Charged Particle Beam Device FOV Control
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Solution Overview
Problem
Charged particle beam devices face limitations in achieving high processing accuracy for large field of view (FOV) sizes with small slice amounts, particularly in biological samples, due to the constraints of existing digital/analog converters (DACs) which require increased hardware costs and bit resolution.
Innovation Solution
A charged particle beam device with a field-of-view setting unit that adjusts the FOV based on a set slice amount, allowing for the use of a smaller number of bits in the DAC by setting a value of one-nth of the slice amount as the input digital value and multiplying it to achieve the desired FOV, thereby eliminating quantization errors and improving processing accuracy without increasing DAC bit resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the field of view size is increased to observe large biological samples, then the observation coverage is improved, but the processing precision deteriorates due to quantization errors in the DAC
Solution Approach 1:
The patent dynamically adjusts the DAC input range based on the selected field of view size. When a large FOV is selected, the system automatically expands the DAC input range to utilize the full conversion capability, thereby maintaining processing precision across different observation scales without requiring hardware changes
Solution Approach 2:
The system changes the parameter mapping between digital and analog domains by adjusting the relationship between DAC input values and deflector control signals based on the FOV size. This parameter transformation allows the same DAC to provide different levels of precision for different field of view requirements
2Manufacturing precision
If the slice amount is decreased to achieve finer cross-section processing, then the processing precision is improved, but the quantization errors increase due to limited DAC bit resolution
Solution Approach 1:
The system dynamically adjusts the DAC input range based on the selected slice amount. When a small slice amount is required for high precision processing, the system automatically configures the DAC to operate in a range that provides sufficient resolution, thereby maintaining processing precision without increasing DAC bit resolution
Solution Approach 2:
The patent transforms the parameter mapping between digital input values and actual beam displacement by adjusting the scale factor based on the slice amount. This allows the system to achieve fine processing control with a fixed-resolution DAC by changing how the digital values are mapped to physical quantities
3Manufacturing precision
If the DAC bit resolution is increased to reduce quantization errors, then the processing precision is improved, but the hardware cost increases
Solution Approach 1:
The patent changes the parameter mapping between digital and analog domains by adjusting the relationship between DAC input values and deflector control signals based on the FOV and slice amount. This software-based parameter transformation allows the same hardware to provide different levels of precision without requiring higher-resolution DACs
Solution Approach 2:
The system dynamically configures the DAC operating parameters based on the observation requirements. By adjusting the input range and mapping relationships in real-time, the system achieves variable precision processing with a fixed-resolution DAC, eliminating the need for expensive high-bit-resolution converters
Data Source
AI summary
A cross-section processing observation apparatus includes an ion beam control unit which controls a charged particle beam generation-focusing portion and a deflector, and a DAC which converts an input digital signal into an analog signal which is to be input to the deflector. A field-of-view setting portion sets a value of a field of view of a charged particle beam where the scanning performed by the deflector is performed on the basis of a set value of a slice amount, and the field-of-view setting portion is configured to set a value of one-nth of the slice amount, where n is a first natural number, as an input digital value “1” of the digital/analog converter and to set a value obtained by multiplying said value set as the input digital value “1” by a second natural number as a value of the field of view.