Astigmatic Correction Lens Axial Alignment Method
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Solution Overview
Problem
Current methods for axial alignment of charged particle beams in systems like scanning electron microscopes are time-consuming and labor-intensive, requiring repetitive scanning and detection processes to achieve balanced deflecting forces, which impairs operational efficiency.
Innovation Solution
A method utilizing an astigmatic correction lens with pairs of coils, where currents through the coils are varied in specific conditions to obtain limited sets of image data, allowing calculation of current values for axial alignment, reducing the need for extensive scanning and improving operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If repetitive scanning and detection is performed to achieve axial alignment, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating the relationship between coil current ratios and beam deflection characteristics. Instead of performing repetitive scanning and detection during alignment, the system uses pre-established data to directly determine the optimal current ratio for axial alignment, significantly reducing alignment time while maintaining precision
Solution Approach 2:
The patent uses copying by creating a computational model that replicates the physical alignment process. Rather than physically scanning and detecting multiple times, the system copies the alignment scenario through calculation based on pre-acquired data, achieving the same alignment precision with minimal time investment
2Manufacturing precision
If repetitive scanning and detection is performed to achieve axial alignment, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The patent applies preliminary action by pre-establishing the mathematical relationships and calibration data needed for alignment. This allows the system to achieve precise axial alignment through direct calculation rather than repetitive iterative scanning, thereby maintaining manufacturing precision while dramatically improving operational efficiency and productivity
Solution Approach 2:
The patent replaces the mechanical iterative scanning and detection process with a computational system. By substituting physical repetitive operations with mathematical calculations based on pre-acquired data, the system maintains alignment precision while eliminating time-consuming mechanical iterations, thus improving productivity
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 approach simplifies the axial alignment process by reducing the number of required image data sets, thereby shortening alignment time and reducing operator burden, enhancing the operational efficiency of charged particle beam systems.
Implementation Method 1
an astigmatic correction lens including a first pair of coils and a second pair of coils... first and second coils which are located on opposite sides of the axis of the charged particle beam... third and fourth coils which are located on opposite sides of the axis of the charged particle beam
Implementation Method 2
the values of the currents through the first to fourth coils for correcting the position of the axis of the charged particle beam passing through the astigmatic correction lens are calculated
Data Source
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AI summary
A method of axially aligning a charged particle beam easily is offered. This method is implemented by a charged particle beam system equipped with an astigmatic correction lens (10) including a first pair of coils (P1) and a second pair of coils (P2). The first pair of coils consists of first (101) and second coils (102) which are located on opposite sides of the axis of the beam (B). The first (101) and second coils (102) have opposite coil surfaces (101f, 102f) having magnetic poles of a first polarity. The second pair of coils (P2) consists of third (103) and fourth coils (104) which are located on opposite sides of the axis of the beam (B). The third (103) and fourth coils (104) have opposite coil surfaces (103f, 104f) having magnetic poles of a second polarity different from the first polarity. The second pair of coils (P2) is angularly spaced from the first pair of coils (P1). The method starts with obtaining via respective image data acquisition means (22, 24, 32) first to sixth sets of image data while varying currents flowing through the first to fourth coils to first to sixth sets of conditions. Then, using respective calculation means (34, 36), the values of the currents through the first to fourth coils for correcting the position of the axis of the beam (B) are calculated based on the first to sixth sets of image data.