Crossover Regulation Edge for Electron Beam Positioning
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Solution Overview
Problem
In electron beam lithography systems, the accurate adjustment of the crossover height and focal length is challenging due to assembly errors, thermal expansion, and resistance variations, leading to decreased throughput and accuracy.
Innovation Solution
A crossover regulation edge with a sharp end face is used to measure and adjust the electron beam shape, ensuring the intermediate image is formed on the front focal plane of the condenser lens, and monitoring changes in focal length to maintain beam parallelism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal electron gun is used to obtain large current and stable electron emission, then electron emission stability is improved, but crossover height adjustment accuracy deteriorates due to assembly errors and thermal expansion
Solution Approach 1:
The patent replaces manual mechanical adjustment of crossover height with an automated control system that uses a measurement marker to detect beam position and feeds back to the deflector to automatically correct crossover height deviations, thereby eliminating the impact of assembly errors and thermal expansion on adjustment accuracy
Solution Approach 2:
The patent introduces a feedback mechanism where the measurement marker detects the actual crossover position and sends signals to the deflector to automatically adjust and maintain the correct crossover height, compensating for thermal expansion and assembly variations in real-time
2Manufacturing precision
If crossover height and focal length are manually adjusted, then initial setup is possible, but throughput decreases due to time-consuming adjustments and drift over time
Solution Approach 1:
The system performs self-adjustment of crossover height and focal length using the measurement marker and feedback control, eliminating the need for frequent manual interventions and maintaining optimal beam focusing automatically during operation, thereby improving throughput
Solution Approach 2:
The measurement marker provides continuous feedback on beam position and focus quality, enabling the system to automatically correct deviations and maintain optimal focusing conditions without manual intervention, thus improving both precision and throughput
3Ease of operation
If assembly errors and thermal expansion occur, then device operation is maintained, but beam parallelism and focal length stability deteriorate
Solution Approach 1:
The measurement marker continuously monitors beam position and focus conditions, providing feedback to the control system which adjusts the deflector and lens excitation to compensate for thermal expansion and assembly errors, maintaining stable focal length and beam parallelism
Solution Approach 2:
The system dynamically adjusts operational parameters such as deflector voltage and lens excitation current based on real-time measurement feedback to compensate for thermal expansion and assembly variations, maintaining stable beam characteristics despite environmental changes
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 approach facilitates precise positional adjustment of the crossover, improving throughput and accuracy by maintaining beam parallelism and stability over time.
Implementation Method 1
The thermal electron gun heats a cathode 101 made of a material with a low work function to provide electrons with energy enough to overcome a barrier of a cathode surface, and accelerates the electrons toward an anode 103 with a higher potential with respect to the cathode 101
Implementation Method 2
A source forming lens 105 is an electromagnetic lens having a function of forming an image by reducing the crossover 104
Implementation Method 3
By using this source crossover 106 as a light source, a condenser lens 107 produces an approximately parallel electron beam
Implementation Method 4
a lens array formed by two-dimensionally arranging electrostatic lenses having the same focal length
Implementation Method 5
a deflector array formed by two-dimensionally arranging electrostatic deflectors capable of being driven individually. The divided electron beams are converged at the height of the blanker array 112 by lens action of the corresponding lens array 109
Data Source
AI summary
In a charged particle beam applying apparatus such as an electron beams lithography system, there is a technology that facilitates positional adjustment of a crossover and improves throughput of the apparatus. A front focal plane of a condenser lens is provided with a sharp end face (crossover regulation edge) for regulating the height of the crossover on a beam axis. By using the crossover regulation edge to measure the shape of an electron beam, the shape of the beam on the front focal plane of the condenser lens can be always checked even if the height of the crossover formed by an electron gun or the resistance of a source forming lens is changed.