Charged Particle Beam Position Correction via Dual-Condition Traces
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Solution Overview
Problem
Existing charged particle beam apparatuses face challenges in accurately processing samples due to deteriorated detection image quality under varying beam conditions, leading to recognition errors and inaccurate sample thickness measurement.
Innovation Solution
A charged particle beam apparatus with a stage, beam column, detector, and controller that generates image data for two-dimensional distribution of secondary particles, allowing for the setting of specific irradiation frames and traces under different beam conditions, enabling accurate position correction by detecting displacement between traces formed under different conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beam current is increased to improve processing speed, then productivity is improved, but detection image quality deteriorates leading to recognition errors
Solution Approach 1:
The patent divides the processing into two separate stages: a first processing using high beam current for fast material removal, and a second processing using low beam current for precise finishing and accurate thickness measurement. This segmentation allows each stage to operate under optimal beam conditions without compromising the other.
Solution Approach 2:
The patent dynamically adjusts beam current based on the processing stage and required measurement accuracy. The beam current is changed from a first value during initial processing to a second value during final processing and measurement, allowing the system to adapt to different operational requirements.
2Reliability
If acceleration voltage is decreased to improve sample preservation, then sample integrity is improved, but detection image quality deteriorates
Solution Approach 1:
The patent segments the processing into distinct stages with different acceleration voltages. The first processing uses higher acceleration voltage for efficient material removal, while the second processing uses lower acceleration voltage for precise work and accurate thickness measurement, ensuring both sample preservation and measurement quality.
Solution Approach 2:
The acceleration voltage is dynamically changed between processing stages. The system switches from a first acceleration voltage during initial processing to a second acceleration voltage during final processing and measurement, optimizing both sample integrity and detection image quality for each stage.
3Measurement precision
If multiple image data are acquired under different beam conditions for position correction, then correction accuracy is improved, but device complexity increases
Solution Approach 1:
The patent uses a single detection image for multiple purposes: both for observing the sample and for position correction by detecting irradiation traces. This multi-functional use of the detection image eliminates the need for separate correction systems while achieving accurate position alignment.
Solution Approach 2:
The system uses its own processing traces as reference marks for position correction. The irradiation traces created during processing serve as self-generated landmarks, allowing the system to perform self-correction without requiring external reference systems or additional complex infrastructure.
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 improves correction accuracy and ensures precise sample processing even when beam conditions change, outperforming methods using image data with poor resolution.
Implementation Method 1
a detector configured to detect a secondary particle emitted from the sample by the irradiation of the charged particle beam
Data Source
AI summary
A charged particle beam apparatus including a column irradiating a sample with a charged particle beam, a detector detecting a secondary particle emitted from the sample, an image data generating section generating image data indicating two-dimensional distribution of an amount of the secondary particle detected by the detector, and a controller that respectively sets first and second position adjustment irradiation frames for first and second beam condition on a surface of the sample in the image data, form a first and second irradiation traces by respectively irradiating the first and second position adjustment irradiation frames with the charged particle beams of the first and second beam conditions, correct a position of the second processing irradiation frame, based on a position displacement amount between a predetermined position of the first irradiation trace and a predetermined position of the second irradiation trace.