Charged Particle Beam Deflector Arrangement for Aberration Control
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Solution Overview
Problem
Existing charged particle beam apparatuses provide limited control over primary charged particle beams and charged signal particles, restricting their application in imaging and manipulation tasks.
Innovation Solution
A charged particle beam apparatus with a post-focusing deflector arrangement downstream of the focusing assembly and a pre-focusing deflector arrangement upstream, allowing for precise control of the beam's tilt angle and direction, enabling the beam to traverse the focusing assembly at or near the optical axis, and a control unit to adjust the deflection directions oppositely to minimize aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a post-focusing deflector arrangement is added to control beam direction, then beam control precision is improved, but device complexity increases
Solution Approach 1:
The deflection system is segmented into pre-focusing and post-focusing deflector arrangements, allowing independent control of beam direction at different stages. This segmentation enables precise beam positioning and tilt control while maintaining system manageability through modular design.
2Adaptability or versatility
If the beam is tilted for three-dimensional profiling, then imaging capability is improved, but aberrations increase
Solution Approach 1:
The pre-focusing deflector arrangement applies preliminary beam tilting before the beam enters the focusing assembly, allowing the system to pre-compensate for aberrations that will occur during tilted beam operation. This preliminary action enables three-dimensional profiling while minimizing the negative effects of beam tilt.
3Productivity
If a post-focusing deflector is used to define charged signal particle paths, then detection efficiency is improved, but device complexity increases
Solution Approach 1:
The post-focusing deflector arrangement serves multiple functions: it controls the primary beam direction, defines the path of charged signal particles to the detector, and works in conjunction with the pre-focusing deflector to minimize aberrations. This multi-functionality improves detection efficiency without requiring additional dedicated components.
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 configuration enhances the precision and flexibility of beam control, reducing aberrations and allowing for improved imaging and manipulation capabilities, including three-dimensional profiling and efficient detection of charged signal particles.
Implementation Method 1
a focusing assembly, such as a charged particle lens, e.g., an electrostatic lens, for focusing the primary charged particle beam on a specimen
Implementation Method 2
a post-focusing deflector arrangement for deflecting the focused primary charged particle beam
Data Source
AI summary
A charged particle beam apparatus is provided, which comprises a charged particle beam column for generating a primary charged particle beam; a focusing assembly, such as a charged particle lens, e.g., an electrostatic lens, for focusing the primary charged particle beam on a specimen; a detector for detecting charged signal particles which are emerging from the specimen; and a deflector arrangement for deflecting the primary charged particle beam. The deflector arrangement is arranged downstream of the focusing assembly and is adapted for allowing the charged signal particles passing therethrough. The detector is laterally displaced with respect to the optical axis in a deflection direction defined by the post-focusing deflector arrangement.