Electron Detector Layout for Medium-Angle Backscatter Collection
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Solution Overview
Problem
Conventional electron microscopes face challenges in efficiently collecting backscattered electrons with medium emission angles, which affects imaging resolution and detection efficiency, especially in the inspection of small integrated circuits.
Innovation Solution
The proposed electron beam apparatus includes a first electron detector with a detection layer parallel to the primary optical axis and a second detector perpendicular to it, combined with electrostatic or magnetic elements to enhance the detection of backscattered electrons with medium emission angles, using beam deflectors or boosters to facilitate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple electron detectors are used to maximize collection of secondary and backscattered electrons, then detection efficiency is improved, but imaging resolution deteriorates due to aberrations of the objective lens assembly and shielding of signal electrons
Solution Approach 1:
The patent divides the detection function into multiple specialized detectors: a first detector for secondary electrons with detection layer parallel to the optical axis, and a second detector for backscattered electrons with detection layer perpendicular to the optical axis. Each detector is optimized for specific signal electrons, improving overall detection efficiency while maintaining imaging resolution through specialized configurations.
Solution Approach 2:
The patent introduces a new spatial dimension for detector placement by positioning the first detector along the primary optical axis (parallel configuration) and the second detector perpendicular to it. This multi-dimensional arrangement allows simultaneous collection of different signal electron types without mutual interference, resolving the contradiction between detection efficiency and imaging resolution.
2Productivity
If the detection layer is placed parallel to the primary optical axis, then collection efficiency of backscattered electrons with medium emission angles is improved, but the complexity of the detection system increases
Solution Approach 1:
The first electron detector with detection layer parallel to the optical axis serves multiple functions: it detects backscattered electrons with medium emission angles, maintains imaging resolution, and works in conjunction with the second detector to provide comprehensive signal electron collection. This multi-functional design improves collection efficiency without proportionally increasing system complexity.
Solution Approach 2:
The patent introduces electrostatic or magnetic elements as intermediaries between the sample and detectors to facilitate signal electron collection. These elements guide and focus electrons onto the detection layers, improving collection efficiency while keeping the detector structures themselves relatively simple and manageable.
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 improves the collection efficiency of backscattered electrons with medium emission angles, maintaining high imaging resolution and enhancing defect detection in integrated circuits.
Implementation Method 1
an electrostatic element or a magnetic element disposed between the sample and the second electron detector
Implementation Method 2
an electrostatic element or a magnetic element disposed between the sample and the second electron detector
Implementation Method 3
The electrostatic element may comprise a beam deflector or a beam booster
Implementation Method 4
the magnetic element may comprise a beam separator
Data Source
AI summary
Systems and methods of observing a sample using an electron beam apparatus are disclosed. The electron beam apparatus comprises an electron source configured to generate a primary electron beam along a primary optical axis, and a first electron detector having a first detection layer substantially parallel to the primary optical axis and configured to detect a first portion of a plurality of signal electrons generated from a probe spot on a sample. The method may comprise generating a plurality of signal electrons and detecting the signal electrons using the first electron detector substantially parallel to the primary optical axis of the primary electron beam. A method of configuring an electrostatic element or a magnetic element to detect backscattered electrons may include disposing an electron detector on an inner surface of the electrostatic or magnetic element and depositing a conducting layer on the inner surface of the electron detector.