Charged Particle Beam Separator for Large-Angle Secondary Deflection
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Solution Overview
Problem
Conventional charged particle beam application apparatuses face challenges in deflecting secondary electrons at a large angle without interfering with the primary beam, leading to restricted optical conditions and increased column length, which degrades resolution and is prone to external vibrations.
Innovation Solution
A charged particle beam application apparatus with a beam separator that generates an internal electromagnetic field using magnetic poles and electrodes, allowing the primary beam to travel straight while separating its trajectory from the secondary beam, enabling simple control of the primary beam and large-angle deflection of the secondary beam for direct detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a magnetic field sector is used to deflect the secondary beam at a large angle, then the secondary beam can be deflected at 90 degrees, but the primary beam optical axis cannot be adjusted and the apparatus becomes tall and interferes with other optical elements
Solution Approach 1:
The beam separator is divided into distinct functional regions: a first region with a magnetic field for deflecting the secondary beam, and a second region with an electric field for guiding the secondary beam to the detector while allowing the primary beam to pass straight through. This segmentation allows independent optimization of each region's function, resolving the contradiction between large deflection angle and optical system arrangement.
2Ease of operation
If an ExB is used for beam separation, then the control of the primary beam is simple, but the deflection angle of the secondary beam is small and requires additional optical elements and longer column length
Solution Approach 1:
The invention merges the functions of primary beam control and secondary beam deflection into a single beam separator apparatus. The primary beam control is achieved through the electric field region, while the secondary beam deflection is achieved through the magnetic field region, both within the same device. This combining approach maintains simple primary beam control while achieving large secondary beam deflection angle.
3Ease of operation
If the column length is increased to accommodate additional optical elements, then the secondary beam can be guided to the detector, but the influence of external vibrations increases and the resolution degrades
Solution Approach 1:
The invention uses spatial dimensionality change by deflecting the secondary beam in a direction perpendicular to the primary beam path. The magnetic field deflects the secondary beam laterally, and the electric field guides it to the detector positioned at the side, rather than requiring the secondary beam to travel a long distance along the primary beam axis. This dimensional approach shortens the column length while maintaining effective secondary beam guidance.
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 allows for improved control of the primary beam and large-angle deflection of the secondary beam, enhancing image contrast and reducing the influence of external vibrations, thus improving the resolution and flexibility of the SEM system.
Implementation Method 1
a beam separator that generates an internal electromagnetic field so that the primary beam travels straight, and a trajectory of the primary beam and a trajectory of the secondary beam are separated
Implementation Method 2
a magnetic field sector that deflects a beam in a wide magnetic field region
Implementation Method 3
a beam separator using an electric field and a magnetic field
Data Source
AI summary
A charged particle beam application apparatus includes a beam separator. The beam separator includes a first magnetic pole, a second magnetic pole facing the first magnetic pole, a first electrode and a second electrode that extend along an optical axis of a primary beam and are arranged in a first direction perpendicular to the optical axis, on a first surface of the first magnetic pole which faces the second magnetic pole, and a third electrode and a fourth electrode that extend along the optical axis and face the first electrode and the second electrode, respectively, on a second surface of the second magnetic pole which faces the first magnetic pole.