Charged Particle Beam Device High-Aspect Structure Imaging
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Solution Overview
Problem
Current charged particle beam devices struggle to achieve high-resolution imaging of high-aspect structures, particularly in semiconductor devices, as electrons discharged from the bottom part are bent by the objective lens, making it difficult to detect secondary electrons emitted at narrow angles relative to the optical axis, leading to inefficient detection of bottom part information.
Innovation Solution
A charged particle beam device incorporating multiple orthogonal electromagnetic field generators and an aperture forming member to selectively deflect and detect high-angle electrons, allowing them to pass through while blocking low-angle electrons, thereby enhancing detection efficiency and resolving power without relying on deflection actions or lens aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the focal distance of the objective lens is decreased to achieve higher resolution, then spatial resolution is improved, but secondary electrons are deflected more largely making detection difficult
Solution Approach 1:
The patent segments the electron detection process by separating secondary electron detection from the main electron beam path. Multiple orthogonal electromagnetic field generators are positioned at different locations to selectively extract and detect secondary electrons without affecting the primary beam, allowing high-resolution imaging while maintaining electron detection capability
Solution Approach 2:
The patent introduces orthogonal electromagnetic fields as intermediary elements between the objective lens and detector. These fields act as mediators that selectively deflect secondary electrons away from the strongly converging beam path while allowing the primary beam to pass through, enabling detection despite the short focal distance
2Productivity
If beam shift is performed by moving the electron beam scanning region to accelerate visual field movement, then productivity is improved, but the beam is irradiated to a position away from the ideal optical axis causing convergence action to deflect secondary electrons
Solution Approach 1:
The patent solves the beam shift problem by operating in another dimension - using orthogonal electromagnetic fields applied perpendicular to the beam path rather than shifting the beam position along the optical axis. This allows visual field movement while maintaining the beam on the ideal optical axis, preventing unwanted deflection of secondary electrons by the convergence action
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 enables high-accuracy, non-destructive measurement of high-aspect structures by selectively detecting high-angle electrons, improving the contrast and resolution of images, especially from the bottom part of structures, while maintaining high spatial resolution and flexibility in signal discrimination.
Implementation Method 1
a first orthogonal electromagnetic field generator (15) for deflecting charged particles discharged from a sample; a second orthogonal electromagnetic field generator (18) for deflecting the charged particles deflected by the first orthogonal electromagnetic field generator (15)
Implementation Method 2
an aperture forming member having a pass-through aperture for the charged particle beam; the third orthogonal electromagnetic field generator (21) for deflecting the charged particles which passing through the aperture forming member
Implementation Method 3
electrons which are discharged from a bottom part of the structure are very important to know information on the bottom part, but electrons (such as secondary electrons) which are discharged from the bottom part
Data Source
AI summary
An objective of the present invention is to provide a charged particle beam device with which information based on a charged particle which is discharged from a bottom part of high-aspect structure is revealed more than with previous technology. To achieve the objective, proposed is a charged particle beam device comprising: a first orthogonal electromagnetic field generator which deflects charged particles which are discharged from a material; a second orthogonal electromagnetic field generator which further deflects the charged particles which are deflected by the first orthogonal electromagnetic field generator; an aperture forming member having a charged particle beam pass-through aperture; and a third orthogonal electromagnetic field generator which deflects the charged particles which have passed through the aperture forming member.