Charged Particle Beam Imaging with Fiducial Drift Compensation
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Solution Overview
Problem
Current charged particle beam (CPB) systems require a significant amount of time to image large volume samples at high resolution, making it impractical for applications that demand rapid imaging of large areas or volumes.
Innovation Solution
A selective high resolution imaging method is implemented, where a large field of view image is acquired at low resolution and high speed, and then specific regions of interest are imaged at higher resolution, reducing the need to image the entire area at high resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire large volume sample is imaged at high resolution using conventional CPB systems, then imaging precision is improved, but imaging time becomes excessively long
Solution Approach 1:
The patent divides the large volume sample into multiple smaller regions or sub-volumes. Instead of imaging the entire sample at high resolution, the system segments the imaging task into manageable portions, allowing high-resolution imaging of specific regions of interest while using lower resolution for other areas, thereby reducing total imaging time while maintaining precision where needed.
Solution Approach 2:
The patent applies different imaging qualities to different regions of the sample. High resolution is applied locally to regions of interest where detailed analysis is required, while other regions are imaged at lower resolution. This local differentiation of quality allows the system to maintain measurement precision for critical areas without the time penalty of imaging the entire sample at maximum resolution.
2Measurement precision
If the entire large area is imaged at high resolution, then measurement precision is improved, but productivity decreases
Solution Approach 1:
The patent segments the large area into multiple smaller imaging zones. The system processes these zones in an optimized sequence, applying high resolution only to regions that require detailed analysis. This segmentation strategy increases imaging throughput by avoiding the unnecessary application of high resolution to entire large areas, while still maintaining measurement precision for critical regions.
Solution Approach 2:
The patent applies high resolution imaging only partially to the areas that truly require it, rather than applying it excessively to the entire large area. By identifying and imaging only the necessary regions at high resolution, the system improves productivity while maintaining adequate measurement precision for the regions of interest.
Data Source
AI summary
A method to compensate for drift while controlling a charged particle beam (CPB) system having at least one charged particle beam controllable in position. Sources of drift include mechanical variations in the stage supporting the sample, beam deflection shifts, and environmental impacts, such as temperature. The method includes positioning a sample supported by a stage in the CPB system, monitoring a reference fiducial on a surface of the sample from a start time to an end time, determining a drift compensation to compensate for a drift that causes an unintended change in the position of a first charged particle beam relative to the sample by a known amount over a period of time based on a change in the position of the reference fiducial between the start time and the end time, and adjusting positions of the first charged particle beam by applying the determined drift compensation during an operation of the CPB system.