined based on the voltage difference.