Concentric Microscope Stage Layout for Wide Travel and Fine Positioning
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Solution Overview
Problem
Charged particle microscopes face issues such as resolution deterioration due to enlarged bore diameters in top entry systems, difficulty in handling applications like heating and signal acquisition, positional drift in side entry systems, limited movement range with piezoelectric elements, and reduced resolution with motor-driven stages.
Innovation Solution
A stage design for charged particle microscopes featuring annular planar shapes with concentric actuators, including motors for rough movement and piezoelectric elements for fine movement, ensuring broad movement range and high resolution without image interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a top entry system is used to insert the sample holder from the upper side of the pole piece, then the sample holder can be fixed with relatively high rigidity, but the bore diameter of the top pole piece must be enlarged which limits the pole piece shape related to resolution performance
Solution Approach 1:
The patent inverts the conventional top-entry approach by using a side-entry system where the holder rod is inserted horizontally between the pole pieces rather than vertically from above. This inversion allows the sample holder to be positioned without enlarging the pole piece bore, thereby preserving resolution performance while still achieving adequate positioning stability through the side-entry configuration.
2Device complexity
If the sample holder is contained inside the top pole piece in the top entry system, then the structure is compact, but the signal such as secondary electrons, backscattered electrons, or characteristic X rays emitted from the sample is shielded and it is difficult to acquire the signal
Solution Approach 1:
The patent extracts the sample holder from the interior of the top pole piece and positions it on the side surface of the pole piece. This extraction removes the shielding effect that prevented signal acquisition, allowing secondary electrons, backscattered electrons, and characteristic X-rays to be detected without obstruction while maintaining a compact overall structure.
3Adaptability or versatility
If a side entry system is used to insert the holder rod between top and bottom pole pieces, then it is easy to acquire signals and handle applications, but the holder rod is influenced by change in pressure and sound waves causing unintended movement of the sample
Solution Approach 1:
The patent employs a nested structure where the holder rod is inserted into a cylindrical stage that is itself positioned within the microscope chamber. The cylindrical stage acts as a nested container that provides a stable, vibration-resistant platform for the holder rod, reducing the impact of pressure changes and sound waves on sample position while preserving the side-entry advantages for signal acquisition and application handling.
4Ease of operation
If a long rod-shaped holder rod is used in the side entry system, then the sample holder can be inserted between pole pieces, but thermal expansion or thermal contraction occurs causing unintended movement of the sample
Solution Approach 1:
The patent addresses thermal expansion by changing the material parameter of the holder rod, selecting materials with low thermal expansion coefficients. Additionally, the holder rod is designed with a segmented structure that can accommodate thermal dimensional changes without transmitting significant movement to the sample holder, thereby maintaining positional stability while preserving insertability.
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
Enhances resolution and positional accuracy, stabilizes against thermal and pressure changes, and allows comprehensive sample observation without image distortion.
Implementation Method 1
a cylindrical stage disposed inside a barrel as a structure that has high stability which is characteristic of the top entry system and easiness of handling of various applications which is characteristic of the side entry system. In PTL 1, a cylindrical stage is disposed inside a barrel of an electron microscope and the stage is fixed to an inner wall of the barrel by using an X-axis pressing member and a Y-axis pressing member each configured by piezoelectric elements.
Implementation Method 2
The holder rod connected to the sample holder has a structure of a long rod shape in an insertion direction of the holder rod. Therefore, when a temperature of the sample holder and the holder rod is changed, thermal expansion or thermal contraction occurs in accordance with a linear expansion coefficient of such a material.
Data Source
AI summary
A charged particle microscope includes an electron gun provided inside a barrel and a stage 20. In the stage 20, a sample holder 30 holding a sample SAM can be installed. The stage 20 includes an annular rough movement stage member 21a and an annular fine movement stage member 21b. An X rough movement actuator 22a and a Y rough movement actuator 23a are connected to the rough movement stage member 21a. An X fine movement actuator 22b and a Y fine movement actuator 23b are connected to the fine movement stage member 21b. Here, a first movable range in which the X rough movement actuator 22a and the Y rough movement actuator 23a are able to move the rough movement stage member 21a is broader than a second movable range in which the X fine movement actuator 22b and the Y fine movement actuator 23b are able to move the fine movement stage member 21b. Accordingly, it is possible to improve performance of the charged particle microscope.