Electron Microscope Lens Arrangement With Dual Crossovers
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Solution Overview
Problem
Conventional charged particle beam systems, such as SEMs, face limitations in maximum working distance and field of view at low landing energies, leading to inadequate navigation and imaging capabilities, particularly when using booster tubes.
Innovation Solution
A lens arrangement in the charged particle beam column comprising a magnetic and electrostatic compound final lens, with additional crossovers, enhances the working distance and field of view by utilizing the booster tube's capabilities at low landing energies, and includes digital post-processing for image distortion correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a booster tube is used in conventional charged particle beam systems, then the system can operate at low landing energies, but the maximum working distance and field of view are limited
Solution Approach 1:
The final lens is segmented into two distinct components: a magnetic lens and an electrostatic lens. The magnetic lens creates a first crossover and the electrostatic lens creates a second crossover, allowing the beam to be focused in two stages. This segmentation enables independent optimization of each lens for different functions, resolving the contradiction between low energy operation and large field of view
Solution Approach 2:
The patent introduces an additional spatial dimension by creating two crossovers along the beam axis rather than a single crossover. The first crossover from the magnetic lens and the second crossover from the electrostatic lens provide an extra degree of freedom in beam control, enabling both low landing energy and large working distance to be achieved simultaneously
2Use of energy by moving object
If a booster tube is used in conventional charged particle beam systems, then the system can operate at low landing energies, but the maximum working distance is limited
Solution Approach 1:
The final lens is segmented into two distinct components: a magnetic lens and an electrostatic lens. The magnetic lens creates a first crossover and the electrostatic lens creates a second crossover, allowing the beam to be focused in two stages. This segmentation enables independent optimization of each lens for different functions, resolving the contradiction between low energy operation and large field of view
Solution Approach 2:
The patent introduces an additional spatial dimension by creating two crossovers along the beam axis rather than a single crossover. The first crossover from the magnetic lens and the second crossover from the electrostatic lens provide an extra degree of freedom in beam control, enabling both low landing energy and large working distance to be achieved simultaneously
3Length of stationary object
If a compound final lens with additional crossovers is used, then the working distance and field of view are enhanced, but the device complexity increases
Solution Approach 1:
The compound final lens combines the magnetic lens and electrostatic lens into a single integrated assembly that performs multiple functions: beam focusing, working distance control, and field of view expansion. This multi-functionality reduces the need for separate components and simplifies the overall system architecture despite the enhanced capabilities
Solution Approach 2:
The magnetic lens and electrostatic lens are merged into a compound final lens assembly where both lenses work together in sequence. The magnetic lens creates the first crossover and the electrostatic lens creates the second crossover, combining their effects to achieve enhanced working distance and field of view while maintaining a compact integrated structure
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
Enables navigation in a large field of view and corrects image distortions, allowing for high-resolution imaging across a broader area, especially at low landing energies, thereby improving imaging capabilities in SEMs and TEMs.
Implementation Method 1
A magnetic lens is formed in the charged particle beam column along an axis based on a magnetic lens excitation in the coils. The magnetic lens focuses the charged particle beam at a first crossover on the axis.
Implementation Method 2
An electrostatic lens is formed in the charged particle beam column along the axis. The electrostatic lens focuses the charged particle beam at a second crossover on the axis. The electrostatic lens is formed based on a gradient of potentials applied to the booster tube and other parts of the final lens.
Data Source
AI summary
A charged particle beam system includes a source of charged particles and a charged particle beam column to focus the charged particles into a charged particle beam having a landing energy. A magnetic lens is formed in the charged particle beam column along an axis based on a magnetic lens excitation in the coils. The magnetic lens focuses the charged particle beam at a first crossover on the axis. An electrostatic lens is formed in the charged particle beam column along the axis based on a voltage applied to the booster tube. The electrostatic lens focuses the charged particle beam at a second crossover on the axis. The first crossover is based on the magnetic lens excitation. The introduction of an extra crossover overcomes previous limitations of the maximum working distance at very small landing energies and maximum field of view.