Scanning Electron Microscope Energy Selection Electrode Configuration
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Solution Overview
Problem
Current scanning electron microscopes (SEM) face challenges in selectively detecting secondary electrons (SEs) due to the mixing of low-energy electrons generated from the sample and those produced by collisions with surrounding structures, which impairs the ability to obtain clear contrast related to surface potential and unevenness.
Innovation Solution
A scanning electron microscope configuration featuring a disk-shaped electrode and control electrodes with specific potential settings to guide SEs generated on the sample to the detector while suppressing the detection of low-energy electrons produced by backscattered electrons, using a deflection field and electric deflection to separate and control the energy bands of detected SEs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If low energy electrons generated by BSE collisions are detected together with SEs, then detection simplicity is maintained, but measurement precision deteriorates due to mixed signal detection
Solution Approach 1:
The energy selector extracts only the SEs within the desired energy range from the mixed electron signal. By taking out the relevant SEs and excluding unwanted low energy electrons, the system achieves precise surface potential and unevenness contrast while maintaining operational simplicity through automated energy filtering
2Device complexity
If no energy selection is applied for SE detection, then device complexity is reduced, but measurement precision deteriorates due to inability to control detection energy band
Solution Approach 1:
The energy selector enables dynamic change of the detection energy band parameter by adjusting its voltage. This allows precise control over which SE energy ranges are detected, improving measurement precision for surface potential and unevenness while adding only minimal device complexity through a single adjustable component
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 configuration allows for selective detection of SEs generated on the sample, reducing the interference from low-energy electrons produced by backscattered electrons, thereby enhancing the contrast and information obtained from surface potential and unevenness, and enabling controlled energy band detection of SEs.
Implementation Method 1
a disk-shaped electrode arranged to be closer to the electron source than the deflection field and having an opening through which the irradiation electron beam passes, and a control electrode arranged along the optical axis to be closer to the sample than the deflection field
Implementation Method 2
A potential lower than the reference potential is applied to the disk-shaped electrode, and a potential higher than the reference potential is applied to the control electrode
Data Source
AI summary
Provided is a scanning electron microscope provided with an energy selection and detection function for a SE1 generated on a sample while suppressing the detection amount of a SE3 excited due to a BSE in the scanning electron microscope that does not apply a deceleration method. Provided are: an electron optical system that includes an electron source 21 generating an irradiation electron beam and an objective lens 12 focusing the irradiation electron beam on a sample; a detector 13 that is arranged outside an optical axis of the electron optical system and detects a signal electron generated when the sample is irradiated with the irradiation electron beam; a deflection electrode that forms a deflection field 26 to guide the signal electron to the detector; a disk-shaped electrode 23 that is arranged to be closer to the electron source than the deflection field and has an opening through which the irradiation electron beam passes; and a control electrode arranged along the optical axis to be closer to the sample than the deflection field. The sample and the objective lens are set to a reference potential. A potential lower than the reference potential is applied to the disk-shaped electrode, and a potential higher than the reference potential is applied to the control electrode.