Electron Optical System Adjustment Using Optical Patterns
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Solution Overview
Problem
In photoelectron emission microscopes, focus adjustment and magnification calibration are time-consuming and require moving the observation field of view, necessitating high-contrast photoelectron images to accurately adjust the electron optical system.
Innovation Solution
An electron beam application apparatus with a pattern forming unit that generates optical patterns on the sample surface, allowing for high-speed and accurate adjustment of the electron optical system using feature data from bright and dark patterns in the photoelectron images, enabling rapid and precise focus and magnification adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If focus adjustment is performed by acquiring a photoelectron image of a pattern with known size to adjust magnification, then the magnification can be adjusted to a predetermined value, but it requires moving the observation field of view and takes a long time
Solution Approach 1:
The patent applies preliminary action by pre-forming an optical pattern on the sample surface before photoelectron image acquisition. The pattern forming unit creates a known geometric pattern that serves as a reference for both focus and magnification adjustment, eliminating the need to move the observation field of view during adjustment. This preliminary preparation enables simultaneous determination of both focus and magnification from a single photoelectron image, significantly reducing adjustment time while maintaining high precision.
2Measurement precision
If high-contrast photoelectron images are obtained to calculate magnification with high accuracy, then the measurement precision improves, but it requires additional time and complex procedures
Solution Approach 1:
The patent introduces an optical pattern as an intermediary element between the sample and the detection system. This predefined pattern with known dimensions and high contrast features acts as a mediator that provides explicit reference points for magnification and focus calculation. The pattern's high-contrast edges and known geometry enable direct measurement without requiring complex image processing or multiple acquisitions, thus improving measurement precision while maintaining high productivity.
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
Enables high-speed and high-accuracy adjustment of the electron optical system, improving the efficiency of photoelectron image acquisition and inspection processes by utilizing the high contrast of bright and dark patterns formed by the optical patterns.
Implementation Method 1
a photoelectron image is projected onto a camera by an imaging lens system... photoelectron image formed by photoelectrons emitted from the sample irradiated with the excitation light
Data Source
AI summary
An electron beam application apparatus includes: an optical system configured to irradiate a sample with excitation light; an electron optical system configured to project, onto a camera, a photoelectron image formed by photoelectrons emitted from the sample irradiated with the excitation light; and a control unit. The optical system includes a light source configured to generate the excitation light and a pattern forming unit. The excitation light forms an optical pattern on a surface of the sample when the pattern forming unit is turned on, and the excitation light is emitted to the sample without forming the optical pattern on the surface of the sample when the pattern forming unit is turned off. The control unit adjusts the electron optical system based on feature data of a bright and dark pattern formed by the optical pattern in the photoelectron image obtained by turning on the pattern forming unit.