Multi-Beam SEM Focus Adjustment via Parallel Image Analysis

The patent divides the single inspection task into multiple parallel inspection tasks by using multiple electron beams. Each beam inspects a different region of the sample simultaneously, allowing focus evaluation to occur in parallel across multiple fields of view rather than sequentially in a single field of view.

The patent combines multiple electron beams into a single multi-beam system that operates simultaneously. The detector assembly integrates signals from all beams, and the controller coordinates their operation to perform focus adjustment evaluation in a single coordinated operation rather than multiple separate operations.

The patent segments the astigmatism evaluation into multiple parallel evaluations across different beams and fields of view. By distributing the evaluation across multiple simultaneous images, the system can assess astigmatism effects more comprehensively without requiring a proportional increase in total inspection time.

The system implements automated feedback by analyzing image quality parameters from the acquired images and using this information to determine optimal focus and astigmatism settings. The controller processes the images and automatically identifies the best settings without requiring manual intervention or additional corrective imaging steps.

The patent segments the focus evaluation process into simultaneous parallel operations across multiple electron beams. Each beam independently evaluates focus in its own field of view while others do the same, transforming a sequential process into a parallel one that achieves the same evaluation accuracy in less time.

The system performs preliminary focus evaluation using the multi-beam configuration before final inspection begins. By pre-establishing optimal focus settings through simultaneous multi-beam evaluation, the system eliminates the need for time-consuming focus adjustments during the actual inspection process.