Particle Beam Alignment via Dynamic Field Sweeping
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Solution Overview
Problem
Existing particle beam apparatuses face challenges in achieving good imaging resolution and contrast due to mechanical tolerances and magnetic inhomogeneities, which cause deflections in the primary electron beam, making it difficult to align the beam along the desired axis of symmetry of both electric and magnetic fields.
Innovation Solution
The system employs a method to sweep the objective lens current and adjust the aperture and deflection units to align the particle beam along the magnetic field axis, followed by adjusting the specimen stage to neutralize the electric field deflection, repeating these steps until minimal image deflection is achieved, allowing for precise alignment and improved imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the particle beam apparatus uses standard alignment procedures, then the operation is simple, but the imaging resolution and contrast are poor due to beam deflections from mechanical tolerances and magnetic inhomogeneities
Solution Approach 1:
The patent applies preliminary action by performing alignment adjustments in a specific sequence before final imaging: first adjusting the objective lens current to align with the magnetic field axis, then adjusting the aperture unit and deflection units to align with the magnetic field axis, and finally adjusting the specimen stage to neutralize electric field deflections. This predetermined sequence of adjustments ensures optimal alignment while managing the complexity of multiple adjustment parameters.
Solution Approach 2:
The patent employs dynamics by making the alignment system adjustable and adaptive rather than fixed. The objective lens current, aperture unit position, deflection unit settings, and specimen stage position are all made dynamically adjustable to compensate for mechanical tolerances and magnetic inhomogeneities. This dynamic adjustment capability allows the system to adapt to variations in the magnetic and electric fields, improving imaging resolution despite manufacturing imperfections.
2Measurement precision
If the apparatus compensates for both electric and magnetic field asymmetries through multiple adjustment steps, then imaging quality improves, but the adjustment process becomes time-consuming and complex
Solution Approach 1:
The patent applies segmentation by dividing the alignment process into distinct, sequential steps: (1) adjusting the objective lens current to align with the magnetic field axis, (2) adjusting the aperture unit and deflection units to align with the magnetic field axis, and (3) adjusting the specimen stage to neutralize electric field deflections. This segmented approach allows each parameter to be optimized independently in a logical sequence, improving imaging contrast while making the complex adjustment process more manageable and systematic.
3Manufacturing precision
If the particle beam is aligned along the intended axis of symmetry, then deflection is minimized and image quality is optimized, but this requires precise compensation for mechanical tolerances and magnetic inhomogeneities
Solution Approach 1:
The patent applies parameter changes by adjusting multiple operational parameters to compensate for manufacturing imperfections: the objective lens current is changed to align the beam with the magnetic field axis, the aperture unit position is adjusted, the deflection unit settings are modified, and the specimen stage position is optimized. These parameter adjustments allow the system to achieve precise beam alignment and minimize deflection despite mechanical tolerances and magnetic inhomogeneities inherent in manufacturing, without requiring stricter manufacturing specifications.
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 enables the achievement of good resolution and desired contrast in imaging by ensuring the particle beam is aligned along the intended axis of symmetry, compensating for asymmetries in the electric and magnetic fields, thereby minimizing deflection and optimizing image quality.
Implementation Method 1
The objective lens generates, firstly, a magnetic field
Implementation Method 2
an electric field between the termination electrode and the object
Implementation Method 3
a beam generator for generating a particle beam with charged primary particles
Data Source
AI summary
A method for operating a particle beam apparatus. An objective lens current may be swept, and a property of a deflection unit and/or of an aperture unit may be set while the objective lens current is swept. Setting the property may implemented in such a way that either an image of the object displayed on a display device does not move or any such movement of the displayed image has a minimal deflection. Moreover, the operating voltage of a beam generator may be swept and the object may be aligned by means of a specimen stage. While the operating voltage is swept, the specimen stage may be moved into an aligned position in such a way that either the image of the object displayed on the display device does not move or any such movement of the displayed image has a minimal deflection.