Beam Separator Device with Electrostatic Lenses for Dispersion Compensation
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Solution Overview
Problem
Charged particle beam devices, such as scanning electron microscopes, face limitations in resolution due to aberrations and spatial dispersion caused by beam shaping and steering elements, particularly at low landing energies, which hinder high spatial resolution imaging in the sub-nanometer range.
Innovation Solution
A beam separator device with multiple magnetic deflection fields and electrostatic lenses is used to deflect and correct the charged particle beam, compensating for dispersion and aberrations by arranging deflector parts symmetrically and placing electrostatic lenses at crossovers to minimize spatial dispersion and maintain beam shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If beam shaping and steering elements (deflectors, beam separators) are introduced to enable beam manipulation, then beam steering capability is improved, but spatial dispersion and aberrations increase, degrading resolution
Solution Approach 1:
A beam separator device is introduced as an intermediary component between the beam source and the specimen. This beam separator includes multiple deflectors arranged to separate the primary electron beam from backscattered electrons while minimizing the introduction of spatial dispersion and aberrations to the primary beam, thus enabling beam manipulation without significantly degrading resolution
Solution Approach 2:
The patent optimizes specific parameters of the beam separator including deflection angles, spacing between deflectors, and magnetic field strengths to minimize spatial dispersion. By carefully controlling these parameters, the beam separator achieves effective beam steering while keeping aberrations at acceptable levels for high-resolution imaging
2Reliability
If multiple deflectors are used to separate beams, then beam separation efficiency is improved, but device complexity increases
Solution Approach 1:
The beam separator is segmented into multiple independent deflector units, each with a specific function. This segmentation allows for modular design where each deflector can be optimized independently, and the overall system achieves high beam separation efficiency through the coordinated action of these simpler, standardized components
Solution Approach 2:
The beam separator device performs multiple functions: it separates primary electrons from backscattered electrons, steers the beam along the desired path, and minimizes aberrations. By designing a single device that accomplishes all these functions, the patent avoids the need for multiple separate components, thereby managing complexity while maintaining high separation efficiency
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 improves the resolution of charged particle beam devices by reducing aberrations and spatial dispersion, enabling high spatial resolution imaging in the sub-nanometer range without introducing significant distortions.
Implementation Method 1
a first deflector providing a first magnetic deflection field for deflecting a charged particle beam propagating along a beam entrance axis by a first deflection angle
Implementation Method 2
a second deflector arranged downstream from the first deflector providing a second magnetic deflection field for deflecting the charged particle beam by a second deflection angle in the direction of an intermediate beam axis
Implementation Method 3
a third deflector arranged downstream from the second deflector providing a third magnetic deflection field for deflecting the charged particle beam by a fourth deflection angle in the direction of a beam exit axis
Implementation Method 4
a first rotation-free lens, particularly a first electrostatic lens, to be arranged at a first crossover of the charged particle beam between the first deflector and the second deflector for at least partially compensating for a dispersion introduced by at least one of the first deflector and the second deflector
Implementation Method 5
a second rotation-free lens, particularly a second electrostatic lens, to be arranged at a second crossover of the charged particle beam between the second deflector and the third deflector for at least partially compensating for a dispersion introduced by at least one of the second deflector and the third deflector
Data Source
AI summary
A beam separator device (200) is described. The beam separator device (200) includes a first deflector (112) providing a first magnetic deflection field (B1) for deflecting a charged particle beam (101) propagating along a beam entrance axis (A1) by a first deflection angle (α1); a second deflector (114) arranged downstream from the first deflector (112) providing a second magnetic deflection field (B2) for deflecting the charged particle beam by a second deflection angle (α2) in the direction of an intermediate beam axis (A2), wherein the second deflector (114) is configured for deflecting the charged particle beam (102) re-entering the beam separator device (200) along the intermediate beam axis (A2) by a third deflection angle (α3); a third deflector (212) arranged downstream from the second deflector (114) providing a third magnetic deflection field (B2) for deflecting the charged particle beam (102) by a fourth deflection angle (α4) in the direction of a beam exit axis (A3); a first rotation-free lens to be arranged at a first crossover (X1) of the charged particle beam between the first deflector (112) and the second deflector (114) for at least partially compensating for a dispersion introduced by at least one of the first deflector and the second deflector; and a second rotation-free lens to be arranged at a second crossover (X2) of the charged particle beam between the second deflector (114) and the third deflector (212) for at least partially compensating for a dispersion introduced by at least one of the second deflector and the third deflector.