Charged Particle Beam Focus Correction from Scan Direction Signals
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Solution Overview
Problem
Existing charged particle beam systems require two-dimensional particle imaging and image processing for focus and astigmatism adjustment, which is time-consuming and limits the speed of adjustment.
Innovation Solution
A charged particle beam system that scans a sample with a charged particle beam to determine signal intensities in different scan directions, generating information for focus deviation and aberration correction based on the relation between these intensities and scan directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two-dimensional particle images are acquired and image processing is executed for focus and astigmatism adjustment, then measurement precision is improved, but adjustment speed deteriorates
Solution Approach 1:
The invention extracts only the essential information needed for focus and astigmatism adjustment from the particle beam data, rather than acquiring complete two-dimensional particle images. By taking out only the necessary signal intensity measurements along scan trajectories, the system achieves adjustment precision comparable to full imaging methods while dramatically reducing the data processing burden and adjustment time
Solution Approach 2:
The invention implements partial action by acquiring particle signal intensities only along specific scan trajectories (one-dimensional paths) rather than performing complete two-dimensional image acquisition. This partial measurement approach provides sufficient information for focus and astigmatism correction without the excessive time cost of full 2D imaging and processing
2Manufacturing precision
If two-dimensional particle images are acquired for focus and astigmatism adjustment, then adjustment accuracy is improved, but productivity deteriorates
Solution Approach 1:
The invention extracts minimal necessary data (signal intensities along scan trajectories) from the particle beam interactions, avoiding the time-consuming acquisition and processing of complete two-dimensional particle images. This extraction approach maintains correction accuracy while significantly improving adjustment throughput and productivity
Solution Approach 2:
The invention skips the time-consuming steps of complete two-dimensional image acquisition and complex image processing by directly measuring signal intensities along simplified scan trajectories. This rushing through the essential measurement steps enables rapid focus and astigmatism correction, dramatically improving productivity without sacrificing correction accuracy
Data Source
AI summary
A charged particle beam system includes: a charged particle beam device configured to emit a charged particle beam from a charged particle source to a sample via a charged particle optical system; and a control system configured to control the charged particle beam device. The control system scans the sample with the charged particle beam in a manner of forming a scan trajectory and determines scores of signal intensities associated with different scan directions in the scan trajectory. The control system generates, based on a relation between the scores and the different scan directions, information on at least one of a focus deviation and an aberration coefficient of the charged particle optical system.