SEM Monochromator for Resolution and Composition
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Solution Overview
Problem
Scanning electron microscopes face challenges in achieving high resolution and pattern recognition for miniaturized semiconductor devices with increasing aspect ratios and complex material compositions, as existing technologies fail to effectively identify and measure patterns formed with different materials.
Innovation Solution
A scanning electron microscope equipped with a monochromator that includes a magnetic field generator for deflecting the electron beam and an energy selection aperture, allowing for energy discrimination of electrons emitted from the sample, enhancing both resolution and pattern recognition capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a monochromator is used to improve resolution, then resolution is improved, but the ability to identify pattern composition is lost
Solution Approach 1:
The electron beam path is segmented into multiple trajectories: one path through the monochromator for high-resolution imaging, and another path through the energy filter for compositional analysis. This allows simultaneous operation of both functions without interference.
Solution Approach 2:
The electron optical system is designed to perform multiple functions: it can operate as a conventional SEM for imaging, as an EELS system for compositional analysis, or in combination modes. The same objective lens and detector system serve both imaging and spectroscopy functions.
2Adaptability or versatility
If energy filter is added for composition analysis, then pattern recognition capability is improved, but device complexity increases
Solution Approach 1:
The energy filter is integrated into the existing electron optical column of the SEM. The filter's magnetic field generator is positioned within the objective lens region, and the aperture is placed in the focal plane, merging multiple functions into a compact configuration that minimizes additional complexity.
Solution Approach 2:
The energy filter system is designed to work with the existing SEM detector and imaging system. The same detector can detect both secondary electrons for imaging and transmitted electrons for EELS, eliminating the need for separate detection systems.
3Measurement precision
If multiple prisms chain is used for aberration suppression, then resolution is improved, but the ability to detect electrons with different energies is reduced
Solution Approach 1:
Instead of using a single complex aberration correction system, the patent segments the correction into two parts: the objective lens provides primary aberration correction for imaging, while the energy filter's magnetic field provides secondary correction that simultaneously enables energy discrimination. This segmented approach allows both functions to coexist.
Solution Approach 2:
Conventional systems use aberration correction to enable energy filtering. This patent inverts the approach: it uses energy filtering to achieve aberration correction. The magnetic field of the energy filter, designed for energy discrimination, is shown to also provide effective aberration suppression, reversing the traditional functional relationship.
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
The configuration enables high-resolution compositional imaging and improved contrast sensitivity, allowing for selective detection of electrons within a specific solid angle, effectively identifying patterns with different materials and enhancing measurement accuracy in complex semiconductor structures.
Implementation Method 1
a magnetic field generator that deflects the electron beam
Implementation Method 2
a magnetic field generator that deflects the electron beam
Implementation Method 3
an electron source and a monochromator that makes an electron beam emitted from the electron source monochromatic
Data Source
AI summary
The purpose of the present invention is to provide a scanning electron microscope that achieves an increase in both resolution and pattern recognition capability. In order to achieve the purpose, the present invention proposes a scanning electron microscope provided with a monochromator that makes an electron beam monochromatic, the monochromator including a magnetic field generator that deflects the electron beam, and an energy selection aperture that passes a part of the electron beam deflected by the magnetic field generator. An aperture that passes some of electrons emitted from the sample and a detector that detects the electrons that have passed through the aperture are disposed on a trajectory to which the electrons emitted from the sample are deflected by a magnetic field generated by the magnetic field generator.