SEM ABCC Parameter Setting Using Detector Simulation
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Solution Overview
Problem
Charged particle beam devices, such as scanning electron microscopes, face challenges in accurately adjusting Auto Brightness Contrast Control (ABCC) parameters due to detector characteristic variations, leading to increased time and effort in setting optimal brightness and contrast for image observation.
Innovation Solution
A measurement system comprising a charged particle beam device and a verification device, where the verification device uses simulator input signals and characteristic information to search for optimal ABCC parameters, simulating detector operations and adjusting amplification factors to achieve specified reference values, thereby reducing the time required for parameter adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predetermined arithmetic formula or table is used to adjust the ABCC parameter, then the adjustment process is simple, but a highly accurate ABCC parameter value cannot be obtained due to detector characteristic variations
Solution Approach 1:
The patent applies preliminary action by pre-storing characteristic information of the detector (such as sensitivity, linearity, and dynamic range) in a storage unit before actual measurement. When measuring a sample, the control unit retrieves and applies this pre-stored characteristic information to automatically calculate accurate ABCC parameters, eliminating the need for complex real-time adjustments and ensuring high accuracy without increasing operational complexity.
2Measurement precision
If manual fine-adjustment of the ABCC parameter is performed to achieve accurate values, then measurement precision improves, but the time required to adjust the parameter increases
Solution Approach 1:
The patent implements self-service by enabling the charged particle beam device to automatically determine accurate ABCC parameters through its own stored characteristic information without requiring external manual intervention. The control unit autonomously retrieves detector characteristics, performs calculations, and sets the ABCC parameter, thereby achieving both high measurement precision and rapid parameter adjustment simultaneously.
3Measurement precision
If detector characteristic variations are not considered, then the adjustment process is faster, but the ABCC parameter value becomes inaccurate
Solution Approach 1:
The patent applies preliminary action by pre-storing characteristic information of the detector (such as sensitivity, linearity, and dynamic range) in a storage unit before actual measurement. When measuring a sample, the control unit retrieves and applies this pre-stored characteristic information to automatically calculate accurate ABCC parameters, eliminating the need for complex real-time adjustments and ensuring high accuracy without increasing operational complexity.
Solution Approach 2:
The patent uses copying by creating a digital representation (copy) of the detector's physical characteristics and storing it in the storage unit. This copied characteristic information can be repeatedly accessed and applied without wearing out or degrading the actual detector, allowing accurate ABCC parameter calculation while maintaining simple operational procedures.
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 significantly shortens the time needed to adjust ABCC parameters, improving the throughput of measurement processes, especially in manufacturing processes like semiconductor device production, and reduces user workload by automating the adjustment process.
Implementation Method 1
The simulation detector executes arithmetic processing on the simulator input signal in a state in which the characteristic information is reflected in an arithmetic parameter of the arithmetic model
Implementation Method 2
The simulated image conversion unit executes arithmetic processing corresponding to the image conversion unit, and converts a signal from the simulation detector into a simulated image
Data Source
AI summary
A method of setting a parameter of a charged particle beam device, for shortening the time required to adjust an ABCC parameter. An inverse conversion processing unit generates a simulator input signal corresponding to an electron emitted from a sample. A simulation detector uses an arithmetic model that simulates a detector and executes arithmetic processing on the simulator input signal in a state in which characteristic information is reflected in an arithmetic parameter. A simulated image conversion unit executes arithmetic processing corresponding to an image conversion unit and converts a signal from the simulation detector into a simulated image. An ABCC search unit searches for an ABCC parameter with respect to the simulation detector so that an evaluation value obtained from the simulated image becomes a specified reference value, and outputs the ABCC parameter as a search result to an ABCC control unit of the actual machine.