Particle Beam Deflection Path for Spherical Aberration Compensation
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Solution Overview
Problem
The use of an objective lens in particle beam devices can cause aberrations, particularly spherical aberrations, leading to unwanted deflections of the particle beam.
Innovation Solution
A method is implemented to guide the particle beam using a combination of first and second guiding devices, which deflect the beam away from and back to the optical axis at specific angles, allowing the beam to be focused along predefined geometrical shapes on the object surface, thereby compensating for aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an objective lens is used to focus the particle beam, then the beam can be focused onto the object, but spherical aberrations cause unwanted deflections of the particle beam
Solution Approach 1:
A dual deflection system is introduced as an intermediary between the beam generator and the object. The first deflection device deflects the beam away from the optical axis, while the second deflection device deflects it back, compensating for spherical aberrations caused by the objective lens. This intermediary deflection system acts as a mediator to correct the unwanted beam deflections while maintaining the focusing capability of the objective lens.
2Reliability
If the particle beam is guided away from and back to the optical axis using deflection devices, then aberration compensation is achieved, but the device complexity increases
Solution Approach 1:
The patent combines the aberration compensation function with the existing beam guiding system. The first and second deflection devices are integrated into the beam path, with the second deflection device potentially serving dual purposes: compensating for spherical aberrations and guiding the beam to different positions on the object. This merging approach reduces the overall complexity by utilizing existing system components for multiple functions.
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 reduces or avoids unwanted deflections of the particle beam caused by aberrations, allowing for more precise imaging, analysis, and processing of objects by maintaining beam focus and accuracy.
Implementation Method 1
an electron beam apparatus, in particular a scanning electron microscope (hereinafter also referred to as SEM)
Implementation Method 2
a particle beam apparatus having an ion beam column is known. Ions are generated using an ion beam generator
Implementation Method 3
the electrons of the primary electron beam are accelerated with an accelerating voltage of 2 kV to 30 kV and are guided through an electron beam column of the particle beam apparatus. In the region between the objective lens and the object, the electrons of the primary electron beam are decelerated to the desired landing energy
Implementation Method 4
guiding the particle beam away from an optical axis of the particle beam apparatus with a first angle with respect to the optical axis using a first guiding device. Moreover, the method according to the system described herein includes guiding the particle beam using a second guiding device, where the particle beam is guided to the optical axis with a second angle with respect to the optical axis
Data Source
AI summary
Operating a particle beam apparatus for imaging, analyzing and/or processing an object includes guiding a particle beam using a first guiding device and a second guiding device in such a way that the particle beam is guided to first positions on a surface of the object. The first positions are arranged along a first geometrical shape on the object. The particle beam is also guided to second positions on the surface of the object using the first guiding device and the second guiding device. The second positions are arranged along a second geometrical shape on the object. Guiding the particle beam along the first geometrical shape and/or along the second geometrical shape is faster in time than guiding the particle beam from the first geometrical shape to the second geometrical shape.