Multi-Beam Electron Inspection Image Correction
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Solution Overview
Problem
The miniaturization of semiconductor patterns requires high accuracy in defect inspection, but existing methods struggle with distortions in electron beams, leading to erroneous defect detection during the comparison of inspection images with reference images.
Innovation Solution
The method involves acquiring inspection images using multiple electron beams, correcting for distortions in each beam's position and beam characteristics, and comparing the corrected images to improve defect detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electron beams are used to scan the sample simultaneously, then inspection speed is improved, but image distortion occurs due to beam position variations
Solution Approach 1:
The system uses a beam position detection apparatus to continuously monitor the actual positions of multiple electron beams during scanning. This position information is fed back to a correction unit that adjusts the reference image accordingly, ensuring that images captured by multiple beams are accurately aligned without requiring mechanical repositioning.
Solution Approach 2:
Instead of using mechanical methods to physically reposition the sample or beams for alignment, the invention substitutes a computational approach where the reference image is digitally corrected based on detected beam positions. This replaces complex mechanical alignment mechanisms with software-based image processing.
2Reliability
If the sample is scanned to acquire an inspection image, then defect detection is performed, but erroneous defect detection occurs due to beam distortions
Solution Approach 1:
Beam position detection apparatus provides real-time feedback on electron beam positions during sample scanning. This information is used to dynamically correct the reference image, ensuring that defects are accurately identified without false positives caused by beam position variations or distortions.
Solution Approach 2:
The system changes the parameters of the reference image based on detected beam positions. By adjusting image coordinates and alignment parameters according to actual beam locations, the system maintains accurate defect detection even when beam positions vary during scanning.
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 effectively suppresses erroneous defect detection by associating electron beams with their respective positions in the inspection image, enhancing the accuracy of pattern inspection in semiconductor manufacturing.
Implementation Method 1
an inspection apparatus that irradiates a substrate to be inspected with a multi-beam constituted by a plurality of electron beams in an array arrangement, in which beams arrayed at the same pitch on a straight line are aligned in rows, and detects secondary electrons corresponding to the respective beams emitted from the substrate to be inspected to obtain a pattern image
Data Source
AI summary
There is provided an inspection method including acquiring an inspection image by irradiating a sample with a plurality of electron beams and by simultaneously scanning the sample by the electron beams, performing first correction of a reference image corresponding to the inspection image or second correction of the inspection image based on a plurality of distortions of each of the electron beams and on a position scanned by each of the electron beams in the inspection image, and performing first comparison of the reference image subjected to the first correction with the inspection image or second comparison of the reference image with the inspection image subjected to the second correction.