Charged Particle Beam Blanking for Low-Damage Image Integration
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Solution Overview
Problem
The STEM mode in charged particle beam devices causes significant electron beam damage to specimens due to high current density, making it difficult to observe and analyze the specimen effectively.
Innovation Solution
A charged particle beam device and method that incorporates a blanker to control blanking of the beam during scanning, acquiring multiple images with alternating irradiated and non-irradiated regions, and integrating these images to reduce specimen damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If normal scanning method is used in STEM mode, then image acquisition is achieved, but electron beam damage to specimen increases due to high current density
Solution Approach 1:
The patent segments the scanning process into multiple passes, where each pass scans only a subset of pixels. By dividing the full image acquisition into multiple segments with different blanking patterns, the electron beam exposure is distributed across multiple scans rather than concentrated in a single continuous scan, thereby reducing cumulative damage to any specific region while maintaining overall image quality.
Solution Approach 2:
The patent implements periodic blanking action during the scanning process. The blanker is activated in a periodic manner to intermittently block the electron beam during scanning, creating alternating periods of beam exposure and rest. This periodic action allows heat and charge to dissipate during non-irradiation periods, reducing specimen damage while still acquiring necessary image data over time.
2Measurement precision
If high current density is applied to acquire position information for each pixel, then data extraction capability is improved, but specimen damage increases
Solution Approach 1:
The patent divides the pixel scanning into multiple segments across different scans. Each segment scans a subset of pixels with high current density to acquire precise position information, but not all pixels are scanned in every pass. This segmentation allows high-resolution data collection while distributing the damaging effects across multiple scanning passes.
Solution Approach 2:
The patent applies partial action by scanning only certain pixels in each pass rather than all pixels continuously. By selectively applying the electron beam to specific pixel regions in each scan and using blanking to protect other regions, the system achieves necessary measurement precision for position information while reducing overall specimen exposure and damage.
Data Source
AI summary
A charged particle beam device scans a specimen with a charged particle beam and generates an image based on a detected signal from a detector that detects a signal generated from the specimen based on the scan performed by the charged particle beam. The charged particle beam device includes: a blanker that performs blanking of the charged particle beam; an image acquisition unit that acquires a plurality of images by controlling the blanking during the scan performed by the charged particle beam, the plurality of images including pixels corresponding to a region of the specimen that is irradiated with the charged particle beam and pixels corresponding to a region of the specimen that is not irradiated with the charged particle beam; and an integrated image generation unit that generates an integrated image by integrating the plurality of acquired images.