Displaceable Retarding Electrode for High-Accuracy Alignment
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Solution Overview
Problem
Conventional scanning electron beam apparatuses face challenges in achieving high-accuracy alignment of the sample and retarding electrode, limiting the observation region due to the fixed positioning of the retarding electrode, which complicates precise alignment and observation.
Innovation Solution
A charged particle beam apparatus with a displaceable electrode member between the beam emitting end and the sample stage, driven by an actuator, allowing for precise alignment and deceleration of the electron beam, while maintaining electrical insulation and avoiding interference with the sample plate tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the retarding electrode is fixed to the objective lens, then the structure is simplified, but alignment accuracy between the electrode and sample deteriorates
Solution Approach 1:
The retarding electrode is made movable relative to the sample stage through a displacement mechanism, allowing dynamic adjustment of the electrode position. This enables high-accuracy alignment between the electrode and sample observation region while maintaining a simplified overall structure when the electrode is in its operational position.
2Device complexity
If the retarding electrode is fixed in position, then the device complexity is reduced, but the observation region range is limited
Solution Approach 1:
The displacement mechanism enables the retarding electrode to be positioned at different locations along the optical axis, allowing the observation region to be adjusted to match different sample areas of interest. This provides versatility in selecting observation regions without increasing overall device complexity.
Solution Approach 2:
The electrode positioning system is separated into an independent displacement mechanism that can be controlled separately from the main beam column, allowing flexible adjustment of the electrode position to access different observation regions on the sample.
3Measurement precision
If high-accuracy alignment is required, then observation quality improves, but alignment difficulty increases
Solution Approach 1:
The system uses feedback from the beam emitting end portion detection to guide the displacement of the retarding electrode, enabling automatic or semi-automatic alignment. This reduces alignment difficulty while achieving high accuracy by providing real-time information about electrode position relative to the beam and sample.
Solution Approach 2:
The displacement mechanism is designed to enable the electrode to self-align with the sample observation region through controlled movement, reducing the need for complex manual alignment procedures while maintaining high alignment accuracy.
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
Enables easy and high-accuracy alignment of the electrode and sample, improving the observation region and reducing electron beam damage by applying a negative voltage to the electrode member, thus maintaining high-resolution imaging.
Implementation Method 1
a power source applying negative voltage to the electrode member from outside the sample chamber to decelerate the charged particle beam with respect to the sample
Data Source
AI summary
A charged particle beam apparatus includes a sample chamber; a sample stage; an electron beam column irradiating a sample S using an electron beam; and a focused ion beam column irradiating the sample S using a focused ion beam. The apparatus includes an electrode member displaceable between an insertion position between a beam emitting end portion of the electron beam column and the sample stage and a withdrawal position distant from the insertion position, the electrode member being provided with an electrode penetrating hole passing the electron beam therethrough. The apparatus includes a driving unit displacing the electrode member; a power source applying a negative voltage to the electrode member; and an insulation member electrically insulating the sample chamber the driving unit from the electrode member.