Specimen Observation via Mixed Secondary and Mirror Electrons
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Solution Overview
Problem
Conventional electron beam inspection methods struggle to effectively detect foreign materials on specimen surfaces, particularly for fine patterns and insulating/conductive areas, due to limitations in resolution and contrast, requiring extensive observation time and inadequate sensitivity.
Innovation Solution
The method involves irradiating a specimen with an electron beam at a landing energy in a transition region between secondary emission and mirror electron detection, mixing both types of electrons to enhance image generation and contrast, allowing for improved detection of foreign materials, patterns, and insulating/conductive area differentiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical microscopes are used for observation, then observation speed is fast, but resolution is insufficient for fine objects of 100 nm or less
Solution Approach 1:
The patent changes the fundamental parameter of the observation beam from optical wavelength to electron wavelength, enabling resolution of 100 nm or less while maintaining relatively fast observation speed through projection-type wide-area imaging capability
2Measurement precision
If SEM is used to increase magnification for observing fine objects, then resolution is improved, but observation time becomes excessively long
Solution Approach 1:
The patent segments the observation process into two stages: first using projection-type electron beam for rapid wide-area screening to locate regions of interest, then using focused electron beam for detailed observation of specific fine objects, thereby reducing total observation time
Solution Approach 2:
The patent transitions from point-by-point scanning observation (1D time consumption) to parallel wide-area projection observation (2D spatial efficiency), dramatically reducing observation time while maintaining resolution through subsequent focused observation
3Productivity
If projection-type observation device is used for wide-area imaging, then observation time is reduced, but resolution becomes insufficient for fine patterns
Solution Approach 1:
The patent segments the observation system into a projection-type electron beam device for wide-area rapid screening and a focused electron beam device for high-resolution detailed observation, combining the advantages of both approaches
Solution Approach 2:
The patent performs preliminary wide-area observation using projection-type electron beam to identify regions containing fine patterns or foreign materials, then concentrates observation resources on those specific areas, achieving both speed and resolution
4Reliability
If conventional electron beam inspection is used for foreign material detection, then detection capability is limited, but observation time is excessively long
Solution Approach 1:
The patent changes the electron beam landing energy to a transition region between secondary emission and mirror electron detection, creating mixed electron signals that enhance contrast for foreign material detection while enabling faster inspection through projection-type wide-area imaging
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 significantly reduces observation time and improves sensitivity, enabling reliable detection of foreign materials and fine patterns with higher contrast, even for ultra-micro sized features, thus enhancing the efficiency and accuracy of electron beam inspection.
Implementation Method 1
a landing energy set in a transition region between a secondary emission electron region in which secondary emission electrons are detected and a mirror electron region in which mirror electrons are detected
Implementation Method 2
a landing energy set in a transition region between a secondary emission electron region in which secondary emission electrons are detected and a mirror electron region in which mirror electrons are detected
Data Source
AI summary
A technique capable of improving the ability to observe a specimen using an electron beam in an energy region which has not been conventionally given attention is provided. This specimen observation method comprises: irradiating the specimen with an electron beam; detecting electrons to be observed which have been generated and have obtained information on the specimen by the electron beam irradiation; and generating an image of the specimen from the detected electrons to be observed. The electron beam irradiation comprises irradiating the specimen with the electron beam with a landing energy set in a transition region between a secondary emission electron region in which secondary emission electrons are detected and a mirror electron region in which mirror electrons are detected, thereby causing the secondary emission electrons and the mirror electrons to be mixed as the electrons to be observed. The detection of the electrons to be observed comprises performing the detection in a state where the secondary emission electrons and the mirror electrons are mixed. Observation and inspection can be quickly carried out for a fine foreign material and pattern of 100 nm or less.